薬理と治療

Abstract

Objectives In the present study, the dose response effect of soy peptide supplementation on cognitive function was examined. Methods A randomized, double-blind, placebo-controlled study was performed in 60 healthy male subjects aged between 20 and 22 years. The groups were as follows: soy peptide group receiving medium dose（4 g）: n＝20, soy peptide group receiving low dose（2g）: n＝20, placebo group: n＝20. Psychological tests were performed at baseline and after two-weeks of supplementation with the test foods. Results The performance of subjects in the Uchida-Kraepelin test showed a dose-dependent effect of soy peptide supplementation. Subjects in the soy peptide groups showed significantly improved performance in the recognition memory test. Subjective evaluation using the visual analogue scale demonstrated that a medium dose of soy peptide reduced fatigue and stress after the psychological tests. Conclusions The present study suggests that daily supplementation with soy peptide, even at low doses, improves cognitive abilities, including memory recognition and sustained attention.