For decades in the U.S. milk had an exalted status, touted as not just good for us, but downright crucial.
We were brought up to believe our bones would crumble if we didn’t force down three big glasses every day.
But what does the science say?
A new study published in the British Medical Journal followed more than 100,000 people in Sweden over periods of 20 to 30 years. The result was a shocker: The good milk drinkers were more likely to die from heart disease and cancer, and among the women, the milk drinkers suffered more overall fractures and hip fractures.
A number of news outlets warned that the results should be viewed with “caution” but failed to explain whether that meant we should keep drinking milk until more evidence comes in, or that there really is no good evidenced for milk’s benefits and we should all just eat and drink what we want because the public health and nutrition communities don’t know what they’re talking about.
It would make sense to urge caution if this were one of those single studies that must be weighed against a huge body of evidence backing the benefits of milk. An editorial in the same journal by Mary Schooling of City University of New York School of Public Health suggests this is not the case. She says that until now the public health guidelines were based more on opinion and assumption than studies that looked directly at the correlation between milk drinking and health. We saw the same thing with salt – with public health guidelines based as much on a religious-type belief in the evils of salt than on any good, solid studies.
There is a reasoned way to react to this shocking milk study. First, you can apply a little personalized medicine even if you haven’t paid to have your genome sequenced. If you’re like me and you hate milk, it’s simple. Eat yogurt. The study also noted that there were no health risks associated with yogurt or cheese. Yogurt was correlated with some benefits.
But what if you love milk? How would I react to the study if the subject were something I loved, such as coffee? There are a couple of reasons milk lovers might want to keep drinking milk despite this new study. First, there are possible explanations for the results other than the hypothesis that milk causes fractures and heart disease. One might be that people with a high risk of fractures, a family history or diagnosis of osteoporosis may be drinking a lot of milk thinking it is protective. So if milk is just neutral, a study like this might find a correlation because having a known fracture risk causes people to drink more milk.
The other problem was that the researchers’ proposed mechanism seemed dubious. They blamed the apparent dangers of milk on a type of sugar called galactose, and claimed that there’s a lot more of this in milk than in fermented products, such as yogurt and cheese. Here’s where the chemistry doesn’t quite add up.
According to scientists, milk sugar, known as lactose is made from two building blocks, galactose and glucose. People who can digest milk break lactose down into these simpler sugars. In yogurt, bacteria do the work for us, breaking down the lactose into these two components. There may be some fermentation processes that also break down the galactose, but at least one study showed that there was indeed galactose present in yogurt. And it wasn’t clear from the study whether anyone ate three cups of yogurt a day, so the difference may come down to moderation on the part of the yogurt consumers.
The message comes back to moderation in all things. If the bad actor in this study were coffee, I might think twice about downing three big cups a day, but I wouldn’t give it up altogether as long as I enjoyed it in moderation. The same goes for red wine. I know drinking three big glasses a day would probably cause trouble. But that’s no reason to stop enjoying an occasional glass.