Effects of Hop Bitter Acids, Bitter Components in Beer, on Cognition in Healthy Adults: A Randomized Controlled Trial

The present study aimed to investigate the effects of
matured hop
bitter acids (MHBAs) on human cognition, mental fatigue, and mood
state. In this randomized double-blind placebo-controlled study, 60
healthy adults (age 45–64 years) with self-awareness of cognitive
decline were randomly divided into 2 groups and received either orally
administered MHBAs (35 mg/day) or placebo for 12 weeks. Cognitive functions and
mental states were assessed using neuropsychological tests or questionnaires
at baseline and weeks 6 and 12 of the intervention. The change in
verbal fluency score at week 6 compared with that at baseline was
significantly higher in the MHBAs-treated group compared with that
in the placebo group (P = 0.034), and Stroop test
score at week 12 was significantly lower in the MHBAs-treated group
compared with the placebo group (P = 0.019). Furthermore,
subjective fatigue and anxiety at week 12 were significantly improved
in the MHBAs-treated group (P = 0.008 and 0.043,
respectively) compared with the placebo group. This is the first study
to evaluate the effects of bitter ingredients in beer on cognition,
subjective mood, and mental fatigue in a clinical trial. Our findings
suggest that hop-derived bitter acids might be beneficial for cognition
and mood state.