1. What are “complementary proteins” and do I need to “compliment” soy
protein when I eat it?
Legumes (beans, nuts, and to a very small extent soy) are a bit low in methionine and
tryptophan. Whole grains, nuts and seeds are a bit low in isoleucine and lycine. Many
studies have shown that taking in the recommended daily allowance of protein in the
form of soy results in just as good a nitrogen balance as taking in protein from animal
sources. Other research has shown a negative nitrogen balance when consuming soy
unless slightly more (5%) protein is consumed (compared to meat intake) [Giuseppe et
al., J Nutr 130 (2000) 528] or unless a small amount of methionine supplementation is
done [Zezulka AY and Calloway DH, J Nutr 106 (1976) 212]. My sense is that if the
recommended intake of protein is consumed, particularly in the form of soy, and whole
grains are eaten as insurance that methionine levels support the use of all the protein
you are eating for tissue building, you will not only have enough nutrients to meet your
athletic needs but will be super healthy.
2. Is a vegetarian diet healthier than a non-vegetarian diet?
In general (compared to the average American diet which has lead to diabetes and
obesity in a large fraction of people), yes. This is because of the vitamin, mineral, anti-
oxidant, fiber, and healthy fat content. A person eating a diet that is one-half
carbohydrate, 1/3 fat, and 1/6 protein (the amounts I recommend) from healthy food
sources will find themselves eating a lot of whole grains, fruits and vegetables
regardless of their protein sources. Of my six daily meals, only one typically contains
meat.
3. Are there particular nutrient deficiencies with a vegetarian diet?
Iron and vitamin B-12 can be low. Iron is in all foods but is most absorbable when
vitamin C is present. Thus, vegetarians should be sure to include a vitamin C source in
each meal (this is easy, since fruits and vegetables are the highest in C; I listed those
containing the most in question #2, section 8). Vitamin B-12 (cobalamine) is in meat,
fish, and dairy but not in fruits and vegetables because it is produced by bacteria in the
digestive tracts of animals (unfortunately, in humans it is produced too far down the
digestive tract to be digested). Vegans should ask their doctors about B-12
supplementation.
protein when I eat it?
Legumes (beans, nuts, and to a very small extent soy) are a bit low in methionine and
tryptophan. Whole grains, nuts and seeds are a bit low in isoleucine and lycine. Many
studies have shown that taking in the recommended daily allowance of protein in the
form of soy results in just as good a nitrogen balance as taking in protein from animal
sources. Other research has shown a negative nitrogen balance when consuming soy
unless slightly more (5%) protein is consumed (compared to meat intake) [Giuseppe et
al., J Nutr 130 (2000) 528] or unless a small amount of methionine supplementation is
done [Zezulka AY and Calloway DH, J Nutr 106 (1976) 212]. My sense is that if the
recommended intake of protein is consumed, particularly in the form of soy, and whole
grains are eaten as insurance that methionine levels support the use of all the protein
you are eating for tissue building, you will not only have enough nutrients to meet your
athletic needs but will be super healthy.
2. Is a vegetarian diet healthier than a non-vegetarian diet?
In general (compared to the average American diet which has lead to diabetes and
obesity in a large fraction of people), yes. This is because of the vitamin, mineral, anti-
oxidant, fiber, and healthy fat content. A person eating a diet that is one-half
carbohydrate, 1/3 fat, and 1/6 protein (the amounts I recommend) from healthy food
sources will find themselves eating a lot of whole grains, fruits and vegetables
regardless of their protein sources. Of my six daily meals, only one typically contains
meat.
3. Are there particular nutrient deficiencies with a vegetarian diet?
Iron and vitamin B-12 can be low. Iron is in all foods but is most absorbable when
vitamin C is present. Thus, vegetarians should be sure to include a vitamin C source in
each meal (this is easy, since fruits and vegetables are the highest in C; I listed those
containing the most in question #2, section 8). Vitamin B-12 (cobalamine) is in meat,
fish, and dairy but not in fruits and vegetables because it is produced by bacteria in the
digestive tracts of animals (unfortunately, in humans it is produced too far down the
digestive tract to be digested). Vegans should ask their doctors about B-12
supplementation.
Vegetarian Athletes
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© Clyde F. Wilson