Article

Zinc status and serum testosterone levels of healthy adults

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Abstract

Zinc deficiency is prevalent throughout the world, including the USA. Severe and moderate deficiency of zinc is associated with hypogonadism in men. However, the effect of marginal zinc deficiency on serum testosterone concentration is not known. We studied the relationship between cellular zinc concentrations and serum testosterone cross-sectionally in 40 normal men, 20 to 80 y of age. In four normal young men (27.5 +/- 0.5 y), we measured serum testosterone before and during marginal zinc deficiency induced by restricting dietary zinc intake. We also measured serum testosterone in nine elderly men (64 +/- 9 y) who were marginally zinc deficient before and after 3 to 6 mo of supplementation with 459 mumol/ d oral zinc administered as zinc gluconate. Serum testosterone concentrations were significantly correlated with cellular zinc concentrations in the cross-sectional study (lymphocyte zinc versus serum testosterone, r = 0.43, p = 0.006; granulocyte zinc versus serum testosterone, r = 0.30, p = 0.03). Dietary zinc restriction in normal young men was associated with a significant decrease in serum testosterone concentrations after 20 weeks of zinc restriction (baseline versus post-zinc restriction mean +/- SD, 39.9 +/- 7.1 versus 10.6 +/- 3.6 nmol/L, respectively; p = 0.005). Zinc supplementation of marginally zinc-deficient normal elderly men for six months resulted in an increase in serum testosterone from 8.3 +/- 6.3 to 16.0 +/- 4.4 nmol/L (p = 0.02). We conclude that zinc may play an important role in modulating serum testosterone levels in normal men.

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... Цинк необходим для нормального функционирования гипоталамо-гипофизарно-гонадной оси. Содержание Zn в организме мужчин связано с продукцией тестостерона, и многие эффекты Zn на репродуктивные характеристики объясняются его множественным действием на метаболизм андрогенов [27,[70][71][72][73][74]. Дефицит Zn тяжелой и умеренной степеней сопровождается гипогонадизмом, а длительный, но более мягкий дефицит Zn вызывает олигоспермическое бесплодие и импотенцию у мужчин. ...
... У мужчин Zn способен модулировать уровень тестостерона в крови [70]. Взаимосвязь между концентрацией Zn в плазме, лимфоцитах и гранулоцитах и тестостерона в сыворотке крови изучалась у 40 здоровых мужчин. ...
... В России успешно используются препараты, содержащие Zn в сочетании с витаминами и другими минералами, для лечения мужской субфертильности, бесплодия и патозооспермии [70,[82][83][84]. Препараты помогают снизить уровень оксидативного стресса, оказывают противовирусное действие, увеличивают объем эякулята, концентрацию сперматозоидов и их подвижность, а также долю морфологически нормальных сперматозоидов, повышают вероятность благоприятных исходов естественного зачатия. ...
Article
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Trace elements play an important role in human health. They are involved in growth, development, reproduction, and other physiological functions. Among them, special attention is paid to zinc, which is an essential trace element required for the normal functioning of many organ systems. Experimental data have been accumulated indicating a significant role of zinc in the functioning of the male reproductive system and the spermatogenesis. Zinc concentration in seminal plasma is considerably higher compared to those in other body fluids. In contrast to its serum concentration, seminal zinc level is associated with the sperm concentration, motility and morphology. Under dietary deficiency, Zinc supplementation can significantly increase the ejaculate volume, sperm motility and morphology and improves overall sperm quality in infertile patients. Zinc, being a structural element of a large number of different macromolecules and enzymes, shows antioxidant, antibacterial and antiapoptotic properties in the testes. It should be considered as one of the trace elements with great potential for the prevention and treatment of male infertility and subfertility. The aim of this review is to analyze current publications and summarize information about the effect of zinc on male fertility and its properties related to sperm quality and successful fertilization.
... Furthermore, different classes of leukocytes are dependent on zinc pertaining ubiquitous defense mechanisms of innate immunity [24]. Prasad et al. observed that zinc gluconate supplementation increased leukocyte and granulocyte zinc stores, but did not increase serum zinc concentrations [25]. Thus, it may be speculated that analyzing zinc in leukocytes is of further interest with respect to biochemical surveillance. ...
... Both medicinal dosages of zinc as well as dietary zinc play a crucial role in T status. Prasad et al. observed that zinc deficiency was associated with a significant decrease in T concentration in healthy men [25]. The researchers submitted four eugonadal young men to a diet with low zinc (z5 mg/d of zinc) for 20 weeks, which led to a dramatic decrease in total T from 1150 to 320 ng/dL [25]. ...
... Prasad et al. observed that zinc deficiency was associated with a significant decrease in T concentration in healthy men [25]. The researchers submitted four eugonadal young men to a diet with low zinc (z5 mg/d of zinc) for 20 weeks, which led to a dramatic decrease in total T from 1150 to 320 ng/dL [25]. After just 8 weeks of induced dietary zinc deficiency, the total T levels had already decreased to 720 ng/dL. ...
Article
Zinc deficiency has a global impact on health in both developing and developed countries, especially among children and the elderly. By modulating anti-inflammatory and antioxidant pathways, zinc supplementation is recommended for the treatment of several ailments, such as liver disease, male hypogonadism, cancers, heart disease (e.g. dyslipidemia) and central nervous system disorders; however, the topic of dietary vs. pharmacological doses of zinc remains controversial. This paper provides a detailed critical review of the effects of zinc supplementation in medicinal doses (i.e. >40 mg/d of elemental zinc) on human health. We further highlight the difficulty in achieving a therapeutic dose of zinc from foodstuffs.
... Zinc helps modulate serum testosterone produced by the leydig cells of the testes, and is necessary for spermatogenesis. Cellular zinc concentrations appear to significantly reflect testosterone levels in healthy men (low zinc levels parallel low testosterone levels) (Prasad AS, 1996, & 1983. Prolactin requires zinc to stimulate breast tissue growth and lactation. ...
... *A mild deficiency can result in oligospermia (low sperm production) from low testosterone levels, poor appetite with associated weight loss, night blindness, and reduced resistance to infections (Prasad AS, 1996). Low epidermal tissue zinc levels are often found in common skin diseases such as psoriasis, dermatitis herpetiformis, acne, and Darier's disease, despite normal serum blood levels (Michaelsson G, 1990). ...
... HIV/AIDS *Compromised nutritional and antioxidant status is thought to begin early in the course of HIV-1 infection, and contributes to its progression (Bogden JD, 2000). Zinc deficiency is common in HIV/AIDS patients, and many of its symptoms are identical to those found in the disease, such as a decrease in CD4+ cells (T-helper cells), weight loss, hypogonadism (50%), and low testosterone in men , Rietschel P, 2000, Prasad AS, 1996, Beach RS, 1992, Humphries L, 1989. A deficiency is also associated with a high viral load, high IgA levels, and cachexia (malnutrition and wasting), often seen during the end-stage of AIDS where modulation of the catabolic cytokine, tumor necrosis factor-alpha (TNF-alpha), is impaired (Wellinghausen N, 2000Scevola D, 2000. ...
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Zinc and Zinc Deficiency with emphasis on the immune system and cancer
... Besides improving sperm parameters, the use of zinc may also increase TT in men. In this regard, Table 2 shows that supplementing 30 mg/d of chelated zinc for a period of 1 to 6 months increases TT levels from 180 to 222 ng/dL [49][50][51]. Conversely, in studies with a duration of 8 weeks, there was no increase in concentrations of T and TT at this dose [52,53]. Interventions with medicinal doses of chelated zinc, ranging from 220 mg to 660 mg/d for 4 to 7 weeks increased TT from 50 to 400 ng/dL (Table 2). ...
... Among the studies in Table 2, five are composed of fertile men [22,[49][50][51][52] and two composed of infertile men [54,55]. The TT value of all studies was in the range of eugonadal men, except in the Prasad et al. study. ...
... However, the mean TT value of this study was only slightly lower at baseline (239 ng/dL). Insofar as the participants' age is concerned, only the Prasad et al. study analyzed the elderly, while other studies focused mainly in middle-aged adults [50]. ...
Article
Hypogonadism affects an extensive part of the male population, especially among the elderly. The quest for treatment regarding low levels of serum testosterone and male infertility has, therefore, worldwide relevance. Zinc has important biological actions insofar as the male reproductive physiology and endocrine system. In general, a common and safe recommendation for zinc in the treatment of male hypogonadism is 220 mg of zinc sulfate (equivalent to 50 mg of elemental zinc) twice a day, over one to four months. Additionally, it may be further required to extend, both the treatment, dose and daily fractionation of this mineral. Albeit medicinal doses of zinc may increase total testosterone and improve sperm count, the current body of evidence does not suggest broad recommendations regarding the use of zinc for all types of hypogonadism. In many cases, the use of zinc supplements is insufficient, with the use of surgery and drugs being required for an effective treatment.
... The summary of the basic influence of zinc on female reproductive system is presented on Figure 1. [19,[25][26][27][28][29][30][31]. Abbreviations: CAT: catalase; Cu/Zn SOD: Cu/Zn superoxide dismutase; FSH: follicle stimulating hormone; GPx: glutathione peroxidase; GSH: glutathione; HDL: high density lipoprotein; LDL: low density lipoprotein; LH: luteinizing hormone; MMPs: matrix metalloproteinases; MTs: metallothioneines; NF-κB: nuclear factor κB; PGs: prostaglandins; TG: triglycerides; TXA2: thromboxane A2. ...
... The first arrest, at prophase I, is maintained by zinc affecting the MOS-MAPK Figure 1. Involvement of zinc in female reproductive system according to [19,[25][26][27][28][29][30][31]. Abbreviations: CAT: catalase; Cu/Zn SOD: Cu/Zn superoxide dismutase; FSH: follicle stimulating hormone; GPx: glutathione peroxidase; GSH: glutathione; HDL: high density lipoprotein; LDL: low density lipoprotein; LH: luteinizing hormone; MMPs: matrix metalloproteinases; MTs: metallothioneines; NF-κB: nuclear factor κB; PGs: prostaglandins; TG: triglycerides; TXA 2 : thromboxane A 2 . ...
... Zinc is considered an anti-androgen by inhibiting 5α-reductase and thus decreasing the production of dihydrotestosterone [28,69]. Its other involvement in metabolism of androgens includes inhibiting aromatase (and thus decreasing testosterone transformation into estradiol) and increasing conversion of androstenedione to testosterone [28,30,69,70]. In addition, it was shown that zinc deficiency disturbed the activity of angiotensin converting enzyme, which seems to be involved in the synthesis of adrenals androgens [71]. ...
Article
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Zinc is an essential microelement that plays many important functions in the body. It is crucial for the regulation of cell growth, hormone release, immunological response and reproduction. This review focuses on its importance in the reproductive system of women of reproductive and postmenopausal ages, not including its well described role in pregnancy. Only recently, attention has been drawn to the potential role of zinc in polycystic ovary syndrome (PCOS), dysmenorrhea, or endometriosis. This review is mainly based on 36 randomized, controlled studies on reproductive, pre- and post-menopausal populations of women and on research trying to explain the potential impact of zinc and its supplementation in the etiology of selected female reproductive system disorders. In women with PCOS, zinc supplementation has a positive effect on many parameters, especially those related to insulin resistance and lipid balance. In primary dysmenorrhea, zinc supplementation before and during each menstrual cycle seems to be an important factor reducing the intensity of menstrual pain. On the other hand, little is known of the role of zinc in endometriosis and in postmenopausal women. Therefore, further studies explaining the potential impact of zinc and its supplementation on female reproductive system would be highly advisable and valuable.
... According to a study, when rats were fed with a zinc-deficient diet, their serum LH and testosterone levels were decreased, and the zincdeficient diet caused a reduction in androgen binding sites [37]. Similarly, 20-week dietary zinc restriction in healthy men led to significant decrease in serum testosterone levels [38]. While in some studies, zinc supplementation resulted in an increase in serum testosterone levels of men [38,39], and some other studies showed no change in androgens after zinc replacement [40,41]. ...
... Similarly, 20-week dietary zinc restriction in healthy men led to significant decrease in serum testosterone levels [38]. While in some studies, zinc supplementation resulted in an increase in serum testosterone levels of men [38,39], and some other studies showed no change in androgens after zinc replacement [40,41]. ...
Article
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Zinc has shown to have an anti-androgenic effect through 5 alpha-reductase enzyme activity inhibition in skin. However, there are contradicting findings concerning the effect of zinc on hirsutism mainly from studies including adult women with polycystic ovary syndrome (PCOS). The aim of our study was to investigate the association between serum zinc levels and hirsutism in adolescents. Between October 2017 and June 2018, 51 female adolescents with hirsutism (mean age: 16.11 ± 1.47 years) and 51 healthy female controls were included in the study (mean age: 15.5 ± 1.40 years). Adolescents with hirsutism were classified under two groups; PCOS (n = 34, 66.7%) and idiopathic causes of hirsutism (idiopathic hirsutism (n = 9, 17.6%) and idiopathic hyperandrogenemia (n = 8, 15.7%)). The serum zinc levels were measured via atomic absorption spectrophotometry. The mean zinc levels of adolescents with hirsutism (102.02 ± 11.64 μg/dl) and the control group (101.72 ± 16.71 μg/dl) were similar (p = 0.915). Additionally, there was no significant difference among the mean zinc levels of the hirsutism sub-groups and the control group (p = 0.979). While some studies demonstrated low zinc levels in women with hirsutism, some studies similar to ours showed no association. Adolescence is a developmental phase where generally isolated mild hirsutism is not associated with hyperandrogenism and more studies are needed to evaluate the effect of zinc on hirsutism in this age group.
