Let’s start with bone health. Evidence shows that drinking milk does increase height in children. After all, dairy milk is designed to help baby cows grow rapidly, says David Ludwig, an endocrinologist at Harvard T.H. Chan School of Public Health. “Its evolutionary purpose is to drive fast growth in grazing animals that are at risk for predation,” he says. “So if you were a buffalo on the grasslands, a baby buffalo, you'd want to grow as fast as possible so as to not be eaten by a lion.”
But according to a recent review from Ludwig and Harvard University endocrinologist Walter Willett in the New England Journal of Medicine, milk may not be the magic bullet for strong bones as once thought. In fact, countries that tend to consume the highest amounts of milk and calcium also have the highest rates of hip fractures. This doesn’t necessarily mean that the milk caused their fractures, but the fact that many low-dairy populations do not suffer from high rates of fracture might help put milk consumption in perspective.
Height is also a risk factor for fractures, Ludwig added. “For every additional serving a day of milk, a kid will grow maybe an extra centimeter of final adult height,” he says. “And tall stature is one of the greatest risks for bone fractures. The bigger they come, the harder they fall," he says. So although milk might be helping kids get taller, those longer bones may be more likely to break.
The researchers concluded that while milk contains essential nutrients for humans, those nutrients can all be found elsewhere. In their work, they also opposed the government recommendation — three servings a day of milk and other dairy products — which they say is too high.