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Inhibitory effect of nuts on iron absorption1'2
Abstract
The effects on iron absorption of nuts, an important source of dietary protein in many developing countries, were measured in 137 Indian women. When the absorption from bread and nut meals (walnuts, almonds, peanuts, and hazelnuts) was compared with that from bread meals, the overall geometric mean absorption from the nut meals (1.8%) was significantly less than from the bread meals alone (6.6%, t = 9.8, p less than 0.0005). In contrast, coconut did not reduce absorption significantly. All the nuts tested contained significant amounts of two known inhibitors of Fe absorption (phytates and polyphenols) but the amounts in coconut were significantly less than in the other nuts. Fifty milligrams ascorbic acid overcame the inhibitory effects of two nuts that were tested (Brazil nuts and peanuts). This is different from that found previously for soy protein, another potent inhibitor of Fe absorption.
... Table 2 shows the phytate content of various plant foods. Nuts and grain-based foods contain rather large amounts of phytate, in contrast to coconut, corn, strawberries, and polished rice that have rather small amounts [46][47][48][49]. On the other hand, grains provide an acid load (Table 1) [45]. ...
... Phytate content of different plant foods (derived from[46][47][48][49]). ...
This paper is a synopsis of an invited lecture entitled, The Future of Renal Nutrition, that was presented at the Japanese Society of Dialysis Therapy, July 2022. The purpose of this presentation is to suggest some of the advances in the field of renal nutrition that the authors think are likely to occur during the next several years. There will be continued development of methods for precisely diagnosing and classifying protein-energy wasting and developing methods to treat this disorder. Why weight loss commonly occurs when the GFR decreases to about 30–35 mL/min/1.73 m2 and why substantial weight loss (>5%/year) is associated with increased mortality will be investigated. Clinical consequences of the interactions between gut microbiota, nutrient intake and other environmental influences will continue to be examined. The clinical value of diets high in fruits and vegetables or other plants for chronic kidney disease (CKD) patients will continue to be studied. Our knowledge of how different diets and medicines affect intestinal absorption, metabolism and excretion of nutrients will expand. Precision medicine will be extended to precision nutrition. There will be more focus on the effects of nutritional disorders and dietary treatment on the emotional status and quality of life of people with kidney disease and their families. Nutritional centers that provide centralized nutritional assessment and dietary counselling for CKD patients may develop in more urban centers. More clinical trials will be conducted to test whether nutritional management improves clinical outcomes in people with kidney disease. It is hoped that the foregoing comments will encourage more research on these topics.
... They function as antioxidants (selenium), biocatalyst (copper and zinc), functions as a co-factor of many enzymes, synthesis of biomolecules, maintenance of electrical potential (magnesium, potassium, sodium), and healthy central nervous system; strong teeth and bone formation, as well as playing crucial function in blood formation and prevention Vitamin A is important for vision, cell growth and differentiation, normal formation and maintainance of body organs, B complex are needed for building strong immune system, reproductive hormones, metabolism of food and regulating body stress while vitamin C and E are important water and lipid soluble antioxidant vitamins respectively (Ross, 2006;2010;Solomons, 2006;Mirbagheri, et al., 2008). Phytate (1.03, 0.08 mg/g), oxalate (1.17, 0.45 mg/g) and tannins (2.34, 1.45 mg/g) were detected in higher concentrations in B. alba than S. bifrae but the values were low compared to the reported values for some common food commodities (Gordan et al., 1984;Macfarlane et al., 1988;USDA, 2011 (Phillippy et al., 2002;Macfarlane et al., 1988;Gordan et al., 1984). The nutritional qualities of the leaves cannot be underestimated as indicated by the presence of minerals and vitamins, their regular consumption can play important roles in promoting good health. ...
... They function as antioxidants (selenium), biocatalyst (copper and zinc), functions as a co-factor of many enzymes, synthesis of biomolecules, maintenance of electrical potential (magnesium, potassium, sodium), and healthy central nervous system; strong teeth and bone formation, as well as playing crucial function in blood formation and prevention Vitamin A is important for vision, cell growth and differentiation, normal formation and maintainance of body organs, B complex are needed for building strong immune system, reproductive hormones, metabolism of food and regulating body stress while vitamin C and E are important water and lipid soluble antioxidant vitamins respectively (Ross, 2006;2010;Solomons, 2006;Mirbagheri, et al., 2008). Phytate (1.03, 0.08 mg/g), oxalate (1.17, 0.45 mg/g) and tannins (2.34, 1.45 mg/g) were detected in higher concentrations in B. alba than S. bifrae but the values were low compared to the reported values for some common food commodities (Gordan et al., 1984;Macfarlane et al., 1988;USDA, 2011 (Phillippy et al., 2002;Macfarlane et al., 1988;Gordan et al., 1984). The nutritional qualities of the leaves cannot be underestimated as indicated by the presence of minerals and vitamins, their regular consumption can play important roles in promoting good health. ...
p>The proximate, mineral and anti-nutritional compositions of Basella alba and Senecio biafrae were determined. The vegetables were also screened for phytochemicals and the polyphenols present in them analyzed using reverse-phase high performance liquid chromatography . The results of proximate in % were: moisture (11.75, 12.24), crude protein (19.22, 20.17), ash (20.95, 21.48), total dietary fibre (16.57, 22.51), crude fat (10.49, 13.34) and carbohydrate (21.02, 10.26). Dietary minerals were present in appreciable quantities: sodium (660, 300), potassium (7800, 1430), calcium (1050, 1150), magnesium (350, 310), zinc (41, 34), copper (0.10, 1.80), iron (1.40, 2.00), and phosphorus (20.50, 13.40) in mg/100g respectively. Lead was not detected in Basella alba but in trace amount in Senecio biafrae (0.002). Vitamins in µg/g were: vitamin A (13.21, 9.78), thiamine (315.22, 315.22), ascorbic acid (14.86, 9.85) and tocopherol (49.89, 192.38). Amino acid profile of the two vegetables showed appreciable essential: histidine (2.14, 2.27), isoleucine (3.01, 3.43), leucine (7.75, 8.85), lysine (2.92, 4.62), methionine (0.89, 0.99), phenylalanine (3.88, 4.22), threonine (2.84, 3.15) and non essential amino acids: valine (3.13, 3.71), arginine (3.97, 4.49), aspartic acid (7.32, 8.28), serine (2.09, 2.22), glutamic acid (10.15, 10.83), proline (2.24, 2.65), glycine (3.07, 3.56), alanine (3.49, 4.03), cysteine (0.79, 0.86), tryosine (2.22, 2.70). Antinutrient factors present in mg/g were: tannin (2.34, 1.45), oxalate (1.17, 0.45) and phytate (1.03, 0.08). Caffeic acid was, most aboundant phenolic acid in both vegetables (32.74, 37.51); and their flavonoid compositions were similar except for catechin which was lacking in Senecio biafrae. The nutritional and nutraceutical potential of both vegetables are good and could be exploited to promote health.
Bangladesh J. Sci. Ind. Res . 52(3) , 201-208, 2017</p
... Vegan diets contain phytate and other factors found in soy protein and other legumes (57-59), nuts (60), and whole grains that inhibit iron absorption. Subjects do not appear to adapt to increased levels of dietary phytate (48), although some adaptation to diets with low iron bioavailability does occur (61). ...
... Ascorbic acid and other dietary factors can promote iron absorption even in the presence of phytates (53,60,(62)(63)(64). Iron bioavailability from soy foods is variable with iron absorption from tempeh and miso being superior to that from soy flour and tofu (65). ...
