[Comparative characteristics of poly- and monomeric protein nutrition in relation to space flight]

The use of pure protein mono- and polymers for human nutrition was studied in a 45-day experiment in which 12 test subjects took part. The first group of 6 persons were given casein (14.8 g nitrogen per day) and the second group--an equivalent mixture made of crystalline L-amino acids. The first group showed no abnormalities in the physiological and biochemical functions. The second group exhibited marked changes in the body: weight losses, negative nitrogen balance, increase of the ammonia concentration in the urine and exhaled air. It appears that amino acid mixtures can be included into the human nutrition only after extensive studies.