High omega-3 index protects people from severe COVID

A recent research published in the American Journal of Clinical Nutrition (AJCN) investigated the impact of omega-3 fatty acids, particularly EPA and DHA, and whether they could be protective against getting COVID-19 infection and/or experiencing negative results.

The study compared the risk for three COVID-19 outcomes: 1-testing positive, 2-hospitalization, and 3-death as a function of baseline plasma DHA levels.

DHA levels (% of total fatty acids) were measured by Nuclear Magnetic Resonance (NMR) spectroscopy but were converted to Omega-3 Index (red blood cell EPA+DHA%) for this analysis. The three outcomes and relevant covariates were available for 110,584 subjects (hospitalization and death) and for 26,595 ever-tested subjects (positive COVID-19 PCR test result) via the UK Biobank prospective cohort study. These COVID-19 outcomes were assessed between January 2020 and March 2021.

In the fully adjusted models, subjects in quintile 5 (with the highest Omega-3 Index levels) were 21% less likely to test positive than those in quintile 1, and the risk for a positive test was 8% lower for each 1-SD (standard deviation) increase in plasma DHA%. Quintile 5 subjects were also 26% less likely to be hospitalized than those in quintile 1, and risk for hospitalization was 11% lower per 1-SD increase in DHA%.

For death with COVID-19, risk was monotonically lower through quintile 4, but in quintile 5, the risk reduction was partially attenuated and became non-significant. Estimated Omega-3 Index values across the five DHA quintiles ranged from 3.5% (quintile 1) to 8% (quintile 5).

"These values comport well with the Omega-3 Index risk cut points [originally proposed in 2004 for death from cardiovascular disease] of <4% (high risk) and >8% (low risk) and imply that these target levels apply to COVID-19 outcomes as well," researchers noted in their paper.

The investigators also point out that South Korea and Japan have reported an extremely low severity of COVID-19 disease and that although masking practices, social distancing policies and other population-wide interventions no doubt contributed to this, it is interesting to note that the Omega-3 Index values of healthy South Korean and Japanese individuals are about 8-12% and 7-11% respectively, which is much higher compared to an Omega-3 Index of 4-5% in Western populations such as the United States.

"A worldwide pattern linking higher omega-3 fatty acid intakes with lower rates of death with COVID-19 was documented by Vivar-Sierra et al. Although only suggestive, this observation adds further support for a potential role of omega-3s EPA and DHA in the prevention of fatal COVID-19 disease," the researchers said.