Effects of magnesium supplementation on blood parameters of athletes at rest and after exercise

The effects of magnesium supplementation on blood parameters were studied during a period of 4 wk in adult tae-kwon-do athletes at rest and exhaustion. Thirty healthy subjects of ages ranging in age from 18 to 22 yr were included in the study. The subjects were separated into three groups, as follows: Group 1 consisted of subjects who did not train receiving 10 mg/kg/d magnesium. Group 2 included subjects equally supplemented with magnesium and exercising 90–120 min/d for 5 d/wk. Group 3 were subject to the same exercise regime but did not receive magnesium supplements. The leukocyte count (WBC) was significantly higher in groups 1 and 2 than in the subjects who did not receive any supplements (p < 0.05). There were no significant differences in the WBC of the two groups under magnesium supplementation. The erythrocyte, hemoglobin, and trombocyte levels were significantly increased in all groups (p < 0.05), but the hematocrit levels did not show any differences between the groups although they were increased after supplementation and exercise. These results suggest that magnesium supplementation positively influences the performance of training athletes by increasing erythrocyte and hemoglobin levels.     

Effects of Magnesium Supplementation on Testosterone Levels of Athletes and Sedentary Subjects at Rest and after Exhaustion

This study was performed to assess how 4 weeks of magnesium supplementation and exercise affect the free and total plasma testosterone levels of sportsmen practicing tae kwon do and sedentary controls at rest and after exhaustion. The testosterone levels were determined at four different periods: resting before supplementation, exhaustion before supplementation, resting after supplementation, and exhaustion after supplementation in three study groups, which are as follows: Group 1—sedentary controls supplemented with 10 mg magnesium per kilogram body weight. Group 2—tae kwon do athletes practicing 90–120 min/day supplemented with 10 mg magnesium per kilogram body weight. Group 3—tae kwon do athletes practicing 90–120 min/day receiving no magnesium supplements. The free plasma testosterone levels increased at exhaustion before and after supplementation compared to resting levels. Exercise also increased testosterone levels relative to sedentary subjects. Similar increases were observed for total testosterone. Our results show that supplementation with magnesium increases free and total testosterone values in sedentary and in athletes. The increases are higher in those who exercise than in sedentary individuals.     

The effect of magnesium supplementation on lactate levels of sportsmen and sedanter

This study was performed to assess how magnesium supplementation affects plasma lactate levels at rest and exhaustion in sportsmen and sedentary. Research was performed on 30 healthy subjects varying between 18-22 years of age for a four-week period. Subjects were separated into 3 groups: Group 1; sedentary taking magnesium supplementation only (10 mg/kg/day) (Mg + S), Group 2; subjects magnesium supplemented + training 90-120 min 5 days a week (Mg + Training), Group 3; training 90-120 min 5 days a week. Lactate levels of the groups were measured 4 times; at rest and exhaustion in the beginning of the research and after the end of the research. At the end of the research, exhaustion measurements both before and after supplement were found significantly higher than rest measurements in terms of lactate levels (p < 0.05). An important decrease was determined in the lactate levels of the 1st and 2nd groups when compared to their first measurements (p < 0.05). The results of this research indicate that lactate increases with exhaustion. However, magnesium supplement may positively affect performance of sportsmen by decreasing their lactate levels.     

Adrenocorticotropic Hormone and Cortisol Levels in Athletes and Sedentary Subjects at Rest and Exhaustion: Effects of Magnesium Supplementation

The effects of a 1-month exercise program and magnesium supplementation on the adrenocorticotropic hormone and cortisol levels were studied in young tae-kwon-do and sedentary subjects both at rest and exhaustion. The hormone levels were compared before and after supplementation with 10 mg of magnesium (as magnesium sulfate) per kilogram of body weight. Both exercise and magnesium supplements caused significant increases of the adrenocorticotropic hormone (p < 0.05). The cortisol levels were increased in training subjects receiving supplements (p < 0.05) but not so in subjects that either trained or received magnesium supplements in an independent manner. The cortisol levels measured in resting individuals were higher in the supplemented and non-supplemented athletes than those in sedentary subjects (p < 0.05). The results of this study show that exercise and/or magnesium supplementation causes a rise of the adrenocorticotropic hormone, whereas cortisol is increased only as a result of combined exhaustion and magnesium supplements.     

