(KRT)—You know it like the Pledge of Allegiance: Milk helps build strong teeth and bones.

But does it really? Or, as nutrition researchers from Harvard and Cornell Universities are radically suggesting: Have we all been duped by the dairy industry’s slick, celebrity-driven “Got milk?” advertising campaign?

Milk, the sacred cow of the American diet, is under attack, and not just by animal-rights activists. Though federal dietary guidelines and most mainstream nutrition experts recommend that people age 9 or older drink three glasses of milk a day, researchers are examining the role of dairy in our every day health.

One fact is indisputable: Our bodies need the mineral calcium to build and maintain bones and teeth. Calcium also helps with blood clotting, muscle function and regulation of the heart’s rhythm.

The debate centers on whether milk is really the best—or even a necessary—source.

For consumers, the issue is profoundly confusing, especially when it comes to osteoporosis. On one hand, we’ve had it hammered home since grammar school that milk is a health food. We were told that increasing calcium intake by drinking milk will prevent osteoporosis, the weakening of bones.

But researchers Walter Willett, chairman of the department of nutrition at the Harvard School of Public Health, and T. Colin Campbell, professor emeritus of nutritional biochemistry at Cornell University, said there is little evidence that shows boosting your calcium intake to the currently recommended levels will prevent fractures.

Willett, who coauthored “The Nurses’ Health Studies,” found that women with the highest calcium consumption from dairy products actually had substantially more fractures than women who drank less milk.

Campbell, who like Willett comes from a dairy-farming family, found the same thing after spending several decades surveying health-related effects of a plant-based diet and death rates from cancer in Asian countries.

Both men said there is no calcium emergency; Americans get plenty. And they argue that the unnecessary focus on calcium prevents us from using strategies that really work in the fight against osteoporosis, including getting enough exercise, vitamin D and avoiding too much vitamin A.

But some can’t imagine life without whole milk in their lattes or mozzarella cheese on their pizza. Chicago’s Trina Kakacek, the adult aquatic director at Lakeshore Athletic Club Lincoln Park, drinks a glass of skim milk and eats cheese and yogurt daily. Once a week she treats herself to ice cream, but then again who doesn’t.

“I would never dream of giving up dairy,” Kakacek said. “Particularly cheese or the real cream in my coffee every morning.”

© 2006 Chicago Tribune