A study recently published in Circulation is challenging our understanding about the effect high levels of omega-6 fatty acids have on human health. A common perception is that omega-6s are too ubiquitous in our diets and fueling chronic inflammation. Omega-3 fatty acids supplementation is supposed to solve the imbalance of omega-6 to omega-3 in our bodies, a healthy ratio of which is supposed to be 4:1.
However, in this individual-level analysis of 30 prospective observational studies involving 69,000 people from 13 countries, researchers observed that high levels of the omega-6 fatty acid, linoleic acid (LA), was significantly associated with lower risks of total cardiovascular disease, cardiovascular mortality, and ischemic stroke. Specifically, those in the top 10% of LA levels were 7% less likely to develop cardiovascular disease, 22% less likely to die of cardiovascular disease, and 12% less likely to have an ischemic stroke compared to those in the bottom 10%.
The authors also controlled for blood EPA levels, and observed that the relationship between omega-6s and lower risk of cardiovascular disease held regardless of what the blood omega-3 levels were for subjects. “This research contradicts the idea that omega-6s are bad for human health, that people should strive to lower omega-6 intakes – ostensibly to get a better omega-6 to omega-3 ratio. This is ill conceived,” explains Bill Harris, founder of OmegaQuant, and one of the study’s authors. “Based on these finding, lowering omega-6 levels is more likely to help. As for the omega-6 to omega-3 ratio, it also is a metric of unclear significance since it’s ‘good/good.’”
Similar results were found in a study published in The Lancet in 2017, which analyzed data from 20 studies involving 40,000 people from 10 countries, and the number of diabetes cases that occurred over time. Results showed that those with the highest LA levels were 35% less likely to develop diabetes than those in the lowest 10% of LA levels. This latest research also confirms predictions made ten years ago in an American Heart Association Scientific Advisory – of which Harris was an author – that stated the reduction of omega-6 fatty acids would increase, rather than decrease, the risk of cardiovascular disease.
1. Marklund M et al. “Biomarkers of dietary omega-6 fatty acids and incident cardiovascular disease and mortality: an individual-level pooled analysis of 30 cohort studies.” Circulation, Published ahead of print on April 11, 2019.
2. Wu JHY et al. “Omega-6 fatty acid biomarkers and incident type 2 diabetes: pooled analysis of individual-level data for 39 740 adults from 20 prospective cohort studies.” The Lancet, vol. 5, no. 12 (2017): 965-974
3. Harris WS et al. “Omega-6 fatty acids and risk for cardiovascular disease: a scientific advisory from the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention.” Circulation, vol 119 (2009): 902-907