New research has shown that a low omega-3 index is as strong of a predictor of early death as smoking.
The landmark finding is from data analysed from the Framingham study, one of the longest-running studies in the world, which has provided unique insights into cardiovascular disease risk factors. It has also led to the development of the Framingham Risk Score based on eight baseline standard risk factors including age, sex, smoking, hypertension treatment, diabetes status, systolic blood pressure, total cholesterol (TC), and HDL cholesterol.
The research paper has been published in the American Journal of Clinical Nutrition.
Cardiovascular disease risk can be reduced by changing behavioural factors such as unhealthy diet, physical inactivity, and use of tobacco, and alcohol, and the researchers say that biomarkers integrating lifestyle choices might help identify individuals at risk and be useful to assess treatment approaches, prevent morbidity, and delay death.
One of these diet-based biomarkers are fatty acids. The acids which most clearly associated with mortality are the omega-3 fatty acids, EPA and DHA, which are typically found in fish like salmon and herring, as well as omega-3 supplements like fish and algal oil.
In a 2018 report that included 2,500 participants in the Framingham Offspring Cohort followed for a median of 7.3 years, the baseline red blood cell EPA and DHA content was significantly and inversely associated with risk for death from all causes.
In fact, individuals with the highest Omega-3 Index were 33% less likely to succumb during the follow-up years compared with those with the lowest Omega-3 Index. Similar associations have been seen in the Women’s Health Initiative Memory Study, the Heart and Soul Study, and the Ludwigshafen Risk, and Cardiovascular Health Study.
Optimal levels of omega-3
The Omega-3 Index measures the amount of EPA and DHA in red blood cell membranes and is a marker of omega-3 status – with an optimal Omega-3 Index being 8% or higher, an intermediate being between 4% and 8%, and a low Omega-3 Index at 4% and below.
According to researchers, the finding that any fatty acid-based metric would have predictive power similar to that of the well-established standard risk factors was unexpected, and it also suggests that red blood cell fatty acids reflects an in vivo milieu that consolidates into one measure the impact on the body of all these standard risk factors.
Michael McBurney, PhD, FCNS-SCN, lead researcher, said: “It is interesting to note that in Japan, where the mean Omega-3 Index is greater than 8%, the expected life span is around five years longer than it is in the United States, where the mean Omega-3 Index is about 5%. Hence, in practice, dietary choices that change the Omega-3 Index may prolong life.
“In the final combined model, smoking and the Omega-3 Index seem to be the most easily modified risk factors. Being a current smoker (at age 65) is predicted to subtract more than four years of life (compared with not smoking), a life-shortening equivalent to having a low vs. a high Omega-3 Index.”
Dr Bill Harris, author on the study, added: “The information carried in the concentrations of four red blood cell fatty acids was as useful as that carried in lipid levels, blood pressure, smoking, and diabetic status with regard to predicting total mortality.
“This speaks to the power of the Omega-3 Index as a risk factor and should be considered just as important as the other established risk factors, and maybe even more so.”