Blood samples were analyzed for the presence of trans-palmitoleic acid, as well as cholesterol, triglycerides, C-reactive protein and glucose levels. Participants also provided information on their usual diets.
People with higher levels of trans-palmitoleic acid had slightly less fat on their bodies, according to the study. They also had higher "good" cholesterol levels and lower overall cholesterol levels. They had lower levels of C-reactive protein, a marker of inflammation. And they showed evidence of lower levels of insulin resistance, according to the study.
Most significantly, however, those with higher trans-palmitoleic acid levels had lower odds of developing type 2 diabetes. Those with the highest levels of trans-palmitoleic acid reduced their odds of type 2 diabetes by nearly two-thirds.
Mozaffarian said it's difficult to know exactly how many servings of dairy it would take to get to the highest levels of trans-palmitoleic acid, but said it was likely three to five servings a day, depending on the type of dairy consumed.
However, he said, it's too soon to make any dietary recommendations based on the results of just this finding.
"This study confirms that something about dairy is linked very strongly to a lower risk of diabetes, but no single study should be enough to change guidelines," he said, adding that he hopes this study will spur more research.
Dr. Sue Kirkman, senior vice president of medical affairs and community information for the American Diabetes Association, agreed that it's too soon to change dietary guidelines, but said the findings do suggest "that things may be more complicated than we might simplistically think. It looks like we can't say all trans-fats are bad, as this one was associated with decreases in diabetes, insulin resistance and C-reactive protein levels."
Dr. Joel Zonszein, director of the Clinical D
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