... Percentage rather than total fat intake was used to account for participant differences in energy intake requirements. 5 No factors which may alter androgen metabolism such as exogenous hormones, medications [31], dietary supplements [32,33], phytoestrogens [34], changes in exercise levels [35], protein >20 % of TEI [36], carbohydrate <15 % of TEI [37], weight loss >2 kg [38], and a difference in TEI between diets ≥10 % [38,39]. ...
... The largest decreases in TT were seen in the 2 studies with vegetarian LF diets Hill 1980 NA) [44,49]. These diets may have been lower in zinc, which is a common feature of vegetarian diets [64], and marginal zinc deficiency has been found to decrease TT [32]. Nevertheless, studies well matched for micronutrient intake showed similar, albeit smaller changes in TT [45,48] (Fig. 2); suggesting the decrease in TT was mostly due to other dietary factors. ...
Article
Background: Higher endogenous testosterone levels are associated with reduced chronic disease risk and mortality. Since the mid-20th century, there have been significant changes in dietary patterns, and men’s testosterone levels have declined in western countries. Cross-sectional studies show inconsistent associations between fat intake and testosterone in men. Methods: Studies eligible for inclusion were intervention studies, with minimal confounding variables, comparing the effect of low-fat vs high-fat diets on men’s sex hormones. 9 databases were searched from their inception to October 2020, yielding 6 eligible studies, with a total of 206 participants. Random effects meta-analyses were performed using Cochrane’s Review Manager software. Cochrane’s risk of bias tool was used for quality assessment. Results: There were significant decreases in sex hormones on low-fat vs high-fat diets. Standardised mean differences with 95% confidence intervals (CI) for outcomes were: total testosterone [-0.38 (95% CI -0.75 to -0.01) P = 0.04]; free testosterone [-0.37 (95% CI -0.63 to -0.11) P = 0.005]; urinary testosterone [-0.38 (CI 95% -0.66 to -0.09) P = 0.009]; and dihydrotestosterone [-0.3 (CI 95% -0.56 to -0.03) P = 0.03]. There were no significant differences for luteinising hormone or sex hormone binding globulin. Subgroup analysis for total testosterone, European and North American men, showed a stronger effect [-0.52 (95% CI -0.75 to -0.3) P < 0.001]. Conclusions: Low-fat diets appear to decrease testosterone levels in men, but further randomised controlled trials are needed to confirm this effect. Men with European ancestry may experience a greater decrease in testosterone, in response to a low-fat diet.
... ACE is reported to increase LH production in pituitary, thus impacting androgen production [152]. Zinc deficiency can impair testosterone synthesis and has been demonstrated to correlate with reductions in testosterone concentrations [153][154][155]. Competitive athletes appear to be at a greater risk for zinc deficiency compared to the general population [156,157]. ...
... Considering that zinc deficiency appears to be related to hypogonadism, efforts to maintain zinc levels within normal ranges appears important. Several studies have shown that zinc supplementation can restore testosterone concentrations to their normal physiological range [153,154,158]. One study examined the effect of zinc supplementation on both TT and FT concentrations in healthy young adults before and after an exhaustive exercise protocol [159]. ...
Article
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Elevations in the circulating concentration of androgens are thought to have a positive effect on the anabolic processes leading to improved athletic performance. Anabolic-androgenic steroids have often been used by competitive athletes to augment this effect. Although there has been concerted effort on examining how manipulating training variables (e.g., intensity and volume of training) can influence the androgen response to exercise, there has been much less effort directed at understanding how changes in both macronutrient and micronutrient intake can impact the androgen response. Thus, the focus of this review is to examine the effect that manipulating energy and nutrient intake has on circulating concentrations of testosterone and what the potential mechanism is governing these changes.
... Additionally, it is unclear whether the association between serum Zn status and the physical functioning status varies by other sociodemographic characteristics. Serum Zn levels have been shown to be associated with sex [23,24]. It is possible that the contribution of serum Zn on functional status may vary by sex. ...
... The effect of sex on Zn homeostasis is complex. Zn is needed for normal development of the male reproductive system and sperm production and may play a role in modulating serum testosterone levels in men [24]. Some studies described differential effects of Zn between men and women, such as in serum leptin levels with Zn supplementation [33], association with metabolic syndrome [34], and prevalence of kidney stones [35]. ...
Article
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Background Serum zinc (Zn) levels have been shown to be associated with functional status; however, it is not clear whether this association differs by other sociodemographic characteristics. We examined the association between serum Zn levels and physical functioning difficulty in a representative sample of older adults in the US. Design and methods A cross-sectional study was conducted on participants 50 years and older from the 2011–12 and 2013–14 National Health and Nutrition Examination Surveys (n = 1136). Serum Zn levels were analyzed as tertiles. The main outcome of interest was physical functioning difficulty, defined as self-reported difficulty of basic physical functioning that included walking, transferring, dressing, and feeding. Results Mean Zn levels (SE) were 0.67(0.1), 0.81(0.1), and 0.98(0.1) μg/mL in the low, middle, and high Zn groups, respectively. Approximately 24.9% participants reported physical functioning difficulty. In the multivariable model, we found a significant multiplicative interaction between sex and serum Zn (P for interaction =0.028) and between education and serum Zn (P for interaction = 0.001) on basic physical functioning difficulty. The stratified analysis revealed that among men, compared to those with low serum Zn, the odds of having physical functioning difficulty were lower in men who had high serum Zn [aOR 0.43 (95% CI: 0.25–0.76)]. For women, compared to those with low serum Zn the odds of having physical functioning difficulty were higher in women who had middle serum Zn [aOR 2.67 (1.58–4.50)]. Among individuals with less than high school education, the odds of having physical functioning difficulty were lower in those who had middle serum Zn compared to those who had low serum Zn [aOR 0.48 (0.26–0.89)]. However, the odds of having physical functioning difficulty were higher in those who had middle serum Zn compared to those who had low serum Zn for individuals with high school [aOR 5.72 (1.92–17.00)] and beyond high school education [aOR 1.77 (1.05–2.97)], respectively. Conclusion Sex and educational attainment interact with serum Zn levels to influence basic physical functioning difficulty in older adults.
... Garlic contains zinc and can thus increase testosterone levels by inhibiting prolactin secretion, a testosterone inhibitor. Furthermore, zinc supplementation will increase the testosterone levels depending on baseline levels [73][74][75]. The histopathological findings show an improvement in the structure of the testes and confirm these results ( Figure 3H). ...
... The results shown in Figure 2A reveal that CsA upregulates fibrosis-related genes. This finding was consistent with several studies which reported that CsA invokes the pathogenesis of nephrotoxicity and may involve TGF-β1 and procollagen α1 [73,74]. The co-administration of garlic with CsA normalized the fibrosis-related genes. ...
Article
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This work aimed to study the hepato-testicular protective effect of garlic in rats treated with cyclosporine A (CsA). Forty male Westar albino rats were randomly distributed in five groups (8 rats each): control, olive oil, garlic, CsA, and CsA co-treated with garlic. CsA induced an upsurge in the alanine transaminase, aspartate transaminase, and alkaline phosphatase levels and decreased albumin and total protein levels, expression of superoxide dismutase (SOD) gene, serum testosterone, triiodothyronine, and thyroxine levels compared to the control group. Additionally, there was an increase in the cholesterol, triglyceride, and low-density lipoprotein levels and a substantial reduction in the high-density lipoprotein levels compared to the control groups. Histopathological investigation of the liver showed abnormalities like hepatic cell degeneration, congestion of blood vessels, and highly active Kupffer cells in the CsA group. Histopathological examination of testes showed damaged seminiferous tubules, stoppage of the maturation of spermatogonia, and the presence of cells with irregular dense nuclei in the lumina of some tubules. For the groups treated with garlic, mitigation of the damage caused by CsA in the liver and testes, liver function tests, lipid profiles, and hormones was seen along with improved gene expression of SOD and steroidogenesis genes, and decreased gene expression of collagen I-α1 and transforming growth factor-1β. Conclusively, garlic had a positive impact on CsA-induced hepatic and sperm toxicity. It is recommended that garlic should be supplemented in transplant treatments using CsA to alleviate the cyclosporin-induced oxidative injuries and other harmful effects.
... In a study involving 553 Dutch athletes it was concluded that users of nutritional supplements have an adequate intake of zinc [188]. Zinc levels have been related to testosterone production [203]. The intake of this mineral has also been associated with greater muscle mass in adults [194]. ...
... Zinc supplementation for 1 year increased anabolic hormone concentrations and promoted growth in children with growth disorders [207]. Long-term zinc supplementation (6 months, 459 µmol/day) was also found to raise testosterone levels in elderly persons with zinc deficiency [203] and in response to 4 weeks of supplementation, the post-exercise testosterone response was enhanced in healthy young subjects (though not basal testosterone levels) [208]. Further, a systematic review concluded that zinc supplementation was associated with increased LBM among children with growth failure [209]. ...
Article
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Purpose Several supplements are purported to promote muscle hypertrophy and strength gains in healthy subjects, or to prevent muscle wasting in atrophying situations (e.g., ageing or disuse periods). However, their effectiveness remains unclear. Methods This review summarizes the available evidence on the beneficial impacts of several popular supplements on muscle mass or strength. Results Among the supplements tested, nitrate and caffeine returned sufficient evidence supporting their acute beneficial effects on muscle strength, whereas the long-term consumption of creatine, protein and polyunsaturated fatty acids seems to consistently increase or preserve muscle mass and strength (evidence level A). On the other hand, mixed or unclear evidence was found for several popular supplements including branched-chain amino acids, adenosine triphosphate, citrulline, β-Hydroxy-β-methylbutyrate, minerals, most vitamins, phosphatidic acid or arginine (evidence level B), weak or scarce evidence was found for conjugated linoleic acid, glutamine, resveratrol, tribulus terrestris or ursolic acid (evidence level C), and no evidence was found for other supplements such as ornithine or α-ketoglutarate (evidence D). Of note, although most supplements appear to be safe when consumed at typical doses, some adverse events have been reported for some of them (e.g., caffeine, vitamins, α-ketoglutarate, tribulus terrestris, arginine) after large intakes, and there is insufficient evidence to determine the safety of many frequently used supplements (e.g., ornithine, conjugated linoleic acid, ursolic acid). Conclusion In summary, despite their popularity, there is little evidence supporting the use of most supplements, and some of them have been even proven ineffective or potentially associated with adverse effects.
... 43 There are also some reports of the improvement of erectile function with vitamin B1 14 and B3 44,45 supplementations. Zinc deficiency has been known to be associated with testosterone deficiency, 46 and zinc supplementation has been shown to reverse the reduced testosterone levels, 47 though the results are mixed. It has not been shown whether zinc supplementation results in increased testosterone in normal individuals, thereby resulting in increased sexual desire. ...
Article
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l-arginine, being a natural precursor of nitric oxide, is one of the more commonly used adjuvants to regular medicines in the treatment of erectile dysfunction. Objectives: Here, in this review article, we aim to highlight various studies and the research studies done on l-arginine in the treatment of erectile dysfunction. Method: Reviewing the databases such as Medline (PubMed), Cochrane Library, Excerpta Medica dataBASE, Trip, PsycINFO, Cumulative Index to Nursing and Allied Health Literature, the Allied and Complementary Medicine Database, and the British Nursing Index. Results:l-arginine has been studied alone as well as in combination with various other molecules for the treatment of erectile dysfunction, but the studies are very limited in number and have very small sample sizes. Conclusion: Positive evidence is available for the efficacy of l-arginine and its various combinations. Further research with larger sample sizes and standardized tools are required to recommend the routine use of these products in erectile dysfunction.
... Because zinc is required for immune functions, zinc-deficient persons experience an increased susceptibility to a broad range of pathogens [2] . Additionally, zinc deficiency may prevent the body from regulating hormones, such as thyroid hormone [3] and testosterone [4] . ...
... Phytochemical analysis of Cyperus esculentus conducted by Allouh et al. (2015) revealed the presence of antioxidants such as quercetin, vitamin C, vitamin E and zinc which are capable of improving male reproductive function. These phytochemicals, including quercetin (Ma, Nguyen, Huynh, Do, & Huynh, 2004;Taepongsorat, Tangpraprutgul, Kitana, & Malaivijitnond, 2008), vitamin C (Ashamu et al., 2010;Biswas, Chaudhuri, Sarkar, & Biswas, 1996), vitamin E (Kawakami, Kobayashi, Hori, & Kaneda, 2015;Mohammadirad et al., 2013) and zinc (Dissanayake, Wijesinghe, Ratnasooriya, & Wimalasena, 2009;Prasad, Mantzoros, Beck, Hess, & Brewer, 1996) have been reported to improve testosterone concentration and quality of spermatozoa. ...
Article
High salt diet (HSD) impairs testicular function via oxidative stress. Cyperus esculentus contains antioxidants and improves testicular function. We investigated the protective effect of hydro-ethanolic extract of Cyperus esculentus on testicular function in HSD-fed Wistar rats. Twenty-five male Wistar rats (125–135 g) 8–9 weeks old were divided into five groups (n = 5): control, HSD-fed (8 % NaCl in feed), extract-treated (500 mg kg−1 day−1), HSD-fed +500 mg kg−1 day−1 of extract and HSD-fed +1,000 mg kg−1 day−1 of extract groups. Treatment lasted for 6 weeks. HSD decreased (p < .05) sperm parameters and serum reproductive hormones levels, while Cyperus esculentus extract improved (p < .05) sperm parameters, and serum testosterone and follicle-stimulating hormone levels in HSD-fed rats. The extract upregulated intra-testicular testosterone level and activities of 3β-hydroxysteroid dehydrogenase (3β- HSD) and 17β-HSD, downregulated malondialdehyde and nitric oxide levels, and exhibited a dose-dependent decrease in pro-inflammatory cytokines, upregulation of activities of enzymatic antioxidants and increase in total antioxidant capacity in testes of HSD-fed rats. The extract at both doses improved Johnsen's score, Leydig and Sertoli cell counts and seminiferous tubular diameter in HSD-fed rats. Cyperus esculentus exhibited a dose-dependent mitigation of HSD-associated testicular dysfunction by targeting testicular steroidogenesis, oxidative stress and inflammation.
