Women with greater adherence to Mediterranean diet have 23% lower risk for death

Key takeaways:

• The reduced mortality risk was significant even after adjusting for lifestyle factors.
• Small molecule metabolites and inflammation contributed to 14.8% and 13% of the association, respectively.

Greater adherence to the Mediterranean diet was associated with a reduced risk for all-cause mortality among women, data in JAMA Network Open showed. Researchers said the association can be partly attributed to cardiometabolic risk factors.

“For women who want to live longer, our study says watch your diet!” Saima Mora, MD, MHS, a professor of medicine at Harvard Medical School and study’s senior author, said in a press release. “The good news is that following a Mediterranean dietary pattern could result in about one-quarter reduction in risk of death over more than 25 years with benefit for both cancer and cardiovascular mortality, the top causes of death in women (and men) in the U.S. and globally.”

The Mediterranean diet has previously demonstrated sex-specific health benefits, with one study showing a 24% lower risk for CVD in women. However, long-term data on its correlations with all-cause mortality and possible underlying mechanisms are limited, Mora and colleagues noted.

They assessed a cohort of 25,315 women from the Women’s Health Study who were initially healthy at baseline, had provided blood samples, biomarker measurements and dietary information and were followed for about 25 years.

The participants’ adherence to the Mediterranean diet was graded on a scale of 0 to 9, with higher scores reflecting greater adherence.

The median score for diet adherence during the study was 4. Overall, there were 3,879 all-cause deaths.

Mora and colleagues found a reduced risk for mortality among women with diet adherence scores of 4 to 5 (HR = 0.84; 95% CI, 0.78-0.9) and scores of 6 or greater (HR = 0.77; 95% CI, 0.7-0.84) vs. women with scores of 3 or less.

Scores of 6 or greater were also associated with a reduced risk for CVD mortality (HR = 0.83; 95% CI, 0.69-0.99) and cancer mortality (HR = 0.8; 95% CI, 0.69-0.92).

The researchers reported that adjusting for lifestyle factors like smoking status, alcohol intake and physical activity attenuated the associations. However, they remained significant for women with scores of 4 to 5 (HR = 0.92; 95% CI, 0.85-0.99) and 6 or greater (HR = 0.89; 95% CI, 0.82-0.98).

When analyzing potential mechanisms, Mora and colleagues found that small molecule metabolites contributed to 14.8% of the reduced risk for mortality, followed by inflammatory biomarkers (13%), triglyceride-rich lipoproteins (10.2%), BMI (10.2%) and insulin resistance (7.4%). Other factors like hypertension, HDL, LDL and HbA1c had smaller contributions of less than 3% .

“Our research provides significant public health insight: even modest changes in established risk factors for metabolic diseases can yield substantial long-term benefits from following a Mediterranean diet,” Shafqat Ahmad, PhD, the study’s lead author and an associate professor of epidemiology at Uppsala University in Sweden, said in the release. “This finding underscores the potential of encouraging healthier dietary habits to reduce the overall risk of mortality.”

There were some study limitations. Participants were mostly middle-aged and non-Hispanic white health professionals, hurting the findings’ generalizability, according to the researchers. In addition, exposure misclassification was possible because of adherence being assessed through food-frequency questionnaires.

“The health benefits of the Mediterranean diet are recognized by medical professionals, and our study offers insights into why the diet may be so beneficial,” Mora said. “Public health policies should promote the healthful dietary attributes of the Mediterranean diet and should discourage unhealthy adaptations.”

References:

• Ahmad S, et al. JAMA Netw Open. 2024;doi:10.1001/jamanetworkopen.2024.14322.
• Mediterranean diet tied to one-fifth lower risk of death in women. https://www.brighamandwomens.org/about-bwh/newsroom/press-releases-detail?id=4722. Published May 31, 2024. Accessed June 3, 2024.