Omega-3 fats are essential polyunsaturated fatty acids (PUFAs) your body needs for a variety of functions such as digestion, blood clotting, brain health and muscle activity. Recent data show people with an omega-3 index greater than or equal to 5.7% had a lower rate of death from COVID-19.1,2
Humans evolved on a diet of omega-6 to omega-3 fats in a ratio of close to 1-to-1.3 However, most Western diets have a ratio of 16.7-to-14 or greater.5 The shift in omega fat ratio began during the industrial revolution when people began eating more omega-6 fats at the expense of foods rich in omega-3 driven by the introduction of vegetable oils and cereal grains.6
While many are becoming more aware of the importance of omega-3 fats to their overall health, they are still unsure of how much is needed to maintain optimal levels. Like vitamin D, you must know what your current level is to know whether it's necessary to make dietary adjustments to optimize your omega-3 level.
The omega-3 index is a blood test that measures the amount of eicosatetraenoic acid (EPA) and docosahexaenoic acid (DHA) — two types of omega-3 fatty acids — in your red blood cell (RBC) membranes.7 Your index is expressed as a percent of your total RBC fatty acids. The omega-3 index has been validated as a stable, long-term marker of your omega-3 status, and it reflects your tissue levels of EPA and DHA.
An omega-3 index over 8% — typical in Japan — is associated with the lowest risk of death from heart disease, while an index below 4%, which is common in much of Europe and the U.S., puts you at the highest risk of heart disease-related mortality. Evidence reveals your omega-3 index may also help predict your risk of death from COVID-19.8
Higher Blood Levels of Omega-3 Fat Linked to Better Outcomes
A study published in January 20219 evaluated 100 individuals' omega-3 index and compared that against their COVID-19 outcomes. The patients had been admitted to Cedars Sinai Medical Center beginning March 1, 2020, with a confirmed COVID-19 infection. Within 10 days of diagnosis, blood samples had been drawn and stored.
The researchers' primary outcome measurement was death and the risk was analyzed as a measure of quartiles. When analyzing the overall data the researchers found, as expected, that older individuals and those admitted with a do not resuscitate order had a higher likelihood of dying.
After separating blood samples from the highest to lowest quartiles, they found there was only one death — a 66-year-old man who was admitted with a do not resuscitate order — in the group in which the omega-3 index measured 5.7% or greater. Within the other three quartiles, a total of 17% of the patients died.
When compared against older age, the researchers found the risk of death from COVID-19 in individuals who had lower levels of omega-3 fatty acids was at least as predictive as being 10 years older.
The researchers also confirmed past research results demonstrating the average person in the U.S. has an omega-3 index near 4%, finding the average index was 5.09% and the median — half the number of people had a higher index and half the number of people had a lower index — was 4.75%.
Omega-3 Fat May Ameliorate Cytokine Storm
Although the highest quartile of individuals with the best outcomes had measurements greater than 5.7%,10 this is still far below the optimal 8% measurement for an omega-3 index.11
This protection may have come from the effect EPA and DHA have on the body. An opinion paper published in June 2020 in the journal Frontiers in Physiology expounded on how “EPA and DHA supplementation can alter many biological pathways which may have a direct influence in the outcome of COVID-19.”12 The writers listed the many nutrients that play a key role in managing a cytokine storm and continued:13
“Among these micronutrients, LC-PUFAs (long-chain polyunsaturated fatty acids) such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are noteworthy because of their direct influence in the immunological response to viral infections.
Among these complex immunomodulatory effects, interleukin-6 (IL-6) and interleukin-1ß (IL-1β)—because of the suspected central regulatory role in the “cytokine storm”—should be highlighted.
These cytokines can be affected by dietary EPA and DHA intake … In addition, poly(ADP-ribose) polymerase enzymes that have anti-inflammatory properties, translatable to human COVID-19 infection were shown to improve tissue levels of DHA and EPA, as well as the downstream anti-inflammatory metabolites of EPA and DHA further underscoring the applicability of DHA and EPA in COVID-19.”
It is also important to note that animal-based omega-3 fats, especially DHA, have demonstrated the capacity to prevent blood clot formation within a blood vessel by reducing platelet aggregation.14,15 As discussed in “COVID-19 Critical Care,” hypercoagulation is another complication of severe COVID-19 infection that may produce lethal consequences.