This article reviews research on the growth and nutrient intake of vegan children and provides guidelines for counselling parents of vegan children. Although diets of vegan children meet or exceed recommendations for most nutrients, and vegan children have higher intakes of fiber and lower intakes of total fat, saturated fat, and cholesterol than omnivore children, some studies indicate that they may be low in calcium. In addition, bioavailability of zinc and iron from plant foods can be low. Protein needs are slightly higher for vegan children but are easily met with a varied diet that provides adequate energy. Special attention should be given to dietary practices that enhance absorption of zinc and iron from plant foods. Further, good sources of the omega-3 fatty acid linolenic acid should be emphasized to enhance synthesis of the long-chain fatty acid docosahexanoic acid. Dietetics professionals who counsel vegan families should help parents identify good sources of vitamin B-12, riboflavin, zinc, calcium and, if sun exposure is not adequate, vitamin D. This should not be problematic, due to the growing number and availability of fortified vegan foods that can help children meet all nutrient needs. Therefore, with appropriate food choices, vegan diets can be adequate for children at all ages.
... Phytic acid can be reacted with two or polyvalent minerals (such as zinc and iron) material obtained from this reaction non-digestible in the digestive tract so this reaction is important in terms of diet [16][17][18][19]. ...
ABSTRACT: In most societies, rich and important source of food considered bread. Some bakeries using sodium bicarbonate as baking soda and extra salt in bread production that his chemical compounds has adverse effects on the public health. That's why in this study we decided to evaluation of produced bread in Qazvin province in terms of sodium bicarbonate and salt. Assessment of pH and salt take place according to Institute of Standards and Industrial Research of Iran (IRIS). Our Results demonstrated the mean±SD of pH for sangak, lavash, taftun, barbari and baguette 5.95±0.37, 5.76±0.54, 5.80±0.71, 6.10±0.68 and 7.86±1.26 respectively, and the mean±SD of salt 1.10±0.47, 1.41±0.57, 1.45±0.36, 1.40±0.32 and 1.55±1.09 respectively and the results demonstrated the value of pH and salt in the samples 65.77% (98 out of 149) and 12.75% (130 out of 149) respectively, out of standard range. Baking Soda in sangak breads and salt in baguette breads, more common of other breads. Although the Ministry of Health has banned officially the use of baking soda in breads production process, but demonstrated in this study baking soda and extra salt used in the process of breads production. Thus require more supervision and training on the non-use of sodium bicarbonate for bakers its necessary.
... Although the consumption of nuts is also a suggestion of the health authorities to face the worldwide obesity and overweight (World Health Organization, 2018), it has to be taken into account that they contain compounds which can prevent some nutrients absorption, such as iron due to the presence of phytates, compromising mineral bio-availability (Macfarlane et al., 1988). Other anti-nutritional factors of nuts are saponins, tannins and oxalates (Nalini and Kapoor, 1999). ...
Pistachio powder was added to flour or semolina to evaluate its contribution to increase the amount of lysine in bread. Bread production was carried out by sourdough technology using a selected 3-species (Lactobacillus sanfranciscensis/Leuconostoc citreum/Weissella cibaria) lactic acid bacterial (LAB) starter culture. All sourdoughs were subjected to a long-time fermentation (21 h) and showed levels of LAB around 109 CFU/g, indicating the suitability of pistachio powder for lactic fermentation. Yeasts were also detected, in particular in semolina trials. MiSeq Illumina technology was applied to investigate the bacterial composition of sourdoughs evidencing a different distribution of LAB species among the trials with Lactobacillus as major LAB group in almost all sourdoughs. Physicochemical parameters were comparable among the trials. After baking, pistachio powder was found not to influence the height of the breads, but pistachio breads were more firm than control breads. Color of the breads, void fraction and cell density, were influenced by pistachio powder. The amount of lysine increased consistently thanks to pistachio supplementation which also determined a higher presence of o-xylene, p-cymene and limonene and the appearance of α-pinene and 1-octen-3-ol in breads. Sensory tests showed the best appreciation scores for the breads produced with flour and pistachio powder.
... We hypothesized that a Mediterranean diet with limited intakes of red and processed meat, an important supply of bioavailable iron (13), together with a higher consumption of whole-grain cereals and nuts containing phytate, which inhibits iron absorption (14,15), would result in lower iron status. Conversely, higher intakes of fish, a good source of selenium (16,17), could increase selenium status. ...
Background:
Mediterranean diets limit red meat consumption and increase intakes of high-phytate foods, a combination that could reduce iron status. Conversely, higher intakes of fish, a good source of selenium, could increase selenium status.
Objectives:
A 1-y randomized controlled trial [New Dietary Strategies Addressing the Specific Needs of the Elderly Population for Healthy Aging in Europe (NU-AGE)] was carried out in older Europeans to investigate the effects of consuming a Mediterranean-style diet on indices of inflammation and changes in nutritional status.
Methods:
Selenium and iron intakes and status biomarkers were measured at baseline and after 1 y in 1294 people aged 65-79 y from 5 European countries (France, Italy, the Netherlands, Poland, and the United Kingdom) who had been randomly allocated either to a Mediterranean-style diet or to remain on their habitual, Western diet.
Results:
Estimated selenium intakes increased significantly with the intervention group (P < 0.01), but were not accompanied by changes in serum selenium concentrations. Iron intakes also increased (P < 0.001), but there was no change in iron status. However, when stratified by study center, there were positive effects of the intervention on iron status for serum ferritin for participants in Italy (P = 0.04) and France (P = 0.04) and on soluble transferrin receptor (sTfR) for participants in Poland (P < 0.01). Meat intake decreased and fish intake increased to a greater degree in the intervention group, relative to the controls (P < 0.01 for both), but the overall effects of the intervention on meat and fish intakes were mainly driven by data from Poland and France. Changes in serum selenium in the intervention group were associated with greater changes in serum ferritin (P = 0.01) and body iron (P = 0.01), but not sTfR (P = 0.73); there were no study center × selenium status interactions for the iron biomarkers.
Conclusions:
Consuming a Mediterranean-style diet for 1 y had no overall effect on iron or selenium status, although there were positive effects on biomarkers of iron status in some countries. The NU-AGE trial was registered at clinicaltrials.gov as NCT01754012.
... The safe limit of phytate in food thus depends on the availability of these nutrients the food. The levels of phytate in all the investigated vegetables are however much lower than the reports for cereals, beans and nuts [39,40,41,42]. Oxalate is a dianion that is synthesized in plants by the incomplete oxidation of carbohydrates. ...
... Finally, a comparison between the phytate content in different foods is shown in Fig. 2 (Harland, Smikle-Williams, & Oberleas, 2004;Macfarlane et al., 1988;Ravindran, Ravindran, & Sivalogan, 1994). As it is seen, the phytic acid content of walnuts (around 11 mg/g, Catalonia walnuts in present experiment) is in the middle range of the selected food and nuts (2-36 mg/g). ...
Bioactive compounds phytic acid (IP6) and pyrophosphate (PPi) are minor components of walnuts with the ability of being inhibitors of urolithiasis, among others. Since simultaneous analysis of IP6 and PPi have known drawbacks, a new method to determine their content in walnuts has been developed with emphasis on their extraction from walnuts by microwave-assisted extraction (MAE). Acid content of extracting solvent, extraction time and temperature were optimized. After extraction, compounds were purified by selective adsorption/desorption on an anion exchange solid phase extraction and analyzed by inductive coupled plasma/mass spectrometry. A mixture of H2SO4 and HCl as solvent to extract both, IP6 and PPi, provided results slightly higher than those determined by conventional extraction with no statistical difference. The possible hydrolysis of phytic acid by MAE was analyzed. Compared with the conventional acid extraction method, significant improvement is achieved by the MAE method reducing extraction time from 3h to 10 min.
... In one of the few studies performed in this sense, it has been reported that calyces of Hibiscus sabdariffa L. (accompanying the fruits) have a relatively high iron content (800-833 mg/kg) and only traces of tannins and phytic acid [179]. A few other studies have tested specifically the effects of polyphenols or other phytochemicals from algae [180], beans [98,156,161,181], cereals [182][183][184][185], nuts [186], a few herbal teas [187] or other plant products [188] on iron bioavailability, but have not simultaneously measured the amounts of iron and polyphenols (and possible correlations thereof). A few such studies where iron and other trace elements were measured simultaneously with polyphenols in a few plant species have been published so far, but they were not specifically focused on investigating the relationship between the two chemical entities (and have not tested correlations between them) [189][190][191][192][193][194]. ...
