Mediterranean diet lowered CV risk more effectively than low-fat diet

A Mediterranean-style diet has a greater effect on reducing CV events than low-fat diets, according to a review published in the American Journal of Medicine.

Additionally, although a Mediterranean diet did not reduce cholesterol, its benefits were found to be “equal to or greater than the benefit observed in statin trials,” the researchers wrote.

The review included data from various studies on diet and CVD conducted between 1957 and 2013.
The researchers described the evolution of studies exploring the link between diet and CV health. Earlier studies focused on the “diet-heart hypothesis,” which held that dietary saturated fat contributes to increased serum cholesterol, which then leads to atherosclerosis. However, the Multiple Risk Factor Intervention Trial, conducted between 1974 and 1982, yielded only modest decreases in total and LDL cholesterol after participants underwent a 7-year regimen of significantly reduced dietary fat.

Subsequent findings, culminating in the PREDIMED study between 2003 and 2012, demonstrated that a Mediterranean-style diet was related to reduced risk for stroke, MI and CV death, although such a diet was not found to decrease cholesterol.

In a separate cross-sectional study of 780 male career firefighters published in PLoS One, compliance with a Mediterranean-style diet was inversely related to metabolic syndrome, LDL cholesterol and self-reported weight gain. Results from this study also indicated a significant and independent link between adherence to a Mediterranean diet and higher HDL cholesterol.

The analysis, conducted within a pre-existing longitudinal study, compiled data on firefighters aged 18 years or older from 11 fire departments in the Midwest. The researchers assigned each participant a modified Mediterranean diet score between 0, indicating no adherence, and 42, indicating maximal adherence, according to their responses to a lifestyle questionnaire.

Significantly lower scores were observed among obese participants, who also reported more frequent fast/takeout food consumption (P<.001) and consumption of sweetened beverages with meals (P=.002). Inverse associations were observed between Mediterranean diet score and body fat percentage (P=.017), triglycerides (P=.0463) and the ratio of total to HDL cholesterol (P=.0047) after adjustment for age and BMI, whereas a positive association was observed between diet score and HDL cholesterol (P=.0001). Additional adjustment according to physical activity and body fat percentage maintained the associations with HDL and the ratio of total to HDL cholesterol.

Ordered logistic regression analysis indicated significant inverse associations between higher diet scores and weight gain within the past 5 years (OR=0.57; 95% CI, 0.39-0.84 for highest score quartile) and metabolic syndrome (OR=0.65; 95% CI, 0.44-0.94 per one-unit metabolic syndrome score increase).

“The observed relationships support the potential effectiveness of a Mediterranean-style diet in younger, working cohorts in non-Mediterranean countries, and justify future intervention studies,” the researchers concluded.

For more information:

Dalen JE. Am J Med. 2013;doi:10.1016/j.amjmed.2013.12.014.

Yang J. PLoS One. 2014;doi:10.1371/journal.pone.0087539.

Disclosure: One of the researchers for the Yang study reports serving as a paid expert witness, independent medical examiner or both in workers’ compensation and disability cases, including cases involving firefighters. No other researchers reported relevant financial disclosures.