Research shows consuming omega-6 may prevent CVD

Omega-6 polyunsaturated fatty acids could be just as important as omega-3 fatty acids in reducing disease risk, according to a new study published in the journal Circulation.

Researchers pooled data from 30 prospective studies in 13 countries involving about 69,000 people. The data included both baseline blood linoleic acid levels and subsequent risk for developing or dying from cardiovascular disease (CVD).

People in the top 10 percent of blood linoleic acid levels were 7 percent less likely to develop CVD and 22 percent less likely to die from CVD, according to the study. They were also 12 percent less likely to have an ischemic stroke compared to those in the bottom 10 percent of linoleic acid levels.

A similar 2017 study published in The Lancet looked at data from 20 studies involving 40,000 people from 10 countries. Among the participants, 4,347 new cases of diabetes occurred over time. These studies included adults with a wide range of ages and without any diagnosis of type 2 diabetes at the onset of the studies, when they were laboratory tested for levels of two key omega-6 markers, linoleic acid and arachidonic acid. In the study, people with the highest levels of linoleic acid were 35 percent less likely to develop diabetes than those in the lowest 10 percent.

The health benefits or harms that may come from the consumption of omega-6 fatty acids, especially linoleic acid, which constitutes 99 percent of the omega-6 fatty acids in the diet, are controversial, said Bill Harris, PhD, one of the study authors.

“These two studies indicate that consuming more [linoleic acid] will likely lower risk for diabetes and CVD,” he said in a statement. “This means that LA is good for us, not bad.”

In a 2009 scientific advisory published by the American Heart Association Nutrition Subcommittee, Harris and colleagues said, “to reduce omega-6 polyunsaturated fatty acid intakes from their current levels would be more likely to increase than to decrease risk."

According to Harris, because linoleic acid can be converted in to arachidonic acid, which is the precursor to many pro-inflammatory molecules, some researchers believe linoleic acid should be considered pro-inflammatory itself. However, Harris said this view is too simplistic. Extremely little linoleic acid is converted to arachidonic acid, Harris said, and linoleic acid can, in some instances, be converted to anti-inflammatory molecules.

"Regardless of the biochemistry, what molecules linoleic acid gets turned into and what they may do in the body,” he said, “the larger question of ‘do people who eat more linoleic acid, or have higher blood levels of linoleic acid, get sicker than people who have lower levels?' is just now beginning to get answered.”