Amino Acid Requirements of Men and Women

Abstract
The quantities of lysine required for nitrogen equilibrium by 10 young men and women were estimated. A diet containing 159 gm of flour and 21 gm of corn meal was supplemented with purified essential amino acids so that the total amounts of the latter simulated 20 gm of whole egg protein, and also with a mixture of glycine, glutamic acid and diammonium citrate so that the subjects received 9.0 gm of nitrogen daily from all sources. Approximately half of the nitrogen was derived from white wheat flour, corn meal and a few foods low in nitrogen, and half from mixtures of purified amino acids and diammonium citrate. The quantities of flour and corn meal in the basal diet approximated the per capita consumption in this country and supplied nearly 500 mg of lysine. The subjects attained equilibrium when consuming quantities of lysine between 500 and 900 mg. Only three subjects needed more than 700 mg per day. No striking difference in lysine needs of men and women was apparent. Nitrogen balances at a given lysine intake were not improved by doubling the amounts of all other essential amino acids.