Drinking your way to weaker bones
I've already documented my own troubled history with milk. I've discussed that the human body doesn't actually need cow's milk to function. I've even braved the disgusting thought that there may be pus in milk. But now, it's time to take on the big guns, the dairy industry's crowning jewel: their claim that drinking milk prevents osteoporosis.
It's a very nice claim. In the United States, an estimated 10 million people have osteoporosis, while another 34 million are at increased risk due to low bone mass. So it would be awfully nice to believe that we could make this problem go away by downing a cool glass of skim.
But here are some facts:
- A 12-year Harvard study of 78,000 nurses showed that those who drank more than one glass of milk per day broke more bones than those who rarely drink milk. In particular, the heavy milk drinkers had a 45% higher chance of getting a hip fracture.
- A 1994 study from Australia showed that those with the highest dairy consumption had twice the risk of hip fracture, as compared to those with the lowest dairy consumption.
- A famous British study (sponsored by the U.K. dairy industry) supposedly showed that girls who drank an extra glass of cow's milk had a 10 percent greater bone growth rate than those who didn't receive extra milk. However, this supposed extra bone density could not be validated by blood enzymes that indicate bone growth. One expert did his own math and found that the extra-milk children, in addition to gaining more weight, also had lower average bone mineral content.
- Overall, despite having one of the highest rates of milk consumption in the world, the United States also has one of the highest rates of osteoporosis.
I could go on and on, but you get the idea. One thing is clear: something doesn't add up.
Calcium and Protein: A One-Two Punch
Another one of milk's claims to fame is its protein content--roughly 8 grams per cup. Since milk offers both a substantial amount of protein and bone-building calcium, it would seem that it's a perfect drink, right?
Unfortunately, when protein and calcium are together in animal milk, it's bad news. Think of them as the friends who are good kids on their own, but are troublemakers together. Animal protein is high in sulfur-containing amino acids which get released into the bloodstream and must be neutralized. Ta-da! Calcium to the rescue! To neutralize the acids, your body leeches calcium from your bones, which then gets released in your urine.
And, keeping in mind those studies mentioned above, the calcium from the milk must not be enough to make up the difference.
The Bottom Line
Calcium is important, as any dietician will tell you. But if your calcium is coming entirely from milk, you might be causing more harm than good. You may want to consider supplementing your calcium with other sources, which I will discuss in a future post.
This is a topic I could ramble about forever, but I want to keep this brief to promote open discussion. What's your take? What do you think of these studies? Does this affect what you think about milk or osteoporosis? How has the dairy industry gotten away with this?
Sources/For more information:
http://thebabybond.com/MilkingYourBones.html (fantastic, in-depth, well-researched article)
http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/calcium-full-story/ (Harvard School of Public Health)