Antioxidants continued
Safety. Excess quantities of antioxidants may produce a ‘pro-oxidant’ effect, which is the opposite of what you would take these supplements for. The Australian Institute of Sport recommends that antioxidant vitamin supplements only be taken for a period of a few weeks while the body adjusts to stressful circumstances. Excess vitamin C may promote excess iron absorption, which may not be healthy for everyone.
How much. 500 milligrams of vitamin C and vitamin E daily is the most that is required and this dose is unlikely to cause adverse health or fitness effects. Consider regular antioxidants if you train in a particularly polluted environment on a regular basis. A multi-vitamin a day may be all that is required to provide that extra reassurance.
Calcium
Women who train hard and reach low body fat levels, say under 10 percent, may be at risk of losing their periods as a result of hormonal disruption to estrogen production. Exercise-induced estrogen declines can result in bone loss in a way similar to that which occurs at the menopause.
Loss of periods from athletic training is not uncommon but does require that you see a doctor, or better still, a sports physician and sports nutritionist to assess what is required to address the problem. Calcium supplements may be a part of the solution if bone health is likely to be affected. However, if disordered eating is a contributing factor, a more comprehensive training and nutrition program may be necessary. Those great abs you see on some women may be ‘to die for’ but they mean very low body fat. Often they have the genetics to produce that outcome. Don’t injure yourself trying to achieve something that may not be possible without health damage.
Zinc and Magnesium
Zinc is important for the production of the male hormone testosterone and in building the immune system. Magnesium is an essential component of the nervous system and in the maintenance of heart health. Both have a range of important biochemical function.
Zinc and magnesium are often marketed to bodybuilders in combination in a supplement called ZMA. This is supposed to increase testosterone and thus improve muscle building. These two minerals are very important components of a balanced diet and some people may be deficient if they do not consume adequate amounts in the diet. Magnesium is in nuts, whole seeds, grains and green vegetables. Zinc is in whole grains, seeds, nuts and particularly meat and oysters.
After years of research no evidence exists to show that either mineral offers bodybuilding or athletic performance enhancement in excess of the recommended dietary requirements. In other words, if you eat well for these minerals, you won’t need supplements nor will supplements help your performance.
Because deficiencies are common enough, a small supplementation such as that found in a multi-vitamin could ensure your needs are met in circumstances where diet is inadequate.
Safety. Zinc can be slightly toxic in excess and zinc can also affect absorption of copper. I see no reason to exceed 20 mg/day in supplements of zinc.
Iron
Iron is the mineral in the body essential for the production of hemoglobin, a blood protein that transports oxygen in the body. It is easy to see how important iron is for people who exercise.
Iron deficiency can occur for the following reasons:
- Poor compliance with optimum vegetarian diets or other eating patterns that do not include substitutions for red meat, chicken and fish with bioavailable iron foods.
- People with increased requirements – women, athletes, adolescents, athletes training in hot temperatures or altitude.
- Other factors including gastrointestinal bleeding due to ulcers, NSAID drugs, surgery, nosebleeds, certain high-impact and contact sports.
The Australian Institute of Sport in it’s supplement program says:
"There is now evidence that supplementation of female athletes, who are not anemic but who have serum ferritin levels less than 16 or 20 ng/ml, may cause improvements in some performance related parameters."
Safety. Iron overload may cause a disease called hemochromatosis in some susceptible people. Iron supplements should only be prescribed by a doctor, and for athletes or those who train heavily, a sports physician in conjunction with a sports dietitian may be preferable. Be sure to take care with this because iron supplements should not be taken casually. Iron supplements may cause constipation and gastric upset in some people.
How much. This needs to be determined by a sports physician or a doctor with some experience of sport-related iron requirements, particularly for women.
Electrolyte and Carbohydrate Replacement Drinks
Electrolytes derive mainly from minerals in the diet and they maintain fluid balance and assist the nervous system to perform muscle contractions. The heart is your most active muscle and electrolytes are intimately involved in the pumping action of the heart. Electrolytes are sodium, potassium, magnesium, calcium and chloride, bicarbonate, phosphate, sulfate. Exercisers are particularly dependent on sodium and potassium balance.
Carbohydrates are important for fueling exercise, including vigorous weight training, and in post-exercise energy replacement nutrition. Carbohydrates, mostly sugars, are formulated in sports drinks with electrolytes such as sodium chloride and potassium and sometimes magnesium.
Sports drinks like Gatorade usually contain about 6-8 percent carbohydrate, sodium chloride (salt) and potassium. Sports drinks can be useful in weight training where sessions proceed beyond an hour of high-intensity exercise or at the end of such sessions where rapid replacement of muscle glucose is good practice. See my article on the Bodybuilding Diet for more information on the use of sports drinks.
