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The Effect of Vitamin A Supplementation on Various Elements in Elite Taekwondo Players
Abstract
The present study aims to examine the effects of both physical activity and vitamin A supplementation on trace element metabolism in individuals engaged in taekwondo. The study registered seven healthy male national taekwondo players whose mean age was 21.86 ± 0.34 years and mean weight was 64.86 ± 2.72 kg. The subjects were supplemented with oral administration of 100 mg vitamin A (retinol) for 6 weeks, and concurrently, they were subjected to taekwondo training 5 days a week. Before starting the vitamin A supplementation, blood samples were taken from the subjects twice, once at rest and once after exhaustion. Similarly, at the end of the 6-week vitamin A supplementation, two blood samples were taken from the subjects, once at rest and once after exhaustion, in order to determine (by atomic emission) and compare serum cobalt, molybdenum, calcium, cadmium, chromium, copper, manganese, sodium, nickel, phosphorus, sulfur, iron, boron, and zinc (mg/L) levels. Values of boron and nickel dropped significantly after 6-week vitamin A supplementation (p < 0.001). Reduced levels of boron and nickel we obtained in the present study are believed to result from the antioxidant effect of long-term vitamin A supplementation.
... Nutritional supplement strategies that may improve performance or recovery as well as aiding oxidative and/or non-oxidative metabolism relevant in combat sport are of interest to taekwondo athletes [4]. However, studies have investigated dietary supplements, such as vitamins [5][6][7], carbohydrate drinks [8], caffeine [9], creatine monohydrate [10] and sodium bicarbonate [3,10] in the context of taekwondo, but no studies have analyzed the possible ergogenic effect of nitrate (NO3 − )-rich beetroot juice (BJ) supplementation. BJ is an ergogenic aid that has received increased attention in the last decade, garnering strong support for enhancing exercise performance [11]. ...
Studies have shown that Nitrate (NO3-) rich beetroot juice (BJ) supplementation improves endurance and high-intensity intermittent exercise. The dose-response effect on taekwondo of BJ supplementation are yet to be determined. This study aimed to investigate two acute doses of 400 mg of NO3-(BJ-400) and (800 mg NO3- (BJ-800) on taekwondo-specific performance tests compared with a placebo (PL) and control (CON) conditions. Eight trained male taekwondo athletes (age: 20±4 years, height: 180±2 cm, weight: 64.8±4.0 kg) completed four experimental trials using a randomized, double‐blind placebo‐controlled design: BJ-400, BJ-800, PL, and CON. Countermovement jump (CMJ) was performed before the Multiple Frequency Speed of Kick Test (FSKT) and Progressive Specific Taekwondo Test (PSTT), respectively, whereas cognitive function was assessed (via the Stroop test) before and after supplementation and 10 minutes following PSTT. Blood lactate was collected before the CMJ tests, immediately, and 3 minutes after the FSKT and PSST, with rating of perceived exertion (RPE) was recorded during and after specific taekwondo tests. Nosignificant difference between conditions were observed (p> 0.05)for PSTT and FSKT performances. In addition, blood lactate, RPE, heart rate, and CMJ height and performance during the specific taekwondo tests were not significantly different among conditions (p> 0.05). However, after the PSTT test, cognitive function was higher in BJ-400 compared to other treatments (p< 0.05). In conclusion, acute intake of 400 and 800 mg of NO3-rich BJ did not improve taekwondo-specific performance tests in trained male taekwondo athletes.
... Retinoic acid acts as a transcription factor ligand in cell proliferation processes. The antioxidant effect of vitamin A was noted after six weeks of supplementation in taekwondo athletes [118]. ...
Advanced nutritional interventions are one of the key components of elite sports performance in general. Combat sports require a high percentage of muscle mass with minimum body weight to generate the maximum power possible. An adequate level of nutrition knowledge, particularly with respect to identifying energy needs while avoiding confusion over dietary supplements and false perceptions of steroid requirement, which may compromise the health condition, is of crucial importance. In this context, the aim of our work is to highlight nutritional require-ments/nutritional assessment, the importance of daily dietary intake in combat players, which increasingly includes a broad range of sports nutrition supplements, and the roles of vitamins, minerals and proteins, combined with antioxidants and strength training, in muscular performance. The main nutrients required in the daily diet of combat players, the mechanisms of action, the main outcomes and possible side effects are summarized. Special attention is paid to natural supplements and their importance and advantages over synthetic ones, along with future trends of development.
