By Kathleen Doheny
WebMD Health News
Reviewed by Michael W. Smith, MD
Dec. 5, 2014 -- Some intriguing new research shows that dairy foods, perhaps even high-fat ones, may play a role in type 2 diabetes prevention.
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Although experts say it's too soon to draw clear conclusions, the findings seem to run counter to current advice to people with diabetes, who are generally told to pick low- or non-fat dairy products.
Recent studies on how dairy products might lower diabetes risk don't all reach the same verdict. Nor do they agree about exactly which types of dairy and which fat contents are best.
Some studies have found that yogurt has a strong effect on cutting diabetes risk, but not other dairy products.
What's clear is that dairy products benefit more than our bones, says Michael Tunick, PhD. He's a research chemist at the Agricultural Research Service at the U.S. Department of Agriculture.
He reviewed recent research on dairy goods and health in a report published in November in the Journal of Agricultural and Food Chemistry. Besides preventing diabetes, lowering blood pressure, and reducing heart disease risk, he found research showing dairy products can even prevent tooth decay, obesity, and cancer.
''Diabetes prevention may be an added benefit that is unexpected," he says.
More on The New Findings
Last year, researchers pooled the results of 17 different studies that had looked at dairy foods and type 2 diabetes. Those who ate dairy products, including low-fat dairy and cheese, had a lower diabetes risk than those who did not.
More recently, Harvard researchers looked at the diet habits of more than 289,000 health professionals, including nurses and doctors. They also checked the results of 14 published studies looking at dairy and diabetes risk.
In this research, yogurt emerged as the star. While other types of dairy were not linked with a substantial drop in diabetes risk, yogurt was. The study didn't focus on one particular type of yogurt, beyond "plain" or "flavored."
Eating a serving a day of yogurt lowered diabetes risk by about 19%, the researchers reported in November in BMC Medicine.
In another recent study, Swedish researchers looked separately at low-fat and high-fat dairy. They reported that men and women who ate eight or more servings of high-fat dairy products daily had a 23% lower risk of getting type 2 diabetes, compared to those who had one or less serving daily.
They found no link with low-fat dairy and diabetes, a finding that some experts say warrants more study.
Explaining the Link
Experts aren't certain why or how the dairy products cut diabetes risk, but they have several ideas.
Yogurt has bacteria that can improve the ''good'' bugs in the intestine while suppressing the ''bad ones." These probiotics may change the gut environment in a way that lowers the risk, says Om Ganda, MD. He's the director of the Lipid Clinic at Joslin Diabetes Center.
If it is the bacteria, it's not yet known if some types are better than others, says Marjorie Cypress, PhD. She's president of health care and education for the American Diabetes Association.
Fatty acids in dairy may also help explain the benefit, Ganda says. They may also improve how well the body uses insulin, he says.
It might also be the calcium, Tunick says. Some researchers suspect that calcium may affect diabetes-related genes and lower risk.
Or, people who eat dairy may not eat as much junk food, as it serves as a healthy substitute, Ganda says. "When you eat more low-fat dairy products and things like yogurt, obviously you are replacing something else in the diet," he says. The dairy may be replacing red meat, for instance, which has been linked with a higher risk of getting type 2 diabetes, he says.
People who eat a lot of yogurt might just be healthier overall, more inclined to exercise, and they might eat right in other ways and watch their weight, others speculate.
What to Do
Yogurt and dairy products are no cure-all to lower diabetes risk, experts say.
It's important to keep the new findings in perspective, Cypress says. The research is still in its early stages, she says -- more study is needed on specific types of dairy and exactly how they may work, among other things.
The American Diabetes Association has no policy on dairy to lower diabetes risk.
If you have diabetes, the ADA continues to recommend you choose lower-fat or non-fat dairy products, she says.
"We don't know whether low-fat or regular-fat dairy is going to make a difference if you already have diabetes," Tunick says.
SOURCES: Michael Tunick, research chemist, dairy and functional food research unit, Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, Pa. Marjorie Cypress, PhD, president of health care and education, American Diabetes Association. Om Ganda, MD, director of the Lipid Clinic, Joslin Diabetes Center, Boston. European Association for the Study of Diabetes 2014 meeting, Sept. 16, 2014. Tunick, M. Journal of Agricultural and Food Chemistry, online Nov. 14, 2014. Chen, M. BMC Medicine, online Nov. 24, 2014. Aune, D. The American Journal of Clinical Nutrition, Aug. 13, 2013.
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