The effects of linoleic acid on the human body are largely dependent on genes, a recent study shows. People with different FADS1 gene variants had a different fasting glucose and inflammatory response when supplementing their diet by linoleic acid rich sunflower oil.
According to Postdoctoral Researcher Maria Lankinen, the findings warrant speculation on whether the recommended intake of linoleic acid – and possibly other fatty acids, too – should be tailored to match a person’s genes. “However, further research is needed before we can make any recommendations based on genes.”
The FADS1 gene is involved in fatty acid and glucose metabolism. Diet, in turn, has a major impact on fatty acid concentrations in the body. Linoleic acid is an essential fatty acid and the most common polyunsaturated omega 6 fatty acid found in plant-based oils, nuts and seeds. A high intake and high blood levels of linoleic acid have been linked to a reduced risk of type 2 diabetes and cardiovascular disease. On the other hand, the metabolites of linoleic acid can mediate inflammation, so a high intake of linoleic acid could also contribute to low-grade inflammation. The study shows these contradictory observations could be explained by genetic differences.
The researchers explored whether point mutations in rs174550 of the FADS1 gene modify the effects of linoleic acid on serum fatty acid, fasting glucose, insulin and CRP levels. These were analysed in more than 1,300 participants in the METSIM (Metabolic Syndrome in Men) Study. In addition, 60 men carrying two different gene variants participated in the FADSDIET intervention, supplementing their daily diet with 30–50 ml of sunflower oil for four weeks.
The findings indicate that the effects of linoleic acid largely depend on the FADS1 gene variant. This affects how effectively a linoleic acid supplement can lower fasting glucose levels. Moreover, depending on the gene variant, increased intake of linoleic acid can make a person’s CRP levels either increase or decrease. The gene variant also had an effect on the levels of inflammation mediators.
The study, carried out by researchers from UEF and Karolinska Institutet, was reported in the American Journal of Clinical Nutrition.