Testosterone Levels in Athletes at Rest and Exhaustion: Effects of Calcium Supplementation

The effects of 4 weeks of calcium supplementation on free- and total testosterone levels were established in active and sedentary adult males at rest and exhaustion. Thirty healthy male athletes were equally divided into three study groups, as follows: Group 1—non-exercising subjects receiving 35 mg calcium/kg body weight; Group 2—subjects receiving 35 mg calcium/kg body weight undergoing training routines for 90 min/day, 5 days a week and Group 3—subjects undergoing training routines for 90 min/day, 5 days a week. The testosterone levels were determined before and after supplementation, at rest and following a hard training routine. The plasma free- and total testosterone levels increased at exhaustion before and after supplementation relative to resting values (p?<?0.05). This was also true when active subjects were compared to inactive subjects (p?<?0.05). Our results show that training results in increased testosterone levels in athletes and that the increase is greater if accompanied by calcium supplementation, which may be useful for increasing overall athletic performance.     

The relation between reduced serum melatonin levels and zinc in rats with induced hypothyroidism

The objective of the study was to explore the changes in melatonin and zinc levels in rats with induced hypothyroidism. Thirty adult male rats used in the study were allocated to three groups with equal numbers. Group 1: General control group which was not subjected to any procedure. Group 2: Sham-hypothyroidism group to which was administered 10 mg kg(-1) intraperitoneal (i.p.) physiologic saline (0.09% NaCl) for 4 weeks. Group 3: Hypothyroidism group which was supplemented with intraperitoneal 10 mg kg(-1) propylthiouracil (PTU) for 4 weeks. Blood samples collected from all animals at the end of the study by decapitation were analysed for serum Total T4 (TT4), Total T3 (TT3), Free T4 (FT4), Free T3 (FT3) (ELISA) as well as for melatonin (RIA) hormones and zinc levels (atomic emission). Comparison of the study groups in terms of thyroid hormones, melatonin and zinc levels showed that TT4, TT3, FT4, FT3, melatonin and zinc levels in group 3 were lower than those in groups 1 and 2 (p < 0.01). These parameters were not different in groups 1 and 2. The results of the study demonstrate that PTU supplementation for 4 weeks results in a significant inhibition in both melatonin and zinc levels. Inhibited melatonin levels may result from the decrease in zinc levels.     

Effects of oral zinc and magnesium supplementation on serum thyroid hormone and lipid levels in experimentally induced diabetic rats

This study was designed to investigate the effects of oral zinc and magnesium supplementation on serum thyroid hormone and lipid levels in alloxan-induced diabetic rats. Thirty-two albino male rats, weighing 234±34 g, were divided into four experimental groups (control, diabetic, diabetic+zinc supplemented and diabetic+ magnesium supplemented). The experiment lasted for 60 d. The first 45 d of the experiment was the supplementation and last 15 d was the supplementation and diabetes-inducing period. Diabetic+zinc-supplemented and diabetic+magnesium-supplemented groups were given orally (by adding in their drinking water) 227 mg/L of zinc and 100 mg/kg body weight (bw) of magnesium, respectively throughout the experiment. Control and diabetic groups served as controls and did not receive zinc or magnesium supplementation. Diabetic, diabetic+zinc-supplemented, and diabetic+magnesium-supplemented groups were given a daily injection (ip) of 100 mg/kg bw of alloxan for 15 d starting on d 46 of the experiment. The control group was only injected with the same volume of isotonic NaCl as the diabetic group received. At the end of the of the experiment, rats in all four groups were fasted for 12 h and blood samples were taken from the heart under ether anesthesia for the determination of thyroid hormone, glucose, total cholesterol, and triglyceride concentrations. It was found that serum glucose, total cholesterol, and triglyceride concentrations were higher and serum T3 and T4 concentrations were lower in diabetic rats than those in the control group. Zinc supplementation did not change any parameter in diabetic rats. However, magnesium supplementation decreased the elevated total cholesterol and triglyceride concentrations of the diabetic rats to the control level. It was concluded that oral magnesium supplementation might decrease the diabetes-induced disturbances of lipid metabolism.     