Iron is an essential mineral nutrient for all living organisms, involved in a plurality of biological processes. Its deficit is the cause of the most common form of anemia in the world: iron deficiency anemia (IDA). This paper reviews iron content in various parts of 1228 plant species and its absorption from herbal products, based on data collected from the literature in a semi-systematic manner. Five hundred genera randomly selected from the Angiosperms group, 215 genera from the Pteridophytes groups and all 95 Gymnosperm genera as listed in the Plant List version 1.1 were used as keywords together with the word “iron” in computerized searches. Iron data about additional genera returned by those searches were extracted and included in the analysis. In total, iron content values for a number of 1228 species, 5 subspecies, and 5 varieties were collected. Descriptive and inferential statistics were used to compare iron contents in various plant parts (whole plant, roots, stems, shoots, leaves, aerial parts, flowers, fruits, seeds, wood, bark, other parts) and exploratory analyses by taxonomic groups and life-forms were carried out. The absorption and potential relevance of herbal iron for iron supplementation are discussed.
... However, functionally the two nutrients are linked because vitamin C is important in iron ingestion and metabolism, and a decrease in vitamin C would leads to a reduction in the physiological bioavailability of iron (Prom-U-Thai 2006). Addition of vitamin C to the diet reduces the chelating efffect of phytates on iron metabolism (Macfarlane et al. 1988). ...
Hereditary hemochromatosis is caused by a potentially lethal recessive gene (HFE, C282Y allele) that increases iron absorption and reaches polymorphic levels in northern European populations. Because persons carrying the allele absorb iron more readily than do noncarriers, it has often been suggested that HFE is an adaptation to anemia. We hypothesize positive selection for HFE began during or after the European Neolithic with the adoption of an iron-deficient high-grain and dairying diet and consequent anemia, a finding confirmed in Neolithic and later European skeletons. HFE frequency compared with rate of lactase persistence in Eurasia yields a positive linear correlation coeffficient of 0.86. We suggest this is just one of many mutations that became common after the adoption of agriculture.
... Other known inhibitors of non-haem iron absorption such as soy protein (Hurrell, Juillerat et al. 1992) , nuts (Macfarlane, Bezwoda et al. 1988) would not have been present in sufficient amounts in the diets of schoolgirls to have any noticeable effect on the main predictive factors in our model. ...
Project Report to Food Standards Agency
... (Adeyeye et al., 2000; Adeyeye and Fagbohun, 2005; Aletor et al., 2007; Aletor, 1995; Al-Wahsh et al., 2005; Amrein et al., 2003; Atukorala and Waidyanatha, 1987; Becker et al., 1981; Beleia et al., 1990; Bhatty and Cherdkiatgumchai, 1990; Bieleski et al., 1997; Bressani et al., 2002; Calhoun et al., 1958; Calhoun et al., 1960; Camire and Clydesdale, 1982; Carlavilla et al., 2006; Cataldi et al., 1998; Chan et al., 2007; Chen, 2004 Fredlund et al., 1997; Gao et al., 2007; Garcia-Estepa et al., 1999; García Estepa et al., 1999; Greiner et al., 2001; Haraldsson et al., 2004; Harland and Frolich, 1989; Harland and Oberleas, 1987; Harland et al., 2004; Helfrich and Bettmer, 2004; Hooda and Jood, 2003; Horbowicz and Obendorf, 1994; Ikawa et al., 1968; Isiguro et al., 2005; Jährig et al., 2000; Kirby and Nelson, 1988; Koziol, 1992; Le Francois, 1988; Lee, 1990; Lehrfeld, 2002; Lestienne et al., 2005; Liu and Chang, 2004; Lolas et al., 1976; Lorenz and Wright, 1984; Lott et al., 2000; Ma et al., 2005; Macfarlane et al., 1988; Mameesh and Tomar, 1993; Masuda et al., 2003; Matsunaga et al., 1989; Mckenzie, 1984; Mckenzie-Parnell and Guthrie, 1986; Michalska et al., 2007; Morris and Hill, 1995; Morris and Hill, 1996; Nayini and Markakis, 1983; Ola and Oboh, 2001; Olguin et al., 2003; Oomah et al., 1996; Oyetayo and Akindahunsi, 2004; Pattee et al., 2000; Phillippy et al., 2003; Phillippy et al., 1988; Phillippy and Wyatt, 2001; Plaami and Kumpulainen, 1995; Pradeep et al., 1993; Proskova, 1998; Ramirez-Cardenas et al., 2008; Ravindran et al., 1994; Repo-Carrasco Valencia et al., 2009; Sanz et al., 2004; Schweizer et al., 1978; Scriban, 1970; Seifert, 1972; Simonet et al., 2003; Somsub et al., 2008; Soria et al., 2009; Sosulski et al., 1982; Souci et al., Khan, 1998; Thompson and Erdman Jr., 1982; Toda et al., 2006; Trugo et al., 1999; Udosen and Ukpanah, 1993; Umeta et al., 2005; Valencia et al., 1999; Venkatachalam and Sathe, 2006; Vitali et al., 2008; Yadav and Sehgal, 2003) ...
... Six other published articles using several different assays and standards measured free polyphenols in raw nuts and four used Folin assays. [37][38][39][40][41][42] Walnuts ranked first in 3/4 studies that used Folin and first in the two studies that used a FRAP antioxidant assay. Walnuts were first in both free and total polyphenols in the study that did a hydrolysis. ...
Free and total (after basic hydrolysis) polyphenols in nine types of raw and roasted nuts and two types of peanut butter (54 commercial samples) were analyzed after methanol extraction by a single step Folin-Ciocalteu reagent using catechin as standard. Walnuts had the highest free and total polyphenols in both the combined raw and roasted samples. Total polyphenols in the nuts were significantly higher than free polyphenols. Roasting had little effect on either free or total polyphenols in nuts. Raw and roasted walnuts had the highest total polyphenols. The efficacy of raw and roasted nut antioxidants was assessed by measuring the ability of the free polyphenol nut extracts to inhibit the oxidation of lower density lipoproteins (LDL + VLDL). A nut polyphenol, catechin, was measured after binding of three nut extracts to lower density lipoproteins. Walnut polyphenols had the best efficacy among the nuts and also the highest lipoprotein-bound antioxidant activity. Based on USDA availability data, the per capita total polyphenols was 162 mg from nuts per day in 2008. This corresponds to 19% of the total polyphenols from fruits and vegetables, nuts, grains, oils and spices in the US diet. Nuts provided 158 mg of polyphenols per day to the European Union diet. Nuts are high in polyphenol antioxidants which by binding to lipoproteins would inhibit oxidative processes that lead to atherosclerosis in vivo. In human supplementation studies nuts have been shown to improve the lipid profile, increase endothelial function and reduce inflammation, all without causing weight gain. These qualities make nuts a nutritious healthy snack and food additive.
... When walnuts are kept in a cool, dry environment they have a shelf life of 12 months [5]. Walnuts are also a rich source of phenolic compounds [6] which contribute to their antioxidant capacity; they inhibit the oxidation of human plasma and low-density lipoproteins (LDLs) in vitro [7] and may influence the low mortality rates from coronary heart disease and cancer in Mediterranean populations as walnuts are important constituents of the daily Mediterranean diet [8] as already mentioned. In addition to the favorable lipid profile of nuts, their phenolic content must be considered as a potential contributor to their apparent antiatherogenic effect. ...
