Not all fats are created equal

You probably recall that dairy products are not a huge part of a Mediterranean-style diet. Most dairy intake is in the form of cheeses and yogurt - fermented dairy - and not in drinking milk. I (and many other doctors) have advised people for years to choose lower-fat versions of these foods as much as they can. (I usually add the exception of small amounts of full-fat cheeses used carefully, for maximum impact in a recipe.)

There's been some research, however, suggesting that consuming higher-fat dairy products may help prevent diabetes, which has understandably led to some confusion: are full-fat dairy products good for you, or not? A team in Sweden sought to clarify the issue by looking more closely at the sources of fats in the diets of those who develop diabetes (Am J Clin Nutr 2015;101:1065-80).

Their research made use of information gathered during a 14-year study of diet and cancer carried out in Sweden. At the start of the study the over 25,000 participants kept a food diary for one week and responded to a detailed dietary questionnaire in addition to providing demographic, health, and lifestyle information. The researchers could then analyze the types of fats - and the food sources of those fats - in the diets of those participants who developed type 2 diabetes and compare them with those participants who did not.

After taking into account the individual's Body Mass Index, waist circumference, smoking status, and other factors, they discovered that compared to those who consumed the least high-fat dairy products, those who ate the most were as much as 23% less likely to develop type 2 diabetes. Even more interesting is that those who ate the most low-fat dairy were 14% more likely to develop diabetes.

The researchers didn't stop at analyzing dairy products but also looked at other foods. High-fat, unprocessed red meat appeared to have virtually no impact on one's risk of diabetes, even at the highest levels of consumption, while the highest levels of low-fat, unprocessed red meat seemed to increase the risk of developing diabetes by 24%.

Just as interesting is their analysis of specific types of fats. Last week I mentioned that palmitic and stearic acids have been associated with a greater risk of diabetes, yet in this study those who consumed the highest levels of those two fats were slightly less likely to develop diabetes (at 8% and 6% less, respectively).

What this means for you

Last week we talked about how not all saturated fats are bad for you - and that some saturated fats might actually help prevent diabetes. This study makes it clear that eating healthy is not about macronutrients at all - it's about food.

First posted: May 13, 2015