A new large-scale international study suggests that a diet rich in omega-6 polyunsaturated fats could significantly reduce the risk of developing diabetes.

Led by Dr Jason Wu of The George Institute for Global Health in Sydney, the study looked at data from 20 studies involving 39,740 adults across 10 countries.

Participants were laboratory tested for levels of two key omega-6 markers -- linoleic acid and arachidonic acid -- at the start of the study, and also for diabetes.

The team found that participants who had the highest blood level of linoleic acid, the major omega-6 fat, were 35 percent less likely to develop type 2 diabetes in the future than those who had the least amount.

Levels of arachidonic acid however, were not significantly associated with either higher or lower risk of diabetes.

"Our findings suggest that a simple change in diet might protect people from developing type 2 diabetes which has reached alarming levels around the world," commented Dr Wu.

Linoleic acid is not formed in the body and so it must be obtained from the diet, with omega-6 found in bean and seed oils such as soybean and sunflower oils, and in nuts. Although some recent studies have suggested that omega-6 may in fact have negative effects on health, such as causing inflammation which can increase the risk of various chronic diseases, others have suggested that we should increase our dietary intake of omega-6 rich foods for better health.

"Some scientists have theorized that omega-6 is harmful to health," said Dr Wu. "But based on this large global study, we have demonstrated little evidence for harms, and indeed found that the major omega-6 fat is linked to lower risk of type 2 diabetes."

"This is striking evidence," added senior author and Professor Dariush Mozaffarian, of the Friedman School of Nutrition Science and Policy at Tufts University in Massachusetts. "The people involved in the study were generally healthy and were not given specific guidance on what to eat. Yet those who had the highest levels of blood omega-6 markers had a much lower chance of developing type 2 diabetes."