The aim of this work was to develop a capillary electrophoresis-mass spectrometry (CE-MS) method to identify and quantify phenolic and other related polar compounds in walnut samples. The extraction capacity of several solvent mixtures of phenolic compounds from walnut by conventional solid-liquid extractions was tested, and CE and electrospray ionization MS parameters were optimized. The finalized procedure is able to determine many well-known phenolic compounds present in walnuts and provide relevant information about the presence of minor polar compounds. A new compound in walnut ((2E,4E)-8-hydroxy-2,7-dimethyl-2,4-decadiene-1,10-dioic acid 6-O-beta-d-glucopiranosyl ester, [M-H](-) 403.161m/z) with a structure similar to glansreginins was also identified. Phenolic compounds correspond to 14-28% of total polar compounds quantified. Aglycone and glycosylated ellagic acid represent the principal components and account for 64-75% of total phenols in walnuts. However, the sum of glansreginins A, B and (2E,4E)-8-hydroxy-2,7-dimethyl-2,4-decadiene-1,10-dioic acid 6'-O-beta-d-glucopiranosyl ester was in the range of 72-86% of total quantified compounds. In addition, this is the first time that separation by CE with detection by electrospray ionization time-of-flight MS has been applied to the analysis of phenolic and other polar compounds in walnut samples, providing results in less than 15min.
... Several legumes 49,50 and members of the nut family reduce nonheme iron absorption. 51 Processing may be important in the case of soybean foods. A number of widely used products such as full-fat soy flour, textured soy flour, and isolated soy protein are markedly inhibitory. ...
Iron is essential for oxygen transport, oxidative metabolism, and cellular growth. Interactions between iron and other dietary factors play a significant role in determining the adequacy of iron nutrition and have important implications for food fortification in developing countries. Vitamin A and vitamin C deficiency states may affect iron transport, metabolism, and storage within the body.
... The active principal is the galloyl group found in tannic and gallic acids, but not present in chlorogenic acid . Fe absorption is reduced by foods containing these compounds, including tea (Hurrell et al. 1999), coffee (Disler et al. 1975;Morck et al. 1983) and nuts (Macfarlane et al. 1988). Phytate (myo-inositol hexaphosphate) also has a powerful inhibitory effect on Fe absorption ). ...
Fe homeostasis is considered in the context of the UK diet, using information on Fe intake and status from the National Diet and Nutrition Surveys. The importance of assessing Fe availability rather than total Fe intake is discussed. Dietary and host-related factors that determine Fe bioavailability (Fe utilised for Hb production) are reviewed using information from single-meal studies. When adaptive responses are taken into consideration, foods associated with higher Fe status include meat (haem-Fe and the 'meat factor') and fruits and fruit juice (vitamin C). Foods that may have a negative impact include dairy products (Ca), high-fibre foods (phytate) and tea and coffee (polyphenols), but the effects are more apparent in groups with marginal Fe deficiency, such as women of childbearing age. Analysis of dietary intake data on a meal-by-meal basis is needed to predict the influence of changing dietary patterns on Fe nutrition in the UK. Current information suggests that in the UK Fe deficiency is a greater problem than Fe overload.
... Nuts are a rich source of antioxidants such as vitamin E and flavonoids. Walnuts have been reported to contain more than 1500 mg/100 g flavonoids [9] and are therefore considered to have powerful antioxidant capacity. Apart from their antioxidant capacity, flavonoids also affect the haemostatic system by decreasing coagulation, platelet adhesion and aggregation, and increasing fibrinolysis [10]. ...
We investigated the effect of a high walnut and cashew diet on haemostatic variables in people with the metabolic syndrome. Factor analysis was used to determine how the haemostatic variables cluster with other components of the metabolic syndrome and multiple regression to determine possible predictors. This randomized, control, parallel, controlled-feeding trial included 68 subjects who complied with the Third National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol criteria. After a 3-week run-in following the control diet, subjects were divided into three groups receiving either walnuts or cashews (20 energy%) or a control diet for 8 weeks. The nut intervention had no significant effect on von Willebrand factor antigen, fibrinogen, factor VII coagulant activity, plasminogen activator inhibitor 1 activity, tissue plasminogen activator activity or thrombin activatable fibrinolysis inhibitor. Statistically, fibrinogen clustered with the body-mass-correlates and acute phase response factors, and factor VII coagulant activity clustered with high-density lipoprotein cholesterol (HDL-C). Tissue plasminogen activator activity, plasminogen activator inhibitor 1 activity and von Willebrand factor antigen clustered into a separate endothelial function factor. HDL-C and markers of obesity were the strongest predictors of the haemostatic variables. We conclude that high walnut and cashew diets did not influence haemostatic factors in this group of metabolic syndrome subjects. The HDL-C increase and weight loss may be the main focus of dietary intervention for the metabolic syndrome. Furthermore, diet composition may have only limited effects if weight loss is not achieved.
Nuts are nutrient-dense foods. They are good sources of plant protein, unsaturated fats, fiber, vitamins and minerals. In botanical terms, the word “nut” is used to describe a wide range of seeds, mostly from trees; however, there are some exceptions, such as peanuts that are considered a legume. Most commonly eaten nuts are almonds, Brazil nuts, cashews, hazelnuts, pecans, peanuts, pine nuts, pistachios, walnuts and macadamias. Nuts and seeds come from a diverse range of different plants (vegetables, flowers, or crops grown for a variety of uses), so their nutritional composition is quite varied. Seeds, such as pumpkin seeds, sesame and sunflower, are sources of plant protein, unsaturated fatty acids, fiber, minerals and vitamins).
Thanks to their nutrient-dense profile, nut consumption has been associated with several health benefits, such as better lipid profile (lower cholesterol and triglyceride levels) and improved endothelial function and overall cardiovascular health, a reduction of postprandial glycaemia and insulin resistance (type 2 diabetes prevention), and delay in age-related cognitive decline, among other health conditions.
Nuts and seeds have a wide range of uses. In the typical Western diet or Mediterranean diet they tend to be used either as snack or added as minor ingredients to savory and sweet dishes, but they have wider applications in vegetarian and other plant-based diets as important sources of plant protein and other nutrients. Certain nuts and seeds are also made into spreads, for example peanut butter and tahini (sesame seed spread) or vegan “cheeses” (mainly made by cashew paste).
p>1754 birth records of South Asian babies born in Southampton in the period of 1979 to 1995 were collected and analysed. Mothers with a maternal Hb level less than 9,9 g.dl, had smaller babies than mothers with higher Hb levels. Forty three percent of mothers were anaemic (Hb < 11 g/dl). Whereas 32% of term babies were born to anaemic mothers, 67% of preterm babies were born from anaemic mothers. A cohort of South Asian births from 1979 to 1985 was searched to study the birth outcome trends of female babies. The mean birth weight for the girls was 2936 g, and the mothers' mean maternal Hb level was 11.1 g/dl. Girls born to mothers with low maternal Hb level had a birth weight significantly lower than girls born to mothers with higher maternal haemoglobin levels ( P < 0.05). To explore the relationship between low maternal haemoglobin, birth weight and the iron status during adolescence, 240 South Asian girls aged 10-16 years born in Southampton, were selected at random from General Practitioners lists, of which 40 girls (16.7%) agreed to participate in the study. They were contacted and interviewed, and they completed a food frequency questionnaire (FFQ). Out of these forty girls, 28 (70%) agreed to give a blood sample for haematological analysis. Birth weight and Hb levels during adolescence were statistically significantly lower in girls born to mothers who had lower Hb levels during pregnancy. Girls born with lower birth weight had lower Hb and serum ferritin (SF) levels during adolescence than other girls ( P < 0.05). Current dietary intakes of iron 12.5 mg (SD ± 4.1), protein 73.5 g (SD ± 18.8), and vitamin C 99g (SD ± 59) in the girls measured by FFQ were not significantly related to adolescent Hb and SF levels. Despite limited number there were statistically significant associations between maternal Hb, and birthweight, and their Hb and SF levels that warrant further investigation.</p
Claims in the lay literature suggest soaking nuts enhances mineral bioavailability. Research on legumes and grains indicate soaking reduces phytate levels, however, there is no evidence to support or refute these claims for nuts. We assessed the effects of different soaking regimes on phytate and mineral concentrations of whole and chopped almonds, hazelnuts, peanuts, and walnuts. The treatments were: 1. Raw; 2. soaked for 12 hours in salt solution; 3. soaked for 4 hours in salt solution; 4. soaked for 12 hours in water. Phytate concentrations were analysed using high-performance liquid chromatography (HPLC) and minerals by inductively coupled plasma mass spectrometry (ICP-MS). Differences in phytate concentrations between treated and untreated nuts were small, ranging from -12% to +10%. Overall, soaking resulted in lower mineral concentrations, especially for chopped nuts, and did not improve phytate:mineral molar ratios. This research does not support claims that ‘activating’ nuts results in greater nutrient bioavailability.
