Rethinking Fat: The Surprising Role of Omega-3s and Omega-6s in Combating Obesity

Obesity has been on the rise for over half a century, and today an alarming 30% of Canadians are affected. In response, researchers have been hard at work discovering ways to mitigate this growing public health crisis – including through dietary changes. But one recent recommendation just might surprise you: consuming certain types of fats. 

When we think of “bad” foods, foods that are high in fat often come to mind. But there are different kinds of fat. The “bad” distinction mainly applies to saturated fats, which can raise your cholesterol and lead to greater risk of heart disease. In contrast, unsaturated fats, and in particular the omega-3 fatty acids, can actually have positive impacts on the body.

Dr. Lindsay Robinson, a professor of nutrition in the Department of Human Health and Nutritional Sciences, recently found that both omega-3 and omega-6 unsaturated fats can reduce two big problems in obesity: inflammation and the inability of muscle cells to use sugar (similar to what occurs with diabetes).

“I’ve always been interested in the connections between diet, inflammation and the development of chronic metabolic disease,” says Robinson. “Obesity, for example, is now considered a low-grade inflammation that drives the development of diabetes and other metabolic disorders.”

Robinson and her research team made their discovery by growing muscle cells and inflammatory cells alongside an omega-3 fat, an omega-6 fat, or a (bad) saturated fat that served as a control. They then allowed the inflammatory cells and muscle cells to interact.

This interaction, notes Robinson, was key to the study’s importance. Different cell types communicate with and influence each other, and by “co-culturing” key cell types, researchers can better capture what happens in the complex environment of the body. 

“We first had to replicate the proportion of the inflammatory cells that you might expect to find in skeletal muscle. Then, at a level similar to what is observed in obesity, we added a compound that naturally induces the inflammatory response to see the impact of different fatty acids under these conditions.”

Inflammatory cells will release either pro-inflammatory or anti-inflammatory proteins, depending on what’s around them. Robinson found that both omega-3 and omega-6 fats reduced release of pro-inflammatory proteins while increasing release of anti-inflammatory proteins, altogether fighting the inflammatory response. Some proteins were more affected by omega-3, and others by omega-6. Both types of fat also improved the ability of muscle cells to use sugar, albeit by different routes. 

The finding that most surprised Robinson was the benefits of omega-6 fats.

“Omega-6 fatty acids have often had a bad reputation,” she says, explaining that they have historically been viewed as pro-inflammatory. But the study’s results suggest their role is not quite so clear cut.  

“We’ve now seen that’s not always the case. They may be more neutral or have some beneficial effects, and it may depend on dosage and timing.”

Until the omega-6 controversy is fully resolved, Robinson recommends consuming foods high in omega-3 fats, such as fish oils, while researchers continue to explore how omega-6 fats impact your health.

“We need to further explore omega-6 fats in the context of what else you have in your diet,” says Robinson.

While Robinson’s study was conducted in a rigorous cell environment that was carefully designed to mimic obesity, she notes that it is still an isolated model.  

“We need to take this to the whole animal, whole diet. The cells used in this study were grown in the lab, so next we could explore what happens in cells taken directly from obese mice. From there, we could then compare humans with and without obesity, and do a nutritional intervention.”

Such studies will be key to unlocking the more nuanced roles of omega-3 versus omega-6 fats, advises Robinson.

In the meantime, for those looking to make a dietary change this year, consuming more fatty fish or omega-3 supplements could be a great place to start.

This study was funded by the Natural Sciences and Engineering Research Council of Canada.

Read the full study in the journal Nutrients.

Read about other CBS Research Highlights.