Editorial NexoScience
A wedge of cheddar in the fridge door. A glass of whole milk with breakfast. Both count as dairy on any nutrition label, and both fall under the same line in most dietary guidelines. A new analysis covering almost a million people suggests your heart does not treat them as the same food at all.
Two of the largest health cohorts on the planet were asked the same question and gave different answers. Researchers at Zhejiang University followed 487,212 adults in the China Kadoorie Biobank and roughly half a million in the UK Biobank, accumulating 4,190,676 person-years of follow-up in China and 4,736,113 in the United Kingdom. Along the way they recorded 66,132 cardiovascular events in the Chinese cohort and 32,822 in the British one. In China, people who ate dairy at least four days a week showed a 9% higher risk of coronary heart disease than non-consumers (HR 1.09, 95% CI 1.05 to 1.13) but a 6% lower risk of stroke (HR 0.94, 95% CI 0.91 to 0.97). The protection was strongest against hemorrhagic stroke, the bleeding kind, where risk fell by 24% (HR 0.76, 95% CI 0.69 to 0.83).
In the United Kingdom the picture flipped. Total dairy intake was associated with a 7% lower risk of cardiovascular disease overall (HR 0.93, 95% CI 0.88 to 0.98), a 7% lower risk of coronary heart disease (HR 0.93, 95% CI 0.88 to 0.99) and a 14% lower risk of ischemic stroke (HR 0.86, 95% CI 0.75 to 0.99). Same food group, opposite direction for the arteries that feed the heart itself.
Pooled worldwide, the evidence leans mildly in favor of dairy. The team combined its own results with 30 publications from 25 earlier prospective cohorts, covering 1,288,420 participants and 73,193 cardiovascular events across 30 countries and territories, with follow-up periods ranging from 5.5 to 30 years. Taken together, higher total dairy consumption was linked to a 3.7% lower cardiovascular risk (RR 0.963, 95% CI 0.932 to 0.995) and a 6% lower stroke risk (RR 0.94, 95% CI 0.90 to 0.98). For coronary heart disease the pooled result was flat, with no association at all (RR 0.98, 95% CI 0.93 to 1.02). Disagreement between studies was substantial, with an I² of 66.1%.
Cheese is the dairy product that behaves best in the numbers. British participants eating cheese at least seven times a week had 12% less cardiovascular disease and 12% less coronary heart disease than those eating it fewer than twice a week (HR 0.88 in both cases). In the pooled global analysis, cheese carried a 6% lower cardiovascular risk (RR 0.94, 95% CI 0.91 to 0.97), while yogurt (RR 0.99) and milk (RR 1.00) showed nothing at all. That is counterintuitive, because hard cheese is loaded with salt, saturated fat and calories. The authors suspect fermentation matters more than fat content here, pointing to vitamin K2, calcium that limits the absorption of saturated fats and cholesterol, conjugated linoleic acid and live cultures that reshape the gut microbiome.
What kind of milk you pour also changes the association. In the British cohort, semi-skimmed and skimmed milk drinkers had lower cardiovascular risk (HR 0.92 and 0.91) and clearly lower stroke risk (HR 0.80 and 0.76) than people who rarely drank milk. Low-fat dairy as a whole category came out protective in the pooled analysis for both cardiovascular disease (RR 0.96) and stroke (RR 0.90). Milk on its own, however, was tied to an 8% higher risk of hemorrhagic stroke (RR 1.08, 95% CI 1.01 to 1.17), which sits awkwardly next to the Chinese cohort, where dairy intake dominated by whole milk went with less hemorrhagic stroke. That tension is part of an honest reading of this evidence. Yogurt’s blank result may have a more mundane explanation, since sweetened and flavored versions fall squarely into the ultra-processed category.
Two plausible reasons explain why China and the United Kingdom diverge. The first is quantity. Average dairy intake in the UK Biobank was more than four times higher than in the China Kadoorie Biobank, and any cardiometabolic benefit may need a certain threshold of intake before it shows up. The second is composition. Cheese is the leading dairy product in Britain, at 46.49% of dairy intake in that cohort, while liquid whole milk dominates in China. Lactose intolerance is also far more common in Chinese populations, and non-fermented milk carries more D-galactose than cheese, a sugar linked in experimental work to oxidative stress and chronic inflammation.
None of this proves that cheese protects anybody’s heart. These are observational cohorts, not randomized trials, so they show associations rather than causes. Diet was measured with food frequency questionnaires, mostly a single time at baseline, and people who consumed more dairy also tended to be wealthier, better educated and more physically active. The authors adjusted for a long list of confounders including income, education, smoking, alcohol, physical activity, body mass index, hypertension, diabetes and the intake of meat, fish, eggs, fruit and vegetables, yet residual confounding cannot be ruled out. Their own GRADE assessment rates overall confidence in these estimates as very low to moderate. The useful takeaway is narrower than a slogan. Dairy as a single block is not a meaningful unit of analysis, and the individual products inside it clearly behave differently.
The findings come from the study “A global analysis of dairy consumption and incident cardiovascular disease”, by Pan Zhuang, Xiaohui Liu and colleagues at Zhejiang University, published in Nature Communications in 2025. DOI: 10.1038/s41467-024-55585-0.