Disorders of Iron Homeostasis affect over a billion people worldwide. These disorders can be grouped according to iron deficiency, the major cause of anemia, and iron overload, the major cause of death in patients with hemochromatosis. Anemia is managed with blood transfusions or iron supplementation, and hemochromatosis is treated with chelation and phlebotomy. These treatments are effective in many cases, but are often poorly tolerated and can take years to improve the quality of life for patients.
The present work describes a novel signaling pathway by which intestinal iron absorption can be controlled by oxygen signaling. This thesis demonstrates that during hemolytic anemia, iron absorption is increased in a HIF-2??-dependent manner, and loss of intestinal HIF-2?? inhibits hematopoietic recovery. In addition, ??-thalassemia is a genetic disorder characterized by anemia and complicated by iron overload, which is the major cause of death in patients. This is thought to be due to frequent blood transfusions required to correct anemia, but many patients develop iron overload in the absence of transfusions. Using a mouse model of the disease, this thesis shows that loss of intestinal HIF-2?? prevents iron overload. Together, these data demonstrate that intestinal HIF-2?? activity is essential for adaptive changes in iron absorption and could be targeted therapeutically to treat anemia and iron overload. Besides the intestine, the liver is also a critical sensor and regulator of iron homeostasis.
Hepcidin is an antimicrobial peptide produced in the liver which acts to restrict iron availability by blocking intestinal iron absorption and release of iron from macrophages, which recycle iron from senescent erythrocytes. Hepcidin is regulated by multiple signaling pathways, and one of the least understood regulators of hepcidin expression is hypoxia. The present work demonstrates that hypoxic repression of hepcidin requires the hypoxia-inducible transcription factors (HIFs) and is mediated by a decrease in C/EBP?? protein in the liver. Subsequently, this work shows that ethanol-mediated hepcidin repression, which exacerbates liver injury, requires HIF activity. Together, these models demonstrate that HIFs are the central regulators of iron homeostasis and can be targeted therapeutically to manage diseases of both anemia and iron overload.
Well-balanced vegetarian diets offer many health benefits including decreased risk of cardiovascular disease, cancer, and possibly type II diabetes.
In botanical terms, the word ‘nut’ is used to describe a wide range of seeds, mostly from trees, with a tough, often lignified, seed coat, or shell. True nuts include the chestnut, brazil nut, and hazelnut. In practice, these are usually classified together with certain other so-called nuts, for example the almond, cashew, and peanut, and other seeds, which are all used in similar ways in the diet. Nuts and seeds come from a diverse range of different plants, so their nutritional composition is quite varied, but like most plant seeds they contain a food reserve designed to meet the needs of the developing plant embryo. In many nuts and seeds this is fat, but in others it is starch or other polysaccharides. Therefore, these foods are concentrated sources of dietary energy, as well as sources of protein, unsaturated fatty acids, various micronutrients, and fiber (nonstarch polysaccharides (NSP)).
Background and aim: Daily bread supplies a great portion of energy, minerals and vitamins necessary for human. In recent decades, baking soda (sodium bicarbonate) which causes rapid leavening of dough, and extra salt which compensate dough deficiencies have been used widely in Iran. Soda can cause digestive problems and block the absorption of calcium, iron and other essential elements necessary for the body. Moreover the extra salt creates serious damages, especially in the patients suffering from hypertension or kidney diseases. The aim of this study was to determine the rate of soda utilization in the bakeries of Kurdistan Province, in Iran from 2008 to 2010 and to find proper ways to decrease use of soda and salt in bakeries. Materials and Methods: This was a descriptive - analytical study which was carried out between 2008 and 2010 in Kurdistan Province, in Iran. The salt percentage and pH of the samples of baked bread were measured according to the specifications and test methods of the Institute of Standard and Industrial Research, for traditional breads (Standard Number 2628). pH above 6.3 indicates presence of soda, and pH lower than this value indicates no soda in bread. Also the allowable salt percentage value is 2.3, and higher values indicate presence of extra salt. Results: The result of the tests on 2098 bread between 2008 and 2010 showed an mean pH of 6.01±0.32 for all types of bread. The mean PH values were: 6.24±0.74, 5.86±.57 and 6.00±0.26 for Barbari, Sangak and Lavash bread respectively which showed significant differences. The mean value of salt percentage was 2.19±0.26. Conclusion: In our study, the mean pH of the bread in the bakeries was in the normal range but the mean salt percentage was slightly higher than the standard value which could be due to flour quality. Despite prohibition of use of soda in baking bread ratified by Ministry of Health and Medical Education, it is still used by the bakeries, more commonly in Barbari than Sangak and Lavash bread. The use of salt is also on the rise.
The content and composition of phenolic compounds are important aspects of olive oil quality, because they affect remarkably its nutritional and organoleptic properties and its resistence to oxidation. However the analysis of these substances needs long procedures, expensive equipment and numerous standard compounds. In this work is described a simple analytical methodology for their extraction from the oil and separation into classes founded on interaction of these substances with metal ions situated in exchange places of cation exchange resins.
Eight registered Hungarian walnut cultivars were tested for composition and sensory properties. The samples were collected at the Experimental Fields of the Research Institute for Fruitgrowing and Ornamentals in Ird-Elvira major. Proximate composition, fatty acids, minerals (P, Na, Ca, Mg, Ca, Fe and Se), polyphenols and vitamins (C, E) were determined in four consecutive years 2003-2006. The tested cultivars have an oil content, which falls within the upper range of the literature values. Polyphenols, iron and selenium contents are also high while the values for potassium and phosphorus are in the lower part of the given range. In our case, the crop years make a larger difference in the composition than the cultivars. Tiszacsécsi 83 is the only cultivar slightly differing from the others in lower mineral and protein content.
Aim: To assess the effects of different amounts and choices within the meats and alternatives food group of the Australian Guide to Healthy Eating (AGHE) on the content of iron, zinc, vitamin B‐12 and long‐chain n‐3 polyunsaturated fatty acids.
Methods: Two sets of diets ranging in energy level were modelled, with constant or varying numbers of serves from meats and alternatives. Exchanges within the meats group were then conducted and the diets analysed. The main outcome measures are changes in iron, zinc, vitamin B‐12 and long‐chain n‐3 polyunsaturated fatty acid content, relative to estimated average requirements (EAR) or adequate intake in diets based on the AGHE.
Results: Diets with a single serve of food of animal origin provided substantially more iron, zinc, vitamin B‐12 and n‐3 fats than diets with a single serve of plant origin (e.g. 125–175% vs 63–111% EAR iron for women and 50–73% vs 29–48% EAR iron for pregnant women; 85–120% vs 57–63% EAR zinc for men and 101–157% vs 68–90% EAR zinc for pregnant women; 95–160% vs 75% EAR for vitamin B‐12; and 26–166% vs 0% EAR n‐3 for men). These differences were accentuated in diets with multiple serves from this food group.
Conclusion: There is a marked lack of nutritional equivalence between the foods of animal and vegetable origin that comprise the meats and alternatives food group of the AGHE. If nutritional similarity is to determine food group composition, the placement of legumes, nuts and seeds in future food guides may need to be reviewed.
