By David L. Katz, MD and Christopher Gardner, PhD.
Re “Not All Vegan Diets Lead to Healthful Eating,” by Jane E. Brody (Personal Health column, Science Times, Oct. 3):
The contention that foods must be dutifully combined in a vegan diet to provide the requisite protein for human health is obsolete. All plant foods contain all 20 amino acids, both essential and nonessential. Grains are proportionally low in lysine and high in cysteine, and beans the converse. The difference is simply a matter of concentration.
This would be of practical importance if someone ate only grains or beans throughout entire days. Such a diet would be inadvisable for many reasons beyond amino acid distribution.
There is no more reason to stress the “complementary” choices required of vegan diets than to remind omnivores that they must carefully “combine” their meat with citrus fruit to avoid scurvy. A diet of wholesome foods in a balanced, sensible assembly is the only combining required in either case.
DAVID L. KATZ
CHRISTOPHER D. GARDNER
The writers are with Yale and Stanford Universities, respectively. Dr. Katz is founder and president of the True Health Initiative, and Dr. Gardner is a board member.