There was a debate about the adequate intake of protein between Voit and Chittenden in early 20th century. Periodically FAO and WHO reported the necessary energy and protein intake after the World War II, and the recent technical report No 935 from WHO is introduced in relationship to the Japanese Dietary Reference Intake. Necessary protein intake becomes lower, and low protein diet is essential for the patients with renal failure.
Necessary essential amino acids is also proposed in WHO report. The special function of particular amino acid in metabolic pathway became important, i.e. sulfur metabolism in methionin cycle, arginin in the intestinal-renal axis, etc. Non-essential amino acids are known to be important for living; arginin for urea cycle, glutamic acid for immune function, serin for neuronal growth, etc.
Peptid supplement has newly appeared in the market. Its rapid absorption and plaucible function may be available for PEM in elderly people. These newly appeared food chemicals could be integrated in the “functional nutriology.” Antioxidant activity is additional aspect of proteins, so it should be also included in the target of functional nutriology.
