Researchers at Brigham and Women’s Hospital have explored potential mechanisms behind the 23 per cent reduction in mortality risk among American women adhering to the Mediterranean diet. This diet’s health benefits are well-documented, yet there has been a lack of long-term data on its effects in U.S. women and a limited understanding of the mechanisms driving its efficacy. In a landmark study, over 25,000 initially healthy U.S. women were monitored for up to 25 years. The study, led by Brigham and Women’s Hospital, part of the Mass General Brigham healthcare system, found significant reductions in all-cause mortality, particularly from cancer and cardiovascular diseases. Researchers noted biological changes in metabolism, inflammation, and insulin resistance, which might explain the observed benefits.
Dr. Samia Mora, MD, the senior author of the study and director of the Center for Lipid Metabolomics at Brigham, played a pivotal role in the research. She underscored the impact of dietary habits on longevity, highlighting that adhering to a Mediterranean diet could reduce the risk of death by approximately a quarter over more than 25 years. The Mediterranean diet, primarily plant-based, includes a large variety of nuts, seeds, fruits, vegetables, whole grains, and legumes, with olive oil as the main source of fat. It also allows for moderate consumption of fish, poultry, dairy, and eggs, with minimal intake of red meats, sweets, and processed foods.
The study tracked the long-term health benefits of the Mediterranean diet and investigated the biological pathways that might explain these benefits. About 40 biomarkers were evaluated, covering different biological pathways and clinical risk factors. Key findings pointed to metabolism and inflammation as significant contributors, supplemented by other factors like triglyceride-rich lipoproteins and insulin resistance. Smaller contributions came from pathways related to branched-chain amino acids, various lipoproteins, glycemic measures, and hypertension.
Dr. Shafqat Ahmad, PhD, the lead author of the study and an associate professor of Epidemiology at Uppsala University in Sweden, highlighted the potential public health implications of these findings. He noted that modest changes in risk factors for metabolic diseases could yield substantial long-term benefits, advocating for dietary adjustments to reduce overall mortality risks. The study’s results, published in JAMA, are promising but come with caveats due to the demographic specificity of the participants—primarily middle-aged, well-educated, non-Hispanic white female health professionals—and the reliance on self-reported data such as food-frequency questionnaires and measurements of height, weight, and blood pressure.
Despite these limitations, the extensive scale and lengthy follow-up period are significant to the study’s conclusions. As the Mediterranean diet gains popularity worldwide, variations have emerged, adapting to different cultural and dietary traditions. Dr. Mora calls for public health policies to promote the Mediterranean diet’s healthful attributes and discourage less beneficial adaptations. The study highlights the health benefits of the Mediterranean diet and provides valuable insights into why it may be so effective at improving longevity and reducing mortality from major diseases.
More information: Shafqat Ahmad et al, Mediterranean Diet Adherence and Risk of All-Cause Mortality in Women, JAMA. DOI: 10.1001/jamanetworkopen.2024.14322
Journal information: JAMA Provided by Brigham and Women’s Hospital
