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

Abstract

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.

Hop bitter acids containing a β-carbonyl moiety prevent inflammation-induced cognitive decline via the vagus nerve and noradrenergic system

“…MHBAs are also derived from α- and β-acids and show mild bitterness 24 , 25 . In addition, we demonstrated that supplements with MHBAs improve cognitive function, including memory retrieval and attention, in older adults 26 . These findings indicate that activation of the vagus nerve by food ingredients is beneficial for preventing cognitive decline and dementia.…”

“…Previous studies have shown that MHBAs activate the vagus nerve and increase the levels of noradrenaline, resulting in the improvement of memory impairment 22 . A clinical trial showed that supplements with MHBAs improved cognitive function in older adults with subjective cognitive decline 26 . We have previously shown that MHBAs are associated with the vagus nerve and nicotinic acetylcholine receptors to improve cognitive function 22,23 ; however, the mechanisms underlying the effects of MHBAs on cognitive decline have not been entirely investigated.…”

Improving Effects of Hop-Derived Bitter Acids in Beer on Cognitive Functions: A New Strategy for Vagus Nerve Stimulation

“…Moreover, IAAs exhibit preventive effects on dementia and cognitive decline, which may be mediated by the anti-inflammatory processes driven by PPARγ activation. Previous reports have estimated that reasonable amounts of beer (containing 0.13-1.3 L of IAAs and 0.17-1.8 L of MHBAs) are sufficient to ingest effective doses of these compounds in humans [31,66]. These compounds may contribute to the dementia prevention effects of alcoholic beverages including beer, and it is expected that certain types of beer brewed with a large amount of hops might be more beneficial.…”

“…Recently, Fukuda et al [66] performed a randomized, double-blind placebo-controlled clinical trial to investigate the effects of MHBAs on human cognitive function. Sixty healthy adults (aged 45-64 years) with insight into their own cognitive decline were randomly divided into two groups and supplemented with MHBAs (35 mg/kg) or placebo for 12 weeks.…”

“…These results suggest that supplementation with MHBAs may be effective for the maintenance of cognitive function. Fukuda et al's clinical trial was the first report to demonstrate the effectiveness of hop-derived bitter acids on human cognitive function [66]. Despite this, however, the mechanism(s) underlying MHBA effects on PFC function have not been elucidated, and further studies are required.…”