Med Diet May Protect Against Air Pollution

A recent study con­ducted by researchers at the NYU School of Medicine revealed that adher­ence to the Mediterranean diet (MedDiet) may mit­i­gate the detri­men­tal effects of air pol­lu­tion.

Author Chris Lim, who pre­sented the find­ings at the American Thoracic Society’s 2018 International Conference ear­lier last month, exam­ined data from a cohort of nearly 550,000 peo­ple across the United States for a period of 17 years.

Lim and his col­leagues wanted to deter­mine whether an antiox­i­dant-rich MedDiet that eschews red meat and processed foods in favor of fruits, veg­eta­bles, legumes, whole grains, fish and olive oil impacts the cor­re­la­tion between pro­longed expo­sure to ambi­ent air pol­lu­tion and cause-spe­cific mor­tal­ity.

“Air pol­lu­tion is hypoth­e­sized to cause bad health effects through oxida­tive stress and inflam­ma­tion,” explained Lim, ​“and the Mediterranean diet is really rich in foods that are anti-inflam­ma­tory and have antiox­i­dants that might inter­vene through those avenues.”

The researchers first grouped par­tic­i­pants based on how closely their eat­ing habits aligned with the MedDiet at the out­set of the trial before ref­er­enc­ing cen­sus tract infor­ma­tion to esti­mate par­tic­i­pants’ long-term expo­sure to three spe­cific types of air pol­lu­tion: par­tic­u­late mat­ter (PM2.5), nitrous oxide (NO2) and ozone (O3).

The sub­se­quent analy­sis focused on the sta­tis­ti­cally sig­nif­i­cant impact of the MedDiet on deaths from all causes, in addi­tion to car­dio­vas­cu­lar dis­ease-related deaths and heart attacks.

When it came to deaths from all causes, the results revealed a 5 per­cent increase for every 10 parts per bil­lion (ppb) increase in NO2 expo­sure for those least adher­ent to the MedDiet, com­pared to 2 per­cent for the most adher­ent.

Results for car­dio­vas­cu­lar dis­ease were sim­i­lar, with a 17 per­cent increase in deaths for every 10 micro­grams per cubic meter increase in PM2.5 expo­sure for those least adher­ent to the diet, com­pared to 5 per­cent for the most adher­ent.

The trends for heart attack deaths were also aligned, with a 20 per­cent increase com­pared to 5 per­cent in terms of expo­sure to PM2.5 expo­sure and 12 per­cent com­pared to 4 per­cent for NO2. In fact, the only mea­sur­able out­lier was O3 expo­sure, which results revealed was not cor­re­lated with a MedDiet.

“Given the ben­e­fits we found of a diet high in anti-oxi­dants, our results are con­sis­tent with the hypoth­e­sis that par­ti­cle air pol­lu­tion caused by fos­sil fuel com­bus­tion adversely affects health by induc­ing oxida­tive stress and inflam­ma­tion,” explained George Thurston, senior study author and direc­tor of the Program in Exposure Assessment and Human Health Effects at the Department of Environmental Medicine. ​“On the other hand, the ozone effect was not sig­nif­i­cantly blunted by a Mediterranean diet, so ozone appar­ently affects car­diac health through a dif­fer­ent mech­a­nism.”

Two key caveats, how­ever, were that the eat­ing pat­terns of par­tic­i­pants may have shifted over the course of the study, as well as the fact that the demo­graph­ics (major­ity white, higher income) were not an accu­rate rep­re­sen­ta­tion of the pop­u­la­tion at large.

However, as Lim noted to Olive Oil Times, the results are nonethe­less inter­est­ing. ​“Our study draws on a very detailed and large cohort, uses lat­est air pol­lu­tion pre­dic­tion mod­els and pro­vides very novel results.”

• American Thoracic Society Journals


• Science Daily


• Time