Introduction Kernel Analysis Postharvest Operations Utilization Future Prospects Literature Cited
Phenolic contents of different fractions (contents of whole nut, skin and kernel) of English walnut (Juglans regia L.) were determined and their antioxidative capacities investigated using a number of in vitro model systems. Phenolic compounds extracted from walnut skin into 95% ethanol contained the highest amount of total phenolics and exhibited the highest antioxidative capacity as evaluated by the trolox equivalent antioxidant capacity assay. Extracts of walnut phenolics showed a high ferrous ion chelating ability and effectively scavenged 2,2′-diphenyl-1-picrylhydrazyl radicals, the latter considerably stronger for the skin with 50% inhibition concentration of 3.4 µg extract per mL. Further, inhibition of 2-thiobarbituric acid reactive substances formation in a bulk corn oil model system was also significant (P < 0.05) for all three phenolic extracts and for pure gallic acid at 10 ppm gallic acid equivalents final assay concentration after four days of storage at 60C.
Walnut is a healthful nut that contains alpha-linolenic acid in its lipid fraction, and its skin is rich in polyphenolics with strong antioxidant properties, as demonstrated in this study. Thus, walnut with skin and skin of walnuts serve as good free radical scavengers and could be effective in reducing oxidative stress among other beneficial health effects, which could be exploited for product development.
Epidemiologic studies have found a relation between body iron stores and risk of chronic disease. Iron-absorption studies from single meals have shown that many dietary factors can influence nonheme-iron bioavailability. However, little is known about the association of these dietary factors with iron stores in free-living elderly populations. To address this question, we investigated the consumption of various dietary components and iron stores in an elderly sample of The Framingham Heart Study participants. Serum ferritin was used as a measure of body iron stores in 634 free-living elderly (67-93 y of age), and dietary intake during the previous year was assessed by a food-frequency questionnaire. The relation between serum ferritin and various dietary factors was assessed by multiple regression analysis. Subjects whose ferritin concentrations might be pathologically elevated because of infection, inflammation, liver disease, or genetic hemochromatosis were excluded from the analysis. After we controlled for sex, age, body mass index, total energy intake, smoking, and use of aspirin and other medications known to affect blood loss, we found five significant dietary factors associated with iron stores. Heme iron, supplemental iron, dietary vitamin C, and alcohol were positively associated with serum ferritin, whereas coffee intake had a negative association. As expected, sex was a strong predictor of serum ferritin-women having significantly lower mean concentrations than men. However, age was not related to serum ferritin in our elderly population. Our results suggest that in typical Western-style diets, a small number of dietary factors probably modulate the bioavailability of dietary iron and influence the accumulation of iron stores.
Thesis (M. Sc.)--University of Toronto, 1997. Includes bibliographical references.
Many researchers report substantial reductions in iron availability when dairy products are consumed with solutions of iron. Yet other studies indicate that dairy products have little effect on iron availability when added to complex meals. The conflicting data may be due to differences in the technique used to measure availability, species of animal used, form of iron in the diet, and meal composition. Human studies show superior bioavailability of iron in human milk when compared with cow's milk. Definitive causes for the differences between human and cow's milk have not been identified. Human milk contains lower amounts of casein, phosphate, and calcium, components thought to inhibit iron absorption. More work is needed to identify the factors that influence iron-dairy interactions. The nutritional benefits provided by dairy products outweigh the slight inhibitory effect they may have on iron availability.
The effects of maize-bran phytate and of a polyphenol (tannic acid) on iron absorption from a white-bread meal were tested in 199 subjects. The phytate content was varied by adding different concentrations of phytate-free and ordinary maize bran. Iron absorption decreased progressively when maize bran containing increasing amounts of phytate phosphorous (phytate P) (from 10 to 58 mg) was given. The inhibitory effect was overcome by 30 mg ascorbic acid. The inhibitory effects of tannic acid (from 12 to 55 mg) were also dose dependent. Studies suggested that greater than or equal to 50 mg ascorbic acid would be required to overcome the inhibitory effects on iron absorption of any meal containing greater than 100 mg tannic acid. Our findings indicate that it may be possible to predict the bioavailability of iron in a diet if due account is taken of the relative content in the diet of the major promoters and inhibitors of iron absorption.
Blue-green alga, Nostoc commune, contained moderate amounts of protein and iron. Its in vitro protein digestibility was 43.50%. The soluble and ionic iron from the alga was extractable to some extent at pH 1.5 but was not detectable at pH 8.0. The digestion by protease did not affect the iron detection. Heat processing at 100 and 120 degrees C failed to increase the digestibility and the content of available iron. The dietary fiber in the alga may be responsible for low protein digestion and low iron availability.
The effect of a variety of traditional oriental unfermented and fermented soy products on iron absorption was evaluated in 242 Indian women. When compared with a soy-flour meal containing an equal amount of protein, iron absorption was found to be significantly improved with silken tofu, natto, tempeh, rice miso, barley miso, and soybean miso. This improvement could not be adequately explained except with reference to changes in the protein composition of the products. The protein fraction profiles of the soy products were obtained by size-exclusion high-performance liquid chromatography. An inverse relationship between food iron absorption and the high-molecular-weight fraction of the soy products was demonstrated (r = 0.66, p = 0.01). However, anomalous results obtained with three products (sufu, tempeh, and fully hydrolyzed isolated soy protein) did not make it possible to reach firm conclusions concerning the effect of the protein fraction of soy on iron bioavailability.
MacPhail, A. P. and Bothwell, T. H. (Joint University and MRC Iron and Red Cell Metabolism Unit, University of the Witwatersrand Medical School, Parktown, Johannesburg, South Africa). Fortification of the diet as a strategy for preventing iron deficiency.
Progress in the fortification of food with iron is reviewed in the light of the different circumstances prevailing in the developed and developing world. Although fortification programmes are well established in developed countries many were not based on sound principles and there is no good evidence that they have proved effective. The important steps in establishing a fortification programme include accurate establishment of the need for iron fortification in a particular group or population, the choice of an appropriate combination of food vehicle and iron compound which is both stable and acceptable, and confirmation that the iron in the chosen blend is bioavailable and in different dietary settings. Only after the successful completion of controlled field trials using the chosen combination is the establishment of a regional or national fortification programme worthwhile. These points are illustrated by the success of field trials in the developing world, at least one of which has led to the implementation of a national programme directed to infants and children. Finally, a case study is described in which these principles were followed in the planning and execution of a successful field trial in an iron deficient Indian population in South Africa. The vehicle was curry powder and the iron compound Fe(111)EDTA.
Studies were carried out on the in vitro availability of iron from a standard cereal meal with and without the addition of bovine milk (BM), groundnut milk (GM) and soybean milk (SM). Further, availability of iron from these milks per se was also investigated. Estimation of the total iron content from BM, GM, and SM revealed that it was highest in case of SM followed by GM and BM. This trend was reversed for percent available iron which was highest for BM followed by GM and SM. The in vitro availability of iron from the cereal meal was low (3.7%). Addition of BM and GM enhanced the availability of iron from the standard meal whereas SM had no particular enhancing quality. The practical implications of the findings for iron nutrition in humans are discussed.
Abstract Bothwell TH, Baynes RD, MacFarlane BJ, MacPhail AP (MRC Iron and Red Cell Metabolism Research Unit, Department of Medicine, University of the Witwatersrand Medical School, Parktown, Johannesburg, South Africa). Nutritional iron requirements and food iron absorption.
