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.

BACKGROUND: Short-term exposure to ambient nitrogen dioxide (NO2) is associated with adverse respiratory and cardiovascular outcomes. Supplementation of omega-3 polyunsaturated fatty acids (PUFA) has shown protection against exposure to fine particulate matter. This study aims to investigate whether habitual omega-3 PUFA intake differentially modify the associations between respiratory and cardiovascular responses and short-term exposure to ambient NO2. METHODS: Sixty-two healthy participants were enrolled into low or high omega-3 groups based on their habitual omega-3 PUFA intake. Each participant was repeatedly assessed for lung function, blood lipids, markers of coagulation and fibrinolysis, vascular function, and heart rate variability (HRV) in up to five sessions, each separated by at least 7 days. This study was carried out in the Research Triangle area of North Carolina, USA between October 2016 and September 2019. Daily ambient NO2 concentrations were obtained from an area air quality monitoring station on the day of outcome assessment (Lag0), 4 days prior (Lag1-4), as well as 5-day moving average (5dMA). The associations between short-term exposure to NO2 and the measured indices were evaluated using linear mixed-effects models stratified by omega-3 levels and adjusted by covariates including relative humidity and temperature. RESULTS: The average concentration of ambient NO2 during the study periods was 5.3±3.8 ppb which was below the National Ambient Air Quality Standards (NAAQS). In the high omega-3 group, an interquartile range (IQR) increase in short-term NO2 concentrations was significantly associated with increased lung function [e.g. 1.2% (95%CI: 0.2%, 2.2%) in FVC at lag1, 2.6% (95%CI: 0.4%, 4.8%) in FEV1 at 5dMA], decreased blood lipids [e.g. -2.6% (95%CI: -4.4%, -0.9%) in total cholesterol at lag2, -3.1% (95%CI: -6.1%, 0.0%) in HDL at 5dMA, and -3.1% (95%CI: -5.5%, -0.7%) in LDL at lag2], improved vascular function [e.g. 8.9% (95%CI: 0.6%, 17.2%) increase in FMD and 43.1% (95%CI: -79.8%, -6.3%) decrease in endothelin-1 at 5dMA], and changed HRV parameters [e.g. -7.2% (95%CI: -13.6%, -0.8%) in HFn and 13.4% (95%CI: 0.2%, 28.3%) in LF/HF ratio at lag3]. In the low omega-3 group, an IQR increase in ambient NO2 was associated with elevations in coagulation markers (von Willebrand Factor, D-dimer) and a decrease in HRV (very-low frequency); however, null associations were observed between short-term NO2 exposure and changes in lung function, blood lipids, and vascular function. CONCLUSIONS: The results in this study imply that dietary omega-3 PUFA consumption may offer respiratory and vascular benefits in response to short-term exposure of healthy adults to NO2 levels below the NAAQS. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT02921048 ).

Dietary Supplementation with Olive Oil or Fish Oil and Vascular Effects of Concentrated Ambient Particulate Matter Exposure in Human Volunteers.

BACKGROUND: Exposure to ambient particulate matter (PM) induces endothelial dysfunction, a risk factor for cardiovascular disease. Olive oil (OO) and fish oil (FO) supplements have beneficial effects on endothelial function. OBJECTIVE: In this study we evaluated the potential efficacy of OO and FO in mitigating endothelial dysfunction and disruption of hemostasis caused by exposure to particulate matter (PM). METHODS AND RESULTS: Forty-two participants (58 ± 1 years of age) received either 3 g/day of OO or FO, or no supplements (naive) for 4 weeks prior to undergoing 2-hr exposures to filtered air and concentrated ambient particulate matter (CAP; mean, 253 ± 16 µg/m3). Endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery preexposure, immediately postexposure, and 20 hr postexposure. Levels of endothelin-1 and markers of fibrinolysis and inflammation were also measured. The FMD was significantly lower after CAP exposure in the naive (-19.4%; 95% CI: -36.4, -2.3 per 100 µg/m3 CAP relative to baseline; p = 0.03) and FO groups (-13.7%; 95% CI: -24.5, -2.9; p = 0.01), but not in the OO group (-7.6%; 95% CI: -21.5, 6.3; p = 0.27). Tissue plasminogen activator levels were significantly increased immediately after (11.6%; 95% CI: 0.8, 22.2; p = 0.04) and 20 hr after CAP exposure in the OO group. Endothelin-1 levels were significantly increased 20 hr after CAP exposure in the naive group only (17.1%; 95% CI: 2.2, 32.0; p = 0.03). CONCLUSIONS: Short-term exposure to CAP induced vascular endothelial dysfunction. OO supplementation attenuated CAP-induced reduction of FMD and changes in blood markers associated with vasoconstriction and fibrinolysis, suggesting that OO supplementation may be an efficacious intervention to protect against vascular effects of exposure to PM. CITATION: Tong H, Rappold AG, Caughey M, Hinderliter AL, Bassett M, Montilla T, Case MW, Berntsen J, Bromberg PA, Cascio WE, Diaz-Sanchez D, Devlin RB, Samet JM. 2015. Dietary supplementation with olive oil or fish oil and vascular effects of concentrated ambient particulate matter exposure in human volunteers. Environ Health Perspect 123:1173-1179; http://dx.doi.org/10.1289/ehp.1408988.

