Article

What’s Fat Got to do With Type 2 Diabetes?

July 28, 2016

Type 2 diabetes (T2D) is a disease characterized by abnormal glucose metabolism, so you may wonder what dietary fat has to do with it. New emerging research is beginning to show a connection.

The recent publication of the first WHO Global Report on Diabetes is a reminder that diabetes, particularly T2D, continues to be a public health concern around the world – but one the authors say is largely avoidable. The report issues a call to action to create and sustain health-promoting environments that reduce risk factors for T2D, namely overweight and obesity, insufficient physical activity and an unhealthy eating pattern.

Maintaining a healthy lifestyle, including a healthy eating pattern, is important for everyone wanting to preserve their health. If you are a health professional counseling people with T2D, you know that in addition to abnormal glucose metabolism, many with diabetes also have risk factors for cardiovascular disease (CVD), such as high blood pressure and abnormal blood lipids. That’s why it’s not surprising that lifestyle modifications recommended by the 2016 American Diabetes Association guidelines include reducing consumption of saturated fat, trans fat and cholesterol and increasing consumption of omega-3 fats to manage blood lipids.

But do all food sources of fat have the same associations with health? While authoritative guidance continues to recommend reducing saturated fat consumption to reduce risk for CVD, a growing body of evidence shows that dairy food consumption, regardless of fat content, has neutral or beneficial associations with risk for CVD. In addition, observational research studies indicate that higher consumption of dairy foods is associated with lower risk for T2D. When evaluating the emerging evidence on the effect of dairy fat on diabetes risk, results suggest that the unique fatty acid profile of dairy fat may contribute to the observed beneficial associations.

A recent example is a large prospective study investigating the association between circulating fatty acid biomarkers of dairy fat (including odd-chained saturated fatty acids and dairy trans fatty acids) and incidence of T2D among more than 3,000 adults aged 30 to 75 years enrolled in the Nurse’s Health Study and the Health Professionals Follow-up Study. Results showed the highest versus the lowest blood levels of three biomarkers of dairy fat (C15:0, C17:0 and t16:1n-7) were associated with a 43-52 percent lower risk of T2D.

A higher body mass index (BMI) is a major risk factor for insulin resistance and T2D. Since whole milk dairy foods contain more calories than lower fat versions, we would expect their consumption to be associated with weight gain, but the study indicated that this was not the case. The association between three measured biomarkers of whole milk dairy consumption and lower T2D risk remained strong, independent of BMI.

Even more recently, a meta-analysis linking butter consumption to reduced incidence of Type 2 diabetes was in the headlines – as my colleague Mickey Rubin reported.

These results are consistent with and build upon those of previous prospective studies that have evaluated fatty acid biomarkers of dairy fat and risk of T2D (Mozaffarian, 2013; Mozaffarian, 2010; Santaren, 2014).

It’s not clear yet how dairy fats may help regulate glucose and insulin metabolism to help lower the risk of T2D. What is clear is the need for more intensive research on the mechanisms responsible for these promising associations. 

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