... Hence, it is hypothesized that the decreased uptake of Zn could possibly explain the observation that serum Zn level was higher in prostate cancer patients than controls. A study also found a positive correlation between serum Zn level with testosterone (Prasad et al., 1996), a known risk factor of prostate cancer (Patel and Klein, 2009). However, contrary to some published studies that proposed Zn to render protection against prostate cancer (Liang et al., 1999;Platz and Helzlsouer, 2001) and its role in regulating epigenetic methylation (Ho et al., 2011), our results showed that Zn is positively associated with prostate cancer risk. ...
Article
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Background: Prostate cancer is one of the most prevalent cancers in men. Exposure to heavy metals and their association with prostate cancer risk has been studied extensively, but combined effects remain largely inconclusive. Objectives: To elucidate the association between serum concentrations of heavy metals and prostate cancer risk. Methods: Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the concentrations of a panel of 10 heavy metals (Mn, Cu, Zn, As, Se, Sb, Co, Cu, Cd and Pb) in serum samples of 141 cases and 114 controls in the Singapore Prostate Cancer Study. Linear probit regression models were used to estimate risk differences (RDs) and 95% confidence intervals (CIs) for the associations between log-centered serum metal concentrations and prostate cancer risk with adjustment for potential confounders. Bayesian kernel machine regression (BKMR) models were used to account for nonlinear, interactive, and joint metal effects. Results: Using probit regression, four heavy metals (As, Zn, Mn, Sb) were significantly and positively associated with prostate cancer risk in the unadjusted models. Using BKMR analysis, both As and Zn had positive risk differences on prostate cancer risk when all other metals were held fixed at the 25th and 50th percentiles (RD, 25th percentile: As: 0.15, Zn: 0.19, RD, 50th percentile: As: 0.45, Zn: 0.37). In addition, the overall mixture risk difference was positive and the 95% credible intervals did not include 0 when all metals in the mixture were jointly above their 55th percentile, as compared to when all metals were below their median values. Conclusions: In summary, we found positive associations between the serum levels of As and Zn and prostate cancer risk on the risk difference scale using BKMR models. The overall mixture effect was also associated with increased prostate cancer risk. Future studies are warranted to validate these findings in prospective studies.
... In the current study, the Cu group displayed a marked reduction in the relative weights of testes as well as the levels of testosterone and LH in serum, in addition to mild hypertension and depletion of testicular Zn. These findings are in harmony with the literature because Cu overload, hypertension and Zn deficiency are pathological conditions affecting male sexual function, by altering the levels of testosterone hormone (Prasad et al., 1996;Vlachopoulos et al., 2013;Tvrda et al., 2015;Guo et al., 2017). The reduction in the transcription of steroidogenic genes in the current study might contribute to the observed decrease in serum testosterone level according to the hypotheses of Hammami et al. (2009). ...
... We attribute the ability of C. esculentus to improve male reproductive function to its antioxidant content. The various antioxidants in C. esculentus including quercetin [77,96], vitamin C [79,97], vitamin E [78,98] and zinc [80,99] are known to improve serum testosterone level and sperm quality. ...
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Aim: Lead acetate impairs testicular function by enhancing testicular oxidative stress and apoptosis. Cyperus esculentus possesses antioxidants and has shown great improvement of testicular function. This study investigated the protective effect of hydro–ethanolic extract of Cyperus esculentus on lead acetate–induced testicular dysfunction in Wistar rats. Materials and methods: Twenty–five male Wistar rats (180–195 g) were randomly divided into 5 groups (n = 5) namely: Normal control (NC), Lead control (PbC) (20 mg/kg b.w. i.p.), C. esculentus-treated (CE) (500 mg/kg b.w p.o.), Pb + CE(500) (20 mg/kg of lead and 500 mg/kg of extract) and Pb + CE(1000) (20 mg/kg of lead and 1000 mg/kg of extract). Administration lasted for 21 days. Results: Sperm count, motility, viability, serum testosterone and follicle stimulating hormone, Johnsen’s score, Leydig cell count, Sertoli cell count, testicular testosterone, B–cell lymphoma protein–2 (Bcl–2), steroidogenic acute regulatory protein, cytochrome P450 A1, 3β–hydroxysteroid dehydrogenase (HSD), 17β–HSD, enzymatic antioxidant activities and total antioxidant capacity were significantly (p < 0.05) decreased in PbC compared with NC. These parameters however increased significantly (p < 0.05) in Pb + CE(500) and Pb + CE(1000) compared with PbC. Lead acetate upregulated (p < 0.05) testicular malondialdehyde, nitric oxide, glucose, lactate, lactate dehydrogenase, C–reactive protein, tumor necrosis factor–α, interleukin (IL)–6, IL–1β, Bcl–2 associated X (Bax), Bax/Bcl–2 and cleaved caspase–3 levels. All these parameters were downregulated (p < 0.05) in Pb + CE(500) and Pb + CE(1000) in comparison with PbC. Conclusion: C. esculentus exhibited a dose-dependent mitigation of lead acetate–induced testicular dysfunction in Wistar rats via its antioxidant, anti–inflammatory and anti–apoptotic effects
... Regarding the statement 1, about counting calories, although the majority expressed disagreement (16.3%) or strong disagreement (25.3%), still some think this is the basis for a healthy diet (31.7% agree or strongly Complimentary Contributor Copy agree). Although it is important to attend to the daily ingestion of some desired levels of calories, it is also true that this is not the basis for a healthy diet, because a very low level of caloric ingestion and/or the ingestion of foods with low calories but poor in essential macro and micronutrients may lead to important nutrient deficiencies and compromise of some vital functions in the human body (Al-Meshal and Hassan, 1982;Gur et al., 2014;Prasad et al., 1996;Soleimani and abbaszadeh, 2011). ...
Chapter
Throughout our lifes we are exposed to different stressors that can make us more vulnerable to suffer from mental disorders, such as depression or anxiety. However, resilient individuals are characterized by their ability to achieve a positive outcome when they are in the face of adversity. Interestingly, both clinical and pre-clinical studies have provided us information about different behavioural interventions that can make us more resilient to challenging situations. These include the aerobic exercise which, at moderate doses, has been shown to be beneficial at all stages of life by promoting a range of physiological and neuroplastic adaptations that reduce the anxiety response. Due to the benefit effects of the exercise on the cognition and brain functionality, the exercise programs have been proposed as a promoter of resilience and neuroplasticity. How to understand the relationship between exercise, neuroplasticity and resilience is one of the objective that will be developed in our chapter. Thus, we will summarize the potential effect of moderate exercise to induce a more successful response toward stressful situations, as well as to describe its neurobiological underlying basis (morphofunctional modifications in HPA axe, neurogenesis, specific neuron types, glia, neurotrophic factors, among others) in different periods of life (adolescence, adulthood and old age).
... Although it is necessary to discuss the roles of gender hormones and gut microbiota to assess serum zinc status in aging, it was complicated to investigate in the study. [26][27] Additional study is needed to discuss the association between serum zinc concentration in aging and these roles. ...
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Background Studies that have examined serum zinc deficiency/marginal deficiency in developed countries, including Japan, are still limited. The aim of this study was to assess serum zinc concentrations and associated characteristics among Japanese subjects. Methods This cross‐sectional study, conducted from September 2016 to December 2018, included 2056 eligible subjects who participated in a voluntary health checkup. Serum zinc concentration categories were defined as deficiency (<60 μg/dL), marginal deficiency (≥60 to <80 μg/dL), and normal (≥80 μg/dL). Serum zinc concentrations were compared between the first age category (<40 years) and other age categories with Dunnett's method. Trends in P‐values were estimated using the Jonckheere‐Terpstra test for continuous variables. Results The proportions of subjects with deficiency and marginal deficiency were 0.4% and 46.0% in men, and 0.6% and 38.4% in women, respectively. The deficiency/marginal deficiency group had significantly lower lipid profiles and nutritional status, and a significantly lower proportion were non–daily drinkers in both genders. Older age was significantly associated with lower serum zinc concentration only in men. Conclusions Our findings clarified a high proportion of serum zinc deficiency/marginal deficiency, especially in men, and suggest a possible association between serum zinc levels and nutritional status and alcohol consumption. It may be necessary to manage nutritional status, including zinc intake.
... Alcohol reduces levels of expression of enzymes that are involved in synthesis of steroids, such as StAR, SF-1, P450scc, 3b HSD, 5a-reductase, P450aro and 3a HSD (Biggio and Purdy 2001). In contrast, level of testosterone is increased when a diet enriched with zinc ions (Zn 2+ ) and branched-chain amino acids are consumed (Prasad et al. 1996). Intravenous injection of morphine in male rats induces expression of P450 aromatase gene. ...
Article
Testosterone is a nuclear androgen receptor ligand that controls multiple pathways in brain. In addition to the active biosynthesis of steroids in classic steroidogenic organs such as gonads, adrenals and placenta, testosterone also produced in astrocyte cells of brain. Testosterone and its level must be regulated in brain; because, it directly and indirectly affects memory and several key behavioral characteristics. The significance of sound waves on key enzymes that regulate levels of testosterone in brain has not been investigated. The aim of our study was to examine physical stress of such as sound on induction behavioral changes in animal models. According to the current study, sound waves with 528 Hz frequency in 100 dB intensity induce testosterone production in brain by enhancing StAR and SF-1 and reducing P450 aromatase gene expression. Frequency of 528 Hz also reduces total concentration of reactive oxidative species in brain tissue. Prolonged exposure to this sound wave showed reduction of anxiety related behaviors in rats. The results reveal that reduced anxiety is related to increased concentration of testosterone in brain. This study may lead to ascertain a possible therapy in which sounds may be utilized to reduce anxiety in individual.
... Thus, zinc is closely related to the male reproductive hormones. Severe and moderate zinc deficiency in males causes hypogonadism (Prasad et al., 1996). Zinc may have functional effects on the male reproductive system in two ways: 1. Zinc affects the testis tissue (Ozturk et al., 2005). ...
Article
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Zinc is essential in the regulation of a variety of physiological and biochemical events in the organism. It plays a critical role in maintaining the cell membrane integrity, protein-carbohydrate-lipid metabolism, immune system, wound injury and in the regulation of a number of other biological processes associated with normal growth and development. Physiological and biochemical levels of many hormones are affected by zinc metabolism. Therefore, growth impairment, hypogonadism, and some endocrine diseases are associated with the deficiency of zinc. These effects of zinc are considered versatile. Zinc increases the synthesis of the growth hormone and its number of receptors; thus, it is an important mediator in the binding of this hormone to its receptor. Found in a large quantity in the pancreas tissue, zinc has a part in the regulation of the effect of insulin. Zinc is involved to much more thyroid hormone metabolism such as hormone synthesis, receptor activity, conversion of T4 to T3, and production of carrier proteins. The low levels of zinc and high levels of leptin in obese individuals point to a critical relationship between zinc and leptin. Zinc is related to enzyme activity to melatonin synthesis. Melatonin has regulatory activity for zinc absorption from gastrointestinal system. Zinc particularly affects the conversion of testosterone to dihydrotestosterone, as 5α-reductase that is involved in this conversion is a zinc-dependent enzyme. In consideration of these relations, zinc is accepted to play critical roles in the endocrine system. The aim of the current review is to draw attention to the effects of zinc on the endocrine system.
... Zn plays a pivotal role in the production of spermatozoa in parallel to the synthesis of DNA and RNA by enhancing the activity of DNA and RNA polymerases [50]. Furthermore, Zn supplementation was reported to duplicate the blood concentration levels of testosterone in adult men [51]. ...
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The present study aimed to determine the effects of zinc oxide nanoparticles (ZnO-NPs), thyme oil (THO), or their combination on the nutrient digestibility coefficients, reproductive parameters, and some blood metabolites of male Californian rabbits. One hundred rabbits, 29-weeks of age (initial body weight 3.48 ± 0.08 kg) were randomly distributed into four groups, 25 rabbits each. Treatment groups were fed a control diet, a control diet supplemented with ZnO-NPs (100 mg/kg), THO (500 mg/kg), or combination of ZnO-NPs (100 mg/kg) and THO (500 mg/kg). The feeding trial lasted for 35 days. Results showed improvements in dry matter, crude protein, ether extract, and crude fiber in ZnO-NPs, THO, and their combination treated groups compared to those of control. Furthermore, semen volume, sperm motility, vitality, and morphology were significantly improved (p < 0.01) in ZnO-NPs and THO groups rather than the control. Both ZnO-NPs and THO, as either individual or combined treatments significantly improved the serum alanine amino-transferase (ALT), aspartate amino-transferase (AST), urea, and creatinine compared to the control. Moreover, serum concentrations of testosterone were significantly increased in rabbits supplemented with ZnO-NPs, THO, or their combination compared to those of control (p < 0.05). In conclusion, ZnO-NPs, THO, or their combination improved the digestibility of nutrients, liver/ kidney functions, semen characteristics, and testosterone concentration in male rabbits.
... With respect to the mechanism of action of the substances investigated, the following data are available. The positive effect of zinc can be explained by the fact that zinc plays an important role in the cell cycle and stabilizes concentrations of testosterone in both infertile and healthy men (Prasad et al., 1996). Polyunsaturated fatty acids such as EPA and DHA are an integral part of the cell membrane, which helps to stabilize individual cells. ...