... Nutritional supplement strategies that may improve performance or recovery as well as aiding oxidative and/or non-oxidative metabolism relevant in combat sport are of interest to taekwondo athletes [4]. However, studies have investigated dietary supplements, such as vitamins [5][6][7], carbohydrate drinks [8], caffeine [9], creatine monohydrate [10] and sodium bicarbonate [3,10] in the context of taekwondo, but no studies have analyzed the possible ergogenic effect of nitrate (NO3 − )-rich beetroot juice (BJ) supplementation. BJ is an ergogenic aid that has received increased attention in the last decade, garnering strong support for enhancing exercise performance [11]. ...
Studies have shown that nitrate (NO3 −)-rich beetroot juice (BJ) supplementation improves endurance and high-intensity intermittent exercise. The dose-response effects on taekwondo following BJ supplementation are yet to be determined. This study aimed to investigate two acute doses of 400 mg of NO3 − (BJ-400) and 800 mg of NO3 − (BJ-800) on taekwondo-specific performance and cognitive function tests compared with a placebo (PL) and control (CON) conditions. Eight trained male taekwondo athletes (age: 20 ± 4 years, height: 180 ± 2 cm, body mass: 64.8 ± 4.0 kg) completed four experimental trials using a randomized, double-blind placebo-controlled design: BJ-400, BJ-800, PL, and CON. Participants consumed two doses of BJ-400 and BJ-800 or nitrate-depleted PL at 2.5 h prior to performing the Multiple Frequency Speed of Kick Test (FSKT). Countermovement jump (CMJ) was performed before the (FSKT) and PSTT, whereas cognitive function was assessed (via the Stroop test) before and after supplementation and 10 min following PSTT. Blood lactate was collected before the CMJ tests immediately and 3 min after the FSKT and PSST; rating of perceived exertion (RPE) was recorded during and after both specific taekwondo tests. No significant differences (p > 0.05), with moderate and large effect sizes, between conditions were observed for PSTT and FSKT performances. In addition, blood lactate, RPE, heart rate, and CMJ height were not significantly different among conditions (p > 0.05). However, after the PSTT test, cognitive function was higher in BJ-400 compared to other treatments (p < 0.05). It was concluded that acute intake of 400 and 800 mg of NO3 − rich BJ reported a moderate to large effect size in anaerobic and aerobic; however, no statistical differences were found in taekwondo-specific performance.
... [4] A proper balance between macro and micronutrients is important for optimum physical performance. [5,6] An athlete's nutritional needs usually encompass a higher energy requirement to account for greater energy expenditure, increased protein and carbohydrate requirements to support lean muscle mass maintenance and glycogen stores, as well as an increased requirement for certain micronutrients. [7,8,9] In young athletes, nutrients identified as of concern due to insufficient intake include carbohydrates (especially during exercise), vitamin E, vitamin D, calcium, iron, magnesium and zinc [10,11,12,13] and low intake may cause poor performance during competition and also result in deficiencies affecting health. ...
... It was evident that most of the players are not much concerned about their food intake during competition due to stress and fear which ultimately lead to the lack of energy for a competitive combat. 24 Also, in Sri Lanka most of the taekwondo coaches are qualified national referees. Therefore, they have to engage as referees in national tournaments such as in this competition. ...
BACKGROUND: Taekwondo is a Korean martial art that had been growing in popularity in Sri Lanka and internationally. Although studies have examined injuries in other non-contact sports, to date, no published medical study has examined injuries in taekwondo competitions in Sri Lanka. The purpose of this study was to identify the injury profile in the "National Sport Festival Taekwondo Championship" in Sri Lanka. METHODS: This is a descriptive cross-sectional study. In the competition, 193 athletes were observed prospectively to detect the injury type, site of injury, severity of injury and the rate of injury. Injury data were recorded using an interviewer administered questionnaire with the help of the attending physician. The software program "SPSS 16.0' was used to analyze the data. RESULTS: Importantly, 78 injuries were recorded. The most prevalent injury type was contusions (67.9%) followed by lacerations (12.8%), sprain (5.1%), concussion (5.1%) and fractures (3.8%). The lower limbs were determined as the most prevalent anatomical region of the body to sustain an injury during a competition followed by the head and neck. The most frequent injuries were mild injures (71.8%) which is followed by moderate injuries (17.9%) and the equal frequency of 5.1% for both severe and critical injuries. The injury rate was found to be 220.3 injuries per 1000 athlete-exposures. CONCLUSIONS: The most common injury location and type were found to be the lower limb and contusion, respectively. The majority of injuries appeared to be of mild in nature. Most importantly, the injury rate in Sri Lankan taekwondo athletes is very much higher than the rates reported from the other parts in the world. There is an urgent need of launching programs related to injury prevention among the players and the referees in order to decrease the rate of taekwondo injuries in Sri Lanka.
