Effects of the egg protein hydrolysate NWT-03 on cognitive function in men and women with the metabolic syndrome: a randomized, double-blind, placebo-controlled study.

Objectives: The metabolic syndrome is associated with cardiovascular diseases and cognitive decline. The egg protein hydrolysate NWT-03 has shown to improve cardiovascular risk factors in humans. This study investigated whether NWT-03 also has an effect on cognitive function. Methods: Men and women with the metabolic syndrome ( n  = 76) with a mean age of 60 ± 10 years participated in this randomized, double-blind, placebo-controlled, cross-over trial with an intervention (5 g/day NWT-03) and control period (5 g/day maltodextrin) of 4 weeks separated by a wash-out period of 2-8 weeks. Cognitive function was assessed with the anti-cue reaction time test (impulse control) and psychomotor vigilance test (sustained attention) at day 0, 2, and 27 of both periods. Serum brain-derived neurotrophic factor (BDNF) concentrations were measured at the start and end of both periods. Results: NWT-03 consumption significantly improved the change (day 27 - day 0) in response times of the anti-cue reaction time test compared with the control period ( P  < 0.001), but not of the psychomotor vigilance test ( P  = 0.487). Serum BDNF concentrations of all subjects did not significantly change ( P  = 0.241). Conclusion: NWT-03 has the ability to improve cognitive function within the executive function domain. The underlying mechanism warrants further research and could either be indirect via inhibition of dipeptidyl peptidase 4 (DPP4) or direct via passage of small peptides over the blood-brain barrier inducing local effects. Trial registration: ClinicalTrials.gov identifier: NCT02561663.