Calcium Supplementation and 4-Week Exercise on Blood Parameters of Athletes at Rest and Exhaustion

In the present study, experiments were designed to investigate if supplementation with calcium during 4 weeks had an effect on blood parameters in sedentary male athletes at rest and exhaustion. Thirty healthy subjects of ages ranging from 18 to 22 years were included in the study. The subjects were separated into three groups, as follows: Group 1 consisted sedentary athletes receiving 35 mg/kg/day calcium gluconate. Group 2 included subjects equally supplemented with calcium training 90 min/day for 5 days/week. Group 3 were subject to the same exercise regime but did not receive calcium supplements. Blood parameters were determined in the experimental subjects at rest and after exhaustion. The leukocyte count (WBC) of athletes in groups 2 and 3 were significantly higher at exhaustion (p < 0.05). There were no significant differences in the WBC of the two supplemented groups. The erythrocyte count (RBC) was increased in the supplemented athletes after training (p < 0.05), but hemoglobin, hematocrit, and trombocyte levels remained unchanged. The mean corpuscular volume increased in the calcium-supplemented group at rest (p < 0.05). These results suggest that calcium supplementation only causes increases in white and red blood cell counts in athletes after exhaustion while other hematological parameters remain unchanged.     

The Effects of Exercise and Zinc Deficiency on Some Elements in Rats

The objective of the present study was to determine the effects of exercise and zinc deficiency on some elements in rats. Forty adult male Sprague–Dawley species male rats were allocated to four groups as follows: Group 1: control, Group 2: zinc-deficient, Group 3: exercise in which exercise group fed with a normal diet, Group 4: zinc-deficient exercise, exercise group fed by a zinc-deficient diet for 15 days. After the procedure ended, rats in groups 3 and 4 were exercised on the treadmill for 60 min at a speed of 6 m/min until the exhaustion. The rats were decapitated 48 h after exercise together with their controls, and blood samples were collected to determine copper (Cu), iron (Fe), magnesium (Mg), calcium (Ca), and phosphorus (P) levels. The highest Cu and Fe values in the serum were obtained in group 2 (p < 0.01). The levels of these elements in group 4 were lower than those in group 2 and higher than the levels in groups 1 and 3 (p < 0.01). Serum Mg levels did not differ significantly between groups. Group 4 had the lowest serum Ca and P levels (p < 0.01). These same parameters in Group 2 were higher than those in group 4 but significantly lower than those in groups 1 and 3 (p < 0.01). There was no significant difference between Ca and P levels of groups 1 and 3. The results of the study indicate that zinc deficiency adversely affects copper, iron, calcium, and phosphorus mechanisms and that these adverse effects much more marked after an effort exercise.     

Effect of magnesium supplementation and training on magnesium tissue distribution in rats

The aim of this work is to study the effect of training and Mg supplementation on body pools of Mg and on Mg tissue distribution. Forty male Wistar rats were divided into four groups (n=10): control group (C); trained group (T); Mg-supplemented group (+Mg); and trained and Mg-supplemented group (+MgT). The Mg supplement (100 ppm of Mg) was given in the drinking water for 21 d. The training consisted of swimming during 60% of maximal swimming time obtained in the first session to exhaustion, during 3 wk (5 d a week). The variables measured were: erythrocytes (RBC), hemoglobin (Hb), hematocrit (Hto), total proteins (TP), and Mg in serum, RBC, liver, muscle, bone, and kidney. There was less Mg in liver, muscle, and erythrocyte in trained animals than in control or supplemented animals (T vs C, +MgT vs C and +MgT vs +Mg) (p < 0.01). Trained antimals (T and +MgT) showed higher Mg kidney rates than the untrained ones (p<0.01). There was less bone Mg in control (C) and in supplemented and trained (+MgT) groups than in trained (T) and in supplemented (+Mg) animals (p<0.01). Serum Mg showed a decreasing concentration profile in the following order: +Mg, +MgT, T, C (p<0.01). We conclude that Mg supplementation improves bone and serum Mg levels, but this does not affect Mg status in soft tissues. Maintained exercise leads to a diminution of Mg in the aforementioned soft tissues that is not noticeable in serum, probably provoked by an increase of renal excretion.     

