Omega 3 intake linked to lower mortality

I recently came across this study, published in June 2021 in the American journal of clinical nutrition, on the benefits of omega 3s. Normally, epidemiological studies on food can be riddled with bias and inconsistencies as they rely on self reported food intake, but this one is stronger as they actually measured the fatty acids in people’s red blood cells (a marker of what kind of fats are in the diet). They monitored 2,200 people from the Framingham heart study offspring cohort over 11 years, and found that the people with the highest level of omega 3s in their red blood cells lived roughly 5 years longer than those with the lowest level. The study was comparing various fatty acids in red blood cells to standard risk factors for cardiovascular disease to see how they affect mortality risk. Measuring the omega 3 index (measure of omega 3s, specifically EPA and DHA) in red blood cells was as good at predicting future heart disease as other standard measurements like blood pressure, smoking status, diabetes and blood cholesterol levels. Cardiovascular disease is the number one killer in western populations, so reducing your risk of this deadly disease will increase your lifespan. The study notes that being a smoker at age 65 reduces lifespan an average of 4.7 years, so increasing omega 3 intake was described as having a similar effect as quitting smoking. Interestingly, in Japan where the average omega 3 index is >8%, the life expectancy is on average 5.6 years more than in the US, where average omega 3 index is under 4%.

The study also showed that 2 other fatty acids were associated with lower mortality risk, and both are saturated; myristic acid, found in butter and coconut oil, and behenic acid which is converted in the body from stearic acid, found in meat, butter and cocoa butter. One fatty acid, palmitoleic acid was linked to higher mortality. This fat is high in macadamia nuts but most of it is produced in response to carbohydrate intake, and is made by the liver; as such, the higher mortality could be due to the metabolic effects of excessive carbohydrate intake, rather than the fatty acid per se (which is why I won’t necessarily be cutting down on my macadamia nut intake!).

This isn’t the first study to show omega 3s are highly protective. They mention a 2018 study, looking at the Framingham heart study offspring cohort, following 2500 individuals over a median of 7.3 years, and found that a higher omega 3 index was associated with a significantly lower risk of death. The top quintile of omega 3 levels (omega 3 index >6.8%) had a 34% lower risk of death from any cause (and 39% lower risk of cardiovascular disease) than the lowest quintile (omega 3 index of <4.2%), with a stronger association for DHA than EPA. Omega 3 had a much stronger association with heart disease than cholesterol, which leads me to suspect that routine measurements of omega 3 index should be standard care. The Womens health initiative memory study, following 65021 women also showed a strong relationship between higher omega 3 levels and survivability, with omega 6 fatty acids having no effect.

This is yet more evidence that omega 3 intake is paramount to good health. The people in the above studies got their omega 3s from eating fish or taking fish oil supplements. I know some vegetarians/vegans who take algae oil but it is important to note that algae oil ONLY contains DHA, while fish contains EPA as well. EPA has health benefits independent of DHA, for example in improving depression, so I think its important to consume both. I have encouraged a few of my vegetarian loved ones to take sustainably produced fish oil in addition to algae oil in order to get the benefits of both. It is also important to remember that plant oils marketed as high in omega 3s (like walnut and flax) are NOT the same as EPA/DHA. They contain a fatty acid called alpha linoleic acid (ALA) which can be converted to the all important EPA/DHA, however conversion rates are very low, at about 3.8% for DHA and 6% for EPA, dropping even lower if there is high omega 6 intake which would occur in anybody who regularly eats seed oils. In some people conversion can be less than 1%.

In summary, this is yet more evidence to the growing body of research that adequate amounts of omega 3s in the diet are paramount to optimal health, and that various saturated fatty acids are in fact healthy. I continue to recommend eating ample amounts of grass fed meat from healthy animals, and for omega 3s, eating fish low in toxins such as sardines, mackerel, and wild salmon, or taking a high quality fish oil supplement that is IFOS certified. How much omega 3? Well there is evidence that in order to reach an omega 3 index of 8% most people require at least 1800mg of EPA and DHA per day, though factors like body weight, sex and activity can affect this. Measuring your omega 3 index is therefore the best way to really know if you are getting enough omega 3, and I anticipate a day when this marker is part of routine standard care to assess for general health.


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