The Kirin-funded study was conducted on 98 adults aged 45 to 69 years with perceived subjective cognitive decline (SCD), but were otherwise healthy.
Published in the Journal of Alzheimer's Disease, researchers said the findings suggest that early intervention through MHBA in people with SCD could be successful in improving cognitive function.
This present study follows a recent study on 60 human participants where MHBA was reported to specifically improve memory recall.
Previously, Kirin had also conducted a study on its MHBA cognitive functions in a mouse model.
However, it must be pointed out that SCD was self-reported, and not formally diagnosed. SCD can consist of symptoms ranging from memory complaints, depression, or people with high neuroticism.
Participants were divided into the treatment (MHBA) and placebo groups.
The treatment group was given a capsule containing 35mg of MHBA to consume daily, while the placebo capsule contained 35mg of dextrin.
MHBA is manufactured from the raw material of beer, hops, which are then heated and oxidised. It contains 4’-hydroxyallohumulinones, 4’-hydroxyalloisohumulones, tricyclooxyisohumulones A, hulupones, and humulinones, which are oxidants of α and β-acids.
The intervention was carried out over 12 weeks, although there was no indication of the recommended time for consumption.
One of the researchers, Takafumi Fukuda from Kirin Central Research Institute, told us: “In this clinical trial, we do not determine the timing, except for taking it once a day. Therefore, it is possible to interpret the effect as being achieved no matter when you take it.”
A series of tests were then carried out to assess attention and memory scores as primary outcomes.
Attention was evaluated using the Symbol Digit Modalities Test (SDMT), memory (word and shape recall) using the Rey Auditory Verbal Learning Test (RAVLT) and Wechsler Memory Scale-Revised (WMS-R).
To measure stress levels, saliva was collected at baseline (week zero) and week 12 of the intervention, analysing cortisol, CgA, α-amylase, and β-endorphin levels.
It was reported that the SDMT scores were significantly higher in the MHBA group compared to the placebo group (p = 0.045) after 12 weeks of intervention.
In the memory assessment, there was no significant difference between groups, although both treatment and placebo groups observed higher scores at week 12, compared to their baseline scores.
In assessing stress levels, researchers found that β-endorphine levels were significantly lower in the treatment group from baseline to week 12 than in the placebo group (p = 0.043).
β-Endorphin is a marker to evaluate psychological stress and found in higher levels in people with depression.
Researchers said the findings of MHBA improving attention and reducing stress in older adults were significant, especially for adults with perceived SCD who they added were important candidates for early intervention when it comes to dementia prevention.
“Early intervention through MHBA supplementation in persons with SCD could be successful in improving cognitive function.”
While MHBA supplementation could be beneficial for improving brain function, they explained that a study on functional MRI was required to confirm its findings.
The researchers acknowledged several limitations in their study.
“We could not evaluate whether MHBA supplementation prevented age-related cognitive decline due to the relatively short study length. Future long-term studies would be required to assess the effects of MHBA supplementation on ageing-related changes. Additionally, the mechanism underlying the cognition-improving effects of MHBA via vagus nerve has not been confirmed, therefore further study is required to elucidate the mechanism.”
MHBA has a similar chemical structure to iso-α-acids, which stimulate the vagus nerve and found to improve cognitive function and depression in animal models.
Fat and cognition
Besides MHBA effects on cognition, it has also been studied for its effect in reducing body fat. Last year, the company released its non-alcoholic beer-taste beverage (Kirin Karada Free) which contains MHBA. The beverage has been clinically tested for its ability to reduce belly fat if consumed once daily for 12 weeks.
In the present study, researchers explained that obesity is known risk factor for dementia and MHBA may prevent dementia by improving metabolic function. “In the future study, we will design the clinical trial to evaluate the effect of MHBA on the association of energy metabolism with cognition,” they wrote.
Ataka Takashima from Kirin Holdings’ corporate communication department told us the company was continuing its research of MHBA with a focus on its health benefits.
Source: Journal of Alzheimer's Disease
“Supplementation with Matured Hop Bitter Acids Improves Cognitive Performance and Mood State in Healthy Older Adults with Subjective Cognitive Decline”
Authors: Fukuda, Takafumi, et al.