Can cheese help prevent dementia? Japanese researchers say yes

In a recent study published in the journal NutrientsScientists checked whether older people who eat cheese at least once a week are less likely to develop dementia.

Their findings, based on the Japanese population aged 65 and over, suggest that weekly cheese consumers may have a lower risk of dementia than non-consumers, although remaining confounding factors cannot be completely ruled out despite controlling for many socioeconomic and health variables.

Background

Dementia is a growing health problem worldwide. By 2050, this problem is expected to affect over 150 million people. Japan, one of the fastest aging societies in the world, is struggling with a sharp increase in disease incidence. Scientists expect the number of cases in Japan to increase from 4.4 million older adults with dementia in 2022 to 5.8 million in 2040.

This increasing burden places a strain on both healthcare systems and the families of people struggling with cognitive decline. Despite medical advances, treatment options remain limited and current preventive strategies targeting modifiable lifestyle factors have become essential. Of these, diet has emerged as a potential protective factor, and growing evidence suggests that certain foods may affect brain health.

In particular, cheese contains bioactive compounds such as vitamin K₂, peptides and probiotics. They may support neuroprotection through anti-inflammatory and metabolic mechanisms. However, epidemiological findings regarding the association between dairy consumption and cognitive decline are inconsistent across studies.

To fill these gaps, the authors of this study focused on older adults in Japan, a group with relatively low dairy consumption. Using an observational cohort design, they sought to determine whether habitual cheese consumption was associated with a reduced risk of dementia. They also aimed to provide real-world epidemiological evidence relevant to public health in aging societies.

About the study

The authors conducted a longitudinal cohort study using data from the Japan Gerontological Evaluation Study (JAGES) 2019, linked to Long-Term Care Insurance (LTCI) data from 2022. The study included adults aged 65 years or older residing in communities that were not previously certified for benefits. LTCI.

Of the 26,408 survey respondents, 10,180 met eligibility criteria after excluding participants with missing or incomplete data. Propensity score matching (PSM) was used to control for potential confounders of age, gender, education, income, health status, instrumental activities of daily living (IADL), and memory complaints.

After 1:1 nearest neighbor matching, 7,914 participants were included, of which 3,957 were cheese consumers and 3,957 were non-consumers. Cheese consumption was defined as eating cheese at least once a week. The prevalence of dementia was determined based on new LTCI certificates indicating dementia during the three-year follow-up period.

The primary analysis used a Cox proportional hazards model to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for incident dementia, comparing consumers and nonconsumers. Covariate balance was confirmed using standardized mean differences. Follow-up continued until the onset of dementia diagnosisdeath, migration or end of tax year 2022.

Key findings

The majority of cheese consumers (72.1%) reported eating cheese one or two times a week, with processed cheese dominating (82.7%). Over three years, 134 consumers (3.4%) and 176 non-consumers (4.5%) developed dementia, corresponding to an absolute risk reduction of 1.06 percentage points (approximately 10.6 fewer cases per 1,000 people).

Kaplan-Meier survival curves showed a significantly lower cumulative incidence of dementia among consumers. In a Cox proportional hazards analysis, cheese consumption was associated with a 24% reduction in the risk of dementia. After further accounting for dietary habits such as consumption of fruit, vegetables, and meat and fish, the association remained significant, although slightly weaker, at 21%.

The restricted mean survival analysis showed an average difference in dementia-free survival of approximately 7.7 days in favor of cheese consumers. These findings suggest that even moderate cheese consumption, at least once a week, is associated with a lower incidence of dementia in older adults in the short-term follow-up.

Conclusions

The study found that older adults who ate cheese at least once a week had a 21-24% lower risk of dementia over 3 years, consistent with previous evidence suggesting that fermented dairy products have a protective effect on cognitive health.

Cheese’s nutritional profile, rich in probiotics, peptides, antioxidants and vitamin K₂, may promote vascular and nervous system health, although most participants consumed processed cheese, which may have contained lower levels of these bioactive compounds.

The absolute reduction in dementia cases was modest but potentially significant at the population level, especially in Japan, where cheese consumption is low.

Strengths of this analysis include the large population-based cohort and rigorous control for confounders through propensity score matching. However, dietary data were collected only once, portion sizes and genotypes were not measured, and dementia diagnoses were based on administrative records, limiting precision and generalizability.

The authors also disclosed that the study was partially funded by Meiji Co., Ltd., a Japanese dairy product manufacturer. However, the funder had no role in the execution, analysis, or interpretation of the data or in writing the manuscript.

Overall, regular cheese consumption may promote cognitive health, but future research should elucidate optimal consumption levels, types of cheese, and biological mechanisms.