Omega-3 Index Is a Predictor of All-Cause Mortality
In addition to reducing your risk during the pandemic, maintaining your omega-3 index within optimal levels can also reduce your potential risk of all-cause mortality, cardiovascular disease and coronary heart disease, according to data published in 2018.16
The researchers measured the omega-3 index, and not omega-3 intake, in 2,500 people in the Framingham Offspring cohort. The primary outcomes included death from cardiovascular disease, cancer and all causes. The researchers followed the participants for a median of 7.3 years.
After analyzing the data they found individuals in the highest quintile with an omega-3 index over 6.8% had a 34% lower risk of all-cause mortality and a 39% lower risk of cardiovascular disease when compared against those in the lowest quintile of individuals measuring less than 4.2%.
A second study published in 202017 engaged 427,678 men and women aged from 40 to 69 years to explore the hypothesis that omega-3 fats found in fish oil would have a protective effect on cardiovascular health. In this study, the researchers measured consistent use of fish oil supplementation and did not use an omega-3 index measurement.
Data were gathered for a median of nine years and researchers found that fish oil reduced the risk of all-cause mortality by 13% and the risk of cardiovascular disease mortality by 16%. While the statistical differences between these two studies are not conclusive, it may suggest results can differ based on the type of supplementation and how omega-3 is measured.
Omega-3 Helps Diabetes, Brain Health and More
A lesser-known benefit is the effect omega-3 fats have on autoimmune diabetes, or Type 1 diabetes, that occurs when the pancreas stops producing insulin,18 which is different from Type 2 diabetes, when the cells in your body become insulin-resistant.
Another study published in 202019 showed adults who tested positive for a marker for Type 1 diabetes could significantly reduce their risk of onset by eating omega-3 rich fatty fish. The data were gathered from 11,247 cases of adult-onset diabetes and matched against 14,288 diabetes-free controls from the EPIC-InterAct case-cohort study conducted in eight European countries.
A much smaller study published in 201420 showed those who ate one or more servings of fatty fish per week had a reduced risk of latent autoimmune diabetes as compared to those who got less than one serving per week, which the writers concluded was “possibly through effects of marine-originated omega-3 fatty acids.”
DHA is also crucial for brain health. In my book, “Superfuel,” co-written with James DiNicolantonio, Pharm.D., we explain how DHA is an essential structural component of your brain and is found in high levels in your neurons, the cells of your central nervous system. When your intake is inadequate, nerve cells become stiff and more prone to inflammation as the missing omega-3 fats are substituted with omega-6.
Once your nerve cells become rigid and inflamed, proper neurotransmission from cell to cell and within cells becomes compromised. Low DHA levels have been linked to memory loss and Alzheimer's disease, and some studies suggest degenerative brain diseases may potentially be reversible with sufficient DHA.21,22 EPA and DHA have other benefits to your health including:
- Reducing inflammation associated with rheumatoid arthritis23 and menstrual pain24
- Optimizing muscle growth, including in people with cancer,25,26 and bone strength that may lower the risk of osteoporosis27
- Improving symptoms of metabolic syndrome28,29 and reducing the risk of kidney disease30 and colon cancer31
- Improving mental health and behavior32,33,34
- Protecting vision35,36
Where You Get Omega-3 Fat Matters
It's important to remember that there are crucial differences between marine and plant-based omega-3 fatty acids, which I discussed in “The Critical Differences Between Omega-3 Fats From Plants and Marine Animals.” The ideal sources for EPA and DHA are marine-based and include cold-water fatty fish, like wild-caught Alaskan salmon, sardines, herring and anchovies.
If you do not eat these fish on a regular basis, consider taking a krill oil supplement. To learn more about why krill oil is preferable to fish oil see the infographic below.
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It is also vital to remember that the type of fish you choose to eat is important. Farmed fish, including farmed salmon, is best avoided altogether due to the exaggerated potential for contamination and because most are fed genetically engineered soy, yeast and chicken fat, which are a completely unnatural diet and loaded with hazardous omega-6 fats.37
When fish are fed these dangerous linoleic acids, it does not correct a high omega-6 to omega-3 ratio. From a nutritional perspective, farmed salmon only have 50% of the omega-3 of wild salmon38,39 and 25% of the vitamin D.40
Alaska does not permit aquaculture, so all Alaskan fish are wild-caught. In the past, sockeye salmon was another good choice as they were not farmed fish. Unfortunately, land-based sockeye salmon farming is now done,41 which makes it difficult to know whether the fish is wild-caught or not. For this reason, it may be best to avoid sockeye salmon unless you can verify that it's wild-caught.