Effects Of Physical Performance

Due to riboflavin's involvement in many metabolic functions critical to exercise performance, its use as a performance enhancer has emerged. Specifically, riboflavin is involved in muscle cell energy metabolism. Recall that FAD and FMN are important in the metabolism of glucose, fatty acids, glycerol and amino acids for energy. When physical activity is performed, stress is put upon the biochemical pathways involved in the metabolism of these substrates.1228 Before we can examine riboflavin's...

Exercise And Ascorbic Acid Requirements

Various tissues such as the adrenal glands, spleen, liver and brain. This would seem to indicate that exercise increased the need for vitamin C in these animals. Studies evaluating the effect of exercise on ascorbic acid needs in humans are greater in number and more diverse in their approach as compared with animal studies. Human studies have addressed the relationship between exercise and vitamin C for blood plasma and leukocyte concentrations of the vitamin, excretion in the urine, immune...

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FIGURE 13.2 Antioxidant supplementation (300 mg vitamin E and 1000 mg vitamin C for 6 weeks) prevented increases in plasma F2-Isoprostane concentrations following a 50 km ultramarathon. There were no statistically significant differences detected between sexes or treatment groups in F2-Isoprostane concentrations (mean SE) at baseline or following 6 weeks daily supplementation with vitamin E and vitamin C (AO) or placebos (PL).24 At post-race, F2- Isoprostane concentrations were elevated in the...

Effect Of Deficiency Or Excess On Physical Performance

Lack of evidence of a significant increase in urinary iodine excretion during exercise suggests that the changes in thyroid hormone metabolism are perhaps transitory and compensated for by feedback mechanisms in the body. Current opinion is that there is no evidence to suggest a greater requirement in physically active individuals, and that iodine intake in athletes is adequate or excessive.74,75 This is probably due to, and may be also a reason for, the complete lack of research on the role of...

Evaluation Of Vitamin A Intake Among Athletes

A great majority of the available studies reported total vitamin A intake without specifying the proportion obtained from animal and plant sources, and many used International Units, which only added to the confusion when reporting total vitamin A intake from mixed foods and supplements. Recently introduced new conversion factors for vitamin A activity of carotenoids4 render all previous reports inaccurate, because of the overestimated contribution from plant sources. Adult athletes are usually...

Toxicity

The hexavalent form of Cr (Cr6+), used for industrial purposes such as dyes, leather tanning and chrome plating, is toxic, and exposure to this form has caused short-term effects such as asthma or bronchitis, or long-term carcinogenic effects.53 Cr6+ passes through the cell membrane where it reacts with DNA in the process of being converted to its trivalent form, with the potential for genotoxic effects.54 One tissue culture study reported that high concentrations of Cr(pic)3 caused chromosome...

General Properties and Metabolic Functions

The signs of molybdenum deficiency in animals have been reviewed.93 In rats and chickens, molybdenum deficiency aggravated by excessive dietary tungsten results in the depression of molybdenum enzymes, disturbances in uric acid metabolism and increased susceptibility to sulfite toxicity. In goats, deficiency uncomplicated by high dietary tungsten or copper resulted in depressed food consumption and growth, and impaired reproduction characterized by infertility and elevated mortality in both...

Copper Requirments Of Athletes

The FNB defines the dietary reference intakes (DRI) as reference values that are quantitative estimates of nutrient intakes to be used for planning and assessing diets for apparently healthy people. They include not only RDAs but also three other types of reference values.4 These reference values include the adequate intake (AI), the recommended average daily intake based on experimental determinations or estimates of nutrient intakes by groups of healthy people the tolerable upper intake level...

Metabolism

The mechanisms involved in the intestinal absorption and blood transport of silicon are unknown. A study with guinea pigs indicated that silicon is absorbed mainly as monomeric silicic acid.182 In humans, monosilicic acid in foods and beverages is readily absorbed, penetrates all body fluids and tissues at concentrations less than its solubility (0.01 ) and is excreted in urine.183 Some of the absorbed monosilicic acid can come from food polymeric silica, which can be partly dissolved by fluids...

Copper and Mitochondrial Oxidative Stress

Four oligomeric enzymes, NADH ubiquinone oxidoreductase (complex I), succinate ubiquinone oxidoreductase (complex II), ubiquinol cytochrome c oxidoreductase (complex III) and ferrocyto-chrome c oxygen oxidoreductase (complex IV), compose the mitochondrial electron transport chain located in the inner mitochondrial membrane. Electrochemical energy derived from the transfer of electrons between these enzymes to molecular oxygen drives the vectorial translocation of protons across the inner...

