Dairy products may lower diabetes risk
A new study in the December 21, 2010, issue of Annals of Internal Medicine suggests that eating whole fat dairy products may help reduce the risk of developing type 2 diabetes mellitus.
The study led by Dariush Mozaffarian of the Harvard School of Public Health and Brigham and Women's Hospital and Harvard Medical School and colleagues showed those who had high levels of a dairy fatty acid - trans-palmitoleic acid were at lower risk of type 2 diabetes mellitus during a 20-year follow-up.
The researchers examined 3,736 participants in the Cardiovascular Health Study, who had been followed for 20 years. They found those who had the highest amounts of trans-palmitoleic acid at baseline were 60 percent less likely to have type 2 diabetes mellitus.
In addition, Mozaffarian et al. found higher circulating levels of trans-palmitoleate were correlated with healthier levels of cholesterol, inflammatory markers, insulin levels, and insulin sensitivity after adjustment for other confounders.
Dairy fat is known to contain high levels of trans fatty acids such as trans-palmitoleate, which is naturally present in dairy products.
It should be noted that this trans fat differs from those artificial partially hydrogenated trans fat used in fries and other processed foods, which has been linked to increased heart risk.
The study is observational and it did not establish any cause-effect relationship, meaning eating trans-palmitoleate may not indeed reduce the risk of type 2 diabetes mellitus. Only clinical trials can demonstrate such a relation.
The researchers acknowledged that there is no biological basis for the potential benefit. Humans can't produce trans-palmitoleate in the body and the compound may not be metabolized as easily as other natural cis-fatty acids.
A health observer suggested it is more than likely that the association is incidental. He speculated that trans fat is hard to digest, but this trans palmitoleate can be a good indicator for the amount of dairy products consumed.
Consumption of dairy products on the other hand have been known to be associated with low risk of type 2 diabetes mellitus.
As early as in 2005, researchers from Massachusetts General Hospital and Harvard School of Public Health; Boston, Mass found a diet full of dairy products was linked to lower risk of type 2 diabetes mellitus in men.
Hyon K Choi and colleagues reported in Archives of Internal Medicine that men in the top quintile of dairy intake were 23 percent less likely to acquire type 2 diabetes mellitus, compared with those in the lowest quintile.
The researchers found this association after they analyzed dietary data and incident cases of type 2 diabetes mellitus in 41254 men with no history of the disease, cardiovascular disease and cancer when they entered the Health Professionals Follow-up Study.
Choi et al. also found each serving per day of dairy products was correlated with a 9 percent reduced risk of type 2 diabetes mellitus.
The risk reduction was more significant for low-fat dairy products.
The researchers concluded "Dietary patterns characterized by higher dairy intake, especially low-fat dairy intake, may lower the risk of type 2 diabetes in men."
By David Liu
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