To prevent nutritional iron deficiency, sufficient iron must be absorbed from the diet to meet the normal physiological requirements. Daily iron losses in males are about 1 mg (14 μg kg−1), while the average additional requirements incurred in women include menstruation (0.6 mg), pregnancy (2.7 mg) and lactation (less than 0.3 mg). Requirements during pregnancy are not evenly distributed and increase to between 5–6 mg in the last trimester of pregnancy, which is more than can be absorbed from even an optimal diet. While the amounts absorbed are affected by the iron content of the diet, the composition of the latter is even more relevant. About one-quarter of the iron in haem proteins is absorbed regardless of the other components in the diet, while non-haem iron absorption is subject to the interplay of promoting and inhibiting substances in the diet. Thus diets rich in enhancers of non-haem iron absorption, chiefly meat and/or ascorbic acid, have high iron bioavailability (about 3 mg d−1) while diets in which inhibitors, such as polyphenols and phytates, predominate are poor sources of iron (less than 1 mg d−1). Examination of the relative proportions of promoters and inhibitors of iron absorption in individual foodstuffs and the measured iron absorption from them may be useful in predicting the overall iron bioavailability from mixed diets.
We report a case of encephalopathy with paranoid psychosis in association with intracranial hypertension. This occurred in a patient whose diet consisted almost solely of walnuts, ginseng tea, and vitamin A supplements. The patient was found to be severely iron- and vitamin B12-deficient. She was vitamin A toxic. Venous sinus thrombosis was also present. Symptoms remitted with serial lumbar punctures, normalization of diet, and repletion of vitamin B12 and iron stores. Physicians should be alerted to the possibility of a potentially confusing clinical presentation with coexistent and seemingly mutually exclusive neurologic conditions in patients with extremely restricted or fad diets.
An appropriately planned well-balanced vegetarian diet is compatible with an adequate iron status. Although the iron stores of vegetarians may be reduced, the incidence of iron-deficiency anemia in vegetarians is not significantly different from that in omnivores. Restrictive vegetarian diets (eg, macrobiotic) are associated with more widespread iron-deficiency anemia. Western vegetarians who consume a variety of foods have a better iron status than do those in developing countries who consume a limited diet based on unleavened, unrefined cereals. Whereas phytates, polyphenolics, and other plant constituents found in vegetarian diets inhibit nonheme-iron absorption, vitamin C, citric acid, and other organic acids facilitate nonheme-iron absorption.
To determine whether adult non-vegetarian Seventh-day Adventists differ in selected nutrition related health aspects from adult vegetarian Seventh-day Adventists.
One hundred and forty-one Seventh-day Adventist church members responded to a general health questionnaire. Forty-seven sex and age matched subjects (23 non-vegetarians and 24 vegetarians) were selected for further investigation. Blood lipids, serum vitamin B12, folate, haemoglobin and ferritin levels were measured along with stature, weight and blood pressure. A quantitative 7-day diet record was also completed.
Body mass index was similar between the non-vegetarian and vegetarian groups but diastolic blood pressure was higher for non-vegetarian than vegetarian males. Even though the dietary vitamin B12 intake was significantly lower (p < 0.01) in the vegetarian group both vegetarians and non-vegetarians recorded similar serum vitamin B12 levels. The vegetarian and non-vegetarian groups had similar haemoglobin concentrations. While dietary iron intake was higher in the female vegetarian group, though predominantly in the non-haem form, the difference was not significant. Low serum ferritin levels were found in both female dietary groups even though the vegetarian group had a significantly (p < 0.05) higher vitamin C intake. Blood lipid levels were similar in the two diet groups even though the vegetarian group had a lower percentage energy contribution from total and saturated fat (p < 0.01) and consumed significantly less cholesterol.
Both non-vegetarian and vegetarian Seventh-day Adventists appear likely to enjoy a lower risk of nutrition related chronic degenerative disease than the average New Zealander and have a satisfactory iron and vitamin B12 status.
The effect of Prunus amygdalus, which is rich in unsaturated fat, fibre diet and low cholesterol was studied in 36 normolipidemic male albino rabbits for 60 days. Three different doses i.e. whole seeds defatted and oil showed a decrease in serum total cholesterol, triglyceride, LDL cholesterol, VLDL cholesterol and an increase in phospholipid, faecal sterol and HDL cholesterol. The maximum effects where shown by whole seeds followed by oil and defatted.
The author and four independent experts evaluated the intent and quality of scientific evidence for a potential beneficial health relationship between the intake of walnuts and the reduction and prevention of coronary heart disease. The report also addresses the supporting evidence for the health benefit of other tree nuts and selected legumes. Compared to most other nuts, which contain monounsaturated fatty acids, walnuts are unique because they are rich in n-6 (linoleate) and n-3 (linolenate) polyunsaturated fatty acids. Walnuts contain multiple health-beneficial components, such as having a low lysine:arginine ratio and high levels of arginine, folate, fiber, tannins, and polyphenols. Though walnuts are energy rich, clinical dietary intervention studies show that walnut consumption does not cause a net gain in body weight when eaten as a replacement food. Five controlled, peer-reviewed, human clinical walnut intervention trials, involving approximately 200 subjects representative of the 51% of the adult population in the United States at risk of coronary heart disease were reviewed. The intervention trials consistently demonstrated walnuts as part of a heart-healthy diet, lower blood cholesterol concentrations. None of these studies were of extended duration that would be essential for evaluation of the sustainability of the observed outcomes. These results were supported by several large prospective observational studies in humans, all demonstrating a dose response-related inverse association of the relative risk of coronary heart disease with the frequent daily consumption of small amounts of nuts, including walnuts.
To develop an algorithm to predict the percentage non-heme iron absorption based on the foods contained in a meal (wholemeal cereal, tea, cheese, etc.). Existing algorithms use food constituents (phytate, polyphenols, calcium, etc.), which can be difficult to obtain.
A meta-analysis of published studies using erythrocyte incorporation of radio-isotopic iron to measure non-heme iron absorption.
A database was compiled and foods were categorized into food groups likely to modify non-heme iron absorption. Absorption data were then adjusted to a common iron status and a weighted multiple regression was performed.
Data from 53 research papers (3,942 individual meals) were used to produce an algorithm to predict non-heme iron absorption (R(2) =0.22, P < 0.0001).
The percentage non-heme iron absorption can be predicted from information on the types of foods contained in a meal with similar efficacy to that of food-constituent-based algorithms (R(2) = 0.16, P= 0.0001).
1. Non-haem-iron absorption from a variety of cereal and fibre meals was measured in parous Indian women, using the erythrocyte utilization of radioactive Fe method.
2. The present study was undertaken to establish whether alteration of the phytate and polyphenol contents of sorghum ( Sorghum vulgare ) affected Fe absorption from sorghum meals, and to assess the influence of fibre on Fe absorption.
3. Removing the outer layers of sorghum grain by pearling reduced the polyphenol and phytate contents by 96 and 92% respectively. This treatment significantly increased the geometric mean Fe absorption from 0.017 to 0.035 ( t 3.9, p < 0.005).
4. The geometric mean Fe absorption from a sorghum cultivar that lacked polyphenols (albino sorghum) was 0.043, which was significantly greater than the 0.019 absorbed from bird-proof sorghum, a cultivar with a high polyphenol content ( t 2.83, p < 0.05).
5. Fe was less well absorbed from the phytate-rich pearlings of the albino sorghum than from the pearled albino sorghum (0.015 v. 0.035 ( t 8.4, P < 0.0005)). Addition of sodium phytate to a highly Fe-bioavailable broccoli ( Brassica oleracea ) meal reduced Fe absorption from 0.185 to 0.037.
6. The geometric mean Fe absorption from malted sorghum porridge was 0.024 when 9.5 mg ascorbic acid were added and 0.094 when the ascorbic acid was increased to 50 mg ( t 3.33, P < 0.005). This enhancing effect of 50 mg ascorbic acid was significantly depressed to 0.04 by tea ( t 38.1, P < 0.0005).
7. Wheat bran significantly decreased the geometric mean Fe absorption from white flour from 0.116 to 0.043 ( t 7.2, P < 0.0005).