Article
This meta-analysis and systematic review investigated evidence of the effect of oral micronutrient supplementation on male fertility. Following searches of PubMed, Ovid/Ovid Medline(r) and Embase, 18 randomized, double-blind, placebo-controlled trials were included in the meta-analysis (seven studies) and/or the systematic review (12 studies). The meta-analysis showed significant improvement in semen parameters for selenium (200µg/day and 100µg/day) (standard mean difference [SMD] 0.64 for oligozoospermia, 1.39 for asthenozoospermia), L-carnitine (2 g/day) and acetyl-L-carnitine (LAC; 1 g/day) combined (SMD 0.57 for asthenozoospermia), and co-enzyme Q10 (200 and 300 mg/day) (SMD 0.95 for oligozoospermia, 1.48 for asthenozoospermia, 0.63 for teratozoospermia). The systematic review identified promising data for supplementation with 66 mg/day zinc combined with folic acid (5 mg/day), and the polyunsaturated fatty acids eicosapentaenoic acid (EPA; 1.12 g/day) and docosahexaenoic acid (DHA; 0.72 g/day). Pregnancy rate was evaluated in a limited number of trials (four in the meta-analysis, three in the systematic review). This analysis suggests supplementation with selenium (alone or combined with N-acetylcysteine), co-enzyme Q10 and the combinations L-carnitine + acetyl-L-carnitine, folic acid + zinc and EPA + DHA is beneficial in the treatment of male infertility. Because of the small number of available studies and low number of participants, further well-designed clinical studies are needed to obtain a better overview of efficient methods of treating male infertility.
... Zinc has been shown to be essential in tumour growth with cell proliferation being halted in the absence of this element [23,24]. Zinc, however, is required for the activity of hundreds of enzymes, and its increase in poor prognostic UM could signify high proliferation/metabolism and justify the apparent increase of intratumoural 66 Zn (Figure 4e,f) [25]. ...
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Matrix assisted laser desorption ionisation mass spectrometry imaging (MALDI-MSI), was used to obtain images of lipids and metabolite distribution in formalin fixed and embedded in paraffin (FFPE) whole eye sections containing primary uveal melanomas (UM). Using this technique, it was possible to obtain images of lysophosphatidylcholine (LPC) type lipid distribution that highlighted the tumour regions. Laser ablation inductively coupled plasma mass spectrometry images (LA-ICP-MS) performed on UM sections showed increases in copper within the tumour periphery and intratumoural zinc in tissue from patients with poor prognosis. These preliminary data indicate that multi-modal MSI has the potential to provide insights into the role of trace metals and cancer metastasis.
... Several studies demonstrated that some substances such as omega 3 fatty acid, lycopene, and Tribulus have a positive effect on sperm parameters (sperm motility, number, morphology, DNA integrity, and mitochondrial function) (72)(73)(74). However, the mechanism of actions was documented for selenium (75), zinc (76,77), and carnitine (78), but just supposed for other ingredients or still unknown in most cases. The synergistic effect of more ingredients can also be supposed. ...
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Content: Dietary supplements (DS) for male infertility marketed in Italy were evaluated for composition, concentration of ingredients, and recommended daily dose. A systematic review of literature identified ingredients potentially effective on sperm parameters and their minimal effective daily dose (mED). Objective: This study was conducted in order to critically evaluate the composition and efficacy of DS marketed in Italy. Design setting and participants: This was a systematic review of randomized controlled trials. Evidence acquisition: A formula allowed us to classify the expected efficacy of each DS, based on composition. Each DS was scored and included into three classes of expected efficacy: high, low, and none. Evidence synthesis: Among 24 supplements, 3 (12.5%) fall in high, 9 (37.5%) in lower, and 12 (50.0%) in no expected efficacy class. DS composition showed 36 substances, 18 with no literature on male fertility and 18 showing positive effect on sperm parameters, thus considered potentially active ingredients (PAI). All DS were mixtures of ingredients, containing from 2 to 17 different substances. Fifteen supplements (65.2%) contained at least 1 ingredient without evidence of efficacy and 21 formulations had PAI dosed below mED. Some PAI were associated to the improvement of specific sperm parameters. Conclusions: DS were usually blends of many substances that are frequently employed at negligible dose or without any evidence of efficacy on male reproduction. Some ingredients have been demonstrated to be effective on specific sperm parameters by RCTs. We report a list of ingredients with potential efficacy on specific sperm parameters, aimed to allow a tailored use of DS. Patient summary: The market of DS for male infertility offers products with potential efficacy in the improvement of sperm parameters but also many with uncertain effects. Based on current scientific literature, our study can help in the choice of DS that are more likely to be effective on specific sperm alterations, so providing the best supplementation for each patient.
... Thus, Zn is closely related to the male reproductive hormones. Severe and moderate zinc deficiency in males causes hypogonadism (Prasad et al. 1996). Low level of zinc may affect the production of these hormones, as well as testosterone level (Yan et al. 2010). ...
Article
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Trace element deficiency in male lambs is a serious problem. It refers to either insufficient nutrients or mineral elements imbalance. This work aimed to investigate the hormonal and some biochemical changes related to some trace element deficiency and the effect of mineral mixture supplementation on these changes. To achieve this aim we induced trace element deficiency in a tested male lambs group (N=10) belonged to our sheep herd and received a mineral mixture as a feed supplement for 10 days. The analysis of tested diet revealed protein 12.32%, calcium 1.21%, phosphorus 0.27%, and zinc 25.96 mg/kg DM. While the control healthy group (N=10) received a traditional diet. The results of serum hormones and biochemical analysis of tested group revealed a significant (P˂0.05) decrease in TSH, T3, T3/T4, testosterone, free testosterone, SHBG, GH, albumin and zinc, with a significant (P˂0.05) increase in T4, total protein and globulin compared to control healthy group. On the other hand, the results obtained after mineral mixture supplementation revealed a significant (P˂0.05) increase of TSH, T3, T3/T4, testosterone, free testosterone, SHBG, GH, albumin and zinc. Also, a significant (P˂0.05) decrease in T4, total protein, and globulin was observed compared with this group before mineral mixture supplementation, with observation of the changes were gradually toward recovery. Moreover, insignificant changes were recorded in calcium, phosphorus and iodine. In conclusion to trace element deficiency have an effect on vital hormones with extension to metabolic process, general health condition and proper growth of male lambs.
... Thus, Zn is closely related to the male reproductive hormones. Severe and moderate zinc deficiency in males causes hypogonadism (Prasad et al. 1996). Low level of zinc may affect the production of these hormones, as well as testosterone level (Yan et al. 2010). ...
Preprint
Full-text available
Trace element deficiency in male lambs is a serious problem. It refers to either insufficient nutrients or mineral elements imbalance. This work aimed to investigate the hormonal and some biochemical changes related to some trace element deficiency and the effect of mineral mixture sup-plementation on these changes. To achieve this aim we induced trace element deficiency in a tested male lambs group (N=10) belonged to our sheep herd and received a mineral mixture as a feed supplement for 10 days. The analysis of tested diet revealed protein 12.32%, calcium 1.21%, phosphorus 0.27%, and zinc 25.96 mg/kg DM. While the control healthy group (N=10) received a traditional diet. The results of serum hormones and biochemical analysis of tested group revealed a significant (P˂0.05) decrease in TSH, T3, T3/T4, tes-tosterone, free testosterone, SHBG, GH, albumin and zinc, with a significant (P˂0.05) increase in T4, total protein and globulin compared to control healthy group. On the other hand, the results obtained after mineral mixture supplementation revealed a significant (P˂0.05) increase of TSH, T3, T3/T4, testosterone, free testosterone, SHBG, GH, albumin and zinc. Also, a significant (P˂0.05) decrease in T4, total protein, and globulin was observed compared with this group before mineral mixture supplementation, with observation of the changes were gradually toward recovery. Moreover, insignificant changes were recorded in calcium, phosphorus and iodine. In conclusion to trace element deficiency have an effect on vital hormones with extension to metabolic process, general health condition and proper growth of male lambs.
... The largest decreases in TT were seen in the 2 studies with vegetarian LF diets Hill 1980 NA) [44,49]. These diets may have been lower in zinc, which is a common feature of vegetarian diets [64], and marginal zinc deficiency has been found to decrease TT [32]. Nevertheless, studies well matched for micronutrient intake showed similar, albeit smaller changes in TT [45,48] (Fig. 2); suggesting the decrease in TT was mostly due to other dietary factors. ...
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Background: Higher endogenous testosterone levels are associated with reduced chronic disease risk and mortality. Since the mid-20th century, there have been significant changes in dietary patterns, and men's testosterone levels have declined in western countries. Cross-sectional studies show inconsistent associations between fat intake and testosterone in men. Methods: Studies eligible for inclusion were intervention studies, with minimal confounding variables, comparing the effect of low-fat vs high-fat diets on men's sex hormones. 9 databases were searched from their inception to October 2020, yielding 6 eligible studies, with a total of 206 participants. Random effects meta-analyses were performed using Cochrane's Review Manager software. Cochrane's risk of bias tool was used for quality assessment. Results: There were significant decreases in sex hormones on low-fat vs high-fat diets. Standardised mean differences with 95% confidence intervals (CI) for outcomes were: total testosterone [-0.38 (95% CI -0.75 to -0.01) P = 0.04]; free testosterone [-0.37 (95% CI -0.63 to -0.11) P = 0.005]; urinary testosterone [-0.38 (CI 95% -0.66 to -0.09) P = 0.009], and dihydrotestosterone [-0.3 (CI 95% -0.56 to -0.03) P = 0.03]. There were no significant differences for luteinising hormone or sex hormone binding globulin. Subgroup analysis for total testosterone, European and American men, showed a stronger effect [-0.52 (95% CI -0.75 to -0.3) P < 0.001]. Conclusions: Low-fat diets appear to decrease testosterone levels in men, but further randomised controlled trials are needed to confirm this effect. Men with European ancestry may experience a greater decrease in testosterone, in response to a low-fat diet.
... Indeed, seminal fluid Zn 2+ concentration is positively correlated with sperm count and normal sperm morphology [157]. Consequently, Zn 2+ supplementation improves sexual dysfunction in rats [158] and uremic men [159], which is likely due to the ability of Zn 2+ to increase serum testosterone levels [160]. The negative effect of fatiguing bicycle exercise on thyroid hormone and testosterone levels in sedentary males is likewise prevented with Zn 2+ supplementation [161]. ...
Article
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The importance of zinc for male fertility only emerged recently, being propelled in part by consumer interest in nutritional supplements containing ionic trace minerals. Here, we review the properties, biological roles and cellular mechanisms that are relevant to zinc function in the male reproductive system, survey available peer-reviewed data on nutritional zinc supplementation for fertility improvement in livestock animals and infertility therapy in men, and discuss the recently discovered signaling pathways involving zinc in sperm maturation and fertilization. Emphasis is on the zinc-interacting sperm proteome and its involvement in the regulation of sperm structure and function, from spermatogenesis and epididymal sperm maturation to sperm interactions with the female reproductive tract, capacitation, fertilization, and embryo development. Merits of dietary zinc supplementation and zinc inclusion into semen processing media are considered with livestock artificial insemination (AI) and human assisted reproductive therapy (ART) in mind. Collectively, the currently available data underline the importance of zinc ions for male fertility, which could be harnessed to improve human reproductive health and reproductive efficiency in agriculturally important livestock species. Further research will advance the field of sperm and fertilization biology, provide new research tools, and ultimately optimize semen processing procedures for human infertility therapy and livestock AI.
... Indeed, seminal fluid Zn 2+ concentration is positively correlated with sperm count and normal sperm morphology [157]. Consequently, Zn 2+ supplementation improves sexual dysfunction in rats [158] and uremic men [159], which is likely due to the ability of Zn 2+ to increase serum testosterone levels [160]. The negative effect of fatiguing bicycle exercise on thyroid hormone and testosterone levels in sedentary males is likewise prevented with Zn 2+ supplementation [161]. ...
Preprint
Full-text available
The importance of zinc for male fertility only emerged recently, propelled in part by consumer interest in nutritional supplements containing ionic trace minerals. Here, we review the properties, biological roles and cellular mechanisms that are relevant to zinc function in the male reproductive system, survey available peer-reviewed data on nutritional zinc supplementation for fertility improvement in livestock animals and infertility therapy in men, and discuss recently discovered signaling pathways involving zinc in sperm maturation and fertilization. Emphasis is on the zinc-interacting sperm proteome and its involvement in the regulation of sperm structure and function, from spermatogenesis and epididymal sperm maturation to sperm interactions with the female reproductive tract, capacitation, fertilization and embryo development. Merits of dietary zinc supplementation and zinc inclusion into semen processing media are considered with livestock artificial insemination (AI) and human assisted reproductive therapy (ART) in mind. Collectively, the currently available data underline the importance of zinc ions for male fertility, which could be harnessed to improve human reproductive health and reproductive efficiency in agriculturally important livestock species. Further research will advance the field of sperm and fertilization biology, provide new research tools, and ultimately optimize semen processing procedures for human infertility therapy and livestock AI.
... [18] Zinc (Zn) plays a significant role in the regulation of the appetite. [22][23][24] A widely accepted mechanism for Zn-induced regulation of appetite is changes in the metabolism of the hypothalamic neurotransmitters. [23,25] The existence of a link between zinc-induced appetite regulation and leptin-induced appetite regulation was suggested by Mantzoros et al., [26] and Mangian et al., [27] when they observed that, in humans and rodents, zinc deficiency decreases, while Zn supplementation increases leptin levels. ...
