Eating a diet rich in omega-6 polyunsaturated fatty acids could reduce the risk of type 2 diabetes by more than a third, a new review published in the George Institute for Global Health in Australia concludes.Study co-author Dr. Jason Wu, (George Institute for Global Health, Australia) and colleagues recently reported their findings in The Lancet Diabetes & Endocrinology.

Polyunsaturated fats (PUFAs) such as omega-3 and omega-6 should form a part of a healthful diet, albeit in moderation. The new review, however, suggests that we might want to consider increasing our intake of omega-6 to protect against type 2 diabetes. Omega-6 fatty acids are considered to be essential for health; not only do they aid brain function, but they also play an important role in skin and hair growth, and they help to regulate metabolism and support bone health. However, since the body is unable to produce omega-6, we can only get these fatty acids from certain foods, including soybean oil, sunflower oil, corn oil, and some nuts and seeds.

Current guidelines from the American Heart Association (AHA) recommend that omega-6 fatty acids should make up no more than 5–10 percent of our daily total energy intake, as they have been linked to increased inflammation and heart disease. "Based on concerns for harm, some countries recommend even lower intakes," says Dr. Wu. However, Dr. Wu and team note that while there are an array of studies that have investigated the effects of omega-6 on heart health, little is known about how omega-6 influences the risk of type 2 diabetes.

To find out more about the link between omega-6 and type 2 diabetes, the researchers conducted an analysis of 20 prospective cohort studies on the subject. The studies included a total of 39,740 adults aged 49–76 years from 10 countries. All study participants were free of type 2 diabetes at study baseline. During a follow-up period of 366,073 person years, 4,347 new cases of type 2 diabetes were observed. As part of the studies, participants' blood was assessed for levels of linoleic acid and its metabolite arachidonic acid, and the team looked at whether or not these levels might be linked to the development of type 2 diabetes.

Compared with subjects who had low blood levels of linoleic acid, the researchers found that those who had consumed higher levels of the omega-6 fatty acid were 35 percent less likely to develop type 2 diabetes.

These findings persisted after accounting for a number of possible confounding factors, including body mass index (BMI), age, sex, race, and levels of omega-3 fatty acids.

Interestingly, the researchers say that their findings — together with results from previous studies — "do not suggest that high levels of dietary omega-6 PUFA[s] are harmful. The researchers believe that their results indicate that we may benefit from increasing our intake of omega-6.

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