Effect of Magnesium Supplementation on Some Plasma Elements in Athletes at Rest and Exhaustion

The effects of magnesium supplementation on plasma magnesium, zinc, and copper levels were determined in young adult tae-kwon-do athletes and sedentary controls at rest and exhaustion. After a 4-week supplementation period with 10 mg/day/kg Mg, the plasma magnesium, copper, and zinc levels significantly increased in sedentary and training (90–120 min training 5 days a week) subjects when compared to nonsupplemented controls (p < 0.05).     

Effect of zinc supplementation on hematological parameters in athletes

The hematological effects of oral supplementation of zinc to training athletes are reported in the present study. A total of 30 subjects between 16 and 22 yr of age volunteered to participate in a 4-wk study. They were equally divided into three groups. Group 1 acted as resting controls receiving daily doses of 3 mg Zn/kg body wt. Group 2 was actively engaged in wrestling and exercised for 90–120 min, 5 d a week. Group 3 was also actively engaged in wrestling and exercised for 90–120 min, 5 d a week, but they were supplemented with 3 mg Zn/kg body wt per day. The erythrocyte, leukocyte, and thrombocyte counts and the hemoglobin values of all subjects participating in the study were measured before and after exercise at the beginning and at the end of the 4-wk study period. In all groups, there were no significant differences in the measured parameters before and after exercise. At the end of the supplementation period, the parameters of the subjects in groups 1 and 3 were significantly higher than those of group 2, both before (p<0.005) and after (p<0.05) exercise. These results suggest that zinc supplementation has a positive effect on hematological parameters in athletes.     

Effects of zinc deficiency and supplementation on some hematologic parameters of rats performing acute swimming exercise

The aim of the study was to investigate how zinc deficiency and supplementation effect some hematologic parameters of rats performing swimming exercise. Forty adult male Spraque-Dawley rats were divided into 4 groups, zinc deficient swimming group (Group 1, n=10, zinc supplemented swimming group (Group 2, n=10), swimming control group (Group 3, n=10), and control group (Group 4, n=10). Blood samples were taken by decapitation and analyzed for the determination of erythrocyte, hemoglobin level, hematocrit, leukocyte, lymphocyte, platelet count and plasma zinc level at the end of the 4 week experiment. Erythrocyte count of group 1 was the lowest whereas erythrocyte count in group 3 was significantly lower than that in group 2 and 4 (p<0.05). Hemoglobin level of group 1 was significantly lower than that of groups 2 and 4 (p<0.05). Hematocrit was significantly lower in both group 1 and group 3 than both groups 2 and 4 (p<0.05). Lymphocyte count in group 2 was significantly higher than in all other groups (p<0.05). Platelet counts in group 2 was significantly lower than in all other groups (p<0.05). Our findings suggest that zinc deficiency effects the hematologic parameters mentioned negatively whereas zinc supplementation has a positive influence.     

Impact of Methimazole Treatment on Magnesium Concentration and Lymphocytes Activation in Adolescents with Graves’ Disease

The aim of this research was to assess plasma magnesium (Mg) concentration, the frequencies of activated T CD4+ and T CD8+ lymphocytes and B lymphocytes in adolescents with hyperthyroidism due to Graves’ disease (GD), and to assess changes in the above-mentioned parameters during methimazole (MMI) treatment. The frequencies of activated T and B cells were measured by flow cytometry method and plasma Mg concentration was determined by spectrophotometry method in 60 adolescents at the time of GD diagnosis and after receiving the normalisation of the thyroid hormones levels. The control group consisted of 20 healthy volunteers. We observed lower plasma Mg concentration, and higher frequencies of activated T and B lymphocytes in the study group before the treatment in comparison with healthy controls, and with study group in MMI-induced euthyreosis (p?<?0.01).Statistically significant negative correlations between the percentages of activated T CD3+, T CD4+, T CD8+ and B CD19+ lymphocytes, and plasma Mg concentration before the treatment were found (r?<??0.335, p?<?0.002). After the treatment no vital differences in plasma Mg concentration, and in percentages of activated cells between GD patients and controls were found, except CD8+CD25+ cells (p?=?0.03). The present study demonstrates that both activated T and B cells might play an important role in the pathogenesis of GD, and activation is related to Mg plasma level. The use of MMI in treatment of hyperthyroidism due to GD leads to decrease the frequencies of activated lymphocytes and normalisation of Mg levels.     

