A recent Instagram post I wrote about milk stirred up far more debate than I expected. One health influencer replied that he usually agrees with me, but that this time I was completely wrong, because a recent review had concluded that drinking milk reduces overall mortality. I had said that for most people I don’t think the evidence justifies drinking milk for health benefits.
This black and white way of arguing highlights a common problem in nutrition. Almost any position can be propped up by cherry picking a single study, or increasingly a review generated by AI. The real question is what the totality of the evidence actually shows.
For decades we were taught that adults should drink plenty of milk to protect their bones and prevent osteoporosis. I passed on that advice myself when I ran the osteoporosis clinic at Guy’s and St Thomas’ Hospital. Sadly, it has not held up. The early studies suggesting strong protection against fractures have largely been overturned by larger and more rigorous research. Most systematic reviews now conclude that drinking more milk has little or no effect on fracture risk, with perhaps a modest reduction in spinal fractures at best, but none in the common wrist and hip fractures. Milk, in other words, is not the bone protecting miracle food many of us once believed, and that I once championed.
The heart story is similarly underwhelming, though it runs in the opposite direction. When I trained, anything containing fat, and saturated fat especially, was demonised as terrible for your heart. The evidence today is broadly neutral. A major 2020 review in the New England Journal of Medicine found no clear association between usual dairy intake and cardiovascular risk. More recent work hints at a small benefit, particularly at around one serving, roughly a glass, a day, but the effect is tiny and the evidence far from settled.
Cancer is where things get more interesting, because the associations are stronger. Daily milk is linked to a lower risk of colon cancer, which is a genuine plus. But higher intakes, especially of full fat milk, are consistently linked to a higher risk of prostate cancer. A trade off between two common cancers makes blanket advice much harder to give.
On overall mortality the picture is mixed. Some reviews suggest small benefits, others find nothing, and a few report higher mortality with more whole milk. Fermented dairy, though, tells a happier and more consistent story. Yogurt above all, and cheese to a lesser degree, tends to line up with better health outcomes. That should not surprise us: fermentation fundamentally changes dairy. It shifts the microbial makeup, produces beneficial compounds, and, probably through our immune system, feeds our gut microbes in a way that plain milk simply does not. There is reasonable evidence that yogurt and other ferments go with a lower risk of type 2 diabetes.
But the question nutrition studies most often miss is this: what are you drinking milk instead of? If milk replaces sugary or heavily sweetened drinks, it is probably a good swap. If it replaces water, it is probably a negative. If it replaces processed meat, it is likely beneficial. But if it replaces a handful of nuts, some beans or other minimally processed foods, it is unlikely to do you any good. This principle matters enormously, and it is why so many contradictory studies can all be technically correct.
Walter Willett, arguably the world’s most influential nutrition epidemiologist, put it well when he argued that the US advice for adults to eat three or more servings of dairy a day was not supported by the evidence. Whether you benefit from dairy depends far more on the quality of your overall diet than on hitting an arbitrary target.
So where do I stand? I don’t think adults need to drink milk if they eat a reasonable diet. One or two glasses a day probably won’t do you much harm. But if it crowds out a diversity of other healthy foods, that is a real downside, especially if you believe milk is doing you a lot of good, which for the most part it isn’t. I am particularly wary of promoting it to men, given the prostate cancer signal. If you enjoy it, there is little reason to avoid it, and no reason at all to give up the splash in your tea or coffee, which will make no real difference either way. But if I had to choose, I would spend my daily food budget on yogurt, kefir and other fermented foods, whether made from dairy or from plants, rather than on another glass of milk.
