Question: My son, who is an athlete, has thought about becoming a vegetarian. Could you discuss the effects of this change in terms of his ability to compete?
Answer: This problem was discussed in some detail by Dr. Susan Kleiner in a Gatorade Sports Science Exchange publication (Volume 8, No. 5, 1995). She made the point that generations of athletes have consumed a diet centered around meat, but that recent evidence about the effects of animal fats on health have changed the way athletes think about the diet. According to this article, almost 7 percent of the American public, or about 12.4 million people, consider themselves vegetarians. Although most athletes do not eliminate all animal foods, increasing numbers avoid beef and other red meats on a fairly regular basis.
Can athletes achieve peak performance on a meatless diet? According to Kleiner, the challenge of a vegetarian diet for athletes relates mostly to the intake of vitamin B12, iron and zinc. Apparently, the quantity of protein in the diets of athletes is rarely a concern, regardless of whether they are meat eaters or not. For example, an average of 21 to 25 percent of the energy in legumes comes from protein calories, and protein constitutes 34 percent of the energy in soybeans. As long as a variety of vegetable proteins is eaten every day, a full array of essential amino acids is available for efficient protein metabolism.
In the traditional Western diet, meats are a major source of B vitamins. However, whole and enriched grain products, eggs, legumes, nuts, seeds, fruits, vegetables and dairy products can fully supply the B vitamins, except for vitamin B12, which is available only from animal products. If your son becomes a vegetarian, he will need to supplement this vitamin.
In terms of iron, several researchers have studied the influence of the dietary source of iron on iron stores. However, there was no clear determination if meat intake was better or the same as taking a daily 50 mg ferrous sulfate supplement. Since iron is required for the formation of hemoglobin, myoglobin, the cytochromes and iron-containing enzymes, supplementation might be needed for a vegetarian athlete.
Meats, particularly red meats, are the major sources of zinc in the Western diet. And, zinc from animal sources is generally regarded as more bioavailable than zinc from vegetables. Therefore, vegetarians need to be concerned with eating high-zinc foods or taking a supplement. However, there is a danger of taking too much zinc; the recommended supplementation is not more than 15 mg/d.
Those who choose to eliminate meat from the diet may find it difficult to plan, prepare and consume the quality and quantity of food required to meet recommended guidelines. If the decision to cut meat out of the diet is not based upon moral or ethical principles, it may be more practical to encourage athletes to include some meat in their diets.