Whether or not you believe that milk "does a body good" depends on which medical or alternative medical practitioner you listen to. The theory that consuming more dairy products increases bone strength and improves osteoporosis has turned out to have some flaws, according to studies that note the high incidence of osteoporosis in Western countries despite high dairy intake. Of course, things are not really that simple -- the Western world also has higher rates of obesity and lower physical activity, both of which impact bone density. The truth may lie between the two positions.
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Dairy products contain large amounts of calcium, an essential mineral that hangs out in the bones until it's needed for nerve impulse transmission and other purposes. Around 99 percent of the calcium in your body lives in your bones, the Harvard School of Public Health explains. To absorb calcium, you also need an adequate intake of vitamin D or your body can't remove calcium from the intestine. It's important to build strong bones when you're young because you lose bone as you age; the more you start with, the less chance of developing osteoporosis if you lose bone.
Milk Helps
It's no surprise that the dairy industry wants you to drink your milk, the more the better, but conventional medicine has also supported the idea that dairy products, or at least the calcium they contain, builds strong bones. A University of Saskatchewan study reported in the 2003 "Journal of Nutrition, Health and Aging" found that higher calcium intake correlated with higher bone density at all locations except the spine, where dietary calcium had no effect.
Except When Milk Doesn't Help
The fact that 90 percent of Asians and 70 percent of African and Native Americans have lactose intolerance, according to the Harvard School of Public Health, may seem like proof that man was never meant to eat dairy. A study conducted by researchers from Brigham and Women's Hospital and Harvard Medical School and reported in the February 2003 issue of the "American Journal of Clinical Nutrition" found that calcium intake had no impact on the rate of hip fractures normally associated with osteoporosis.
Drawing Conclusions
It's not possible to say whether high dairy intake will prevent or cause osteoporosis without more studies. A review of studies conducted by researchers from the University of Alabama at Birmingham and reported in the September 2000 "American Journal of Clinical Nutrition" found that no clear conclusions could be drawn from current studies on dairy intake and bone health because methods and types of dairy varied. Some dairy products, such as yogurt, have more benefit than others, such as cottage cheese. Getting some of your calcium from vegetable sources can keep your levels high without your relying completely on dairy intake.
References
- "Healthy Times"; Are Dairy Products the Answer to Osteoporosis?; Anna Quisel, M.D.; July 2003
- Harvard School of Public Health: Calcium and Milk: What's Best for Your Bones and Health?
- "The Journal of Nutrition, Health and Aging"; Total Calcium Intake Is Associated With Cortical Bone Mineral Density in a Cohort of Postmenopausal Women Not Taking Estrogen; Y. Suzuki, et al.; 2003
- "American Journal of Clinical Nutrition"; Dairy Foods and Bone Health: Examination of the Evidence; Ronald Weinsier, et al.; September 2000
- "American Journal of Clinical Nutrition"; Calcium, Vitamin D, Milk Consumption,and Hip Fractures: A Prospective Study Among Postmenopausal Women; D. Feskanich, et al.; February 2003
