Protecting Your Health from Air Pollution with Diets Rich in Omega-3 Fatty Acids
Published June 7, 2022
Eating fish high in omega-3 fatty acids such as salmon, tuna, and other seafood as part of a healthy diet is recommended by the American Heart Association to lower the risk of heart disease and stroke. Researchers at EPA are taking a different look at the regular consumption of omega-3 fatty acids and whether they protect the heart and lungs from outdoor air pollution.
The EPA’s PISCES study, named for the Latin word for “the fish,” has shown that omega-3 polyunsaturated fatty acids may help to reduce adverse effects of air pollution on the cardiovascular system in the short term.
Researchers recruited 62 healthy adults who were grouped as low or high consumers of omega-3 fatty acids, based on their diets for six months or more and blood tests to measure omega-3 fatty acids. They followed the subjects over the course of a month or longer. Volunteers with high levels had at least 3 grams weekly of omega-3 fatty acids (specifically, EPA and DHA) from the food they consumed or fish oil supplements, while those with low levels took 0.5 grams weekly. Three grams of omega-3 fatty acids are equivalent to about 2-3 servings of fatty fish.
Three recently published papers from the PISCES study provide insights into the link between an omega-3 high diet and protection from short-term exposure to outdoor air pollution.
Researchers took cardiovascular measurements such as cholesterol, inflammation of the blood vessels, heart rate variability, and blood coagulation during five sessions separated by at least seven days. They also obtained daily fine particulate matter (PM2.5) and maximum eight-hour ozone concentrations from nearby air quality monitoring stations where the volunteers lived in the Raleigh-Durham area of North Carolina. The average air pollution concentrations for PM2.5 and ozone were well below the national standards during the study period from 2016 to 2019.
“In the low omega-3 group, we saw a significant association between short-term PM2.5 and ozone exposure and changes in cholesterol, (blood) coagulation markers, and vascular injury markers,” says Haiyan Tong, research biologist and principal investigator of the PISCES study. The changes over the long term can lead to atherosclerosis, which is the formation of plaque in the arteries, she says. The research is published in the February 2022 issue of Particle and Fibre Toxicology.1
The study’s findings could help with dietary intervention strategies to reduce the cardiovascular effects from air pollution. “People may benefit from increasing their omega-3 intake when they experience high exposure to air pollutants such as during a wildfire event or if they live in an area where air pollution exceeds the national standards for PM2.5,” explains Tong. As of 2020, more than 30 percent of the United States population lives in areas that have air pollution concentrations above the standards, according to the EPA’s air trends report.
The study shows a benefit to healthy adults but has implications for those with certain health conditions such as cardiac patients. “In this study we only looked at a healthy population, so people who have a health problem such as cardiovascular disease, we think could derive an even greater benefit from adding polyunsaturated omega-3 fatty acids to their diet,” says Tong.
The researchers also looked at health effects of exposure to the the regulated pollutant, nitrogen dioxide (NO2). The PISCES study is believed to be the first to investigate the potential health benefits of diets rich in omega-3 fatty acids from NO2 exposure.
They found short-term NO2 exposure did not alter lung function and most cardiovascular markers in the low omega-3 group. In the high omega-3 group, researchers observed improvement in health markers, including increased lung and vascular function and decreased cholesterol following short-term exposure. The research was published in December 2021 in Environmental Health.2
Researchers also examined the potential effects on lung function from short-term exposure to PM2.5 and ozone in low and high omega-3 groups. The findings came as a surprise, Tong says.
“In the high omega-3 group, we saw early protection from PM2.5 and ozone exposure. But those protections disappeared two days after exposure and lung function worsened four days after exposure.”
Additional research is needed to better understand this finding. In the meantime, researchers say those with chronic lung disease, such as asthma or chronic obstructive pulmonary disease (COPD), should talk to their physicians before taking high levels of fish oil supplements. The research is published in the April 2022 issue of the Annals of the American Thoracic Society.3
Although the PISCES study has not provided conclusive evidence, it has shed significant light on the potential benefits of omega-3 fatty acids as a dietary approach to reducing the health impacts of short-term exposure to air pollution. Additional data analyses continues and researchers anticipate more findings to be published from this extensive research project.
Related Resources:
1. Chen, H., S. Zhang, W. Shen, C. Salazar, A. Schneider, A. Rappold, D. Diazsanchez, R. Devlin, J. Samet, and H. Tong. Omega-3 Fatty Acids Attenuate Cardiovascular Effects of Short-term Exposure to Ambient Air Pollution. Particle and Fibre Toxicology. BioMed Central Ltd, London, Uk, 19(12):1, (2022). https://doi.org/10.1186/s12989-022-00451-4
2. Chen, H., S. Zhang, W. Shen, C. Salazar, A. Schneider, L. Wyatt, A. Rappold, D. Diazsanchez, R. Devlin, J. Samet, and H. Tong. The influence of dietary intake of omega‑3 polyunsaturated fatty acids on the association between short‑term exposure to ambient nitrogen dioxide and respiratory and cardiovascular outcomes among healthy adults. ENVIRONMENTAL HEALTH. Academic Press Incorporated, Orlando, FL, 20(123):1, (2021). https://doi.org/10.1186/s12940-021-00809-9
3. Tong H, Zhang S, Shen W, Chen H, Salazar C, Schneider A, Rappold AG, Diaz-Sanchez D, Devlin RB, and Samet JM. Lung function and short-term ambient air pollution exposure: differential impacts of omega-3 and omega-6 fatty acids. Annals of the American Thoracic Society. 2022 Apr;19(4):583-593. doi: 10.1513/AnnalsATS.202107-767OC.