Mediterranean diet reduces pollution-related cardiovascular mortality
Eating foods rich in antioxidant compounds, such as the Mediterranean diet, helps protect against the risk of cardiovascular disease (CVD) mortality associated with long-term exposure to air pollution, according to data from the NIH-AARP Diet and Health Study.
“Mediterranean diet has shown beneficial effects on cardiovascular health, improving blood pressure, endothelial function and lipid profiles while reducing inflammatory responses and oxidative stress. These benefits have been consistently observed in meta-analyses, cohort studies and randomized control trials,” the investigators pointed out. [N Engl J Med 2013:368;1279-1290; Adv Nutr 2014:5;330S-336S; Am J Med 2015:128;229-238]
“Attenuation of the CVD mortality risk associated with air pollution exposure by dietary patterns, as observed here, is therefore consistent with past evidence of oxidative stress as underlying mechanism for air pollution-induced health effects and suggests that a healthful dietary pattern enriched in antioxidant and anti-inflammatory compounds could interact with mechanisms underlying air pollution-induced health effects,” they added.
The current analysis included 548,845 individuals (mean age at study entry, 62.2 years; 59.1 percent male; 41.3 percent overweight). Over 17 years of follow-up, 126,817 participants (23.1 percent) died: 39,532 from all CVD, 22,329 from ischaemic heart disease (IHD), 5,592 from cerebrovascular diseases (CER) and 6,811 from cardiac arrests (CAR).
During the study period, the overall average concentrations of ambient air pollutants were 12.9 μg/m3 for particulate matter (PM2.5) and 13.3 ppb for nitrogen dioxide (NO2). Cox proportional hazards models revealed long-term exposure to PM2.5 to be significantly associated with elevated risks of the following cause-specific mortality outcomes: CVD (hazard ratio [HR], 1.13; 95 percent CI, 1.08–1.18), IHD (HR, 1.16; 1.10–1.23) and CAR (HR, 1.15; 1.03-1.28). [Circulation 2019;doi:10.1161/CIRCULATIONAHA.118.035742]
Long-term NO2 exposure likewise carried increased risks of CVD (HR, 1.06; 1.04–1.08) and IHD (HR, 1.08; 1.05–1.11) mortality.
Of note, following a Mediterranean-style diet modified the observed associations, such that individuals with higher alternative Mediterranean Diet Index scores were at lower risk of both PM2.5/NO2-related CVD and IHD mortality (p<0.01 for interaction).
When specific components of the diet were examined, higher consumption levels of vegetables conferred protective benefits for PM2.5-CVD, PM2.5-IHD, NO2-CVD and NO2-IHD deaths; whole grains for PM2.5-CVD and PM2.5-IHD death; and fruits for NO2-CVD death.
“These results add to a growing body of literature suggesting [that] dietary patterns may help reduce CV events due to air pollution exposure, potentially through augmenting antioxidants and reducing oxidative stress,” the investigators said.
More than 4.2 million people die from air pollution-related diseases every year, which by any measure is an immense global public health burden. According to the World Health Organization, exposure to ambient air pollution is the fifth leading mortality risk factor in the world. [https://www.who.int/newsroom/detail/02-05-2018-9-out-of-10-people-worldwide-breathe-polluted-air-but-morecountries-are-taking-action]
“Thus, in concert with air quality standards and emission control policies to protect … against the most harmful effects of air pollution, individual-level prevention strategies and population-wide policy efforts to promote healthier diets, aimed at countering the oxidative stress induced by air pollution exposure, may provide complementary approaches,” the investigators said.