Pooled analysis of data for 39,740 adults from 20 prospective cohort studies has found that individuals who had the highest blood level of linoleic acid, the major omega-6 fat, were 35% less likely to develop type 2 diabetes in future than those who had the lowest blood level of the acid.
The findings have been published in Lancet Diabetes & Endocrinology. Academics from the George Institute for Global Health said they would add weight to clinical recommendations to increase the intake of omega-6 foods, such as nuts, and soybean and sunflower oils.
The paper states: "This international collaboration of 20 prospective cohorts showed that biomarker levels of linoleic acid, the major dietary omega-6 PUFA, were inversely associated with the risk of incident type 2 diabetes, whereas levels of arachidonic acid were not significantly associated with risk of the disease."
The researchers analysed data from 10 countries, where 4,347 new cases of diabetes had occurred. These included adults of widely varying 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.
Linoleic acid was associated with lower risk, while levels of arachidonic acid were not significantly associated with either higher or lower risk of diabetes.
Lead author Dr Jason Wu, from the George Institute for Global Health in Sydney, said: "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.”
"Some scientists have theorised that omega-6 is harmful to health. But based on this large global study, we have demonstrated little evidence for harm, and indeed found that the major omega-6 fat is linked to lower risk of type 2 diabetes."
Professor Peter Clifton, an NHMRC principal research fellow and professor of the Nutrition School of Pharmacy and Medical Sciences at the University of South Australia, said the paper clearly showed that blood linoleic acid levels are associated with a large reduction in the incidence of type 2 diabetes.
"Thus, this data shows that it is likely that consuming margarines and oils rich in linoleic acid will not only reduce the incidence of heart attack, it will reduce the incidence of type 2 diabetes. We already know that consumers of nuts have lower total mortality, and mortality from heart disease, cancer and type 2 diabetes," he said.
Source: Lancet Diabetes & Endocrinology
"Omega-6 fatty acid biomarkers and incident type 2 diabetes: pooled analysis of individual-level data for 39740 adults from 20 prospective cohort studies"
Authors: Jason HY Wu, et al.