Cheese And Dementia Risk: Why Researchers Keep Finding A Surprising Association

For a food that brain-health diets tell people to limit, cheese keeps landing on an unexpected side of the dementia research: the lower-risk side.

Studies in Sweden and Finland have linked heavier cheese eating to lower dementia rates. Lab experiments show that compounds formed during fermentation can calm inflammation in immune cells and in mice. Yet researchers in the UK, Japan and Australia have watched the link weaken or disappear. What scientists still can’t say is whether cheese does something for the brain, or whether cheese eaters simply differ in ways that protect them.

What Did The Swedish Study Actually Find?

Only high-fat cheese showed a link, and only in some analyses. In the Neurology study, researchers at Lund University and partner institutions followed 27,670 adults from Sweden’s Malmö Diet and Cancer study, ages 45 to 73 at enrollment, for a median of 25 years. Swedish health registers recorded 3,208 dementia cases in that time.

Participants who reported eating at least 50 grams (about 1.8 ounces) of cheese containing more than 20% fat each day had a 13% lower adjusted risk of dementia than those who reported less than 15 grams (about half an ounce). “Adjusted” means researchers accounted for other differences between the groups, such as smoking, alcohol use and physical activity. That higher intake was also linked to a 29% lower adjusted risk of vascular dementia, a form tied to damaged blood vessels in the brain. Low-fat cheese, milk, fermented milk and butter showed no clear link to dementia overall.

Heavy cheese eaters were not a random slice of the group. Participants chose their own diets, and those in the highest-intake group had more education, lower body weight and less diabetes, high blood pressure, heart disease and stroke than those in the lowest-intake group. They were also more likely to be current or past smokers. Diet was measured once, at the start, and researchers did not test memory and thinking at enrollment, so early, undiagnosed decline could have shaped what people ate. Broad cheese categories and diagnoses pulled from medical registers, which can miss cases, add more uncertainty.

Do Other Cohorts Find The Same Pattern?

Sometimes, but the results disagree. A cohort is a group of people followed over time, and four other cohorts tell different stories.

A University of Eastern Finland study followed 2,497 dementia-free men, ages 42 to 60 at the start, for an average of 22 years. Men in the highest quarter of cheese eating had a 28% lower adjusted risk of dementia, though that result barely cleared the bar: the range of plausible values ran from 48% lower to just 1% lower. Across all the foods examined, the researchers reported little evidence of any link to dementia.

A study using UK Biobank data of 249,511 people aged 55 and older found that eating cheese once a week was linked to lower dementia risk even after accounting for social, lifestyle, and health factors. That link faded once researchers analyzed cheese alongside all the other food groups at once.

In Japan, the Tohoku University Ohsaki cohort followed 11,637 adults ages 65 and older for an average of five years. Daily cheese eaters showed no lower risk. Their estimated risk actually ran 28% higher, though that result was not statistically clear and could reflect chance.

And in Australia, a study of 966 adults ages 70 to 90 found no link between cheese intake and dementia over about five years.

How Strong Is The Wider Evidence?

Still thin, especially for cheese itself. A 2023 systematic review in Advances in Nutrition, which pooled 15 long-term studies of more than 300,000 people, found that moderate dairy intake, around 150 grams a day, was linked to a somewhat lower rate of cognitive decline or dementia. Comparing the highest dairy eaters with the lowest, though, showed no difference. Results also varied widely from study to study, and the cheese-specific dose analysis drew on only two studies.

A 2018 review in the International Journal of Molecular Sciences describes compounds formed when dairy ferments, such as oleamide, that calmed inflammation in lab-grown immune cells, including brain immune cells, and in mice. Those experiments cannot show that cheese prevents dementia in people. Cheese also varies widely, and how much people eat, how it’s prepared and what they eat it with differ from one population to the next, so results can be sensitive to surrounding factors.

What Does The Evidence Actually Support?

Not enough to treat cheese as medicine. According to the National Institute on Aging, there is so far no evidence that eating or avoiding a specific food can prevent Alzheimer’s disease or age-related cognitive decline, and evidence for the Mediterranean and MIND diets is mixed.

Better answers would need studies that tell cheese types apart and track diet over time, since the Swedish study measured it only once. For now, the National Institute on Aging’s prevention overview keeps the practical focus on healthy eating overall, physical activity, blood-pressure control and social connection, rather than on hopes pinned to one item in the refrigerator.

Disclaimer: This article summarizes observational studies, which track what people report eating and later health outcomes. Studies of this kind can show associations but cannot prove that cheese, or any single food, causes or prevents dementia. Laboratory findings described here come from cell and animal experiments and have not been shown to apply to people. This article is for general information only and is not medical or nutritional advice. Readers with concerns about dementia risk or diet should speak with a health care provider.