Copper Concentrations In Blood And Body Organs

The human body contains about 1.6 mg of Cu kg of body weight with variable distributions in various organs and blood. Examples of Cu concentrations in various tissues include kidney, 12 mg kg liver, 6 mg kg brain, 5 mg kg heart, 5 mg kg bone, 4 mg kg and muscle 0.9 mg kg. Bone contains 40 of body Cu, the highest percentage of any other organ muscle is second at about 23 . These organs also make up the greatest percentages of the body mass. Blood contains about 6 of total body Cu. The Cu...

Thiamin In Physical Activity And Exercise

Thiamin is important for physically active individuals, given its critical role in carbohydrate and amino acid metabolism. Manore67 reported that thiamin, riboflavin, vitamin B-6, niacin, pantothenic acid and biotin are involved in energy production during exercise. Consequently, it has been suggested that thiamin deficiency may lead to decreased athletic performance.68 To investigate whether physical activity and exercise increase the dietary requirements of thiamin, researchers have compared...

Effect of Exercise on Thyroid Function

Exercise appears to enhance the rate of utilization or disposal of T4.25 Evidence for an increase in T4 metabolism induced by physical activity comes from research, using the radioactive T4 turnover technique in which the loss of a single injection of T4 125I from the plasma was determined as a function of time, in horses26 and rats,27 28 as well as in athletes.29 In athletes, exercise resulted in the degradation of circulating T4 by 17 per day compared with 10 in the control group.29 This...

Watersoluble Vitamins And Choline

Numerous researchers have investigated the ergogenic effects of ascorbic acid (vitamin C) and the results of these studies are mixed. Vitamin C deficiency or even marginal vitamin C status is known to adversely influence physical performance. Reports exist that up to 25 of athletes consumed less than the RDA for vitamin C. Several studies indicate that strenuous or prolonged exercise increases the need for vitamin C. For subjects having adequate vitamin C status prior to supplementation,...

Identity And Roles Of Vitamins And Trace Minerals

Vitamins are an extremely diverse range of low-molecular-weight compounds that have been classified more by legislative definitions than by common biochemical functions. Vitamins recognized by the Food and Nutrition Board of the Institute of Medicine of the National Academy of Science in the United States include Vitamin A (retinols and beta carotene) Vitamin Bj (thiamin) Vitamin B2 (riboflavin) Vitamin B3 (niacin and niacinamide) Vitamin B6 (pyridoxine and related congeners), Vitamin Bj2...

Metabolic Functions Of Selenium

Since the discovery of cytosolic GSHPx, other selenoproteins including additional antioxidant enzymes have been identified in mammals. A distinct, glycosylated GSHPx has been found in the plasma and a membrane-associated enzyme, phospholipid hydroperoxide GSHPx (PLGSHPx) has been reported to be widely distributed in tissues.1011 While an exact function is not totally clear, selenoprotein-P is found in plasma and tissues and appears to have some antioxidant or selenium transport properties.1012...

Effects Of Selenium On Athletic Performance

Most research in the area of Se and exercise has focused on the role of Se in the antioxidant enzyme GSHPx which, using GSH, converts H2O2 to water. Whole-body and especially muscle oxygen uptake increases sharply during intense physical exercise leading to increased oxidative stress.61 This oxidative stress may be related to production of ROS such as superoxide in the mitochondria during exercise. Superoxide, when acted on by superoxide dismutase (SOD), produces H2O2, which can then be...

Role of Copper in Blood Cell Formation and Function

Although knowledge of the exact role of Cu in blood cell formation is limited, observations in Cu-deficient animals and humans show prominent connections between Cu status and blood cell production, survivability and function. These functions could be compromised during strenuous exercise. In both animals and humans, Cu deficiency presents with a reduced population of RBCs that are smaller than normal and with a reduced hemoglobin concentration. Although the signs mimic Fe deficiency,...

Vitamin b6 in sports and exercise

Vitamin B6 is a cofactor for many metabolic reactions that produce energy, including the transamination of amino acids and the release of glucose from glycogen. Thus, it is not surprising that researchers would ask whether exercise and physical activity increases the need for vitamin B6. This section will review the current literature examining whether physical activity increases the need for vitamin B6 due to training-induced changes in metabolism that require the vitamin. First, the...

Interaction Of Selenium With Other Nutrients

Vitamin E and Se function as synergistic antioxidants, and many of the signs and symptoms of a double deficiency of these two nutrients can be prevented or will be improved by supplementation with either nutrient.22 Beck et al.32 reported that vitamin E deficiency increased the cardiac pathology associated with Coxsackie B3 infection in mice, especially in mice fed diets high in menhaden oil as opposed to lard, for dietary fat. Work by Beck et al.30,32 on the effects of both Se and vitamin E...

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FIGURE 10.2 Metabolic Pathways of Choline. Adapted from Blusztajn.27 in the liver. The betaine pathway also provides methionine for protein synthesis.32 Third, choline is a precursor for compounds that serve critical cell signaling functions, including phosphorylcholine 33 platelet-activating factor, (PAF), a choline plasmalogens and sphingophosphorylcholine.34 In addition, the choline-containing phospholipids, phosphatidylcholine and sphingomyelin, are precursors for two other molecules that...

