New research published last week in the American Journal of Clinical Nutrition showed that a low omega-3 index is as effective as smoking in predicting early death. This groundbreaking finding is based on data taken and analyzed from the Framingham Study, one of the longest-running studies in the world.
The Framingham Heart Study provided unique insight into risk factors for cardiovascular disease (CVD) and resulted in the development of the Framingham Risk Score based on eight basic standard risk factors – age, gender, smoking, hypertension treatment, diabetes status, systolic blood pressure, total cholesterol (TC) and HDL cholesterol.
CVD is still the leading cause of death worldwide, and changes in behavioral factors such as unhealthy diet, sedentary lifestyle, and tobacco and alcohol consumption can reduce the risk. Hence, the researchers in this study say that biomarkers that incorporate lifestyle choices could help identify individuals at risk and could be useful in evaluating treatment approaches, preventing morbidity, and delaying death.
Diet-based biomarkers include fatty acids (FS), which are measured in plasma or in the membranes of red blood cells (RBC). The FS that are most clearly associated with reduced risk for cardiovascular disease and for all-cause mortality (i.e., death from any cause) are the omega-3 FS, EPA, and DHA that are typically found in fish such as salmon and herring occur, as well as omega-3 food supplements such as fish and algae oil.
In a 2018 report that included 2,500 participants in the Framingham descendant cohort, followed by a median of 7.3 years (i.e., between the ages of 66 and 73), the base value for RBC-EPA and DHA levels [the omega-3 index (O3I)] was significantly and inversely related to the risk of death from all causes.
In fact, people with the highest omega-3 index were 33% less likely to succumb during the follow-up years compared to those with the lowest omega-3 index. Similar connections were found in the Memory Study of the Women’s Health Initiative, the Heart and Soul Study and the Ludwigshafen Risk and Cardiovascular Health Study.
The omega-3 index measures the amount of EPA and DHA in the red blood cell membranes and is a marker of omega-3 status. An optimal omega-3 index is 8% or higher, a medium omega-3 index is between 4% and 8%, and a low omega-3 index is 4% and below. Most Americans have an omega-3 index below 4%, which puts them at a significantly higher risk of early death.
According to the researchers in this study, the finding that any FA-based metric would have predictive power similar to the established standard risk factors was unexpected and suggests that RBC-FAs – via mechanisms that are not perfectly understood – somehow represent an in vivo environment, that consolidates the effects of all these standard risk factors on the body into one measure.
Interestingly, in Japan, where the average omega-3 index is above 8%, the expected lifespan is about five years longer than in the United States, where the median omega-3 index is about 5%. . Therefore, dietary choices that alter the omega-3 index can, in practice, extend life. In the final combined model, smoking and the omega-3 index appear to be the most easily modifiable risk factors. A current smoker (aged 65) is likely to subtract more than four years of life (compared to not smoking), a life shortening that equates to a low vs. a high omega-3 index. “
Michael McBurney, PhD, FCNS-SCN, Study Director, Wright On Marketing & Communications
“The information contained in the levels of the four red blood cell fatty acids was as useful in predicting all-round mortality as the information on lipid levels, blood pressure, smoking and diabetes,” said Dr. Bill Harris, who is also the author of this study. “This speaks to the strength of the Omega-3 Index as a risk factor and should be viewed as just as important as the other established risk factors, perhaps even more important.”
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McBurney, M., et al. (2021) Using an erythrocyte fatty acid fingerprint to predict all-cause mortality risk: the Framingham descendant cohort. American Journal of Clinical Nutrition. doi.org/10.1093/ajcn/nqab195.