[Free amino acid content in the blood plasma of cosmonauts before and after a 175-day flight on Saliut-6].

Measurements of 17 free amino acids were performed before and after the Salyut-6 175-day space flight. At R + 1 both crewmembers showed a reduced concentration of most amino acids as compared to the preflight level. By R + 7 the preflight status was not yet reached. It is recommended to enrich the space diet with the following essential amino acids: preflight--methionine, leucine, isoleucine, phenylalanine, lysine, threonine, cystine, and tyrosine; postflight--lysine, threonine, valine, leucine, isoleucine, phenylalanine, methionine, and cystine.