Amino Acid Requirements of Men and Women

The minimum quantities of lysine that maintained nitrogen equilibrium were estimated for 5 men and 5 women who consumed 9.0 gm of nitrogen principally as cereals, purified amino acids and diammonium citrate. Requirements of the men varied from 400 to 1200 mg, and of the women from 300 to 700 mg per day. The mean lysine requirement of 10 men was 750 mg and of 10 women 550 mg. These mean values are useful in estimating needs of population groups but not of individuals. Regressions of lysine requirement of men on body weight, metabolic body size, surface area and creatinine excretion were highly significant, and on basal caloric expenditure was significant. Little correlation was found between lysine requirements of the 10 women and any physical or metabolic measurements, but regressions of lysine requirement of 8 women on body weight and creatinine excretion were highly significant, and on metabolic body size and surface area were significant.