Omega-3 fatty acids appear promising for lung health

Omega-3 fatty acids, which are abundant in fish and fish oil supplements, appear promising for maintaining lung health, according to a large, multi-faceted study in healthy adults. Funded largely by the National Heart, Lung, and Blood Institute (NHLBI), part of the US National Institutes of Health (NIH), the study was published in the American Journal of Respiratory and Critical Care Medicine.

“We know a lot about the role of diet in cancer and cardiovascular diseases, but the role of diet in chronic lung disease is somewhat understudied,” said corresponding author Dr Patricia A Cassano, Director of the Division of Nutritional Sciences at Cornell University. Past studies have suggested that omega-3 fatty acids may help lung disease prevention efforts, due largely to their established anti-inflammatory actions, but robust studies of this association have so far been lacking.

To learn more, researchers developed a two-part study investigating the link between omega-3 fatty acid levels in the blood and lung function over time. In the first part, the researchers conducted a longitudinal, observational study involving 15,063 generally healthy Americans from the NHLBI Pooled Cohorts Study — a large collection of NIH-funded studies that helps researchers to study determinants of personalised risk for chronic lung disease. The researchers followed participants for an average of seven years and up to 20 years.

The longitudinal study showed that higher levels of omega-3 fatty acids in a person’s blood were associated with a reduced rate of lung function decline. The researchers observed the strongest associations for docosahexaenoic acid (DHA), an omega-3 fatty acid that is found at high levels in fatty fish such as salmon, tuna and sardines. DHA is also available as a dietary supplement.

In the second part, the researchers analysed genetic data from a study of over 500,000 participants from the UK Biobank. They studied certain genetic markers in the blood as an indirect measure of dietary omega-3 fatty acid levels to see how they correlated with lung health. The results showed that higher levels of omega-3 fatty acids — including DHA — were associated with better lung function.

The study is understood to provide some of the strongest evidence to date of this association, underscoring the importance of including omega-3 fatty acids in the diet. As the study only included healthy adults, the researchers are now collaborating with the COPDGene Study to examine blood levels of omega-3 fatty acids in relation to the rate of decline in lung function among people with chronic obstructive pulmonary disease (COPD) — including heavy smokers — to determine if the same beneficial associations are found.

For now, the researchers point out that the US Department of Agriculture’s Dietary Guidelines for Americans recommends that people eat at least two servings of fish per week. In addition to fish and fish oil, other sources of omega-3 fatty acids include nuts and seeds, plant oils and fortified foods.

“We’re starting to turn a corner in nutritional research and really moving toward precision nutrition for treating lung diseases,” said first author Dr Bonnie K Patchen, a nutritionist and researcher at Cornell. “In the future, this could translate into individualised dietary recommendations for people at high risk for chronic lung disease.”

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