Article
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Background: Micronutrient replacement is done indiscriminately, without recourse to peculiar socioeconomic and sociodemographic variables. Particularly, the relationship between parity, body weight, and some micronutrients has received minimal attention in Nigeria. Aim: To determine the relationship between parity, body weight, and some micronutrients during pregnancy. Subjects and Methods: This is a cross-sectional study involving 130 pregnant women and 30 nonpregnant control. They were recruited from two health care facilities in Nigeria and grouped into nulliparous and multiparous. After a 24-h dietary recall, the weight (W) and height (H) were measured. The body mass index (BMI) (W in kg/H in m 2) was calculated. Serum copper and zinc were estimated using flame atomic absorption spectrophotometer. Results: Multiparous nonpregnant subjects parity=3.0 (0.58) had higher weight (P=0.037) and BMI (P=0.035) than their nulliparous counterparts (parity=0). In addition, there were no significant difference in Cu and zinc levels between the two groups (P=0.243 and 0.402, respectively). Expectedly, weight and BMI increased as pregnancy progressed. There was no significant difference in Cu levels between the three trimesters in the nulliparous pregnant and multiparous pregnant subjects. In the pregnant nulliparous subjects, the Zn levels of the 2 nd and 3 rd trimesters were significantly lower than that of the nonpregnant nulliparous subjects (P<0.001 and 0.039, respectively). However, in multiparous pregnant subjects, only the 3 rd trimester Zn level was significantly lower than that of the nonpregnant controls (P=0.017). Conclusion: Pregnancy weight gain is more pronounced in multiparous than nulliparous women. This parity-related pattern only affects the serum zinc levels, a situation that should be taken into consideration when formulating policies for nutritional replacement.
... Concentrations of both metallothionein and Zn increase with age in the liver and kidney of humans (Yoshida et al., 1998) and harbor seals (Phoca vitulina; Tohyama et al., 1986). Correlations between serum Zn and hormone concentrations have been reported for humans (Castro-Magana et al., 1981;Favier, 1992;Prasad et al., 1996;Hamza et al., 2012). Zn plays an important role in skeletal development and is involved in the mineralization of bones and teeth (Ganss and Jheon, 2004;Stock et al., 2017). ...
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Age at maturity is an important parameter in many demographic models and, for some species, can be difficult to obtain using traditional methods. Incremental growth structures act as biological archives, recording information throughout an organism's life and possibly allowing for the reconstruction of life history events. Concentrations of zinc (Zn) in animal tissues are known to be linked to life history, physiology and reproduction and may be retained in incremental growth structures. This study reconstructed lifetime Zn concentrations in teeth (n = 93) of female Pacific walruses (Odobenus rosmarus divergens) collected from 1932-2016. Zn displayed a characteristic pattern of accumulation, with a change point marking the beginning of a lifelong, linear increase in Zn concentrations. We hypothesized that this change point marks the onset of reproductive maturity. The age at which the change point occurred (age cp) was estimated by counting tooth cementum growth layers. These estimates closely matched literature values of timing of first ovulation in female walruses. Total number of ovulations (estimated from ovary corpora counts from paired tooth/ovary specimens) was closely related to reproductive lifespan (total lifespan-age cp ; R 2 = 0.70). Further, age cp tracked changes in Pacific walrus population size as a proportion of carrying capacity, decreasing when the population was depleted by commercial hunting and peaking when carrying capacity was exceeded. This novel approach will aid walrus management, and is likely applicable to other species, offering a potentially powerful tool for research, management and conservation of wildlife populations.
Chapter
Es gibt einige Hormone, die im täglichen Leben eine maßgebliche Rolle spielen und zeitgleich deutlich vom Lebensstil, also zum Beispiel auch von den Ernährungsgewohnheiten, abhängen. Wachstumshormone flicken den Körper wieder zusammen, mobilisieren Stammzellen, heilen damit Gewebe und machen „schlank im Schlaf“. Zwei Bier am Abend, als Beispiel, senkt die nächtliche Produktion von Wachstumshormon um bis 75 %. Die Wirkung von Vitamin D ist heutzutage in aller Munde – das als „Sonnenhormon“ bezeichnete Vitamin D, aus dem das Hormon Calcitriol entsteht, beeinflusst maßgeblich die physische und psychische Leistungsfähigkeit. Deutsche erreichen sogar in den Sommermonaten kaum optimale Vitamin-D-Spiegel. Weniger bekannt ist, dass auch aus Vitamin A ein Hormon namens Retinsäure entsteht, das ebenfalls eine vielfältige Wirkung im Körper besitzt. Daneben sind Testosteron, das aktive Schilddrüsenhormon T3 und die Zellbotenstoffe Kalzium und cAMP Hormone bzw. hormonähnlich wirkende Substanzen, die beispielsweise maßgeblich bestimmen, wie gut der menschliche Organismus Fett verbrennen kann.
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Purpose: Testosterone replacement and associated pharmacologic agents are effective strategies to treat male hypogonadism; however, nutraceutical agents and lifestyle modification approaches have gained medical interest. The purpose of this scoping review is to highlight the evidence (or lack thereof) of nutraceuticals and lifestyle modification approaches in the management of testosterone levels and sperm parameters. Methods: A scoping review of nonpharmacologic interventions (supplements, herbal medicines, diets, sleep, and exercise) with the potential to improve male health was undertaken to elucidate changes in testosterone levels and sperm parameters in men with hypogonadism or infertility compared with healthy patients. Findings: A multitude of nutraceuticals and functional nutrients are purported to stimulate testosterone production; however, only a select few have had promising results, such as zinc, vitamin D (in case of hypovitaminosis D), l-arginine, mucuna, and ashwagandha, based on well-controlled randomized clinical trials of men with low testosterone levels and related problems. Except for l-arginine, these natural agents, as well as tribulus and ω3 fatty acids, can improve some degree of sperm parameters in infertile men. Before implementing these nutraceutical agents, adequate sleep, exercise, and weight loss in patients with obesity are imperative. The effects of nonpharmacologic interventions on testosterone levels are modest and hence do not directly translate into clinical benefits. Correspondingly, androgen receptor content, but not endogenous androgens, has been regarded as the principal factor in muscle hypertrophy. Implications: A limited number of supplements and herbal medicines can be considered as adjunctive approaches in the management of testosterone levels and sperm parameters, primarily in men with low testosterone levels and infertility, whereas most nonpharmacologic supplements appear to lack evidence. Although proper physical exercise, sleep, and diet are indisputable approaches because of the general benefits to health, the use of nutraceuticals, if considered, must be personalized by physicians and/or registered dietitians.
Article
Introduction Erectile dysfunction (ED) is the inability to attain or sustain an erection for sexual intercourse. Affected men endorse difficulties with intimacy and feelings of guilt and shame. Although medical treatments are available, patients are reluctant to discuss ED with physicians and often use dietary supplements to attempt to treat their ED. As such, there is a need to better understand the effects of ingredients used in nutraceuticals for ED treatment. Objectives To summarize the literature on the efficacy and safety of the most common ingredients used in ED supplements. Methods 10 of the most common ingredients in ED supplements were reviewed using PubMed-indexed literature to assess their efficacy and safety in treating ED. Key findings were summarized to include historical use, active ingredients, prior animal studies, human studies, and toxicity. Results Nutraceuticals used in ED treatment include a variety of ingredients. Although L-arginine is a safe supplement with clinical data supporting improved erectile function, limited data exist on the efficacy of other ingredients in the treatment of ED. Conclusion Despite the growing use of supplements for treatment of sexual dysfunction, ED supplements remain poorly studied, with limited data demonstrating efficacy of individual ingredients. Further study is required to definitively determine the efficacy of nutraceuticals in ED treatment. Srivatsav A, Balasubramanian A, Pathak UI, et al. Efficacy and Safety of Common Ingredients in Aphrodisiacs Used for Erectile Dysfunction: A Review. J Sex Med 2020;XX:XXX–XXX.
Chapter
Furan is common compound that can be found in many products in pure form and as its derivatives. It is abundant in environment as in processed food, industrial process, pharmaceutical products and smoke. When furans are heated, they enhanced oxidative processes in lipids and proteins, and therefore play a toxic role in many cases. In many body systems furans are examined to cause toxic effects. It is commonly formed from four precursors amino acids, carbohydrates, ascorbic acids and PUFA. To detect the presence of furan and its amount in sample many methods have been involved. Most common of them are headspace analysis, headspace sampling by solid phase microextraction, and GCMS. As furan toxic effect is confirmed in many animals and it can be harmful to human health as well. The quantity of furan taken by humans are measured through quantification of furan in many food products. Many health agencies such as EFSA, FDA and IARC determine amount of furan in different foods. Further experiments were conducted to determine its harmful effects. Mouse and rats were mostly used in such tests. In rat metabolism of furan is tested and recorded that 80% of furan was eliminated through different pathways. Furan affects on digestive track is also determined. It mostly affects liver due to its prolonged presence in liver, but it was also observed to be harmful for kidneys. Some products are also tested to mitigate furan toxicity, apigenin and lycopene were found to be effective against furan toxicity. Moreover, furan itself was known to be effective against oxidative stress, which may cause many neurodegenerative disorders.
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Endocrine disorders like diabetes, adrenal fatigue, hyper and hypothyroidism, menstrual abnormalities, and sexual dysfunctions are growing day by day due to many environmental pollutants and endocrine disrupting chemicals coming from food and breakages. Hormonal imbalances can affect life of millions of people. Herbs and spices normalize the hormone in normal ranges. Hormones are key messengers for controlling almost all body systems. Hormonal imbalance is a troublous condition which has adverse effects on mood, appetite, metabolism, aging, and mental health. Adaptogenic herbs are unique healing herbs that promote hormonal balance, enhance immune functions, and reduce mental stress. These herbs eliminate toxins from the body and detoxify liver from harmful chemicals and endocrine disrupting chemicals. Herbal infusions and their essences have potential to cure hormonal disorders.
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Zinc is an essential trace element required for normal cell growth, development, and differentiation. It is involved in DNA synthesis, RNA transcription, and cell division and activation. It is a critical component in many zinc protein/enzymes, including critical zinc transcription factors. Zinc deficiency/altered metabolism is observed in many types of liver disease, including alcoholic liver disease (ALD) and viral liver disease. Some of the mechanisms for zinc deficiency/altered metabolism include decreased dietary intake, increased urinary excretion, activation of certain zinc transporters, and induction of hepatic metallothionein. Zinc deficiency may manifest itself in many ways in liver disease, including skin lesions, poor wound healing/liver regeneration, altered mental status, or altered immune function. Zinc supplementation has been documented to block/attenuate experimental ALD through multiple processes, including stabilization of gut‐barrier function, decreasing endotoxemia, decreasing proinflammatory cytokine production, decreasing oxidative stress, and attenuating apoptotic hepatocyte death. Clinical trials in human liver disease are limited in size and quality, but it is clear that zinc supplementation reverses clinical signs of zinc deficiency in patients with liver disease. Some studies suggest improvement in liver function in both ALD and hepatitis C following zinc supplementation, and 1 study suggested improved fibrosis markers in hepatitis C patients. The dose of zinc used for treatment of liver disease is usually 50 mg of elemental zinc taken with a meal to decrease the potential side effect of nausea.
Article
Zinc is a prime prescribed element that is involved in the development and maturing of the human body. The abundance of Zinc on the earth’s surface is around 0.004%. Zinc is an essential mineral because it shows many catalytic activities in the human body. Zinc is mandatory for the action of around 300 enzymes that back in catabolism, dissolution, neurology, and many more activities. Due to many catalytic activities Zinc behaves as an immunity booster and keeps the immune system healthy and strong. Zinc is also beneficial to the well-being of the skin, DNA merging, and protein-producing. It is also required for your perception of flavor and scent because the enzymes determining genuine flavor and scent are based on this nutrient, a zinc inadequacy can lower your potential to flavor or scent Zinc deficiency may influence human health such as retard wound healing, common cold, neuro sensory disorder, reduce body mass, poor immune system, chronic diarrhea, skin rashes, delayed sexual maturity. The prime reason for zinc deficiency involves improper intake of diet, poor absorption, alcoholism, genetic transformation, and old age. Zinc insufficiency is hard to recognize using lab tests because our body tightly controls the zinc level in the body. Thus, we may still be deficient but even the lab tests show the normal level of zinc in the body. Zinc supplementation restores specific resistant cells and lowers oxidative tension. Zinc is an essential mineral for your body that does not make on its own thus you only get it through zinc-rich food or supplements.
Article
The present study was aimed at determining the effect of green coffee supplementation on androgens level in women with Poly-Cystic Ovary Syndrome (PCOS) through double-blind Randomized Clinical Trial (RCT). Each patient (n = 17) in the treatment group received one green coffee capsule (400 mg) and the control group (n = 17) received one placebo for six weeks. Then, the levels of free testosterone, dihydrotestosterone, and androstenedione; lipid profile; glycemia and insulinemia indices; and anthropometric indices before and after the intervention were determined and compared. The results showed green coffee supplements reduced testosterone level (P = 0.038). There was no significant difference in general characteristics of the participants, including education, occupational status, age of illness, and metformin usage. At the beginning and the end of the study, there was a significant decrease in triglyceride (P = 0.007) and total cholesterol level (P = 0.035) in the green coffee group in comparison with the placebo group. However, no significant difference in anthropometric data including weight, Body Mass Index (BMI), waist circumference, and waist-to-hip ratio was observed. Moreover, no significant difference was observed in fasting blood glucose, insulin levels, insulin resistance index, LDL, HDL, dihydrotestosterone, and androstenedione. The results of the clinical trial showed that supplementation of 400 mg green coffee a day for six weeks significantly reduced free testosterone, triglyceride, and cholesterol levels. Therefore, green coffee might help to improve Poly-Cystic Ovary Syndrome (PCOS).
