Bones need calcium. Doctors, dietitians and researchers agree on this point.
Conventional wisdom holds that dairy foods are the best source of calcium, and that American adults need to pump up their dairy intake to get the large amount of calcium their bodies need every day. Not everyone, however, believes the conventional wisdom.
Researchers are even raising questions about whether children need as much milk as guidelines recommend. A review article in the current issue of the journal Pediatrics concludes that there is "scant evidence" that increasing dairy intake is the right way to promote bone health in children.
Lately a small but highly respected band of scientists has been speaking out. They say Americans need less calcium than dietary guidelines recommend, and that drinking cup after cup of milk is not the best way to get it.
On one side are the federal government, the dairy industry and the majority of the nutrition community.
Milk plays a big part in the dietary guidelines recently released by the federal government. Anyone older than 8 is urged to drink three cups of low-fat or fat-free milk or eat an equivalent amount of yogurt or cheese each day. The thinking behind this recommendation is that the calcium in dairy products helps build strong bones and wards off osteoporosis, a disease in which bones become porous and break easily.
On the other side are nutrition researchers from Harvard and Cornell universities who say that when it comes to dairy, the U.S. dietary guidelines have gone too far. They believe that exercise, heredity, hormone levels, smoking, protein intake and intake of vitamins D and K matter more than milk.
The debate over dietary calcium is occurring because of rising concern over osteoporosis, or low bone mass. An estimated 10 million Americans older than 50 -- most of them women -- have osteoporosis, and 34 million are at risk for developing it.
By 2020, one in two Americans older than 50 will be at risk for fractures from osteoporosis or low bone mass, according to the U.S. Surgeon General, who issued a report in October that sounded an alarm on bone health. Bone health is so important that President Bush has declared 2002-11 as the "decade of the bone and joint."
As for the link between dairy products and osteoporosis, "there's no solid evidence that merely increasing the amount of milk in your diet will protect you from breaking a hip or wrist or crushing a backbone in later years," says Walter C. Willett, chairman of the Department of Nutrition at the Harvard School of Public Health.
