Study: Linoleic Acid Is Beneficial for Prevention of Type 2 Diabetes

Findings from a new study show that linoleic acid has long-term benefits for the prevention of type 2 diabetes (T2D) and that arachidonic acid is not harmful.

The study, published in The Lancet, focused on assessing the association of both linoleic acid and arachidonic acid biomarkers with incident T2D, using data from 20 cohort studies from 10 countries.

“The metabolic effects of omega-6 polyunsaturated fatty acids (PUFAS) remain contentious, and little evidence is available regarding their potentional role in primary prevention of type 2 diabetes,” wrote the authors.

The effects of linoleic acid on an individual’s health is often disputed. While most major guidelines recommend that 5%-10% of energy is attributed to linoleic acid, some researchers have said it might be harmful because it competes with omega-3 PUFA or because its metabolite arachidonic acid might have harmful effects.

Results of the study showed that biomarker levels of linoleic acid were inversely linked with incident T2D, with high linoleic acid levels being associated with a 43% lower risk of T2D. The association was not influenced by age, body-mass index, sex, race, omega-3 PUFA levels, aspirin use, or variation in genes encoding FADS. Further, levels of arachidonic acid biomarkers were not associated with T2D.

Past studies have found that incorporating linoleic acid into phospholipids alters membrane fluidity and might modulate insulin receptor activity. In a meta-analysis of 102 randomized controlled feeding trials, predominantly linoleic acid dietary PUFAs improved glycaemia, insulin resistance, and insulin secretion. Other randomized controlled trials found that linoleic acid—rich vegetable oil reduced markers of inflammation, visceral fat deposition, and hepatic steatosis.

The current study expanded upon these findings. Knowing that dietary linoleic acid intake correlates with levels of circulating and tissue linoleic acid, the authors were able to provide evidence that linoleic acid might have long-term benefits for preventing the onset of type 2 diabetes using their biomarker-based findings. This supports clinical recommendations to increase dietary intake of linoleic acid—rich vegetables.

“The prevalence of type 2 diabetes is escalating rapidly around the world, so identification of dietary and other modifiable risk factors for the prevention of the disease is of clinical, scientific, and public health importance,” concluded the authors.

Even with the known benefits of PUFAs for blood cholesterol levels and glucose-insulin homeostasis, some scientists insist that omega-6 PUFA has negative effects for health. A common theory is that the conversion of linoleic acid to arachidonic acid is considered pro-inflammatory and potentially harmful for glucose metabolism, weight regulation, and eating behavior.