Cheese and Dementia Risk: What the Japanese Study Found

As populations around the world grow older, the number of dementia cases is rising sharply too. Treatments that can genuinely halt cognitive decline are still unavailable. Researchers are therefore increasingly examining everyday habits – especially what people eat. A recent Japanese study now suggests that regularly eating cheese could measurably reduce the risk of dementia.

Dementia: a global challenge

More than 50 million people worldwide currently live with some form of dementia, and the World Health Organization expects this figure to triple by 2050. Behind these stark statistics are families, carers and healthcare systems that are already under considerable strain. The impact is felt not only in Europe; Asian countries such as Japan are particularly affected as well.

Japan is among the world’s fastest-ageing societies. More than one in eight people aged over 65 there already has dementia. Since there is currently no cure, attention has turned to a key question: which lifestyle factors can be changed to reduce risk or delay the onset of the condition?

A Japanese cohort study involving almost 8,000 older adults shows that eating cheese just once or twice a week is associated with a significantly lower risk of dementia.

What the Japanese study examined

The analysis used data from the large-scale JAGES study (Japan Gerontological Evaluation Study), collected between 2019 and 2022. It included 7,914 people aged 65 and over who were living at home and did not require classification within a long-term care system at the start of the study.

The researchers divided these older participants into two groups:

• People who ate cheese at least once a week
• People who reported never eating cheese

To reduce the possibility that other factors could distort the findings, the team used a statistical approach called “propensity score matching”. This enabled the groups to be matched as closely as possible for age, sex, income, educational attainment, self-rated health and ability to manage everyday activities. The aim was to isolate the effect of cheese consumption.

The onset of dementia was identified through official assessments for care and support services. In Japan, this is regarded as an established proxy measure for the start of clinically relevant cognitive impairment.

How large was the observed effect?

After around three years, there was a clear difference:

• In the cheese group, 134 out of 3,914 people developed dementia (3.4 per cent).
• In the no-cheese group, 176 out of 3,910 people developed dementia (4.5 per cent).

This equates to a relative risk reduction of around 24 per cent among people who ate cheese at least weekly. Once the analysis was additionally adjusted for the rest of participants’ diets, the figure fell slightly to around 21 per cent, but remained statistically significant.

The researchers stress that these figures demonstrate an association, not a proven cause-and-effect relationship. Even so, the size of the effect suggests that cheese itself may play a part, rather than merely acting as an indicator of generally health-conscious behaviour.

Why cheese could benefit the brain

The study authors discuss several possible biological pathways through which cheese may affect the brain.

Vitamins and blood vessels: protecting the brain

Cheese contains, among other nutrients, vitamin K2, a fat-soluble vitamin with an important role in vascular health. It helps direct calcium into bones rather than allowing it to build up in arteries. Narrowed or calcified blood vessels increase the risk of impaired blood flow to the brain – a major driver of vascular dementia.

If vitamin K2 helps blood vessels remain more flexible, it could indirectly protect the brain as well. This is particularly relevant for people with high blood pressure, diabetes or cardiovascular disease.

Protein, amino acids and bioactive peptides

Cheese provides high-quality protein and essential amino acids, both of which are vital for nerve cells. It also contains bioactive peptides formed during ageing and fermentation. Laboratory studies indicate that these peptides may:

• have anti-inflammatory effects
• act as antioxidants by neutralising free radicals
• positively influence blood pressure and metabolism

Chronic inflammation and oxidative stress are among the factors that accelerate cognitive decline. A diet that dampens these processes could potentially slow its progression.

Gut flora: the link between the plate and the brain

Another promising line of research concerns the gut. Matured and fermented cheeses in particular – including Camembert and Brie – contain micro-organisms that colonise the gut. These bacteria communicate closely with the central nervous system through the so-called gut-brain axis.

Studies show that an imbalanced gut microbiome is common in neurodegenerative conditions such as Alzheimer’s disease. Whether probiotic cheese can counteract this has not yet been conclusively established, although the evidence is growing.

Cheese eaters often have healthier lifestyles overall

The Japanese study also found that people who eat cheese tend to choose other foods considered “brain-friendly” more often. These include:

• fruit
• vegetables
• fish
• lean meat

This dietary pattern partly resembles the Mediterranean diet, which has been linked to a lower risk of dementia for years. The central question is therefore whether cheese is truly an active protective factor or simply one feature of an overall healthier lifestyle.

Using their statistical models, the researchers attempted to account for the influence of the rest of the diet. The apparent effect of cheese weakened slightly but remained clearly detectable. This supports the possibility of an independent contribution, without diminishing the importance of other habits.

Cheese could be one component of a brain-protective lifestyle – alongside exercise, not smoking, controlling blood pressure and staying socially active.

How often counts as “regularly”?

Most participants who ate cheese did so once or twice a week. Much higher intake was uncommon in Japan, where cheese is far less widely consumed than in countries such as Germany or Switzerland.

The findings suggest that even this moderate amount may be enough to make a difference at population level. Whether increasing intake further offers additional benefits in regions where cheese consumption is already high remains unknown.

Limitations of the evidence: what the study cannot answer

Despite its interesting findings, the research remains an observational study with clear limitations:

• Cheese consumption was recorded only once, so changes over the years were not captured.
• There was no information on quantities – 1 gram and 50 grams per serving carried the same statistical weight.
• Dementia diagnoses were based on administrative records rather than detailed clinical assessments.
• Genetic risk factors such as APOE ε4 were not recorded.
• The Japanese setting, with low cheese consumption, differs substantially from Europe.

The final point is especially important. In a population consuming an average of only 2.7 kilograms of cheese a year, even small differences in intake may be noticeable. In countries where cheese appears on the table almost daily, the effect may be weaker or different.

What does this mean for everyday life in the UK?

Anyone assuming that extra slices of cheese will automatically protect them from dementia is oversimplifying matters. Alongside valuable nutrients, cheese also contains saturated fat and calories. People with markedly raised blood lipid levels or cardiovascular disease should discuss appropriate quantities with a doctor and a registered dietitian.

It may be more useful to incorporate cheese deliberately into an otherwise balanced diet. A few practical ideas include:

• A small piece of hard cheese after lunch on two days a week
• An evening meal once a week featuring wholemeal bread, cheese, vegetables and nuts
• Occasionally using a little feta or Parmesan in a meal instead of heavily processed convenience foods

The study also found that many participants ate processed cheese varieties rather than high-quality cheeses matured for a long time. The effect was still visible. This suggests that even straightforward varieties may make a positive contribution when they form part of an overall sensible dietary pattern.

How diet and the brain influence each other over time

Dementia does not develop overnight. The process probably begins decades before the first noticeable lapses in memory. Anything that protects blood vessels, reduces inflammation and keeps metabolism stable may support brain health over the long term.

Alongside cheese, the following are considered beneficial for cognitive health:

• eating fish regularly, particularly oily varieties rich in omega-3 fatty acids
• plenty of vegetables and fruit, especially berries and green leafy vegetables
• plant-based fats such as olive oil or rapeseed oil
• wholegrain foods instead of highly refined white flour products

Together with physical activity, good-quality sleep, mental stimulation and social contact, these habits can create a kind of “protective shield” for the brain. As the Japanese analysis suggests, cheese may be another practical element of that shield when consumed in moderation.