The higher the linoleic acid level in the body, the lower the risk of cardiovascular diseases, according to new study analysing nearly 70,000 people in 13 different countries. Linoleic acid is the most common polyunsaturated omega-6 fatty acid. The findings were published in Circulation.
It has been speculated that a high intake of omega-6 polyunsaturated fatty acids may increase the risk of several chronic diseases by, e.g., promoting low-grade inflammation. However, studies conducted on humans have not established a link between even a high intake of omega-6 fatty acids and inflammation. Furthermore, omega-6 fatty acids have beneficial effects on, for example, lipid and glucose metabolism. The most common omega-6 fatty acid in particular, i.e. the essential linoleic acid, has been consistently associated with a lower risk of cardiovascular diseases.
The researchers analysed data from 30 population-based studies involving 68,659 adults from 13 different countries. The Finnish studies included in the analysis were the University of Eastern Finland’s Kuopio Ischaemic Heart Disease Risk Factor Study, KIHD, and the Metabolic Syndrome in Men Study, METSIM. No previously published findings were used in this meta analysis; instead, new analyses were carried out in each set of data by using pre-defined criteria. This promotes comparability between the findings and reduces the effect of various confounding factors.
At the onset of the study, the study participants were between 49 and 77 years of age, and 15,198 of them developed a cardiovascular disease during the follow-up period. The study found an association between a high linoleic acid level and a reduced risk of cardiovascular diseases and ischemic stroke.
A great strength of the study is that it determined omega-6 fatty acids from blood or tissue biomarkers, eliminating people’s memory errors relating to their diet, among other things.
The intake of linoleic acid from food greatly impacts the body’s linoleic acid level. The most important dietary sources of linoleic acid are vegetable oils, plant-based spreads, nuts and seeds.