When most of us were growing up, we were taught that dairy products are rich sources of calcium, making them essential for building strong bones. Calcium loss from bone is said to cause osteoporosis, which is particularly prevalent in postmenopausal women.
Now it seems that, as with other foodstuffs, the dairy products story may not be quite what it originally seemed. Or so some experts believe.
In a startling study on bone health, published in the American Journal of Clinical Nutrition in February 2003, Harvard researchers reported that they found no link between high calcium consumption, or milk consumption, and bone strength.
After tracking hip fractures and eating habits in 72,337 women for 20 years, they failed to find a correlation between consuming more than 700mg of calcium a day and stronger bones. However, they did find a link between higher intake of vitamin D and a lower risk of fractures.
“There is really no requirement for dairy products in the diet,” says Amy Lanou Ph.D., nutrition director for the Physicians Committee for Responsible Medicine in Washington, DC. “The countries with the highest rates of osteoporosis are the ones where people drink the most milk and have the most calcium in their diets. The connection between calcium consumption and bone health is actually very weak, and the connection between dairy consumption and bone health is almost nonexistent.”
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In his book Diet and Health: New Scientific Perspectives Dr. Veith says that while calcium is essential for normal growth and development of the skeletal system, a distinct correlation exists between the consumption of dairy products and the incidence of osteoporosis:
“In a comparative study between 1,600 ovo-lacto-vegetarians and omnivorous women in Michigan USA it was found that the vegetarians had only 18% loss of bone mineral by age 80, whereas closely paired omnivores had 35% loss of bone mineral. High-protein diets cause calcium loss in the urine, and evidence suggests that the rates of osteoporosis are higher in Western countries than in developing countries where diets tend to be vegetarian.
“In our modern society the notion exists that dairy products are essential for maintenance of calcium levels and prevention of osteoporosis. Vegan diets are often criticized on the grounds that they will lead to severe calcium depletion. In fact there is no evidence that this is the case and if anything, the reverse is true, as osteoporosis is more prevalent in Western countries where an abundance of milk is consumed than in countries where vegan diets are more common. There is also no clear evidence that dietary calcium supplementation will show the rate of bone loss in postmenopausal women, a position also held by the US department of Health and Human services,” says Dr. Veith.
But just when you think Mom was wrong when she commanded you to drink your milk…. She wasn’t, according to an article “Milk at 10, strong bones at 50,” published in the Reader’s Digest Medical Breakthroughs:
“Kids who ignore the age-old parental command to ‘drink your milk!’ may live to regret it. New findings show that women over 50 who drank less than a glass of milk a day as girls have significantly lower bone density and twice the risk of fractures compared with those who drank a glass or more a day. It also appears there is no undoing past damage: in the study, the added risk existed no matter how much milk the women drank as adults or how much calcium they took. Childhood and adolescence are key bone development stages and require sufficient calcium intake. Calcium supplements taken during those years help, but you have to keep taking them to sustain the benefits.
“Milk, on the other hand, appears to impart bone-strengthening benefits that last well past menopause, even if you don’t drink it as an adult. The study, published in the January 2003 issue of the American Journal of Clinical Nutrition, stops short of concluding that the more milk you drink in childhood, the more benefits you receive. But it clearly shows that drinking your milk while your bones are growing pays big dividends later — when you’re trying to save them.”