No acute effects of grape juice on appetite, implicit memory and mood

Abstract

Background: Animal experiments document effects of grape juice on cognitive performance and motor skills,
and observational studies in humans suggest an inverse association between flavonoid intake and cognitive
decline. These effects may be related to the antioxidant properties of polyphenols. Juice consumption and
flavonoid intake may also affect appetite.
Objective: To study the acute effects of grape juice consumption on appetite, mood and implicit memory
during a time of increased lethargy - the post-lunch dip.
Design: Thirty-five participants with a mean age of 26 years who smoked a mean of 11 cigarettes/day for 8
years were included in the study. It included a practice session and two treatment sessions. All sessions
involved consumption of grape juice or an energy-matched placebo with lunch followed by assessments of
mood, implicit memory, appetite and food intake.
Results: Mood decreased over time for both treatments, but there were no differences after lunch between
grape juice and placebo for any measure.
Conclusion: This study did not document any acute effects of grape juice consumption on mood, implicit
memory, appetite or food intake in smokers.