Cheese and Yogurt May Be Good for Your Knees, a Large Japanese Study Suggests, but Milk Isn't

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What the Study Found

Researchers in Japan tracked 10,411 community-dwelling adults aged 40 to 74 for 11 years. Participants filled out questionnaires about their lifestyle, body size, medical history and eating habits when the study began in 2011–2013.

The team then looked at who went on to develop symptomatic knee osteoarthritis that also showed up on X-rays. The study was published online in August 2026 in the journal Clinical Nutrition.

Higher intake of both cheese and yogurt was linked to a lower risk of the disease. Milk showed no such link. The authors conclude that the benefit "appears to be largely driven" by fermented dairy products rather than by milk.

One detail matters: the link was seen among people who otherwise ate relatively little dairy. For those who already consumed a lot, the picture was less clear.

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What Is Knee Osteoarthritis?

Osteoarthritis is the most common joint disease in older adults. The cartilage that cushions the knee gradually wears down. This leads to pain, stiffness and, over time, reduced mobility.

Known risk factors include excess weight, previous joint injuries and heavy physical strain on the knees. Diet has been studied far less, which is why this research draws attention.

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Why Fermented Foods?

Cheese and yogurt are both made by fermentation, a process in which bacteria change the milk. Milk itself is not fermented.

Scientists have long suspected that fermented foods affect the gut and the body's inflammation levels, and inflammation is thought to play a role in joint damage. This is a working hypothesis, not a proven explanation. Observational studies like this one cannot show why the pattern appears.

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Earlier Research Points in Different Directions

The Japanese result fits some earlier findings but contradicts others.

Netherlands (Maastricht Study): Among 3,010 adults aged 40–75, those who ate the most full-fat dairy and semi-hard Dutch cheese were less likely to have knee osteoarthritis. As in Japan, milk showed no link. That study captured a single point in time, so it could not tell what came first, and its authors called for long-term follow-up studies.

United States (Osteoarthritis Initiative): Researchers at Brigham and Women's Hospital in Boston reported in 2014 that women who drank low-fat or fat-free milk showed slower progression of existing knee osteoarthritis. In the same analysis, women who ate cheese showed faster progression, and yogurt made no difference.

Australia (hip osteoarthritis): A study of nearly 39,000 people found that higher dairy intake was linked to more hip replacements for osteoarthritis in men. No such link appeared in women.

Taken together, the evidence is inconsistent. Results seem to depend on the country, the type of dairy and the stage of the disease.

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Why You Shouldn't Overinterpret the Result

This was an observational study. It can show that two things occur together, but not that one causes the other. People who eat more cheese and yogurt may differ from others in ways the researchers could not fully measure, such as overall diet, income or activity level.

Food intake was also self-reported, which is never perfectly accurate. And the participants were Japanese, whose diets, genes and typical dairy consumption differ from those in Western countries.

The researchers themselves point to the need for further work before any dietary advice can be drawn from the finding.

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What It Means for You

Nobody should start eating large amounts of cheese because of one study. Cheese can be high in salt and saturated fat, and people with lactose intolerance or milk allergies may react poorly to dairy.

The more useful takeaway is modest. Fermented dairy such as plain yogurt may be a sensible part of a balanced diet, and it is unlikely to harm your joints. The proven ways to protect your knees remain unchanged: keep a healthy weight, stay active and avoid joint injuries.

Larger, longer studies in different countries will show whether the Japanese finding holds up.

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Sources

1. Bulycheva I. et al. "Fermented dairy intake and symptomatic radiographic knee osteoarthritis risk in middle-aged and older adults: An 11-year cohort study." Clinical Nutrition, 2026. PubMed: https://pubmed.ncbi.nlm.nih.gov/42628251/ (DOI: 10.1016/j.clnu.2026.106756)
2. Denissen K.F.M. et al. "Consumption of dairy products in relation to the presence of clinical knee osteoarthritis: The Maastricht Study." European Journal of Nutrition. https://pmc.ncbi.nlm.nih.gov/articles/PMC6768906
3. Brigham and Women's Hospital. "Drink Milk? Women Who Do May Delay Knee Osteoarthritis." Press release, April 7, 2014. https://www.brighamandwomens.org/about-bwh/newsroom/press-releases-detail?id=1713
4. Hussain S.M. et al. "Association between dairy product consumption and incidence of total hip arthroplasty for osteoarthritis." Journal of Rheumatology, 2017. https://research.monash.edu/en/publications/association-between-dairy-product-consumption-and-incidence-of-to/

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