New Study Delves Into Mechanisms Behind MedDiet's Health Benefits

In the first ran­dom­ized clin­i­cal trial in the United States on the long-term effects of the Mediterranean diet (MedDiet), researchers iden­ti­fied some of the mech­a­nisms that under­lie the eat­ing plan’s ben­e­fits for heart health.

The most influ­en­tial effects of the diet involved improved inflam­ma­tion, blood sugar and body mass index (BMI).

Research on the MedDiet began in the 1950s, and since that time, evi­dence of its value for car­dio­vas­cu­lar health has accu­mu­lated. In more recent years, stud­ies have shown the eat­ing plan may help pre­vent or alle­vi­ate a wide range of other ail­ments as well.

However, the mech­a­nisms by which it ben­e­fits the heart have been poorly under­stood, so sci­en­tists recently under­took an inves­ti­ga­tion to pin­point these fac­tors.

The research pub­lished in JAMA Network Open involved an exam­i­na­tion of data on more than 25,000 women enrolled in the Women’s Health Study. At the onset, the par­tic­i­pants com­pleted a detailed food ques­tion­naire on their dietary intake. This infor­ma­tion was used to assign them scores from one to nine based on how much their eat­ing plan resem­bled the MedDiet.

The indi­vid­u­als were then divided into three groups: those with low-adher­ence scores of between one and three, those with mid­dle-adher­ence scores of four and five, and those with high-adher­ence scores of six and greater.

Cardiovascular health of the par­tic­i­pants was fol­lowed for 12 years. Individuals in the mid­dle adher­ence cat­e­gory had a 23 per­cent lower risk, while those in the high cat­e­gory had a 28 per­cent lower risk.

To deter­mine the ​“why” behind the ​“how” of the reduced risk, blood pres­sure mea­sure­ments, blood test results and self-reported infor­ma­tion on weight and height were ana­lyzed.

The find­ings showed that improve­ments in inflam­ma­tion, glu­cose metab­o­lism and body mass index accounted for 27.3 to 29 per­cent of the risk decrease. In addi­tion, smaller links were found to health­ier blood pres­sure, lipids and other bio­mark­ers. Notwithstanding these dis­cov­er­ies, some ways in which the MedDiet ren­ders its heart ben­e­fits remain a mys­tery.

“Our study has a strong pub­lic health mes­sage that mod­est changes in known car­dio­vas­cu­lar dis­ease risk fac­tors, par­tic­u­larly those relat­ing to inflam­ma­tion, glu­cose metab­o­lism and insulin resis­tance, con­tribute to the long-term ben­e­fit of a Mediterranean diet on car­dio­vas­cu­lar dis­ease risk. This under­stand­ing may have impor­tant down­stream con­se­quences for the pri­mary pre­ven­tion of car­dio­vas­cu­lar dis­ease,” lead author Shafqat Ahmad, a research fel­low at the Brigham and at the Harvard Chan School, said in a press release.

Registered nurse Jody Bergeron of Cape Cod Healthcare in Falmouth, MA, told Olive Oil Times that char­ac­ter­is­tics of the MedDiet may have played a role in the results.

“It is well known that chronic low grade inflam­ma­tion and oxida­tive stress are asso­ci­ated with car­dio­vas­cu­lar dis­ease, can­cer and other chronic con­di­tions,” she said.

“The MedDiet focuses on the fol­low­ing anti-inflam­ma­tory and nutri­ent dense foods: fish, veg­eta­bles, fruits, extra vir­gin olive oil, whole grains, nuts, and seeds,” she added. ​“It has a higher omega‑3 to omega‑6 fatty acid ratio, which leads to decreased inflam­ma­tion. The diet’s high quan­tity of phy­tonu­tri­ents and fiber, along with its low glycemic load and low con­tent of sat­u­rated fat, con­tributes to less inflam­ma­tion in the body.”

• JAMA Network Open


• EurekAlert!