Study Shows Milk and Other Dairy Products May Have Weight Loss Benefits
By Denise MannWebMD Health News
Reviewed by Laura J. Martin, MD
Sept 22, 2010 -- Drinking milk may help you get rid of unwanted weight.
Drinking higher amounts of milk or eating other dairy foods may help you win the battle of the bulge, according to new research published online in the American Journal of Clinical Nutrition.
Adults who ate or drank the highest amount of dairy per day -- about 12 ounces of milk or 580 milligrams of dairy calcium -- at six months lost about 12 pounds at the end of the two-year study. People who got the least amount of calcium from dairy foods -- about 150 milligrams of dairy calcium, or half of a glass of milk per day -- lost 7 pounds after two years. Higher levels of vitamin D in the blood were also linked with successful weight loss, the study showed.
More than 300 overweight men and women aged 40 to 65 followed a low-fat diet, a low-carb diet, or a Mediterranean-style diet. All foods were readily available in the cafeteria at their workplace.
Participants filled out questionnaires regarding how many dairy products (and other foods) they ate or drank. The dairy section comprised 12 foods, such as low- and regular-fat milk, chocolate milk, low- and regular-fat yogurt, and yellow and white hard cheeses. Researchers also measured participants blood levels of vitamin D and body mass index (BMI).
"Our study suggests that both higher dairy calcium intake and increased [blood] vitamin D are related to greater diet-induced weight loss," conclude the researchers, who were led by Danit R. Shahar, of Ben-Gurion University of the Negev in Beer-Sheva, Israel.
Exactly how -- or if -- dairy foods aid in weight loss is not fully understood. Several theories exist, including the possibility that eating more calcium results in losing more fat via the stool, the study researchers say.
Vitamin D and Weight Loss
Overweight participants had lower blood levels of vitamin D when the study began, but vitamin D levels increased among those who lost more weight. The higher the blood levels of vitamin D, the greater the weight loss, the study showed.
Vitamin D is also known as the sunshine vitamin because our bodies make it when exposed to sunlight. Recent studies have linked vitamin D deficiency to a host of medical problems, including heart disease and certain cancers.
"Low vitamin D is associated with weight gain, and raising vitamin D is looking more and more like it is able to help with weight loss," says Vincent Pera, MD, director of the Miriam Hospital Weight Management Program in Providence, R.I.
"I am more and more convinced that there is something helpful about vitamin D at regulating weight," he says.
"Milk is a great source of vitamin D, and it is also taking the place of other foods that are higher in fat and calories," he tells WebMD.
"This study is part of an emerging body of research that suggest boosting key milk nutrients like calcium and vitamin D could aid weight loss," says Constance Brown-Riggs, RD, a diabetes educator in Massapequa, N.Y.
"The 2005 Dietary Guidelines for Americans recommend three cups of milk daily and this study provides consumers another good reason to grab a glass of low-fat milk -- especially if you are trying to lose weight," she tells WebMD in an e-mail.
"A lot of times with weight maintenance and management, there is so much focus on what you should not eat, but we have to look for more tools in the box," says Carolyn O'Neil, MS, RD, an Atlanta-based dietitian and the author of The Dish on Eating Healthy and Being Fabulous.
Milk is chock full of important vitamins and nutrients, she says. "It's rich in vitamin D, protein for satiety, and is one-stop-shopping for nine different nutrients, which can fill in gaps that may be created when cutting back on calories."
Some weight loss experts, including David Katz, MD, MPH, director and co-founder of the
Yale Prevention Research Center and an adjunct associate professor of public health at Yale University School of Medicine in New Haven, Conn., urge caution in interpreting these new findings.
"This is not a cause-and-effect study," he tells WebMD in an email.
"It may mean the dairy helps with weight loss or it may be that what is not being eaten helps with weight loss," he says. "For instance, more dairy intake may mean less soda intake."
The vitamin D effect seen in the study could be a result of sun exposure as we make vitamin D when we are exposed to sunlight, he says. "Perhaps the people who lost the most weight were the ones who spent the most time walking outdoors."
Katz is not sold on dairy as a miracle weight loss aid, but he does think it can be "a very nutritious choice that provides valuable nutrients at a low cost in calories or unwelcome nutrients such as added sugar, sodium, and harmful fats," he says. High levels of dairy have been linked to increased risk for certain cancers, he points out.
The new study was supported by the Israel Ministry of Health, the Israel Dairy Council, the Israel Chief Scientist Office, German Research Foundation and the Dr. Robert C. and Veronica Atkins Research Foundation.