Research studies show that a Mediterranean style diet reduces the risk of heart disease and factors associated with increased risk, according to MayoClinic.com. One such study, The Lyon Diet Heart Study, was a randomized control trial of free-living subjects known to have had a previous heart attack. The study suggests that following a Mediterranean-style diet can reduce future recurrence of heart disease events.
The goal of the Lyon Diet Heart Study was to test the effectiveness of the Mediterranean- style diet on preventing recurrent heart attacks compared to a Western-type diet over a five-year period. It is considered a secondary prevention trial, as the subjects were known to already have heart disease and researchers were attempting to reduce or prevent further damage.
Patients under the age of 70 years old who were hospitalized for a heart attack were asked to participate in the study. Those that agreed were randomized into two diet groups: The experimental group with 302 subjects, was asked to follow a strict Mediterranean-style diet. The control group with 303 subjects was not provided dietary instructions, but was asked by their doctors to follow a "prudent" diet.
The subjects in the experimental group were asked to consume a diet high in fruits and vegetables, particularly root and green vegetables, olive oil, bread, legumes, consume more fish and poultry and less red meat, lamb and pork. Fruit consumption was encouraged daily. Butter and cream was replaced with a margarine containing alpha-linolenic acid. Those in the experimental group consumed more dietary fiber, alpha-linolenic acid and oleic acid and less saturated fat and cholesterol than the control group.
The original study was stopped because there was a significant difference between the two groups. Study results, published in the "Lancet" in June 1994, showed that after a mean follow-up of only 27 months, the experiment group had significantly fewer additional heart attacks and deaths than the control group. The benefit of the Mediterranean diet was attributed to the increase in alpha-linolenic acid intake.
Alpha-Linolenic Acid, or ALA, is an omega-3 fatty acid found in plants. It can be converted by the body into the two omega-3 fatty acids found in fish oil, eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA. Omega-3s are associated with decreased inflammation, heart disease and arthritis. They are required for cognitive and behavioral health and normal growth. Flaxseed is the best source of ALA, but it can also be found in walnuts, canola oil and soy.