A recent study conducted by investigators at Brigham and Women’s Hospital aimed to assess the underlying mechanisms that may explain the Mediterranean diet’s significant reduction in all-cause mortality risk for American women. The study followed over 25,000 initially healthy U.S. women for up to 25 years and found that those with greater adherence to the Mediterranean diet had up to a 23% lower risk of all-cause mortality, with benefits for both cancer and cardiovascular mortality. The researchers identified changes in biomarkers of metabolism, inflammation, insulin resistance, and other factors that may help explain the diet’s health benefits. These results were published in JAMA.
The Mediterranean diet includes a plant-based diversity of foods such as nuts, seeds, fruits, vegetables, whole grains, and legumes, with olive oil as the main fat source. It also includes moderate intake of fish, poultry, dairy, eggs, and alcohol, while limiting consumption of meats, sweets, and processed foods. The study sought to investigate the long-term benefits of adhering to a Mediterranean diet in a U.S. population and explored the biological mechanisms that may account for its positive effects. A panel of approximately 40 biomarkers representing various biological pathways and clinical risk factors was evaluated by the researchers.
The study found that biomarkers of metabolism and inflammation made the largest contribution to the beneficial effects of the Mediterranean diet, followed by triglyceride-rich lipoproteins, adiposity, and insulin resistance. Other biological pathways related to branched-chain amino acids, lipoproteins, glycemic measures, and hypertension also played a role, albeit to a lesser extent. The authors suggest that even modest changes in established risk factors for metabolic diseases can lead to substantial long-term benefits from following a Mediterranean diet, emphasizing the potential of promoting healthier dietary habits to reduce overall mortality risk.
While the study provides important insights into the biological pathways that may help explain the benefits of the Mediterranean diet, the authors acknowledge certain limitations, such as the study’s focus on middle-aged and older well-educated female health professionals who were predominantly non-Hispanic and white. The reliance on self-reported measures, such as food-frequency questionnaires and biometric data, also poses potential limitations. However, the study’s strengths include its large scale and long follow-up period, offering valuable insights into the potential health benefits of the Mediterranean diet.
As the popularity of the Mediterranean diet continues to grow, the authors stress the importance of promoting the diet’s healthful attributes while discouraging unhealthy adaptations in different countries and cultures. The study highlights the significant public health implications of encouraging individuals to adopt healthier dietary habits, particularly those linked to metabolic diseases, inflammation, and insulin resistance, in order to reduce the overall risk of mortality. Overall, the findings emphasize the potential of the Mediterranean diet in improving long-term health outcomes and reducing the risk of death, particularly from cancer and cardiovascular diseases.