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Effect of Supplementation of a Whey Peptide Rich in Tryptophan-Tyrosine-Related Peptides on Cognitive Performance in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled Study.
Kita, M, Obara, K, Kondo, S, Umeda, S, Ano, Y
Nutrients. 2018;10(7)
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Previous studies have suggested that consumption of dairy products may be related to a reduction in the risk of cognitive decline in later life. Studies in mice suggest that particular components of whey known as whey peptides may be partly responsible for improvements in cognitive performance. The aim of this randomised, double-blind, placebo-controlled study was to evaluate the effects of whey peptides on cognitive functions in healthy adults. 101 healthy Japanese adults (aged 45 to 64 years) with a tendency to forget names of people and places, took part in the study. They received either tablets containing 6g of whey peptide (including 1.6mg of glycine–threonine–tryptophan–tyrosine (GTWY) peptide) or placebo supplements for 12 weeks. Changes in cognitive function were assessed using memory and cognitive function tests at the start of the study and 6 and 12 weeks after supplementation. Whey peptide intake tended to improve the verbal fluency test (VFT) score. Further analysis showed that subjects with high-level fatigue from the whey peptide group improved their scores in the VFT as well as some other memory function tests significantly more compared to the placebo group. The authors concluded that intake of whey peptide might improve cognitive function in healthy middle- and older-aged adults with high subjective fatigue levels. Further studies are needed to examine the relationship among cognitive improvement, whey peptides, and psychological fatigue.
Abstract
Background: Previous epidemiological and clinical studies have shown that dairy products have beneficial effects on cognitive decline and dementia. Enzymatic digestion of whey protein produces a whey peptide rich in tryptophan-tyrosine-related peptides which improve cognitive performance in mice. We evaluated the effects of whey peptides on cognitive functions in healthy adults in a randomized, double-blind, placebo-controlled design. Methods: 101 healthy adults (45 to 64 years), with a self-awareness of cognitive decline received either whey peptide or placebo supplements for 12 weeks. Changes in cognitive function were assessed using neuropsychological tests at 6 and 12 weeks after the start of supplementation. Results: Verbal fluency test (VFT) score changes tended to be higher in the whey peptide group compared with the placebo at 12 weeks. Subgroup analysis classified by the degree of subjective fatigue showed that changes in the VFT as well as the Stroop and subjective memory function tests between baseline and 6 weeks of intervention were significantly better in subjects with high-level fatigue from the whey peptide group as compared to the placebo group. CONCLUSIONS Intake of whey peptide might improve cognitive function in healthy middle- and older-aged adults with high subjective fatigue levels. Further studies will elucidate the relationship among cognitive improvement, whey peptides, and psychological fatigue.