References

Bender, D.A., Nutritional Biochemistry of the Vitamins, 2nd ed., Cambridge University Press, Cambridge, U.K., 2003. 2. Combs, G.F., The Vitamins. Fundamental Aspects in Nutrition and Health, 2nd ed., Academic Press, San Diego, 1998. 3. Institute of Medicine, Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B& Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline, National Academy Press, Washington, D.C., 1998. 4. Rucker, R.B., Suttie, J.W., McCormick, D.B., and...

Functions Of Iodine

Iodine functions as an integral part of the thyroid hormones, the pro-hormone thyroxine (T4), and the more potent active form 3,5,3'-triiodothyronine (T3) which is the key regulator of important cell processes.3 Selenium is essential for normal thyroid hormone metabolism as a component of the iodothyronine 5'-deiodinases that control the synthesis and degradation of the biologically active hormone, T3.4 The thyroid hormones are required for normal growth and development of individual tissues...

Effects Of Increased Intake Of Vitamins And Trace Minerals On Exercise Performance And Metabolism

Other chapters in this book are concerned with individual vitamins and minerals therefore, a brief review of the effects of multiple vitamin-mineral supplementation on exercise parameters will be presented in this chapter. At present, there is considerable controversy over the use of and need for essential micronutrient supplementation in exercising humans. After examination of the existing human studies on multiple vitamin-mineral supplementation and physical performance, the reader should...

Basis for Sports Nutrition Interest

There is relatively little reason for molybdenum to be of interest to physically active people. Molybdenum is a transition element that readily changes its oxidation state and can thus act as an electron transfer agent in oxidation-reduction reactions in which it cycles from Mo6+ to reduced states. This is the basis for molybdoenzymes' catalyzing the hydroxylation of various substrates using oxygen from water. Molybdenum hydroxylases may be important in metabolizing drugs and foreign compounds...

Assessment of thiamin

The total thiamin concentration in the body is about 25-30 mg, where TPP is the primary form. In addition, about 80 of the thiamin in whole blood is present in erythrocytes.60 Because the body cannot store thiamin for long periods, thiamin deficiency may develop without adequate regular ingestion of thiamin. Therefore, thiamin assessment provides a useful tool not only in identifying thiamin deficiency, but also to evaluate the nutritional status of different groups. Many procedures are used to...

Effect of Exercise on Iodine Metabolism

There has been very little study of the effects of exercise on iodine metabolism. Just two studies22-24 have investigated the iodine in sweat and urine of athletes. In a study of 10 Japanese rowing club students in 1985, the iodine concentration in sweat was close to 37 g l regardless of urinary iodine excretion, which was 50-393 (mean 149) g day during 6 consecutive days of a summer training camp, similar to that of 40-441 (mean 153) g day in five sedentary students,22 In a subsequent Chinese...

Dietary Intake And Status Assessment

Dietary and Supplemental Sources 1. Pantothenic Acid Human requirements for pantothenic acid have not yet been quantified. Hence, recommendations for adequate intake (AI) are based on the average daily intake in healthy individuals.58 The AI is 5 mg day of pantothenic acid for adults of both genders. The AI of pantothenic acid in pregnant and lactating women is 6 mg day and 7 mg day, respectively.17,58 Pantothenic acid is widely distributed in plant, animal and microbial cells. In...

Nicotinic Acid And Substrate Availabilityperformance

Nicotinic Acid Effects on Fuel Utilization at Rest Numerous investigators have demonstrated changes in FFA mobilization as a result of ingesting or infusing nicotinic acid. The articles that were reviewed all indicated that plasma or serum FFA levels were lowered by the presence of nicotinic acid. Havel, Carlson, Ekelund and Holmgren37 investigated the effects of norepinephrine and nicotinic acid on energy metabolism in seven 21-26-year-olds. They ingested 1-3 g of nicotinic acid daily for 3...

Choline And Exercise Interactions

A role for choline in physical activity evolved based on the importance of ACh in neuromuscular function.7111617 It was reasonable to postulate that, as a neurotransmitter released at the neuromuscular junction in response to nerve stimulation, ACh may be rate limiting for exercise performance. In particular, if release of ACh by cholinergic neurons were related to the level of physical activity,16 then as the duration or intensity of the physical activity increased, comparable increases in ACh...

Conclusions And Future Issues

Choline is an essential nutrient that is only beginning to be fully appreciated and understood. There is little doubt that choline serves a multitude of important roles, both functional and structural, that can influence overall health and physical and cognitive performance. Whether supplementation with choline will overcome existing deficits, enhance selected physical activity and performance or provide a safe and effective approach for treating various illness and disorders remains to be...