Vitamins & Minerals Chapter 9

Vitamins Organic compounds that are essential for the optimal functioning of many different physiological processes in the body Major Functions –Coenzymes –Hormones –Neurotransmitters –Antioxidants

Vitamin Categories Water Soluble –Vitamin C –B-Vitamins (thiamin, riboflavin, niacin, B 6, B 12, folic acid, pantothenic acid, biotin) Fat Soluble –Vitamin A (Retinol or beta carotene) –Vitamin D (calciferol) –Vitamin E (  -tocopherol) –Vitamin K (menaquinone)

Exercise and Vitamin Requirements Inadequate vitamin status impairs performance Dies exercise increase vitamin requirement –Decreased absorption? –Loss in sweat? –Increased mitochondrial density? –Muscle hypertrophy? –Anti-oxidant requirement?

Athletes at Risk Low energy intake –Females –Gymnasts, dancers, wrestlers Unbalanced diet

Vitamin Supplementation Above the DRI or RDA Vitamin B6 may improve aerobic power Vitamin C may enhance heat acclimatization Vitamin E may enhance aerobic power at altitude B-complex vitamins may increase short term performance/recovery in hot climates

Antioxidants & Free Radicals Oxygen Free Radicals –Molecules with an unpaired electron in their outer orbit –Produced by the reduction of molecular oxygen, and ongoing process during normal cellular respiration –Examples are superoxide (O 2 - ), hydrogen peroxide (H 2 O 2 ), and hydroxyl radical (OH - ) –Between 2-5% of the total electron flux during normal metabolism generate free radicals

Consequences of Free Radicals Deterioration of membrane lipids Changes in membrane protein structure Mitochondria appear to be most susceptible to free radical damage Free radical damage has been implicated in diseases such as heart disease, cancer, diabetes, immune dysfunction, accelerated aging

Exercise and Free Radicals Increase in cellular respiration increases FR production Increase in body temperature increases rate of FR formation Increase in catecholamines increases FR formation

Natural Defenses Against Free Radicals Protective antioxidant enzymes Exercise training increases the level of antioxidant enzymes but oxidative potential of the muscle increases more Nutritional antioxidants work with the enzymes Primary nutritional antioxidant vitamins are C, E, and beta-carotene

Recommended Intake of Antioxidant Vitamins Beta-Carotene –DRI: mg –Recommended: 20 mg Vitamin C –DRI: mg –Recommended: 250 mg Vitamin E –DRI: 22.5 IU –Recommended: 150 IU

Minerals Minerals are inorganic solid elements found in nature in plants, animal tissue, and water. 15 known essential minerals and 5 nonessential composing less than 4% of the body weight

Functions of Minerals Building blocks for body tissues such as bones, teeth, & muscles Components of metalloenzymes which regulate metabolism Exist as ions or electrolytes involved in metabolism & body water regulation Components of hormones

Classification of Minerals Macrominerals –RDA or ESADDI is > 100 mg per day or body contains more than 5 grams –Calcium, phosphorus, magnesium, potassium, sodium chloride, sulfur Trace Minerals –Needed in quantities < 100 mg –Iron, copper, chromium, selenium, boron, vanadium, cobalt, fluoride, iodine, manganese, molybdenum

Calcium Major Functions –Bone formation –Enzyme activation –Nerve impulse transmission –Muscle contraction –Cell membrane potentials

Current DRIs for Calcium Ages 9-18 –Males: 1300 mg –Females: 1300 mg Ages –Males: 1000 mg –Females: 1000 mg

Factors Altering Ca Absorption/Utilization Dairy sources absorbed better than plant –Vitamin D and lactose increase –Phytates in plants decrease Fiber decreases Excessive protein decreases Excessive coffee decreases Excessive alcohol decreases

Consequences of Low Ca Low serum calcium is rare because of the ability to absorb Ca from bones –Muscular cramping –Impaired muscular contraction Colon Cancer Osteoporosis

Consequences of Too Much Ca Abnormal heart rhythms Kidney stones Reduces iron and zinc absorption

Calcium Supplements Calcium citrate, carbonate, lactate, gluconate, antacids Citrate is the best for absorption Taken with meal is best Taken in mg doses is best

Female Athlete Triad Disordered eating Secondary amenorrhea due to hormonal deficits and imbalances Osteoporosis

Iron Major Functions –Used to form hemoglobin, cytochromes, and Kreb-cycle metalloenzymes 70% is activety used 30% is stored as ferritin –As many as 90% of females get less than RDA but body partly compensates by increasing absorption –16% of females have iron-deficiency anemia

RDA for Iron Ages 9-13 yr –Males: 8 mg –Females: 8 mg Ages yr –Males: 11 mg –Females: 15 mg Ages yr –Males: 8 mg –Females: 18 mg

Types of Iron Heme iron –Animal sources –Best absorption: 10-30% –Animal sources are 40% heme, 60% non- heme Non-heme iron –Plant sources –Poorly absorbed: 2-10%

Factors Affecting Iron Absorption Increases absorption –Vitamin C for non-heme iron –MPF for both heme and non-heme Decreases absorption –Tannins in tea (by 60%) –Phytic acid in whole grains –Oxalic acid in green leafy vegetables –Calcium for non-heme

Sources of Iron Animal –4 oz liver- 10 mg –4 oz beef, pork, dark poultry – 5-6 mg –4 oz white poultry – 1 mg Plant –8 oz prune juice – 3 mg –1/3 cup dates, raisins, prunes – 1 mg –½ cup spinach, beans, broccoli – 2 mg

Iron Deficiency Stage 1 –Depletion of bone marrow stores and decrease in serum ferritin Stage 2 –Further decrease in serum ferritin and loss on some Hb, but Hb still normal –30-50% of female and 15-30% of male distance runners are in this stage Stage 3 (iron-deficiency anemia) –Very low serum ferritin and low Hb –< 13 grams Hb for males –< 11 grams Hb for females

Sports Anemia Low Hb levels due to expanded blood volume Iron stores are normal

Iron Supplementation and Performance Iron supplementation will improve performance in iron-deficiency anemia Iron supplementation will improve iron status in iron deficiency (stage 2) without anemia but may not improve performance Iron supplementation will not improve performance when iron stores are normal

Sodium or Natrium (Na + ) Functions –Primary electolyte in extracellular fluid –Fluid balance and osmotic pressure –Nerve conduction and muscle contraction

Recommended Na + Intake No RDA Minimal requirement is 500 mg Salt is 40% sodium Most recommendation is < 3000 mg/day

Effects of High N + Intakes Associated with high BP in ~ 20% of population Water retention

Effects of Low Na + Intakes Muscle cramps???? Disruption of cardiac electrical activity which can result in death

Sources Containing 300 mg Ca 8 oz of milk 1.5 oz of cheese 1 cup yogurt 1.75 cups ice cream 8 oz fortified OJ 1 serving fortified cereal