[Nitrogen metabolism in elderly persons on a low-calorie diet]

The clinical trials covered 9 men aged 58-73 years with daily energy losses of 2200-2350 kcal and given for 10 days the diet (1128 kcal/day) containing different food ingredients. A study was made of the main parameters of nitrogenous metabolism. During the time of being kept on a low-caloric diet, the test subjects lost 2.1 kg body mass. Excretion of total nitrogen dropped 34%, urea 57%. Excretion of creatinine appreciably rose (208% of the initial). The calculation of nitrogenous balance demonstrated protein deficiency to be equal to 209 g during experiments. The concentration of free amino acids in blood plasma decreased: that of replaceable by 29.5%, that of essential ones by 37.6%. It is assumed that the tension of body metabolism affected protein synthesis, whereas the protein quota in the diet did not appear sufficient for elderly subjects.