Grape seed polyphenol extract and cognitive function in healthy young adults: a randomised, placebo-controlled, parallel-groups acute-on-chronic trial

ABSTRACT

Grapes are polyphenol-rich, and grape juice intake has shown cognitive benefits in middle-aged females and older adults with mild cognitive impairment. Extracts obtained from grape seeds have similarly been associated with cognitive benefits in older adults. The aim of this research was to investigate whether a highly purified grape seed-derived polyphenol extract was associated with cognitive benefits in healthy young adults following a single acute dose, and chronically following repeated daily dosage over 12 weeks. Following an acute-on-chronic, parallel groups, randomised, double-blind, placebo-controlled design, sixty adults aged 18-30 consumed either a 400 mg grape seed polyphenol extract (GSPE, n = 30) or a placebo (n = 30). Cognitive function was assessed acutely at baseline and 2, 4 and 6 h post consumption, and chronically at 6 and 12 twelve weeks with a computerised battery of multiple cognitive tests. Mood was assessed with the Positive and Negative Affect Schedule. Linear marginal model analysis with baseline included as a covariate did not reveal a consistent pattern of cognitive benefits following the GSPE relative to the placebo either acutely or chronically when considering all outcome measures. GSPE was associated with some improvements in reaction time (acutely) and psychomotor skill (chronically), however the placebo was also associated with some benefits to reaction time and memory. Therefore, a 400 mg GSPE did not consistently improve cognitive function in healthy young adults. These findings suggest that younger, healthy populations are perhaps less sensitive to polyphenol extract doses <400mg relative to older, or cognitively compromised populations.

KEYWORDS:

• Grape seed extract
• cognition
• polyphenols
• cognitive performance

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by funding from Polyphenolics, Madera, CA, USA, a division of Constellation Brands, Inc.

Notes on contributors

Lynne Bell

Lynne Bell is a postdoctoral researcher working in the Nutritional Psychology laboratory at the School of Psychology & Clinical Language Sciences, University of Reading, UK.

Adrian R. Whyte

Adrian R. Whyte is a postdoctoral researcher working in the Nutritional Psychology laboratory at the School of Psychology & Clinical Language Sciences, University of Reading, UK.

Daniel J. Lamport

Daniel J. Lamport is a Lecturer in cognition and nutrition at the School of Psychology & Clinical Language Sciences, University of Reading, UK. Daniel's research interests include the effect of diet, nutritional interventions, and metabolic disorders on neuropsychological function, and prevention of neurodegenerative disease.

Jeremy P. E. Spencer

Jeremy P.E. Spencer is Professor of Molecular Nutrition at the Department of Food and Nutritional Sciences, University of Reading, UK. Jeremy's research is focused on investigating the molecular mechanisms that underlie the accumulating body of epidemiological and medical anthropological evidence on a positive correlation between the consumption of diets rich in fruits and vegetables and a decreased risk of neurodegenerative disorders.

Laurie T. Butler

Laurie T. Butler is Pro Vice-Chancellor and Dean of Science of Engineering at Anglia Ruskin University, Cambridge, UK. Laurie is also a visiting Professor at Tohoku University, Japan and at University of Reading, UK. His research interests include nutrition and cognition, ageing, memory and choice, and behaviour change.

Claire M. Williams

Claire M. Williams is Chair of Neuroscience in the School of Psychology & Clinical Language Sciences at the University of Reading, UK. Her research group, the Nutritional Psychology laboratory, investigates the health benefits of plant-derived chemicals. The focus of her laboratory is the interplay between dietary intake and measures of psychological well-being such as cognitive performance, food preference, mood, and quality of life using animal studies, randomised controlled trials, and neuroimaging across different populations.