... It has been also demonstrated that vitamins E (Patlar et al., 2011a) and A (Patlar et al., 2011b) supplementation significantly increased blood Co levels in athletes. ...
Cobalt is an essential trace element that is known to mimic hypoxia and hypoxic training. Inorganic Co compounds are capable of Hypoxia-inducible factor-1 (HIF-1) activation, resulting in up-regulation of gene expression including erythropoietin (Epo). Experimental studies have demonstrated that Co treatment may increase hypoxic tolerance of different tissues, improve muscle metabolism and exercise performance. Other mechanisms may also involve modulation of steroid hormone and iron metabolism. Based on these experimental studies, in 2017 inorganic cobalt compounds were added into the World Anti-Doping Agency (WADA) prohibited list as doping agents. However, the existing data on beneficial effects of cobalt on exercise performance in athletes are scarce. Similarly, only experimental studies demonstrated exercise-induced decrease in tissue Co levels, whereas human data are inconsistent. In addition, multiple studies have demonstrated that excessive Co intake may be toxic due to prooxidant, proinflammatory, and proapoptotic activity. Therefore, monitoring of Co deficiency and overload is required to prevent potential health hazards in athletes. At the same time, modulation of Co status should be performed through supplementation avoiding excessive doses of inorganic cobalt that are used for doping and are accompanied by adverse health effects of metal toxicity.
... In clinical trials, it has been shown that vitamin C supplementation may be done by 1000 mg for 60 days at humans (15). Thereafter, we have supplemented vitamin C as 300 mg/day for 1 month (16). ...
Background. Exercise has significant affects on free radical production.
Objective. The objective of the present study was to explore the effect of vitamin C supplementation on lipid peroxidation and lactate levels in sedentary individuals who performed exhaustion exercised.
Methods. 10 healthy sedentary male athletes participated to study. They were supplemented with 300 mg oral vitamin C (L-ascorbic acid, Ester-C Plus 500 mg, Solgar-USA) and subjected to acute exhaustion exercise by fatigue developed one time a week for 4 weeks. Exhaustion exercises were carried out until exhaustion developed according to Bruce protocol once a week for 4 weeks. Blood samples were collected from the subjects four times, at the beginning and at the end of the supplementation and before and after exercise, over the 4-weeks study period. The samples were used to analyze MDA, GSH, GSH-Px, CAT, SOD and NO levels by using ELISA colorimetric method and plasma lactate levels by an autoanalyzer device.
Results. Exhaustion MDA, GSH, GSH-Px, CAT, SOD and NO levels measured both before and after supplementation were higher than resting levels (p
... Described as a set of activities that improve one's health and help one maintain good health, sports or exercise, in addition to the protective function, serve as a treatment tool (1)(2)(3). However, despite its ameliorative effects, exercise (which is also considered to be a controlled catabolic process) leads to the destruction of muscle and even bone tissue, to a certain extent (4,5). Given the mechanisms of immune responses, it can be argued that tissue injury in the skeletal muscle resulting from exercise paves the way for activation of immune reactions (6). ...
The aim of the present study was to examine how a 4-week exercise program affects the serum levels of certain cytokines in Taekwondo athletes. The study involved 10 elite male Taekwondo athletes (mean age, 20.67±0.24 years; mean weight, 65.45±1.69 kg) who were studying at the Physical Education and Sports High School of Selçuk University (Konya, Turkey) in June 2014. The subjects were involved in a Taekwondo exercise program on every weekday for 4 weeks. The subjects were also engaged in an exercise to exhaustion session twice; once before starting the 4-week exercise program and once upon completion of the program. Blood samples were collected from the subjects in four rounds: During rest, upon fatigue, and before and after the 4-week exercise program. These samples were analyzed to establish the serum levels of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin (IL)-2 and IL-6 using enzyme-linked immunosorbent assay test kits. Pre- and post-exercise program, the IFN-γ and TNF-α levels did not show any significant difference. When compared with the pre-exercise levels, serum IL-2 levels of the subjects were found to be elevated after the 4-week exercise program. The highest serum IL-6 values were established after the subjects were exercised to fatigue before the exercise program was initiated (P<0.05). The 4-week exercise program resulted in a decrease in IL-6 levels (P<0.05). The findings of the study indicate that a 4-week exercise program did not result in significant changes in IFN-γ and TNF-α levels, but led to an increase in IL-2 levels. The notable finding of the present study is that a 4-week exercise program reduces cellular immune functions and, thus, the levels of IL-6, which negatively influences performance.
