Got Milk? What it Means for Bone Health
Did you grow up with a mom who insisted that you finish your milk before you left the dinner table? If so, it’s most likely she knew that drinking milk made for a lifetime of good bone health. While you may hesitate to challenge mom’s wisdom, a new study in JAMA Pediatrics
found that drinking more milk as a teenager does not lower your risk of hip fracture as an older adult. And it appears to increase that risk for men.
Health Matters: Let’s start with the basics. How does milk affect bone health? Are the effects all good or are there negatives? Is the impact different for various ages or stages of growth?
Mendelson: Milk is an excellent source of calcium, vitamin D, and protein, all of which are important for good health and building strong bones. How it works to help your body is a complicated process with a lot of variables that interact. In general, milk can be a healthy part of a balanced diet and most Americans would be unlikely to get too much, but it is possible. I like to tell patients, “All things in moderation; nothing to excess, including moderation!” Infants, children, pregnant women, and nursing mothers all have higher recommended daily calcium and vitamin D intake and often benefit from additional milk in their diets.
Health Matters: While drinking milk during adolescence is recommended to achieve peak bone mass, the study also says it is linked to getting taller, which can be a risk factor for hip fracture later in life. Why is the risk for fracture different for men than for women, whose risk does not appear to increase, according to this study?
Mendelson: These types of studies are interesting because they look at very large populations, but you have to be careful about reading too much into them. Milk, calcium, and vitamin D metabolism are complicated and the data cited does not specifically look at the interaction between these factors and fractures.
Men and women are different when it comes to bones. They differ in average height, muscle mass, muscle-to-fat ratio, bone density, and bone length and diameter. All of these can affect fracture risk. Women are more prone to osteoporosis and fractures after menopause because of a decrease in estrogen, which impacts bone metabolism. Some older men have a decrease in testosterone as they age, which can also be a cause of osteoporosis. At the end of the day, milk can be an important source of necessary calcium and vitamin D for men and women of any age.
Health Matters: For parents, providing healthful nutrition for their children is a priority from birth to when the child is out on their own. How much milk should children be getting, particularly teenagers, in light of this study, which says the risk to men increases with each glass of milk consumed as a teenager? And how much should adults get?
Mendelson: This study does not change what I would recommend for my patients, their children, or my own children. Most children and teens will benefit from between 2 to 4 cups of milk per day. Parents with specific concerns should check with their child’s primary care provider. Adults, especially over 50, usually benefit from 2 to 3 cups of milk each day.
Health Matters: Are there others ways or nutritional sources that can improve bone health and reduce risk of fractures of all kinds for both men and women?
Mendelson: There are many small studies suggesting a variety of benefits from different diets. There is no magic diet or pill. The best thing for healthy bones is a balanced diet rich in natural and whole foods with adequate vitamin D and calcium, as well as weight-bearing exercise and activity.