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Chiral macrocyclic cavitands prepared by a template free, high dilution methodology have been discovered to function as molecular containers accommodating small organic molecules and host transition metal ions with specific sensing ability while having an outstanding capability to sense Zn2+ with switch‐on fluorescence and also act as a selective colorimetric sensor for Cu2+. The cavitand acts as a unique two‐directional molecular tweezers for the guest molecules. 26‐Member chiral macrocycles 3 a–d are prepared using high dilution methodology. The cavitand shape was discovered for 3 a with two acetone molecules nesting in the cavity with the host acting as a unique two directional tweezers holding the perpendicularly placed organic guest molecules. The cavitands are also studied for transition metal ion binding ability. Cavitand 3 a is found to selectively sense the biologically essential trace metal ions, Cu2+ colorimetrically and Zn2+ with a prominent switch‐on fluorescence.
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Several medicinal plants are traditionally used in different regions of Africa for the treatment of male infertility, sexual asthenia, erectile dysfunction, and impotency or used as an aphrodisiac. Scientific studies, mostly conducted in vitro or in animals, have proven the acclaimed traditional use of these plants to enhance sexual activities or sperm concentration, motility, and viability. Some of the mechanisms of actions associated with these plants include increased level of testosterone and the relaxation of the smooth cavernosal muscles. However, some plants were also shown to have detrimental effects on the male reproductive system. This may be due to the varying modes of plant extraction, duration of treatment, experimental design, dosage used, quality of the plant, or toxic effects. There is a need to standardize the protocols as well as to better understand the mechanism of actions of the respective plants. Further studies should be conducted using human subjects.
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Testosterone is the male hormone produced by the Leydig cells of the testis. Approximately 98% of testosterone circulates in the blood bound to protein and the remaining 2% is free. Normal level of testosterone decrease the risk of cardiovascular disease, decrease the visceral fat mass and total cholesterol, maintain glycemic control, and increase lean body mass. Semen is an organic fluid consisting of secretions of the testes and the accessory sexual glands. Semen quality is a measure of the ability of the male germ cells to accomplish fertilization and pregnancy. Decreased semen quality causes male infertility. Semen quality is influenced by lifestyle, food intake, and exposure to chemicals. The Aging Male Symptoms Score Chart is an instrument to measure the severity of aging symptoms in men, and their impact on quality of life. Erectile dysfunction (ED) is the inability to achieve or maintain an erection adequate enough for satisfactory sexual intercourse. The organic causes of ED are cardiovascular disease, diabetes, neurological problems, hormonal insufficiencies, and drug side effects. The first-line treatment of erectile dysfunction consists of a trial of phosphodiesterase-5 inhibitor. Male hypogonadism is caused by deficiency in testosterone. There are two basic types of hypogonadism, primary, which originates in the testicles, and secondary, which originates in the hypothalamus or the pituitary gland. Hypogonadism is suspected when the serum testosterone levels are less than 300 ng/dL. The prostate is an accessory sex organ that contributes about 20%–30% to the total seminal ejaculate. The prostate is 3.4 cm in length, 4.4 cm in width, 2.6 cm in thickness, and the weight is between 15 and 20 g. It is located in the pelvis. Benign prostatic hyperplasia (BPH) is a noncancerous increase in size of the prostate. BPH is a progressive disease that is commonly associated with lower urinary tract symptoms. Validated questionnaires such as the American Urological Association Symptom Index, the International Prostate Symptom Score, and the UWIN score are useful aids to making the diagnosis of BPH and quantifying the severity of symptoms. Prostate cancer is the development of cancer in the prostate. Initially it is symptomless but in later stages, it can lead to dysuria, hematuria, or pain in pelvis, back, or when urinating. About 99% of the cases occur in males over the age of 50. Prostate cancer is diagnosed by biopsy with medical imaging. Screening is done by PSA (blood test).
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Mixed pollution due to heavy metals (HMs), especially cadmium (Cd), lead (Pb), and arsenic (As), seriously endangers the safety of food produced in paddy soil. In the field experiments, foliar application of 2,3-dimercaptosuccinic acid (DMSA) at the flowering stage was found to significantly reduce the levels of Cd, Pb, total As, and inorganic As (iAs) in rice grains by 47.95%, 61.76%, 36.37%, and 51.24%, respectively, without affecting the concentration of metallonutrients, including Mn, K, Mg, Ca, Fe, and Zn. DMSA treatment significantly reduced the concentrations of Cd, Pb, and As in the panicle node, panicle neck, and rachis, while those in the flag leaves were significantly increased by up to 20.87%, 49.40%, and 32.67%, respectively. DMSA application promoted the transport of HM from roots and lower stalks to flag leaves with a maximum increase of 34.55%, 52.65%, and 46.94%, respectively, whereas inhibited the transport of HM from flag leaves to panicle, rachis, and grains. Therefore, foliar application of DMSA reduced Cd, Pb, and As accumulation in rice grains by immobilizing HMs in flag leaves. Thus, this strategy could act as a promising agronomic measure for the remediation of mixed HM contamination in paddy fields.
Article
This study aimed to investigate the effect of zinc supplementation on testosterone levels and sexual function in postmenopausal women. This randomized clinical trial was performed on 116 postmenopausal women with serum zinc levels below 62, and low sexual function who were randomly divided into two groups: intervention and control. Serum zinc levels, testosterone, hemoglobin and hematocrit, as well as their Female Sexual Function Index (FSFI) were evaluated before and after the intervention. Data analysis was performed using paired and independent t-tests, Fisher’s exact test, and Chi Square test. The use of zinc supplementation in the intervention group significantly improved sexual desire, arousal, orgasm, satisfaction, vaginal moisture, and pain during intercourse and also the overall score of sexual function compared to the control group (p < 0.001). Zinc supplementation in the intervention group, resulted in a significant increase in testosterone levels compared to the control group, which improved sexual function in postmenopausal women non-significantly. The results of this study showed that zinc supplementation can improve testosterone levels and sexual function in postmenopausal women. Using this supplement in postmenopausal women having zinc insufficiency is recommended. Also, there is need for more studies to prove the effect of zinc on testosterone and sexual function.
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Цинк является одним из жизненно важных элементов организма человека. Пребывая в нем в виде двухвалентного иона, он в физиологических условиях не проявляет редокс-активности, участвуя вместе с тем в осуществлении разнообразных физиологических функций путем характерного для этого микроэлемента влияния на разнообразные биологические процессы. Например, цинк может быть представлен в качестве структурного, каталитического, внеклеточного или внутриклеточного сигнального компонента.К настоящему времени описаны многие симптомы, вызванные дефицитом цинка в организме, однако проблема лабораторной диагностики этого состояния все еще окончательно не решена. В данном обзоре представлена информация о современных биомаркерах (уровень содержания цинка, металлотионеинов и цинк-зависимых ферментов в плазме и клетках крови, моче) оценки метаболического статуса цинка в организме человека и их лабораторно-диагностическая значимость. Также уделено внимание методам оценки уровня содержания цинка в биологических системах. Zinc is one of the essential elements for humans, which exists as a bivalent cation and does not exhibit redox activity under physiological conditions. Exactly this feature explains its various physiological functions in various biological processes. For example, zinc can be present as a structural, catalytic extracellular or intracellular signaling component. Therefore, it is not surprising that zinc deficiency is a significant global health problem. Today, many symptoms caused by zinc deficiency have been described; however, laboratory diagnostics of this condition is a problemthat has not been fully resolved. This review provides information about the modern biomarkers (serum, blood cells, urine zinc levels, level of metallothioneins, as well as zinc-dependent enzymes, etc.) for assessing the metabolic status of zinc in humans and its laboratory diagnostic significance. The methods for assessing the zinc level in biological systems are also described in general.
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Royal jelly is essential for the fertility of honey bees, but it has a fertility enhancer effect in mammals, too. Rodent experiments proved the mechanisms of action of royal jelly on fertility, including antioxidant, sex hormone, and antiinflammatory effects. In farm animals (chicken, rabbit, buffalo, and sheep), the application of royal jelly contributes to improving the rates of pregnancy and birth and enhances the success rate of in vitro fertilization methods. Human studies proved that royal jelly has a beneficial effect on sperm count and motility and improves the fertilizing ability of male gametes. However, no reliable clinical data support the fertility-improving effect of royal jelly in women, although used widely during assisted reproductive processes. Beyond royal jelly, drone milk has a promising effect on fertility in both sexes in rats, but the clinical evidence is still missing. Further clinical studies are required to explore the real potency of these apiary products in the enhancement of human fertility.
Article
Background: The relationship between men's testosterone levels and their sexual behaviors is unclear as existing studies find mixed results. Objectives: The key objective of this study is to assess whether men's testosterone levels are affected by sexual behaviors, and to explore whether this relationship varies by age. Specifically, this study addresses the question: Are men's testosterone levels affected by the number of sexual partners they accrue? Methods: This analysis was based on a nationally-representative sample of 977 unpartnered heterosexual men between the ages of 20 and 65 in the United States. Serum testosterone levels were measured from blood samples using isotope dilution liquid chromatography tandem mass spectrometry (ID-LC-MS/MS) and the number of sexual partners in the past 12 months was ascertained from an Audio Computer-Assisted Personal Self-Interview (ACASI). Using ordinary least squares regression, serum testosterone levels were predicted as a function of the number of sexual partners that men reported, sociodemographic characteristics, and factors known to affect endocrine regulation. An interaction term between the number of sexual partners in the past 12 months and age was included. Results: The correlation between the number of sexual partners in the past 12 months and testosterone levels is contingent upon age: The relationship is positive for younger men but negative for older men. Among 20-year-old unpartnered heterosexual men, an additional sexual partner in the past 12 months is associated with an increase of 5.55 ng/dL of testosterone (95% CI: 2.92, 8.19). This initial positive effect at age 20 is reduced by 0.25 ng/dL of testosterone (95% CI: -0.44, -0.06) with each year that men age. Conclusion: Testosterone levels in men are related to reproductive behaviors, but the direction of this relationship changes as men age. This article is protected by copyright. All rights reserved.
Article
Introduction As men age, progressive testosterone deficiency syndrome becomes an increasingly common problem. However, the decreased testosterone levels are not only the result of advanced age. Areas covered PubMed search of published data on testosterone, nutritional deficiency, stress, sleep and obesity. Many factors impact the male HPG axis (the hypothalamic-pituitary-adrenal), including body weight, calorific and nutritional value of a diet, the amount and quality of sleep, as well as the level of stress. In the case of persons of healthy weight, a below-average calorific value of a diet may decrease the levels of testosterone in men. On the other hand, the same caloric deficiency in obese persons may result in a neutral or positive impact on testosterone levels. Expert opinion Many factors, including external, environmental and internal factors, influence testosterone levels. Undoubtedly, nutritional deficiency, and particularly of such nutrients as zinc, magnesium, vitamin D, together with low polyphenols intake, affects the HPG axis. The levels of mental and oxidative stress can also adversely impact the axis. Hence, a diagnosis of the cause of disturbance in testosterone levels depends on many factors and requires a broad range of research, as well as a change of patients’ lifestyle.
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Serum pituitary levels of growth hormone (GH), thyrotropin (TSH), prolactin (PRL), luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured in sexually mature (adult) and sexually immature (juvenile) male rats who had been deprived of dietary zinc for 15 and 7 weeks, respectively. When compared to pair-fed control rats receiving a zinc supplemented diet, both the adult and juvenile zinc deficient rats had significantly lower body weights, tail lengths and ventral prostate weights. The testes of the sexually immature rats were also smaller than those of the pair-fed animals. In sexually mature, zinc deficient rats serum concentrations of GH and testosterone were significantly lower and serum LH levels significantly higher than in ad libitum fed control rats. Pituitary and hypothalamic levels of other hormones did not differ from values recorded in control animals. In sexually immature zinc deficient rats serum concentrations of GH were also significantly depressed; pituitary content and concentration of LH and pituitary and serum levels of FSH were significantly increased over control values. No discernible effects of zinc deficiency upon hyplthalamic content of LH-releasing hormone or serum concentrations of PRL or TSH were recorded in juvenile rats. Zinc deficiency has minimal effects upon the hypothalamic-pituitary axis of sexually mature rats. In sexually immature males, zinc deprivation leads to impairment of gonadal growth and increased synthesis and/or secretion of the pituitary gonadotropins.
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The activity of thymulin (a thymic hormone) is dependent on the presence of zinc in the molecule. We assayed serum thymulin activity in three models of mildly zinc-deficient (ZD) human subjects before and after zinc supplementation: (a) two human volunteers in whom a specific and mild zinc deficiency was induced by dietary means; (b) six mildly ZD adult sickle cell anemia (SCA) subjects; and (c) six mildly ZD adult non-SCA subjects. Their plasma zinc levels were normal and they showed no overt clinical manifestations of zinc deficiency. The diagnosis of mild zinc deficiency was based on the assay of zinc in lymphocytes, granulocytes, and platelets. Serum thymulin activity was decreased as a result of mild zinc deficiency and was corrected by in vivo and in vitro zinc supplementation, suggesting that this parameter was a sensitive indicator of zinc deficiency in humans. An increase in T101-, sIg-cells, decrease in T4+/T8+ ratio, and decreased IL 2 activity were observed in the experimental human model during the zinc depletion phase, all of which were corrected after repletion with zinc. Similar changes in lymphocyte subpopulation, correctable with zinc supplementation, were also observed in mildly ZD SCA subjects. Inasmuch as thymulin is known to induce intra- and extrathymic T cell differentiation, our studies provide a possible mechanism for the role of zinc on T cell functions.