This study aims to investigate the effects of vitamin A supplementation on cytokine release in 10 male elite taekwondo players. The subjects who were supplemented with 100 mg of vitamin A in daily tablet form for 4 weeks were exercised to exhaustion twice, before and after the supplementation. In the course of the four-week study period, blood samples were collected from the subjects four times in exhaustion and at rest, before and after supplementation. The blood samples were analyzed for IFNγ, TNF-α, IL-2, and IL-6 levels. Vitamin A supplementation resulted in a significant increase in serum IL-2 levels (p<0.05). However, vitamin A supplementation led to the inhibition of serum TNF-α levels, in comparison to pre-supplementation (exhaustion and resting) values (p<0.05). The results of the study indicate that vitamin A supplementation might cause changes in the release of cytokines independent of exercise.
It is the position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine that physical activity, athletic performance, and recovery from exercise are enhanced by optimal nutrition. These organizations recommend appropriate selection of foods and fluids, timing of intake, and supplement choices for optimal health and exercise performance. This updated position paper couples a rigorous, systematic, evidence-based analysis of nutrition and performance-specific literature with current scientific data related to energy needs, assessment of body composition, strategies for weight change, nutrient and fluid needs, special nutrient needs during training and competition, the use of supplements and ergogenic aids, nutrition recommendations for vegetarian athletes, and the roles and responsibilities of sports dietitians. Energy and macronutrient needs, especially carbohydrate and protein, must be met during times of high physical activity to maintain body weight, replenish glycogen stores, and provide adequate protein to build and repair tissue. Fat intake should be sufficient to provide the essential fatty acids and fat-soluble vitamins, as well as contribute energy for weight maintenance. Although exercise performance can be affected by body weight and composition, these physical measures should not be a criterion for sports performance and daily weigh-ins are discouraged. Adequate food and fluid should be consumed before, during, and after exercise to help maintain blood glucose concentration during exercise, maximize exercise performance, and improve recovery time. Athletes should be well hydrated before exercise and drink enough fluid during and after exercise to balance fluid losses. Sports beverages containing carbohydrates and electrolytes may be consumed before, during, and after exercise to help maintain blood glucose concentration, provide fuel for muscles, and decrease risk of dehydration and hyponatremia. Vitamin and mineral supplements are not needed if adequate energy to maintain body weight is consumed from a variety of foods. However, athletes who restrict energy intake, use severe weight-loss practices, eliminate one or more food groups from their diet, or consume unbalanced diets with low micronutrient density, may require supplements. Because regulations specific to nutritional ergogenic aids are poorly enforced, they should be used with caution, and only after careful product evaluation for safety, efficacy, potency, and legality. A qualified sports dietitian and in particular in the United States, a Board Certified Specialist in Sports Dietetics, should provide individualized nutrition direction and advice subsequent to a comprehensive nutrition assessment.
It is the position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine that physical activity, athletic performance, and recovery from exercise are enhanced by optimal nutrition. These organizations recommend appropriate selection of foods and fluids, timing of intake, and supplement choices for optimal health and exercise performance. This updated position paper couples a rigorous, systematic, evidence-based analysis of nutrition and performance-specific literature with current scientific data related to energy needs, assessment of body composition, strategies for weight change, nutrient and fluid needs, special nutrient needs during training and competition, the use of supplements and ergogenic aids, nutrition recommendations for vegetarian athletes, and the roles and responsibilities of the sports dietitian. Energy and macronutrient needs, especially carbohydrate and protein, must be met during times of high physical activity to maintain body weight, replenish glycogen stores, and provide adequate protein to build and repair tissue. Fat intake should be sufficient to provide the essential fatty acids and fat-soluble vitamins and to contribute energy for weight maintenance. Although exercise performance can be affected by body weight and composition, these physical measures should not be a criterion for sports performance and daily weigh-ins are discouraged. Adequate food and fluid should be consumed before, during, and after exercise to help maintain blood glucose concentration during exercise, maximize exercise performance, and improve recovery time. Athletes should be well hydrated before exercise and drink enough fluid during and after exercise to balance fluid losses. Sports beverages containing carbohydrates and electrolytes may be consumed before, during, and after exercise to help maintain blood glucose concentration, provide fuel for muscles, and decrease risk of dehydration and hyponatremia. Vitamin and mineral supplements are not needed if adequate energy to maintain body weight is consumed from a variety of foods. However, athletes who restrict energy intake, use severe weight-loss practices, eliminate one or more food groups from their diet, or consume unbalanced diets with low micronutrient density may require supplements. Because regulations specific to nutritional ergogenic aids are poorly enforced, they should be used with caution and only after careful product evaluation for safety, efficacy, potency, and legality. A qualified sports dietitian and, in particular, the Board Certified Specialist in Sports Dietetics in the United States, should provide individualized nutrition direction and advice after a comprehensive nutrition assessment.
