TOKYO, Oct. 7, 2025: A large-scale Japanese study has found that individuals with higher dietary intake of riboflavin, also known as vitamin B2, had a significantly lower risk of developing disabling dementia over a 15-year period. The findings, published in the peer-reviewed European Journal of Nutrition, are based on data from 4,171 adults aged between 40 and 69 years who were part of the long-running Circulatory Risk in Communities Study. Researchers tracked participants for a median duration of 15.4 years, during which 887 cases of disabling dementia were recorded.
Using a 24-hour dietary recall method, participants’ vitamin intakes were calculated and divided into quartiles. Individuals in the highest quartile of riboflavin intake showed a 49 percent lower risk of developing disabling dementia compared to those in the lowest quartile. The adjusted hazard ratio was 0.51 with a 95 percent confidence interval of 0.42 to 0.63. The study also examined other B vitamins. Higher intake of vitamin B6 and folate was linked with modestly reduced dementia risk, with adjusted hazard ratios of 0.80 and 0.79 respectively.
No statistically significant association was found for vitamin B12. The analysis adjusted for a wide range of variables including age, sex, body mass index, alcohol consumption, smoking status, blood pressure, cholesterol levels, diabetes status, physical activity, and total energy intake. Disabling dementia was identified based on certifications issued under Japan’s national long-term care insurance system, which evaluates cognitive and functional impairment. The study did not differentiate between dementia types such as Alzheimer’s disease or vascular dementia.
Study highlights dietary B2 as key factor in brain health
Researchers noted that riboflavin plays an important role in cellular energy production, oxidation-reduction reactions, and the metabolism of fats, drugs, and steroids. It is a precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), both of which are essential cofactors in various enzymatic processes. The study’s methodology included multiple sensitivity analyses, and the associations remained consistent even after excluding participants who developed dementia within the first five years of follow-up.
The authors acknowledged limitations such as the use of a single-day dietary recall and the inability to assess long-term dietary patterns or vitamin supplementation. The findings are consistent with previous nutritional research showing potential protective effects of certain B vitamins on brain health. Riboflavin is found naturally in foods including dairy products, eggs, green leafy vegetables, lean meats, and fortified cereals. The World Health Organization (WHO) estimates that more than 55 million people worldwide live with dementia, a number projected to increase substantially due to aging populations.
Study supports food-first approach for dementia prevention
Identifying modifiable risk factors such as dietary components is considered a public health priority. While the study stops short of recommending specific dietary changes, the researchers emphasized the importance of balanced nutrition in overall health and aging. They concluded that riboflavin intake was inversely associated with disabling dementia and warranted further investigation in diverse populations.
The research was funded by national health agencies in Japan and received full ethical approval. Findings from the study are expected to contribute significantly to future research in nutritional epidemiology and guide public health strategies targeting cognitive decline, dietary guidelines, and long-term brain health initiatives across aging populations, while also informing clinical recommendations for preventative care and dementia risk reduction. – By Content Syndication Services.