Cheese and dementia: Japanese study suggests a lower risk

Millions of people fear the gradual fading of their memories. As medicines have so far offered only limited help, researchers are increasingly looking at what is on the plate: which diet can protect the brain in later life? A new study from Japan now suggests that regular cheese consumption could measurably lower the risk of dementia.

Dementia: a global challenge

Dementia is already among the most significant medical and social challenges worldwide. Estimates indicate that well over 50 million people globally are living with some form of the condition. This figure is likely to rise sharply over the coming decades as populations age and more people live to a very advanced age.

Japan acts as something of a laboratory for the future in this respect. Its proportion of older people is particularly high, and more than one in eight people aged over 65 already has dementia. Since there is still no curative treatment, attention is focused primarily on factors individuals can influence themselves – above all physical activity, social relationships and diet.

“A large cohort study from Japan suggests that people who eat cheese at least once a week develop dementia slightly less often on average.”

What the Japanese study examined

The newly published research drew on data from a nationwide study involving 7,914 women and men aged 65 and over. All participants were living independently at home and had no officially recognised need for care when data collection began.

The researchers divided the older adults into two groups:

• people who ate cheese at least once a week
• people who never ate cheese

To make the groups as comparable as possible, the team used a statistical method that balanced a wide range of influencing factors. These included age, sex, income, education, self-rated health and everyday abilities. The aim was to reduce distortions unrelated to cheese consumption.

Dementia status was determined using official long-term care insurance records, which are routinely used in Japan. During the observation period of around three years, 134 people in the cheese group developed dementia (3.4 per cent). In the comparison group that did not eat cheese, the figure was 176 people (4.5 per cent).

At first glance, the difference may appear small. Statistically, however, it equates to a relative risk reduction of roughly 24 per cent. The authors stress that these figures do not provide definitive proof of cause and effect, but consider the association sufficiently robust to warrant further research.

Why cheese nutrients may be relevant to the brain

Why might cheese, of all foods, offer some degree of protection? The study itself provides no proof of biological mechanisms, but refers to known properties of ingredients commonly found in cheese.

Vitamin K2 and blood vessels in the brain

Cheese – particularly matured varieties – contains vitamin K2. This fat-soluble nutrient is involved in regulating calcium in blood vessels. Calcified, stiffened vessels raise the risk of impaired blood flow in the brain, which in turn may encourage dementia, especially vascular dementia.

By helping to counter vascular calcification, vitamin K2 could also protect cognitive function indirectly. It has not yet been conclusively established whether this occurs to a meaningful extent in people, although the hypothesis is regarded as plausible.

Proteins, amino acids and bioactive peptides

Cheese provides high-quality protein and essential amino acids. Both are building blocks for signalling substances and structures in the nervous system. Fermented varieties also produce small protein fragments known as bioactive peptides. Laboratory studies suggest that some of these peptides could have anti-inflammatory or antioxidant effects – two processes closely linked with Alzheimer’s disease and other forms of dementia.

Fermented varieties and the gut

The gut is another area of interest. Soft cheeses with white mould, such as Camembert or Brie, contain living microorganisms. These can influence the gut microbiome, which communicates with the nervous system through the so-called gut-brain axis. Researchers find disruptions to the microbiome considerably more often in people with various neurodegenerative conditions.

In the Japanese study, however, most participants chose processed cheese, which contains far fewer live cultures. Only a small proportion regularly ate traditional white-mould cheeses. This suggests that the observed effect cannot be explained by probiotic properties alone.

Is cheese a marker of an overall healthier lifestyle?

One important aspect of the study is that people who ate cheese had a different overall diet from those who avoided it. They ate fruit, vegetables, fish and meat more frequently – foods that are already associated with better brain health.

The researchers therefore calculated an additional model that took the effect of the overall diet into account. This reduced the effect from a 24 per cent to an approximately 21 per cent relative risk reduction. The association nevertheless remained statistically significant. In the team’s view, this indicates that cheese forms part of a healthier dietary pattern, while possibly also making an independent contribution.

Notably, around 70 per cent of those whose diets included cheese ate it only once or twice a week. Large quantities therefore did not appear necessary to see a measurable difference over the years.

In addition, the cheese group already showed slightly better everyday abilities at the outset, such as shopping, cooking or handling money, and reported fewer memory problems. This may point to a more favourable starting condition for the brain that cannot be fully adjusted for statistically.

Limitations of the data – and what they mean for Germany

As interesting as the findings are, the study has clear limitations. Dietary intake was recorded only once, at the beginning. Changes in eating habits were not considered, nor were the actual quantities consumed. It is therefore impossible to say from what portion size any protective effect might occur, or whether more cheese provides any greater benefit.

Dementia status was taken from long-term care insurance administrative records rather than detailed medical assessments. The specific type of dementia was usually not known. Genetic factors, including recognised Alzheimer’s risk genes, were also not included. As a result, it remains unclear for whom any possible benefit of cheese may be particularly large – or perhaps limited.

Japan is not traditionally a cheese-eating country either. On average, people there eat considerably less cheese than people in Germany or Switzerland, for example. Small differences in consumption could therefore carry more weight than they would in places where cheese already appears regularly on the table.

Applying the findings to everyday life

What does this mean for people in German-speaking countries? Nobody should start eating kilograms of Gouda or Camembert in the hope of protecting themselves from dementia. Cheese is high in fat and, depending on the variety, can also contain plenty of salt, which may be counterproductive for people with cardiovascular disease.

A moderate approach makes more sense: a few slices on bread, some hard cheese over vegetable dishes, or an occasional piece of soft cheese – all as part of a varied, predominantly plant-based diet. The Japanese data suggest that even one or two portions a week could be associated with a small, albeit limited, benefit.

• Regard cheese as one component, not a miracle cure.
• Prioritise variety: vegetables, fruit, wholegrains, pulses and fish.
• Keep an eye on body weight and blood lipids.
• Do not neglect exercise, social contact and mental activity.

What the study shows about diet and the brain more broadly

The research highlights how closely diet and lifestyle are connected to cognitive fitness in later life. Even a seemingly modest detail – whether someone eats cheese once a week or not – can be statistically linked to dementia risk.

For research, this means future projects will need to examine more precisely which types of cheese, quantities and combinations with other foods matter. It would be particularly interesting to establish whether traditionally fermented cheeses with high vitamin K2 levels or especially large numbers of microorganisms have a greater effect than heavily processed products.

For consumers, the practical message remains straightforward: taking a considered approach to diet is worthwhile, and moderate portions of cheese can certainly have a place within it. People who also monitor their blood pressure, cholesterol and body weight combine potential brain benefits with sound prevention for the heart and blood vessels.