Minerals are naturally occurring substances, chemical elements, that the body needs to carry out its processes. The are macrominerals, those that are found in body in amounts greater than 5 grams, and trace elements, those found in amounts less than 5 grams. Minerals help the body to maintain fluid balance and acid-base balance (pH). Each mineral has a specialized role in this process.
Macrominerals
Calcium is the body’s most abundant mineral and is stored in the bones and teeth. It is an important part of bone structure and this stored calcium can release into the body if a drop in blood calcium concentration occurs. Calcium is important in nerve transmission, helps maintain blood pressure, aids in blood clotting, is needed for muscle contraction, allows secretion of hormones, digestive enzymes, and neurotransmitters, and activates cellular enzymes. Deficiencies cause bone loss or stunted growth; toxicity interferes with the absorption of other minerals and risk of kidney stones.
DRI: Adults 19-50 yrs old 1,000mg/day
Food sources:
1c milk 300mg
1.5c broccoli 93mg
1.5 oz cheddar cheese 306mg
Phosphorus is found mostly in the bones and teeth and helps to maintain acid-base balance, assists in energy metabolism, and forms part of cell membranes. Phosphorus needs are easily met by most diets. Deficiencies cause muscle weakness and bone pain; toxicity causes calcification of soft tissues.
DRI: 700mg/day
Food sources:
1c cottage cheese 341mg
3oz sirloin steak 208mg
1c milk 235 mg
Magnesium is used in building protein, helps the body use energy, and plays a role in immune function.
DRI: Men 400 mg/day; Women 310mg/day
Food sources:
½c black beans 60mg
1c yogurt 43mg
½c spinach 78mg
Sodium maintains fluid and electrolyte balance and is essential to muscle contraction and nerve transmission. A sodium deficiency in an athlete can lead to cramping. Most diets in the US are extremely high in sodium and if you look at food labels you will quickly see how much sodium is in many of your favorite foods. Too much sodium can increase blood pressure. DRI recommended intakes for sodium is 1,500mg/day. Tolerable Upper Intake Levels are set at 2,300mg. Try to stay below the UI by monitoring your daily sodium intake, eating less processed foods, and cooking without salt.
Potassium plays a role in maintaining fluid and electrolyte imbalance, cell integrity and heartbeat. Dehydration leads to a loss of potassium . Potassium from foods is safe, but when injected into the vein, can stop the heart. Please check with a physician before taking potassium supplements that may deliver a large dose causing muscle weakness or vomiting.
DRI: 4,700mg/day
Food sources:
1c orange juice 496mg
1 baked potato 844mg
1 banana 422 mg
Chloride helps maintain fluid and electrolyte balance. No known diets lack chloride, and the principal food source is salt.
Sulfate is used to synthesize sulfur-containing compounds such as hair, skin, and nails.
Trace Minerals
Iodine is part of thyroxine, the hormone that influences energy metabolism. It is an additive in milk and bakery products as well as being found naturally in seafood. The DRI is 150 micrograms.
Iron carries oxygen in the blood and muscles. It is required for energy metabolism. The amount absorbed increases when the body is deficient and decreases when iron is abundant. Iron deficiencies can cause anemia, weakness, fatigue, impaired immunity, and other health issues. Iron fortified foods can help individuals avoid deficiency.
DRI: Men 8mg/day; Women 18mg/day
Food sources:
½c black beans 1.8mg
½c spinach 3.2mg
3oz beef steak 2.6mg
Zinc assists enzymes in cells associated with hormones, taste perception, synthesis of genetic material and proteins, reproduction, wound healing and transport of vitamin A. Too much zinc from supplements can block copper and iron absorption. Zinc from foods is nontoxic.
DRI: Men 11mg/day; Women 8mg/day
Food sources:
1c yogurt 2.2mg
3oz pork chop 2mg
3oz shrimp 1.5mg
Selenium works to help prevent oxidative harm to the body’s cells and tissues. Selenium is abundant in unprocessed foods such as vegetables and grains grown in selenium rich soil, as well as meats and shellfish. DRI: 55micrograms/day
Fluoride is beneficial to the diet because it helps stabilize bones and prevent tooth decay. It is found most often in drinking water. DRI: Men 4mg/day; Women 3mg/day
Chromium works to control blood glucose concentrations. It can be found in unrefined foods and whole grains. DRI: 50 micrograms/day
Copper is needed to form hemoglobin and collagen and also plays roles in the body’s handling of iron. Water, seafood, nuts, and vegetables are all sources of copper. DRI: 900micrograms/day.
Molybdenum (DRI: 45 micrograms/day) and manganese (DRI: Men 2.3mg/day; Women 1.8mg/day) work with enzymes within the body.
All trace minerals can be toxic in excess, which is usually a result from high levels taken in a variety of nutrient supplements.
Supplementation of antioxidants does not improve exercise performance and athletes can obtain sufficient intakes of natural antioxidants by eating a well-balanced diet including a variety of fruits and vegetables. There has not been evidence that supplementation of minerals can act as an ergogenic aid, although some athletes may need to pay attention to sodium and potassium levels if exercising for long periods of time or in hot, humid environments. Sports drinks include these minerals to help replenish losses due to sweat during exercise.
If you compete in a sport such as wrestling, gymnastics, or dance, where weight may be restricted or kept low, talk with a sports nutritionist or registered dietitian for suggestions on foods you need to include to get adequate nutrients.
Poor diets are the most common reasons for nutrient deficiencies in athletes. A well balanced diet including all food groups (meat, dairy, fruits, vegetables, and grains) can provide all the minerals the body needs. The increase in calories needed to fuel performance and maintain energy, increases the intake of minerals and satisfies the needs of athletes. Supplements do not make up for a poor diet.
Sources:
Bonci, L. Sports Nutrition for Coaches. 2009.
Jeukendrug, A. and M. Gleeson. Sport Nutrition: An introduction to energy production and performance, 2nd ed. 2010.
Sizer, F. and E. Whitney. Nutrition Concepts and Controversies, 10th ed. 2006.
Skolnik, H. and A. Chernus. Nutrient Timing for Peak Performance. 2010.
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