8. Some of the constituents of the dietary fibre complex, such as apple pectin, guar gum, gum tragacanth and microcrystalline cellulose did not inhibit Fe absorption. On the other hand, hemicellulose and lignin decreased absorption. The geometric mean absorption of Fe given with hemicellulose was 0.079 v. 0.269 with microcrystalline cellulose ( t 2.95, P < 0.05). Addition of cocoa, which contains approximately 280 g lignin/kg, reduced the geometric mean Fe absorption from milk from 0.075 to 0.035 ( t 2.7, P < 0.05).
Radioiron absorption studies were performed in male volunteer subjects to determine the effect on nonheme iron absorption of various semipurified proteins. When egg albumen and casein were substituted in protein-equivalent quantities in a semisynthetic meal, similar mean absorptions of 2.5 and 2.7% were observed. In contrast, isolated soy protein reduced absorption sharply, to an average of 0.5%. When egg albumen in the semisynthetic meal was replaced with full fat soy flour, textured soy flour, and isolated soy protein, absorption fell from 5.5 to 1.0, 1.9, and 0.4%, respectively, indicating an inhibitory effect by a wide range of soy products. The effect of substituting textured soy flour for meat in a meal containing a hamburger, french fries, and a milkshake was also evaluated. With 3:1 and 2.1 ratios of meat to unhydrated textured soy flour, absorption decreased by 61 and 53%, respectively. The soy products tested in this study have a pronounced inhibitory effect on the absorption of nonheme iron.
The cause of marked inhibitory effect of bran on absorption of dietary nonheme iron was studied in man by double-radioiron technique. Washing bran with hydrochloric acid but not with water removed inhibitory factor(s). Inhibition was almost restored by reconstituting phytate level. Removal of phytates in bran by endogenous phytase significantly increased absorption of iron. Removing, by washing with water, phosphates formed from phytates during enzymatic dephytinization led to a bran fraction with only a small remaining inhibitory effect on iron absorption. Half the iron in bran is in the form of monoferric phytate, which is well-absorbed. When potassium and magnesium phytates were added in amounts present in bran, the same inhibitory effect on iron absorption was seen. Although there appear to be other factors in bran that partly explain the inhibition, phytates are the main cause of the inhibitory effect of bran on iron absorption.
The effects of whole wheat bran and its components on the absorption of nonheme dietary iron were measured using a double isotope technique in human volunteers. When 12 g bran was added to a light meal, absorption decreased by 51 to 74%; this inhibitory effect of bran was shown for meals of both high and low iron availability. Inhibition was not explained by monoferric phytate, the major form of iron in bran, because labeled iron from monoferric phytate was absorbed at least as well as the common pool of nonheme dietary iron. Furthermore, removal of phytate from bran by endogenous phytase did not in itself alter the inhibitory effect of the bran on iron absorption. Studies in which dephytinized bran was separated into a soluble, phosphate-rich fraction and an insoluble, high-fiber fraction indicated that the soluble fraction was more inhibitory than the insoluble fraction.
Publisher Summary This chapter discusses that the knowledge of phytic acid had its beginning in the discovery by Hartig, who isolated small particles or grains (which were not starch grains) from the seeds of various plants. Phytic acid has been generally regarded as the primary storage form of both phosphate and inositol in almost all seeds. The amount of phytic acid varies from 0.50% to 1.89% in cereals (except polished rice), from 0.40% to 2.06% in legumes, from 2.00% to 5.20% in oil seeds except soybeans and peanuts (grouped under legumes), and from 0.40% to 7.50% in protein products. Many foods and seeds contain myo-inositol hexaphosphate as an important source of phosphorus, and accurate methods for its determination are needed. Phytase (meso-inositol hexaphosphate phosphohydrolase, EC 3.1.3.8) is widely distributed in plants, animals, and fungi. In mature cereal grains, legumes, and oil seeds, the major portion of the total phosphorus is present in the form of phytic acid (phytate). Experiments with animals have suggested that phytic acid in plant foods complexes with dietary essential minerals such as calcium, zinc, iron, and magnesium and makes them biologically unavailable for absorption. The correlation of phytate with the cooking quality of peas was first suggested by Mattson. Phytic acid, myo-inositol 1,2,3,4,5,6-hexakis dihydrogen phosphate serves as the main phosphorus store in mature seeds and grains. In cereals and legumes, phytic acid content ranges from 0.14% to 2.05%, which accounts for 18 to 88% of the total phosphorus.
The effects of proteins and protein digestion products on iron bioavailability were studied. Iron dialyzability, under simulated gastrointestinal conditions, in the presence of selected proteins and fractionated protein digestion products, was used as a measure of iron bioavailability. Dialyzability was high for bovine serum albumin and beef, intermediate for egg albumin, and low for soy flour, gelatin, casein, soy protein isolate, and gluten. Low molecular weight digestion product fractions from bovine serum albumin and beef enhanced iron dialysis; similar fractions from casein and soy protein isolate did not affect iron dialysis. The influence of proteins on iron bioavailability appears to be related to the affinity of undigested or partially digested protein for iron and to the stability of small molecular weight soluble iron complexes formed from protein digestion products.
The effect of varying concentrations of ascorbic acid on the absorption of iron from a soy-based infant milk formula containing 6 mg iron/100 g was examined in 64 adult Indian females using the extrinsic radioactive tag method. The corrected geometric mean absorption from the basic soy formula was only 1.8%. Addition of ascorbic acid in a concentration of 40 mg/100 g, did not significantly increase absorption (3.3%; t = 1.8, p greater than 0.07) but raising the concentration to 80 mg/100 g did so (6.9%; t = 2.4, p less than 0.02). No further significant increase was noted when the concentration of ascorbic acid was increased to 160 mg/100 g (7.7%; t = 0.4, p greater than 0.7). The inhibitory effect of soy on iron absorption was further demonstrated by a direct comparison between the soy-based formula and a similar product based on cows' milk. The comparison was made at two concentrations of ascorbic acid. At 40 mg/100 g the geometric mean iron absorption from the soy formula was 2.4% compared with 5.3% from the milk formula (t = 2.8, p less than 0.02), while the corresponding values at 80 mg ascorbic acid/100 g were 7.2 and 19.5%, respectively (t = 3.4, p less than 0.02). The present results confirm the marked inhibitory effect of soy protein on iron absorption and calculations from the absorption figures suggest that such formulas should contain at least 12 mg/100 g iron together with ascorbic acid in a molar ratio of approximately 4:1 if they are to be adequate in terms of iron nutrition.
The iron status of 320 Indian women living in Chatsworth, Durban, who had volunteered for iron absorption studies, was assessed using a number of measurements. These included: radio-iron absorption, the transferrin saturation, the serum ferritin concentration and the haemoglobin concentration. In the sample as a whole, the prevalence of iron deficiency anaemia (haemoglobin concentration less than 12 g/dl, with two or more abnormal measurements of iron status) was 14,4%. A further 26% had depleted iron stores (serum ferritin less than 12 micrograms/l) and 8,4% also had evidence of iron-deficient erythropoiesis (serum ferritin less than 12 micrograms/l and transferrin saturation below 16%). A profile of iron status based on the cumulative frequency distribution of iron stores showed that the sample, with calculated median iron stores of 150 mg and lower and upper 10 percentiles of -355 mg and 655 mg respectively, was significantly more iron deficient than a sample of women studied in Washington State, USA. Of interest was the observation that all measurements of iron status were better in the older age groups, presumably as a result of the cessation of menstruation. In addition, there was evidence that the duration of menstruation, as volunteered in a brief history, had a significant effect on several measurements of iron status. This was particularly true of the serum ferritin concentration and radio-iron absorption, both of which reflect the size of the iron stores.
Code of practice for medical use of ionizing radiations. Pretoria: South African Bureau of Standaftis
- South African
- Bureau
- Standards
South African Bureau of Standards.
Code of practice for medical
use of ionizing radiations. Pretoria: South African Bureau of Standaftis, 1972. (Document
07.)
MethOds for analysis of wines and musts
- Vl Singleton
- Ja Rossi
7.
13. Singleton
VL, Rossi JA. MethOds
for analysis of wines and musts.