Omega-3 fatty acid supplementation appears to attenuate particulate air pollution-induced cardiac effects and lipid changes in healthy middle-aged adults.

BACKGROUND: Air pollution exposure has been associated with adverse cardiovascular health effects. Findings of a recent epidemiological study suggested that omega-3 fatty acid (fish oil) supplementation blunted cardiac responses to air pollution exposure. OBJECTIVES: We conducted a randomized, controlled exposure study to evaluate the efficacy of fish oil supplements in attenuating adverse cardiac effects of exposure to concentrated ambient fine and ultrafine particulate matter (CAP). METHODS: Twenty-nine healthy middle-aged participants (mean, 58 ± 1 years of age) were supplemented in a randomized, double-blinded manner with 3 g/day of either fish oil or olive oil for 4 weeks before sequential chamber exposure to filtered air and CAP (mean mass concentration 278 ± 19 µg/m3) for 2 hr. Cardiac responses were assessed by comparing time and frequency domain changes in heart rate variability (HRV) and electrocardiographic repolarization changes measured before, immediately after, and 20 hr after exposure. Changes in plasma lipids were also evaluated at these time points. RESULTS: Fish oil supplementation appeared to attenuate CAP-induced reductions in high-frequency/low-frequency ratio, as well as elevations in normalized low-frequency HRV and prolongation of the QT interval corrected for heart rate (QTc). Very low-density lipoprotein and triglyceride concentrations increased significantly immediately after exposure to CAP in participants supplemented with olive oil, but not in those supplemented with fish oil. CONCLUSIONS: Exposure of healthy middle-aged adults to CAP for 2 hr induced acute cardiac and lipid changes after supplementation with olive oil, but not fish oil. Our findings suggest that omega-3 fatty acid supplements offer protection against the adverse cardiac and lipid effects associated with air pollution exposure.

The role of soluble components in ambient fine particles-induced changes in human lungs and blood.

Normal individuals developed pulmonary neutrophilic inflammation and increased blood fibrinogen following inhalation of concentrated ambient particles (CAPS). In this study, we sought to determine how soluble components in CAPS contributed to these changes. We expanded and reanalyzed data from 37 young healthy volunteers from a previous study (Ghio et al., 2000) who were exposed to either filtered air or CAPS. Postexposure bronchoalveolar lavage (BAL) as well as pre- and postexposure venous blood samples was analyzed for cellular and acute inflammatory endpoints. Nine most abundant components in the water-soluble fraction of CAPS were correlated with these endpoints using principal component analysis. We found that a sulfate/Fe/Se factor was associated with increased BAL percentage of neutrophils and a Cu/Zn/V factor with increased blood fibrinogen. The concentrations of sulfate, Fe, and Se correlated highly with PM mass (R > 0.75) while the correlations between PM and Cu/Zn/V were modest (R = 0.2-0.6). These results from controlled human exposure linked specific PM components to pulmonary neutrolphil influx and blood fibrinogen increase, and indicated the soluble components of pollutant particles may differentially affect pulmonary and hematological systems in humans exposed to PM.