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The present studies were performed to evaluate the role of zinc in the regulation of testosterone 5 alpha-reduction by the 800 g supernatants prepared from human benign prostate hyperplasia specimens. The results show that when zinc is added at low concentrations the 5 alpha-reduction of testosterone is increased but at higher cation concentrations the metabolism is significantly inhibited. This decrease was mediated by both a non-competitive inhibition of the binding of testosterone to the 5 alpha-reductase enzyme and by a reduction in the formation of the NADPH cofactor. We have also demonstrated that the decreased synthesis of NADPH was produced by a competitive inhibition of both G6P and NADP binding to the G6PD enzyme. The data also suggests that the increase in testosterone metabolism observed at low zinc concentrations does not produce any changes in the binding of testosterone to the 5 alpha-reductase enzyme. In spite of the above observations we were unable to establish any correlation between the endogenous zinc content of the tissue and the in vitro capacity of the BPH samples to 5 alpha-reduce testosterone. The present study suggests a possible physiological role for the regulation of testosterone metabolism by zinc in the human prostate gland.
Article
Eight healthy male volunteers with normal zinc status were studied in a metabolic ward. During the first 8 weeks of their stay, subjects were fed a hospital diet containing animal protein and providing zinc intake of 12 mg/day (baseline period). During the next 24 weeks, the subjects were fed a semipurified, vegetable protein-based diet, which provided 3.2-5.6 mg/day (zinc depletion period). Following the zinc depletion period, the subjects received 30 mg zinc/day while the experimental diet was continued for 3 months (zinc repletion period). Zinc concentration in plasma, neutrophils, lymphocytes, and platelets; taste detection and recognition thresholds for sodium chloride (salt), sucrose (sweet), hydrochloric acid (sour), and urea (bitter); and relative threshold for dark adaptation were determined before and at the end of zinc depletion and zinc repletion. Zinc levels decreased significantly in plasma (seven of eight subjects), neutrophils and lymphocytes (six of six subjects), and platelets (three of six subjects) after 6 months of dietary zinc restriction. Taste detection and recognition thresholds increased significantly for salt, sweet, sour, and bitter in all subjects, while log relative threshold for dark adaptation became abnormal in five of eight subjects. Zinc repletion for 3 months normalized plasma zinc levels in six of six subjects and cellular zinc (neutrophils, lymphocytes, and platelets) in four of four subjects. Taste detection and recognition thresholds returned to baseline in five of five subjects tested, while abnormality of dark adaptation was reversed in three of five subjects following zinc repletion. These results indicate that even a mild dietary zinc restriction may cause subclinical but measurable changes in taste acuity and dark adaptation in normal subjects.
• Zinc levels were measured in hair and serum of boys with constitutional growth delay and familial short stature and in several boys before and after oral administration of methyltestosterone. These results show the following: (1) zinc levels in boys beyond stage 3 of genital development are significantly higher than in stage 1 and 2; (2) there is a linear relationship between zinc levels and serum testosterone concentration (up to 250 ng/dL); and (3) methyltestosterone administration raised the zinc concentration in serum and hair, especially in boys with constitutional growth delay. Therefore, increased endogenous production or exogenous supply of testosterone are associated with increased zinc levels. We speculate that the relative testosterone deficiency and hypogonadotropism seen in constitutional growth delay may result in decreased zinc levels, which in turn could cause a further delay in the appearance of secondary sexual characteristics and greater growth retardation. (Am J Dis Child 1981;135:322-325)
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IN CONTRAST to the situation in women, where the menopause marks the end of the fertile period, in men fertility persists into old age. Nevertheless old age in men is accompanied by clinical signs, such as a decrease in muscle and bone mass, decrease in sexual hair growth, and decreased libido and sexual activity, suggesting decreased virility. These clinical signs are supported by histological evidence for a decreased Leydig mass and function. Evidence for decreased plasma testosterone in elderly men As to biochemical evidence for decreased androgenicity in elderly men, 25 yr ago the blood production rate of testosterone was reported to be decreased, which at least partially is caused by a decrease of the metabolic clearance. Whether or not aging is also associated with a decrease in plasma testosterone concentrations has long been highly controversial. Indeed, a large series of publications in the 1960s and early 1970s reporting decreased plasma testosterone concentrations in elderly
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In eight impotent haemodialysed men with low plasma-zinc levels sexual function, including potency, frequency of intercourse, libido, and plasma testosterone, follicle-stimulating hormone, and luteinising hormone levels, was determined before and after therapy with zinc (four patients) or placebo (four patients). Dialytic administration of zinc strikingly improved potency in all patients and raised the plasma-testosterone to normal in the two with low pretreatment plasma-testosterone levels. Placebo did not improve sexual function in any patient. Zinc deficiency is a reversible cause of gonadal dysfunction in uraemia.
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Low seminal plasma zinc is an indication of prostatic secretory dysfunction. We have identified a group of patients referred for infertility evaluation who demonstrated low seminal plasma zinc and decreased sperm motility, in the absence of infection. Treatment of these patients with oral zinc sulfate results in improved sperm motility.
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Serum zinc was measured in 154 male and 95 female blood donors. Men had higher serum zinc levels than women, the difference being statistically significant (p less than 0.001). The correlations between serum zinc and serum testosterone, serum zinc and serum FSH and serum zinc and serum LH were studied in 40 men aged 28-60 years and a statistically significant positive correlation was found only between serum zinc and serum testosterone in men of age 36-60 years (p less than 0.005). These results do not support the theory that slight zinc deficiency primarily effects pituitary gonadotropins but indicate that it would rather act on testicular level.
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The role of zinc in gonadal function was investigated in rats. The increases in luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone were assayed after intravenous administration of synthetic luteinizing-hormone-releasing hormone (LHRH) to zinc-deficient and restricted-fed control rats. Body weight gain, zinc content of testes, and weight of testes were significantly lower in the zinc-deficient rats compared with the controls. The serum LH and FSH response to LHRH administration were higher in the zinc-deficient rats but serum testosterone response was lower in comparison with the restricted-fed controls. These studies indicate a specific effect of zinc on testes and suggest that gonadal function in zinc-deficient state is affected through some alteration of testicular steroidogenesis.
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Thirty-two adult patients with sickle cell anemia were evaluated endocrinologically. Secondary sex characteristics were abnormal in 29, and eunuchoidal skeletal proportions were present in all except one. The age at which different stages of pubic hair growth were attained in these patients was delayed in comparison to normals (P less than 0.005). Hormonal assays were carried out in 14 patients. Basal serum testosterone, dihydrotestosterone, and androstenedione values were lower (P less than 0.02) in patients than controls. Serum LH and FSH levels before and after stimulation with gonadotropin-releasing hormone were consistent with primary testicular failure. Erythrocyte and hair zinc concentrations were significantly decreased, and there was positive correlation between erythrocyte zinc and serum testosterone (r = 0.61, P less than 0.01) in sickle cell anemia. Our study shows that androgen deficiency in this disease is a result of primary rather than secondary hypogondadism. Further studies are required to establish the role of zinc in the pathogenesis of testicular failure in sickle cell anemia.
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The age related changes on free plasma testosterone (T), dihydrotestosterone (DHT) and oestradiol (Oe 2 ) were determined in 82 healthy adult males. Forty-six subjects were between 22 and 61 years of age (group I), 36 between 67 and 93 years (group II). The percentage of free, non protein bound hormone was determined by equilibrium dialysis of undiluted plasma against isotonic phosphate buffer at 37°C. Total hormone concentrations were measured by radioimmunoassay. The percentage of free T was 2.24 % (median), 1.65–3.42 (95 percentiles) in group I and 1.65 % (1.24–2.26) in group II. The percentage of free DHT decreased from 1.17 % (0.80–2.03) in group I to 0.83% (0.52–1.55) in group II. The decrease in % free Oe 2 was only very small: group I = 2.49% (2.13–2.96), ad group II = 2.31% (1.95–3.17). The fall in free T by 43.3% from 12.2 ng/100 ml (6.74–25.0) in group I to 6.90 ng/ml (3.57–10.6) in group II was twice as high as that of total T, which decreased on an average by 20.6%. Free DHT decreased by 25.8 %: group I = 578 pg/100 ml (266–987), group II = 429 pg/100 ml (168–723), while total DHT was not significantly different between the two groups (–1.9%). Free Oe 2 was increased in old age: group I = 42.4 pg/100 ml (26.0–69.4), group II = 55.7 pg/100 ml (35.8–118.9). The increase in free Oe 2 by 31.4% was almost as high as that of the total Oe 2 (46.9%).
Article
The semen zinc levels were determined in 18 volunteers, 132 patients postvasectomy, and in 19 patients with prostatitis. The mean values for semen zinc were the same in the volunteers and postvasectomy patients. However, the mean zinc concentration in the volunteers and postvasectomy patients was significantly different from that of the patients with prostatitis. When a group of 12 patients with prostatitis was given supplementary zinc sulfate, the levels of semen zinc rose dramatically and were significantly different from those before treatment. As part of an infertility evaluation, 153 specimens from 72 men who had not fathered a child were examined. A complete semen analysis of each specimen was made, including the semen zinc concentration. The specimens were separated into four arbitrary groups with differing fertility potential. The groups were organized by sperm counts (less than 20 million sperm/ml, 20 to 60 million sperm/ml, 60 to 100 million sperm/ml, and greater than 100 million sperm/ml). There was a trend toward increasing zinc concentrations in the groups with increasing fertility potential. Eleven patients with oligospermia and low semen zinc levels were given supplementary zinc sulfate, 80 mg three times/day for 6 months to 1 year. The parameters of the semen analysis improved in all categories. There were three pregnancies during the period of treatment.
Article
Zinc is a very important element in the reproductive cycle of species. In humans, it is necessary for the formation and maturation of spermatozoa, for ovulation, and for fertilization. During pregnancy, zinc deficiency causes a number of anomalies: spontaneous abortion, pregnancy-related toxemia, extended pregnancy or prematurity, malformations, and retarded growth. Delivery is adversely affected by deficiency. These different effects of zinc can be explained by its multiple action on the metabolism of androgen hormones, estrogen and progesterone, together with the prostaglandins. Nuclear receptors for steroids are all zinc finger proteins. Zinc supplementation has already proven beneficial in male sterility and in reducing complications during pregnancy. However, it would be worth conducting larger-scale trials to confirm these beneficial effects.
Article
Ecto 5' nucleotidase (5'NT) is an integral plasma membrane enzyme located on most mammalian cells, and it is zinc dependent. We assayed 5'NT activity in the lymphocytes of two groups of subjects. The first group of six subjects had a mild state of zinc deficiency, as measured on the basis of zinc levels in lymphocytes, granulocytes, and platelets, but were otherwise healthy. They received 50 mg zinc as acetate orally for 12 weeks. The second six subjects were normal human volunteers in whom a mild state of zinc deficiency was induced experimentally by dietary techniques (4.2 to 5.6 mg daily zinc intake). For the assay of 5'NT, intact lymphocytes were incubated with 8-14C-labeled inosine monophosphate as substrate. Product and substrate were separated by thin-layer chromatography. Zinc level in cells was measured by flameless atomic absorption technique. In the first group of subjects with zinc deficiency, the decreased activity of 5'NT was corrected and the cellular zinc levels were normalized by oral zinc supplementation (p less than 0.01). In the second group of subjects, the baseline data were compared with those in early zinc depletion (4 to 8 weeks) and late depletion periods (greater than 20 weeks). A decrease in the activity of 5'NT was observed during the early zinc depletion phase. Zinc levels in lymphocytes, granulocytes, and platelets decreased significantly only during the late zinc depletion phase (p less than 0.01). Plasma zinc level did not change even during the late zinc depletion phase. Our studies show that 5'NT activity may be a sensitive and useful indicator of mild deficiency of zinc in human subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Zinc metabolism was studied in normal subjects and patients with the syndrome of iron deficiency anemia, hepatosplenomegaly, dwarfism, and hypogonadism. The zinc content of plasma, red blood cells, and hair was consistently decreased in the dwarfs as compared with the normal subjects. Plasma Zinc-65 disappearance curve was resolved into 5 phases; Phase I beginning with zero time and extending to 30 minutes. Phase II extending up to 60 minutes, Phase III extending up to 10 hours, Phase IV up to 7 days, and Phase V extending beyond 7 days. In the second and third phases T( 1/2 ) was shorter in dwarfs as compared with normal subjects, and the plasma zinc turnover rate was greater in dwarfs in the second phase. Twenty-four hour exchangeable zinc pool was decreased in these patients. The cumulative excretion of Zn5 in urine and stool in 13 days was decreased in dwarfs indicating body conservation in the zinc-deficient state. No evidence for cirrhosis of the liver was present. It is believed, therefore, that zinc deficiency in these dwarfs has been established. Further investigations are underway to determine whether this zinc deficiency is a primary cause of the dwarfism and hypogonadism or whether these are concomitant manifestations of a more fundamental metabolic defect. Poor diet, blood loss from parasitic infestations such as hookworm and schistosomiasis (which causes not only iron deficiency but also zinc deficiency since red blood cells are rich in zinc as well), and loss through sweating in tropical climate, are possible factors responsible for iron and zinc deficiency in such patients.
Article
We present here a 13-year-old boy with partial growth hormone deficiency due to chronic mild zinc deficiency. When zinc administration was started, his growth rate, growth hormone levels, and plasma zinc concentrations increased significantly. His poor dietary intake resulted in chronic mild zinc deficiency, which in turn could be the cause of a further loss of appetite and growth retardation. There was also a possibility of renal zinc wasting which may have contributed to zinc deficiency. Zinc deficiency should be carefully ruled out in patients with growth retardation.