Effect of selenium supplementation on thyroid hormone levels and selenoenzyme activities in growing lambs

The aim of the present study was to evaluate the effects of selenium supplementation on thyroid hormone metabolism and selenoenzyme activities in lambs. Twelve 20-d-old male lambs were assigned to one of two diets: A (0.11 ppm Se) and B (supplemented with 0.2 ppm selenium as sodium selenite). Blood samples were collected weekly for the determination of T₃, T₄, and selenium levels. The response to thyrotropin-releasing hormone (TRH) challenge was estimated at the 11th and 20th wk. Animals were slaughtered at wk 20 and tissues were collected for enzyme determination. Plasma selenium concentration was significantly higher in supplemented lambs (p<0.001). Plasma T₃ and T₄ levels remained similar in both groups. Type I deiodinase activity (ID-I) was decreased in the liver (p<0.05) and increased in the pituitary (p<0.01) of supplemented animals. No ID-I activity was detected in the thyroid. Pituitary type II deiodinase activity (ID-II) remained unchanged. The response to TRH challenge did not differ between the two groups for both challenges, but in group B, the second TRH challenge (20th wk) resulted in a significantly higher T₃ response compared to the first one (11th wk) (p<0.05). In conclusion, the lack of effects of Se supplementation on thyroid hormone metabolism demonstrates that enzyme activity is homeostatically controlled and selenium is incorporated in that order to ensure the maintenance of thyroid hormone homeostasis.     

Association of Thyroid Function with Posttraumatic Stress Disorder: a Systematic Review and Meta-Analysis

Objective: To conduct a systematic review and meta-analysis describing the association of thyroid function with posttraumatic stress disorder (PTSD) in adults.Methods: The authors conducted a comprehensive search from databases’ inception to July 20, 2018. The meta-analysis included studies that reported mean values and standard deviation (SD) of thyroid hormone levels (thyroid-stimulating hormone &lsqb;TSH], free thyroxine &lsqb;FT4], free triiodothyronine &lsqb;FT3], total T4 &lsqb;TT4], and total T3 &lsqb;TT3]) in patients with PTSD compared with controls. Five reviewers worked independently, in duplicate, to determine study inclusion, extract data, and assess risk of bias. The mean value and SD of the thyroid function tests were used to calculate the mean difference for each variable. Random-effects models for meta-analyses were applied.Results: The meta-analysis included 10 observational studies at low-to-moderate risk of bias. Studies included 674 adults (373 PTSD, 301 controls). The meta-analytic estimates showed higher levels of FT3 (+0.28 pg/mL; P = .001) and TT3 (+18.90 ng/dL; P = .005) in patients with PTSD compared to controls. There were no differences in TSH, FT4, or TT4 levels between groups. In the subgroup analysis, patients with combat-related PTSD still had higher FT3 (+0.36 pg/mL; P = .0004) and higher TT3 (+31.62 ng/dL; P<.00001) compared with controls. Conversely, patients with non–combat-related PTSD did not have differences in FT3 or TT3 levels compared with controls.Conclusion: There is scarce evidence regarding the association of thyroid disorders with PTSD. These findings add to the growing literature suggesting that thyroid function changes may be associated with PTSD.     

Anticonvulsants and thyroid function.

Serum total and free thyroid hormone concentrations were estimated in 42 patients with epilepsy taking anticonvulsants (phenytoin, phenobarbitone, and carbamazepine either singly or in combination). There was a significant reduction in total thyroxine (TT4), free thyroxine (FT4), and free triiodothyronine (FT3) in the treated group compared with controls. Free hormone concentrations were lower than total hormone concentrations, suggesting that increased clearance of thyroid hormones occurs in patients receiving anticonvulsants. Detailed analysis indicated that phenytoin had a significant depressant effect on TT4, FT4, FT3, and reverse T3 (rT3). Phenobarbitone and carbamazepine had no significant main effects, but there were significant interactions between phenytoin and carbamazepine for TT4 and FT4. phenobarbitone and carbamazepine for FT3, and phenytoin and phenobarbitone for rT3.     

