Don’t Fear Fat: Study Finds Some Fatty Acids, Including Omega-3s, Increase Lifespan By Almost 5 Years

Beating over 100,000 times per day and pumping up to 2,000 gallons of blood throughout the body, the heart is undoubtedly one of our most vital and active organs. But with age, the functionality of our hearts can decline — its walls thicken, blood vessels constrict, fat deposits accumulate, and blood flow to the rest of the body reduces. Unfortunately, cardiovascular-related conditions are the top cause of death in America, leading researchers to hunt for new ways to slow down this risk — one of which might be fatty acid levels in our blood.

We know that certain factors increase the risk of dying from heart-related conditions (like smoking, cholesterol, and diet). But, it’s been relatively unknown how fatty acids — long-chained molecules that mostly come from the breakdown of dietary fat — in our blood cells compare to these common risk factors in predicting mortality.

Published in the American Journal of Clinical Nutrition, a research team out of Spain, Canada, and the United States determine that a “fatty acid fingerprint” better predicts older adults’ mortality risk than currently used markers, with higher amounts of some of these fatty acids boosting lifespan by almost five years. With these fat-based blood markers, doctors could identify otherwise healthy people at increased risk of mortality — a growing public health problem our nation faces.

Why Our Cells Need Fats

It’s well-known that omega-3 fatty acids are good for our hearts — previous research has found that people with the highest levels of two omega-3 fats, EPA and DHA, were 33% less likely to die over seven years than people with the lowest levels.

Although there are many types of omega-3 fats, EPA and DHA (found in high amounts in oily fish and seafood) are the two that make up the “omega-3 index” — the percentage of EPA and DHA found in the membranes of red blood cells (RBCs), also known as erythrocytes. A higher omega-3 index (8% or above) is linked to better health, while those in the lower categories (<4%) have an increased risk of mortality. 

In addition to omega-3s, McBurney and colleagues guessed that other fatty acids might also play a role in mortality — for better or for worse. As fats provide structural components to cells and are considered essential “building blocks” of cell membranes, the research team chose to analyze fatty acid levels in the RBC membranes rather than testing blood plasma levels.

Four Fatty Acids Found to Modify Lifespan

The research team assessed RBC fatty acid levels of almost 2,300 older American adults who were a part of a long-term study group called the Framingham Offspring Cohort, following their health for 11 years in this study. 

Out of the 26 fatty acids measured, four were significantly associated with all-cause mortality: myristic acid, palmitoleic acid, behenic acid, and the omega-3 index — which is technically two fatty acids, DHA and EPA. Briefly, myristic acid is a saturated fat found in dairy, coconuts, and palm products, while behenic acid is less widespread, found in peanut oil and peanut butter. Palmitoleic acid, found primarily in macadamia nuts, is an omega-7 fatty acid — a lesser-known type of unsaturated fat that exhibits somewhat conflicting outcomes when it comes to metabolic and heart health. 

The researchers split the study participants into five groups, or quintiles, based on their fatty acid levels. People in the higher quintiles of myristic acid, behenic acid, and the omega-3 index had significantly increased lifespans compared to those in the lower quintiles. The results were reversed for palmitoleic acid — lower levels were found to be better for longevity. 

Specifically, the highest quintile of myristic acid, behenic acid, and omega-3 indices in the RBC membranes added 5.6, 3.2, and 4.7 additional years to lifespan, respectively. Conversely, being in the lowest quintile for palmitoleic acid levels boosted lifespan by 6.6 years. As one of the study’s authors, Dr. Aleix Sala-Vila, states of these results, “Having higher levels of these [omega-3 fatty] acids in the blood, as a result of regularly including oily fish in the diet, increases life expectancy by almost five years.” 

Another relevant marker that the researchers looked at was smoking status — a well-known risk factor for worsened heart health. In this study, the greatest survival rates were found in non-smokers with the highest omega-3 indices, at 85% over the 11-year follow-up period. People who were non-smokers, but had a lower omega-3 index, had their survival rates drop to 71%, and the lowest survival rates were for smokers combined with low omega-3 index, at 47%. Dr. Sala-Vila adds, “Being a regular smoker takes 4.7 years off your life expectancy, the same as you gain if you have high levels of omega-3 [fatty] acids in your blood.” 

Saturated Fat: Not the Villain Anymore

Interestingly, both myristic acid and behenic acid are saturated fats, which many health professionals have previously claimed are harmful to the heart. However, more recent research has revealed that saturated fats may not be as bad as once thought — and the results from this study indicate that some are even protective against premature mortality. Dr. Sala-Vila, reflects, "This reaffirms what we have been seeing lately — not all saturated fatty acids are necessarily bad."

Conversely, palmitoleic acid is an unsaturated fat that is not consumed in high amounts in the typical American diet. Instead, this fat is produced in the body from a process called de novo (Latin for “from scratch”, essentially) lipogenesis. This metabolic pathway creates fatty acids from excessive availability of carbohydrates, which are then stored in the body as fat cells. This process is thought to be implicated in the detrimental accumulation of fat in the liver. 

A Fish-Forward Focus for Fighting Mortality 

As low levels of omega-3 fats were as predictive of all-cause mortality as smoking, these results suggest that more attention should be paid to ensuring adequate intake of these healthy fats in the American diet — a simple way is to add oily fish, like salmon or fatty tuna, to your plate two times per week. Plus, McBurney and colleagues uncover that measuring levels of myristic, palmeolitic, and behenic acids could potentially be used as biomarkers for evaluating the risk of premature mortality in otherwise healthy adults.  

Dr. Sala-Vila concludes, "What we have found is not insignificant. It reinforces the idea that small changes in diet in the right direction can have a much more powerful effect than we think, and it is never too late or too early to make these changes.” 

References: 

Harris WS, Tintle NL, Etherton MR, Vasan RS. Erythrocyte long-chain omega-3 fatty acid levels are inversely associated with mortality and with incident cardiovascular disease: The Framingham Heart Study [published correction appears in J Clin Lipidol. 2020 Sep-Oct;14(5):740]. J Clin Lipidol. 2018;12(3):718-727.e6. doi:10.1016/j.jacl.2018.02.010

McBurney MI, Tintle NL, Vasan RS, Sala-Vila A, Harris WS. Using an erythrocyte fatty acid fingerprint to predict risk of all-cause mortality: the Framingham Offspring Cohort [published online ahead of print, 2021 Jun 16]. Am J Clin Nutr. 2021;nqab195. doi:10.1093/ajcn/nqab195