Will Omega-6 Fats Prevent Type 2 Diabetes?

Health reporters are having fun this week with another observational study. A large analysis of prospective cohorts from all over the world found a strong association between linoleic acid and a lower risk of type 2 diabetes. So naturally, the researchers sent out a press release:

Omega-6 Fats May Help Prevent Type 2 Diabetes

Is it time for dietary supplement makers to crank out more omega-6 and linoleic acid supplements? Maybe not.

An Observation Is Only a Start

This is a good study in many ways. The researchers are looking at an objective marker of dietary behavior: linoleic acid levels. They’re not relying on self-reports of what people ate. The data comes from many different countries. So it’s less likely to be skewed by regional dietary factors. And they had a pre-specified analysis plan – no data dredging here.

However, it’s still an observational study. There’s no intervention here, no control group, no advice on what to eat. The people whose diets gave them the highest levels of linoleic acid had a lower risk of type 2 diabetes. In fact, the risk was 35% lower. That’s a pretty big difference.

A Big Leap to Dietary Advice

Maybe the omega-6 fats caused those outcomes. Or, maybe it’s what comes along with those omega-6 fats in the diets of people who had the high levels. This observational study is a pretty good clue that something is going on.

But the leap to dietary advice is a big one. And many pitfalls are possible. Simply advising people to eat more omega-6 fats might not do the trick. The real answer will come from randomized, controlled studies of whole diets and dietary prescriptions.

The balance of fats – omega-6 and omega-3 – seems to be an important factor. So we need more information. We need more context. And most of all, we need whole dietary advice.

Chasing a single nutrient is, more often than not, a fool’s errand. Don’t count on omega-6 fats by themselves to protect you from diabetes.

Click here for the study and here for the press release. For more perspective on omega-3 and omega-6 fats, click here and here.

Sweet & Spicy Toasted Pumpkin Seeds, photograph © Rebecca Sims / flickr

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October 14, 2017