Article
The result of the hormone concentration of one blood sample was used to determine the accuracy of predicting not only the hormone concentrations of a second and third sample drawn 15 minutes apart, but also the mean value of the three samples. Three blood specimens from 73 men involved in two previously reported studies (A and B) were assayed individually for luteinizing hormone, follicle-stimulating hormone, prolactin, testosterone, androstenedione, dehydroepiandrosterone sulfate, estradiol, and cortisol. The predictive correlation of one single hormone value, when compared with the mean of three values, was 0.90 or greater, except for prolactin in study A (0.86) and testosterone in study B (0.86). Since the hormone level obtained for one sample has such a high predictive value for the hormone levels of the other two samples, drawing more than one sample is redundant.
Article
A semipurified diet based on soy protein was developed to induce mild zinc deficiency in five male volunteers. Each of seven daily menus provided (mean +/- SD) 2248 +/- 128 kcal, 56.6 +/- 5.7 protein, 261 +/- 30 g carbohydrate, 110 +/- 21 g fat, 8.5 +/- 1.4 g fiber, and 4.8 +/- 1.3 mg zinc. The analytical value for phytate:zinc molar ratio was 21 +/- 9. One subject, who received five of the menus for 28 wk, lost approximately 200 mg body zinc and 7% weight; zinc concentration declined 25% in plasma, 30% in lymphocytes, and 55% in neutrophils. This dietary model allowed simple formulation of new menus for subjects in diverse states of health. It caused no ill effects after prolonged consumption, and all deficiency symptoms were reversed by zinc supplementation of 30 mg/d for 20 wk. With simple manipulation, this dietary model may be used safely for gradual induction of zinc and/or other micronutrient deficiencies in humans.
Article
Plasma zinc and pituitary and testicular hormone concentrations were measured in two groups of male adolescents. One group comprised insulin-dependent diabetes mellitus patients, aged 14-19 years; the other, as control, included 12 healthy youngsters aged 13-19 years. Plasma concentration of zinc, prolactin, testosterone, and dihydrotestosterone were lower in diabetics than in controls, whereas the ratios of androstenedione and androstenedione to testosterone + dihydrotestosterone were higher. Plasma FSH and LH were normal. These results suggest a diminished conversion of androstenedione to testosterone and relate zinc with the 17-beta-hydroxysteroid dehydrogenase enzyme activity.
Article
This study explores the effects of several divalent metal ions on the in vitro production of cyclic AMP, cyclic GMP, and testosterone by rat testicular tissue and on the amount of binding of [125I]human chorionic gonadotropin (hCG) in the testis. Zn2+ at concentrations of 10(-6) to 10(-4) M enhanced the hCG-stimulated production of cyclic AMP and testosterone, but only in the presence of Ca2+ X [125I]hCG binding to rat testicular tissue was not affected by Zn2+ X Cu2+, Ni2+, Co2+, and Mn2+ did not increase cyclic AMP or testosterone production in concentrations of 10(-7) to 10(-3) M and even inhibited them at a high concentration (10(-2) M). Cyclic GMP production was not affected by these divalent ions. These results suggest that Zn2+ may play an important role in rat testicular steroidogenesis.
Article
Hypogonadism is a major manifestation of zinc deficiency in humans and animals, but the mechanisms responsible for this hypogonadism are unclear. We evaluated the pituitary gonadal axis of zinc-deficient rats with basal testosterone, follicle-stimulating hormone, and luteinizing hormone measurements and both luteinizing hormone releasing hormone (GnRH) and human chorionic gonadotropin (HCG) stimulation tests, and we utilized pair-fed (isocalorically fed to zinc deficient), weight-restricted (fed to weigh the same as zinc deficient), and ad libitum-fed controls. Basal testosterone levels were significantly decreased in rats with zinc deficiency (0.6 +/- 0.2 ng/ml) and weight-restricted rats (0.6 +/- 0.1 ng/ml) compared with pair-fed rats (1.2 +/- 0.2 ng/ml) and ad libitum-fed rats (1.6 +/- 0.2 ng/ml, p less than 0.01). Appropriate pituitary response to GnRH were noted in each group of rats. In a final study, zinc-deficient and weight-restricted rats were given injections of 1 U HCG for 5 days. Weight-restricted rats demonstrated a highly significant increase in stimulated testosterone (7.6 +/- 0.9 ng/ml) compared with zinc-deficient rats (2.1 +/- 0.3 ng/ml, p less than 0.0005). We conclude: (1) hypogonadism occurs in both zinc-deficient and weight-restricted rats compared with pair-fed and ad libitum-fed controls; (2) pituitary reserve is intact in zinc-deficient rats; (3) HCG stimulation demonstrates Leydig cell failure in zinc-deficient but not weight-restricted hypogonadal rats; and (4) the hypogonadism in zinc-deficient rats results mainly from Leydig cell failure.
Article
A cross-sectional study on 220 men, aged 41-93 yr, was conducted to determine whether age-related changes in circulating pituitary and gonadal hormone levels are related to quantitatively assessed changes in sexuality over this age span. The conclusion of most previous studies, that total and free plasma testosterone (T) levels decline with advancing age as gonadotropins increase, was corroborated. These changes were found to roughly parallel a decline in sexual function affecting the level of sexual activity, libido, and potency measures. PRL and estradiol did not change with age, and the age-related decline in free T was greater than that in total T. Decreases in free T and increases in LH manifested significant, but small, correlations with sexual hypofunction. Behavioral variables were also clearly related to LH and to the ratio of free T to LH and estradiol. The data also suggested that aging and hormonal changes were more strongly related to sexual activity and nocturnal erections that to libido (enjoyment, drive, and thoughts). Partial correlation procedures demonstrated that diseases and drugs were not responsible for the hormone-behavior relationships. Declining androgen levels, reduced sexual activity, and decreased sexual interest thus appear to be related sequelae of the aging process in men. Hormonal factors do not completely account for age-related changes in sexuality, although the full explanation of these changes must include a consideration of hormonal factors.
Article
13 short children aged 7-13 years who had a retarded bone age and low hair zinc concentration (under 140 micrograms/g) were treated with oral zinc supplements for a year. There was a significant increase in the growth rate in the children whose hair zinc concentration increased. Growth hormone, testosterone and somatomedin C also increased after oral zinc supplementation. Data from 755 short healthy children who have attended our Growth Clinic are presented which describe their hair and serum zinc concentration at different ages. The data indicate a decline in hair zinc concentration after birth with a gradual increase at age 4-6 years, finally reaching adult normal levels after adolescence.
Article
Dietary zinc intake was restricted (2.7 to 5.0 mg daily) for 24 to 40 weeks in five male volunteers. Their mean age was 57 years. Oligospermia (total sperm count less than 40 million per ejaculate) was induced in four out of five subjects. A decrease in the sperm count occurred during zinc restricion and the early phase of zinc repletion before body stores of zinc were restored to normal. The duration of oligospermia in the four subjects ranged from 6 to 14 months. Oligospermia was reversed after zinc supplementation in physiologic amounts. The baseline sperm concentration and total sperm count per ejaculate in all five subjects dropped significantly (p < 0.05) after zinc restriction and returned to normal 6 to 12 months after zinc supplementation. The decrease in sperm count coincided with decline in Leydig cell function and was reversed after zinc supplementation in low doses. Our study has demonstrated that dietary restriction of zinc can affect testicular function adversely. This effect of zinc deficiency, however, is a reversible process and can be corrected by proper supplementation with zinc.
Article
Previously, we have documented primary testicular failure in adult male subjects with sickle cell anemia. We have also reported the occurrence of zinc deficiency and suggested that androgen deficiency may be related to zinc deficiency in such patients. In this study, we present data with respect to the efferent of oral zinc supplementation on serum testosterone levels in adult male patients with sickle cell anemia. An increase in serum testosterone, neutrophil zinc, and neutrophil alkaline phosphatase activity ws observed in the zinc-supplemented group in comparison with the group on placebo. Additionally, body weight increased and serum lactic dehydrogenase activity decrease in response to zinc supplementation. We conclude that androgen deficiency in adult male subjects with sickle cell anemia is correctable with zinc supplementation and that the determination of neutrophil zinc and alkaline phosphatase activity in the neutrophils may be utilized as good indicators of body zinc status in such subjects.
Article
Zinc deficiency may account for the persistence of gonadal dysfunction in a majority of uremic men despite adequate dialysis. Twenty stable patients having hemodialysis three times a week completed a double-blind trial using either 50 mg of elemental zinc as zinc acetate (10 patients) or placebo (10 patients), orally. At the end of the 6-month study period, a significant increase in the mean (+/- SE) plasma zinc (75 +/- 2 micrograms/dL to 100 +/- 2 micrograms/dL, p less than 0.001), serum testosterone (2.8 +/- 0.3 ng/dL to 5.2 +/- 0.5 ng/mL, p less than 0.001), and sperm count (30 +/- 3 million/mL to 63 +/- 5 million/mL, p less than 0.001) occurred in the zinc-treated group, but not in those receiving the placebo. The zinc-treated group also had a significant fall in serum luteinizing hormone (92 +2- 10 mIU/mL to 49 +/- 26 mIU/mL, p less than 0.005) and follicle stimulating hormone (45 +/- 9 mIU/mL to 25 +/- 7 mIU/mL, p less than 0.05), not seen in the placebo group. Patients receiving zinc had an improvement in potency, libido, and frequency of intercourse not found in the placebo group. These results suggest that zinc deficiency is a reversible cause of gonadal dysfunction in patients having regular hemodialysis.
Article
Zinc levels were measured in hair and serum of boys with constitutional growth delay and familial short status and in several boys before and after oral administration of methyltestosterone. These results show the following: (1) zinc levels in boys beyond stage 3 of genital development are significantly higher than in stage 1 and 2; (2) there is a linear relationship between zinc levels and serum testosterone concentration (up to 250 ng/dL); and (3) methyltestosterone administration raised the zinc concentration in serum and hair, especially in boys with constitutional growth delay. Therefore, increased endogenous production or exogenous supply of testosterone are associated with increased zinc levels. We speculate that the relative testosterone deficiency and hypogonadotropism seen in constitutional growth delay may result in decreased zinc levels, which in turn could cause a further delay in the appearance of secondary sexual characteristics and greater growth retardation.
Article
The effects of zinc therapy on plasma testosterone (T), dihydrotestosterone (DHT), and sperm count were studied in 37 patients with idiopathic infertility of more than five years duration. In the first group (T less than 4.8 ng/ml; 22 patients), T and DHT rose significantly after oral administration of zinc, as did the sperm count. Nine wives became pregnant, six within 3 months and three within 2 months of a second trial. In the second group (T greater than or equal to 4.8 ng/ml; 15 patients), T and sperm count were unaffected by zinc, while DHT increased significantly. There was no conception observed. The rationale of this treatment and the significance of the results are discussed.
Article
The effects of dietary zinc deficiency on testicular development in young Merino rams (initial live mass, 22 kg) were tested. Four groups of five rams were fed ad libitum with diets containing 4, 10, 17 or 27 micrograms Zn g-1. To control the effects of loss of appetite caused by zinc deficiency, a fifth group (pair-fed control) was fed the diet containing 27 micrograms Zn g-1, but the amount of feed offered was restricted to that eaten voluntarily by the zinc deficient (4 micrograms Zn g-1) rams they were paired with. After 96 days on the diets, epididymal and testicular masses did not differ significantly between the animals fed 10, 17 or 27 micrograms Zn g-1 ad libitum, but were significantly lower in pair-fed controls, and lowest in the zinc-deficient animals. Testicular responsiveness to LH, as measured by testosterone production, increased substantially in most rams as the experiment progressed, the only exception being the zinc-deficient group, in which the response to LH was lower than in any of the other groups. Testicular concentrations of zinc and testosterone were lower in the zinc-deficient animals than in all the other groups. Plasma inhibin concentrations fell as the experiment progressed in rams fed 17 and 27 micrograms Zn g-1 ad libitum, but not in the other groups. The pair-fed control rams had smaller seminiferous tubules and less lumen development than did the controls fed ad libitum (27 micrograms Zn g-1), which were similar to the animals fed 10 or 17 micrograms Zn g-1. In zinc-deficient rams, the tubule development was further retarded and the interstitial regions were more extensive than in the other groups. We conclude that the overall effect of zinc deficiency on testicular development is due to a combination of a non-specific effect (low gonadotrophin concentrations caused by the low feed intake) and a specific effect due to the lack of zinc. The zinc-specific effect is localized within the testis where it reduces the development of the capacity to produce testosterone, leading to low intratesticular concentrations of testosterone, a critical factor for the growth, development and function of the seminiferous tubules.
Article
Zinc is needed for growth and development, DNA synthesis, neurosensory functions, and cell-mediated immunity. Although zinc intake is reduced in elderly people, its deficiency and effects on cell-mediated immunity of the elderly have not been established. Subjects enrolled in "A Model Health Promotion and Intervention Program for Urban Middle Aged and Elderly Americans" were assessed for nutrition and zinc status. One hundred eighty healthy subjects were randomly selected for the study. Their mean dietary zinc intake was 9.06 mg/day, whereas the recommended dietary allowance is 15 mg/day. Plasma zinc was normal, but zinc in granulocytes and lymphocytes were decreased compared with younger control subjects. Of 118 elderly subjects in whom zinc levels in both granulocytes and lymphocytes were available, 36 had deficient levels. Plasma copper was increased, and interleukin 1 (IL-1) production was significantly decreased. Reduced response to the skin-test antigen panel and decreased taste acuity were observed. Thirteen elderly zinc-deficient subjects were supplemented with zinc, and various variables were assessed before and after zinc supplementation. Zinc supplementation corrected zinc deficiency and normalized plasma copper levels. Serum thymulin activity, IL-1 production, and lymphocyte ecto-5'-nucleotidase increased significantly after supplementation. Improvement in response to skin-test antigens and taste acuity was observed after zinc supplementation. A mild zinc deficiency appears to be a significant clinical problem in free-living elderly people.