The finding sheds new light on the potential health benefits of omega-6 fats and supports clinical recommendations to increase dietary intake of omega-6 rich foods.
"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," said Jason Wu, of The George Institute for Global Health in Australia.
"This is striking evidence," said Professor Dariush Mozaffarian, from Tufts University in the US.
Recent studies have raised concerns that omega-6, which is found in bean and seed oils such as soybean and sunflower oils and in nuts, may have negative health effects, such as inflammation leading to the increased risk of chronic diseases.
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The study published in The Lancet Diabetes and Endocrinology journal explored these concerns in studies from around the world.
They analysed data from 20 studies involving 39,740 adults from 10 countries, in whom 4,347 new cases of diabetes occurred over time.
These 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.
"Some scientists have theorised that omega-6 is harmful to health," said Wu, lead author of the study.
"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," Wu said.
Linoleic acid is not formed in the body and can only be obtained from the diet. US dietary guidelines recommend between 5-10 per cent of energy should be derived from polyunsaturated fats.