Wear of metal-on-metal bearings causes elevated levels of cobalt and chromium in blood and body fluids. Metal-on-metal bearings have two distinct wear phases. In the early phase, the wear rate is high. Later, it decreases and the bearing enters a steady-state phase. It is expected that as the wear rates decline, the level of cobalt detected in plasma will also decrease. We studied the baseline and exercise-related cobalt rise in 21 patients (13 men and eight women) with a mean age of 54 years (38 to 80) who had undergone successful hip resurfacing at a mean of 44 months (10 to 96) earlier. Our results showed that circulating baseline cobalt levels were not significantly correlated with the time since implantation (r = 0.08, p = 0.650). By contrast, the exercise-related cobalt rise was directly correlated with the inclination angle of the acetabular component (r = 0.47, p = 0.032) and inversely correlated with the time since implantation (r = −0.5, p = 0.020).
Inclination of the acetabular component should be kept less than 40° to decrease the production of wear debris.
The aim of this study was to evaluate the effects of an official Taekwondo competition on the heart rate (HR), salivary α-amylase (sA-A), salivary free cortisol (sC), and Profile of Mood States (POMS) in 10 young male (14±0 years) and six female (13±1 years) athletes. POMS and hormones were measured 15 min before and directly after the competition. During the recovery phase (30 and 90 min), sA-A and sC were also measured. HR measured during the competition was expressed as a percentage of individual's maximal heart rate (%HR(max) ) to evaluate the intensity of exercise. During the competition, athletes spent 65% of the time working at HR>90% of individuals HR(max). A significant increase (P<0.0001) in sA-A (115%) was observed at the end of the match. At 30 min of recovery, sA-A returned to the pre-competition level. The peak sC values were observed at 30 min of recovery (P<0.001), returning to the pre-competition level at 90 min of recovery. A gender difference (P=0.01) emerged only for sC, although a similar trend was observed for female and male athletes. Significantly higher post-match scores emerged for Anger-hostility (pre: 6.1±1.1, post: 11.2±1.9; P=0.03) and Depression-dejection (pre: 4.5±0.5, post: 10.2±1.9; P=0.006), whereas the reverse picture was observed for Vigour-activity (pre: 23.2±1.2, post: 16.3±1.7; P=0.0006). Taekwondo competition results in temporary changes in the stress-related parameters measured in this study. The present findings suggest that this experimental paradigm can represent a useful model for further research on the effects of various stressors (i.e., training and competition) in Taekwondo athletes of different levels (i.e., novice, international).
To determine whether during hypokinesia (diminished movement) periodic physical exercise affects calcium (Ca(2+)) balance and Ca(2+) loss.
Studies were conducted on 30 physically healthy male volunteers during the preexperimental period of 30 days and the experimental period of 364 days. They were equally divided into three groups: active control subjects (ACS), hypokinetic subjects (HKS), and periodic training subjects (PTS). The ACS group ran an average distance of 9.3+/-1.2 km/d; the HKS group walked an average distance of 1.3+/-0.2 km/d; and PTS group walked and ran average distances of 1.3+/-0.2 km/d and 9.2+/-1.2 km/d for 5 and 2 days per week, respectively.
Serum Ca(2+) level, fecal and urine Ca(2+) loss, and Ca(2+) imbalance increased (P<0.05) in the PTS and HKS groups compared with their preexperimental levels and the values in their respective ACS group. The serum Ca(2+) concentration, urine and fecal Ca(2+) loss, and Ca(2+) imbalance increased more (P<0.05) in the PTS group than in the HKS group.
