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New United States research has found that eating a Mediterranean diet may provide some protection from the harmful effects of long-term exposure to air pollution, helping to reduce the risk of heart attacks, stroke and other causes of death.

Carried out by researchers at the New York University School of Medicine, the study looked at data taken from 548,699 people with an average age of 62 who were followed for a 17-year period.

The researchers categorized the participants into five groups based on how strongly they adhered to a Mediterranean diet and estimated their long-term exposure to fine particulate matter (PM2.5), nitrous oxide (NO2) and ozone (O3).

They found that for every 10 parts per billion (ppb) increase in long-term average NO2 exposure, deaths from all causes increased by 5 percent in the least adherent group, compared to 2 percent among the most adherent.

Cardiovascular disease deaths increased by 10 percent in those least adherent, compared to 2 percent among the most adherent, while heart attack deaths also increased by 12 percent in those least adherent, compared to 4 percent among the most adherent.

For every 10 micrograms per cubic meter (μg/m3) increase in long-term average PM2.5 exposure, cardiovascular disease deaths increased by 17 percent in those least adherent compared to 5 percent among the most adherent, and heart attack deaths increased by 20 percent in those least adherent, compared to 5 percent among the most adherent.

However, the diet did not reduce deaths from all causes, heart attack or other cardiovascular diseases associated with O3 exposure.

“Previous studies have shown that dietary changes, particularly the addition of antioxidants, can blunt the adverse effects of exposure to high levels of air pollution over short time periods,” said co-author Chris C. Lim. “What we did not know was whether diet can influence the association between long-term air pollution exposure and health effects.”

Rich in antioxidnts, a Mediterranean diet encourages a high intake of fruits, vegetables, whole grains, legumes, olive oils, fish and poultry, and a low intake of red meat and processed foods.

Antioxidants are molecules that help to combat the highly reactive molecules known as free radicals, which cause cell and tissue damage.

With about one-fourth of the study population living where air pollution levels were 10 μg/m3 or more above the lowest exposure, senior study author George Thurston added that, “adoption of a Mediterranean diet has the potential to reduce the effects of air pollution in a substantial population in the United States.”

The research was presented at the ATS 2018 International Conference, taking place May 18 to 23 in San Diego, U.S. JB

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