Effect of Selenium Supplementation on Lipid Peroxidation,Antioxidant Enzymes,and Lactate Levels in Rats Immediately After Acute Swimming Exercise

The present study aims to evaluate the effect of selenium supplementation on lipid peroxidation and lactate levels in rats subjected to acute swimming exercise. Thirty-two adult male rats of Sprague–Dawley type were divided into four groups. Group 1, control; group 2, selenium-supplemented; group 3, swimming control; group 4, selenium-supplemented swimming group. The animals in groups 2 and 4 were supplemented with (i.p.) 6 mg/kg/day sodium selenite for 4 weeks. The blood samples taken from the animals by decapitation method were analyzed in terms of erythrocyte-reduced glutathione (GSH), serum glutathione peroxidase (GPx) and superoxide dismutase (SOD), and plasma malondialdehyde (MDA) and lactate using the colorimetric method, and serum selenium values using an atomic emission device. In the study, the highest MDA and lactate values were found in group 3, while the highest GSH, GPx and SOD values were obtained in group 4 (p < 0,001). Group 2 had the highest and group 3 had the lowest selenium levels (p < 0,001). Results of the study indicate that the increase in free radical production and lactate levels due to acute swimming exercise in rats might be offset by selenium supplementation. Selenium supplementation may be important in that it supports the antioxidant system in physical activity.     

Leptin injection during lactation alters thyroid function in adult rats.

The aim of this study was to evaluate the effects of hyperleptinemia during the first ten days of life on thyroid function in adulthood. After birth, pups were separated into two groups: L8 - receiving daily injections of recombinant mouse leptin (8 microg/100 g body weight, sc) and control (C) - receiving the same volume of saline. Both groups were treated for the first 10 days of lactation. The animals were sacrificed at 150 days of age, and the blood was collected for leptin, TSH, total triiodothyronine (TT 3 ) and total thyroxin (TT 4 ) serum concentration determinations by radioimmunoassay. The thyroid gland was excised to determine thyroid iodine uptake. Leptin, TT 3 and TT 4 serum concentrations in L8 group were significantly (108 %, 47 % and 32 %; p < 0.05) higher than that of controls. There was no significant difference between the groups related to thyroid iodine uptake and TSH serum concentration. These data suggest that the first half of lactation period is important in determining thyroid function in adulthood, and that it can be programmed by serum leptin concentration.     

The Effect of Low Dose Zinc Supplementation to Serum Estrogen and Progesterone Levels in Post-menopausal Women

The objective of the present study is to investigate how low-dose zinc supplementation for 2 weeks in the post-menopausal period influences levels of estrogen and progesterone in the serum. The study registered 32 natural menopause patients, who were allocated to four groups with equal number of patients. Group 1, control group, which was not subjected to any procedure. Group 2, the group that was supplemented with 15 mg/day zinc sulfate for 2 weeks. Group 3, the group that was given hormone replacement therapy (0.625 mg estrogen?+?5 mg medroxyprogesterone acetate/day) for 2 weeks. Group 4, the group that received hormone replacement therapy (0.625 mg estrogen?+?5 mg medroxyprogesterone acetate/day) and zinc sulfate (15 mg/day) for 2 weeks. Blood samples were collected twice from each subject, once at the beginning of the study, and once at the end of the 4-week procedure to determine estrogen (E2) and progesterone levels. Variance analysis was employed in the statistical evaluation of data. Level of significance was set at p?<?0.05. No significant difference was found between the estrogen and progesterone levels of groups 1 and 2. Groups 3 and 4 had higher estrogen and progesterone levels than groups 1 and 2 (p?<?0.05). Estrogen and progesterone levels in groups 3 and 4 were not different. Results of the study show that low-dose zinc supplementation to post-menopausal women for 2 weeks does not have a significant effect on the concerned parameters.