During hypokinesia, Ca(2+) imbalance is more evident with than without physical exercise and Ca(2+) loss is exacerbated more with higher than lower Ca(2+) imbalance.
Vitamins, just as minerals and trace elements, meet with great interest in the world of sports because of their supposed role in enhancing physical performance. Of the 13 compounds now considered as vitamins, most water-soluble vitamins and vitamin E are involved in mitochondrial energy metabolism. The influence of vitamin supplementation on mitochondrial metabolism is largely unknown. The principal argument for vitamin supplementation is the assumed increased vitamin requirement of athletes. Theoretically, an increased requirement can be caused by decreased absorption by the gastrointestinal tract, increased excretion in sweat, urine and faeces, increased turnover, as well as biochemical adaptation to training. Of course, a marginal low vitamin status can simply be the consequence of a long-term inadequate intake. However, considering the RDAs there are no indications that long-term vitamin intake among athletes is insufficient. Neither are there indications that vitamin excretion or turnover is increased in athletes. However, it is very likely that the (apparently) increased requirement is the consequence of biochemical adaptation to training and does not indicate a decreased intake. Although a marginal vitamin status, induced by inadequate vitamin intake, may have a negative effect on performance, there is no evidence to support the view that this occurs in trained athletes. Moreover, vitamin supplementation in athletes with an adequate vitamin status has no effect on physical working capacity. Possibly, exceptions have to be made for the use of vitamin E at high altitudes and for the use of vitamin C and multiple B-vitamin supplements in hot climates.
Boric acid is an inorganic acid that impairs fertility in male rodents. A reproductive assessment by continuous breeding study found that male rats treated with boric acid had decreased fertility and sperm motility. In order to determine the cell type that is first affected by boric acid, we have examined the development of the boric acid-induced testicular lesion by light and electron microscopy. Adult F344 male rats were fed 9000 ppm boric acid in NIH-07 rat chow for up to 4 weeks. The first testicular lesion noted was an inhibition of spermiation, which appeared by Day 7. Widespread exfoliation of apparently viable germ cells, and pachytene cell death in stages VII and XIV, appeared as exposure continued. After 28 days of dosing, extreme epithelial disorganization and germ cell loss were evident. To determine if there was a hormonal component to the boric acid-induced testicular lesion, serum levels of basal, hCG-, and LHRH-stimulated testosterone levels were measured. After 4 days of dosing, basal testosterone levels were lower than controls and remained low during dosing. However, serum testosterone levels were similar in both boric acid-treated and control animals after either hCG or LHRH challenge. To determine if boron was preferentially accumulated by the testis, boron levels in testis, epididymis, liver, kidney, and blood were measured. Boron levels had effectively reached steady-state levels by Day 4 and were not differentially concentrated in the tissues examined. Thus, these studies characterize the testicular lesion produced by boric acid exposure and identify a decrease in basal serum testosterone levels in the absence of selective accumulation of boron in the testis.
Adult male rats were dosed orally on d 0 with 0 or 2000 mg/kg of boric acid and killed on posttreatment d 2, 14, 28, and 57, or dosed with 0, 250, 500, 1000, or 2000 mg/kg of boric acid and killed on posttreatment d 14. At d 14, atypical structures that appeared to be enlarged irregular cytoplasmic lobes of Step 19 spermatids were observed in Stage VIII seminiferous tubules of rats dosed with 1000 and 2000 mg/kg. Abnormal retention of Step 19 spermatids and residual bodies was also observed in Stage IX-XIII tubules of these rats. The retained spermatids and residual bodies were seen in both the luminal and basal regions of the epithelium. A substantial increase in the testicular sperm head count occurred in animals dosed with 2000 mg/kg. Abnormal caput epididymal sperm morphology and reduced caput epididymal sperm reserves were observed at 1000 mg/kg and higher. Serum LH, FSH, TSH, and prolactin values were not affected at any dosage. At d 28, rats dosed with 2000 mg/kg exhibited continued retention of Step 19 spermatids into Stage X, abnormal caput and cauda sperm morphology, and decreased percentages of motile cauda spermatozoa with reduced straight-line swimming velocities. By d 57 substantial recovery was apparent; some retention of Step 19 spermatids into Stage X tubules was still present in two out of six rats but the sperm parameters were comparable to controls. The study indicated that acute oral exposure to boric acid adversely affected spermiation and sperm quality in the adult male rat. At the dosages used the effects appeared reversible. The no-effect level was 500 mg/kg.