Ingestion of a variety of non-animal-derived dietary protein sources results in diverse postprandial plasma amino acid responses which differ between young and older adults

Whole-body tissue protein turnover is regulated, in part, by the postprandial rise in plasma amino acid concentrations, although minimal data exist on the amino acid response following non-animal-derived protein consumption. We hypothesised that the ingestion of novel plant- and algae-derived dietary protein sources would elicit divergent plasma amino acid responses when compared with vegan- and animal-derived control proteins. Twelve healthy young (male (m)/female (f): 6/6; age: 22 +/- 1 years) and 10 healthy older (m/f: 5/5; age: 69 +/- 2 years) adults participated in a randomised, double-blind, cross-over trial. During each visit, volunteers consumed 30 g of protein from milk, mycoprotein, pea, lupin, spirulina or chlorella. Repeated arterialised venous blood samples were collected at baseline and over a 5-h postprandial period to assess circulating amino acid, glucose and insulin concentrations. Protein ingestion increased plasma total and essential amino acid concentrations (P < 0 center dot 001), to differing degrees between sources (P < 0 center dot 001), and the increase was further modulated by age (P < 0 center dot 001). Postprandial maximal plasma total and essential amino acid concentrations were highest for pea (2828 +/- 106 and 1480 +/- 51 mu mol center dot l(-1)) and spirulina (2809 +/- 99 and 1455 +/- 49 mu mol center dot l(-1)) and lowest for chlorella (2053 +/- 83 and 983 +/- 35 mu mol center dot l(-1)) (P < 0 center dot 001), but were not affected by age (P > 0 center dot 05). Postprandial total and essential amino acid availabilities were highest for pea, spirulina and mycoprotein and lowest for chlorella (all P < 0 center dot 05), but no effect of age was observed (P > 0 center dot 05). The ingestion of a variety of novel non-animal-derived dietary protein sources elicits divergent plasma amino acid responses, which are further modulated by age.