Milk Study Leaves a Sour Taste
Dairy industry challenges study questioning bone benefits
FRIDAY, March 11, 2005 (HealthDay News) -- Got controversy?
Earlier this week, a leading medical journal ran an article that found little evidence that children need a milk-heavy diet to build strong bones. Now, the dairy industry is on the defensive, trying to poke holes in the research and claiming the article authors are biased.
At stake are the diets of millions of American children. Should they get their calcium by consuming as many as three servings of dairy products a day, as the federal government now suggests? Or would a glass-and-a-half of milk -- perhaps replaced by tofu or fortified orange juice -- be all right instead?
The milk skeptics are still a minority view among nutritionists. But the new article, in the March issue of Pediatrics, gave them a powerful platform.
The authors analyzed findings from 27 studies focused on diet and bone health in children and young adults. According to the authors, only nine of those studies found a relationship between calcium intake and bone health, and the effects were small.
"We didn't see any difference between kids who are consuming around 500 milligrams (of calcium) and those consuming 800 or 1200," said study co-author Amy Lanou, nutrition director for the Physicians Committee for Responsible Medicine.
About a glass-and-a-half of milk would provide 500 milligrams of calcium, Lanou said, but she recommends non-animal sources of calcium instead, such as dark greens, tofu, nuts and seeds, and calcium-fortified products such as rice milk, soy milk and orange juice.
Getting more calcium from dairy products simply isn't necessary, she said. "The bottom line for parents is that if your child is lactose-intolerant, or if your child doesn't like milk or is allergic to milk, you really don't have to worry," she said.
Instead, she suggests that parents look at other ways to promote the growth of strong bones. "The best option is to get your kids outside playing, getting some exercise and some sunshine, and make sure they have an overall healthy diet rich in fruits, vegetables, grains and legumes."
Lanou is a vegetarian herself, as is one of the study's other two authors. The Physicians Committee for Responsible Medicine, based in Washington, D.C., promotes vegetarianism.
Not surprisingly, the dairy industry accuses the authors of pushing a pro-vegetarian agenda and bucking conventional wisdom supporting the three-servings-a-day dairy recommendations.
"Go out and look at where mainstream medical and health professionals are saying," said Greg Miller, the National Dairy Council's senior vice president of nutrition and product innovation. "This opinion piece really stands out as an anomaly compared to what every other group is saying."
According to him, one problem is that the Pediatrics article failed to rely upon studies using the "gold standard" of medical research to determine cause-and-effect relationships between, say, milk consumption and bone heath.
Lanou responded that few of the studies Miller refers to -- known as randomized controlled studies -- were available.
Other industry critics questioned the study selection used in the article by Lanou and colleagues. Speaking to the Durham, N.C., Herald Sun, David Martosko, of the nonprofit advocacy group Center for Consumer Freedom, said Lanou's group "cherry-picked which studies they included because they knew if they included more actual clinic trials that the results wouldn't be very animal-rights friendly."
"What we object to," he said, "is a group claiming to represent the mainstream medical community when it pronounces that dairy foods are inherently unnecessary."
However, Lanou had her supporters, too.
When it comes to its role in forming and maintaining strong bones, "the data for calcium is quite weak, as compared to looking at vitamin K and vitamin D," Susan Brown, director of the Osteoporosis Education Project, told the Syracuse, N.Y., Post-Standard. She believes many Americans overestimate the amount of calcium they need to incorporate into their daily diet.
But Miller contends that even small calcium-related changes in bone strength can be important. While genetics accounts for 60 percent to 80 percent of a persons' bone health, "you've got about 20 percent that you can impact," he said. He suggests that children consume three servings a day of dairy products. Teen-agers may need as many as four servings, he said. (A serving is equivalent to a glass of milk, a container of yogurt, or two dice-sized pieces of cheese.)
Why consume so much dairy?
"Because not having calcium would be like trying to build a brick house without bricks," Miller said.
Bone up on kids' bone health at the National Institute of Arthritis and Musculoskeletal and Skin Diseases.