How Healthy Is Milk, Really? Science Is Divided

Opinions aren’t the only sources of conflict about the effects of milk consumption. Studies also tend to butt heads when it comes to humans drinking cow’s milk.

Milk is rapidly becoming the food you hear about every other month in a new study. One month it’s good for you and the next it’s bad for you. Of course, reporting the science news like this just makes people shake their heads at science, not to mention the news. The only thing to do with so much conflicting information is just ignore it the next time around.

As a writer, ignoring science news isn’t really an option for me, but what I can do is report the juicy stuff. And when it comes to milk, the scientific battle lines are being drawn. The showdown is about to commence.

You may wonder what all the fuss is about. After all, people have been drinking milk for a long time. Some people are lactose intolerant, which means they lack the enzymes for digesting the sugar found in milk, but for everyone else, milk should be fine, right? Well, in a recent study in the Nutrition Journal, one of the BioMed scientific journals, a research team from the University of Osnabruck in Germany questioned just that. The researchers hypothesized that, from an evolutionary perspective, milk is new to humans and may not be in our best interest as a food.

We all have heard the delightful argument that cow’s milk is for making baby cows grow very fast. Some people take this as good reason to avoid the calorie-dense liquid, but others, often athletes, see its virtues as a nutrient-dense, high-protein beverage. Athletes who are looking to gain weight tend to be especially favorable toward milk consumption.

The German research team determined a major way that milk helps us gain weight is by signaling mTORC1, an enzyme that supports growth. Milk also has microRNA signaling agents that prevent growth from stopping. This is all well and good when you’re a baby and you grow rapidly, but as an adult human, the researchers postulated, it’s the foundation for numerous diseases.

One of these diseases, and perhaps the most serious of the bunch, is hallmarked by uncontrolled growth: cancer. The researchers also pointed to other possible diseases as well, not the least of which are diabetes, hypertension and Alzheimer’s. The mTORC1 enzyme may trigger any or all of these, and milk could exacerbate the process.

On the other side of the coin, researchers at the University of Auckland in New Zealand published a paper a few weeks later in Nutrition and Metabolism, another BioMed journal. This study touted milk’s ability to eliminate disease. The team performed a literature review, citing mounting evidence that milk and milk proteins, like whey and casein, decrease metabolic risk factors like hypertension, dyslipidemia, and hyperglycemia, and may even improve body composition in a way that improves health in the long run.

As you can see, scientists are taking a stand on both sides of the fence. There are good reasons to support or reject the consumption of milk for health or athletic purposes on both sides. Which side is right has yet to be seen. It is very possible that both are right. Perhaps metabolic diseases decline with milk, but mTORC1 triggered diseases increase. What’s important is which side wins out in the end.

Until this dramatic scientific standoff comes to a conclusive end, consume milk as you normally would, as long as it’s either in moderation or not at all. For those on the GOMAD (Gallon of Milk a Day) diet, you may want to rethink your nutritional strategy.


1. Bodo C Melnik, et. al., “Milk is not just food but most likely a genetic transfection system activating mTORC1 signaling for postnatal growth,” Nutrition Journal 2013, 12:103.

2. Robin A McGregor, et. al., “Milk protein for improved metabolic health: a review of the evidence,” Nutrition & Metabolism 2013, 10:46.

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