Summary: Following a Mediterranean diet reduces the risk of all-cause mortality by 23% in U.S. women over 25 years. The diet’s benefits include lower cancer and cardiovascular mortality, linked to positive changes in metabolism, inflammation, and insulin resistance. Researchers analyzed biomarkers to understand these health improvements. The study highlights the diet’s potential for long-term health benefits.
Key Fact:
- The Mediterranean diet reduces all-cause mortality risk by 23% in U.S. women.
- Benefits include lower cancer and cardiovascular mortality.
- Positive changes in metabolism, inflammation, and insulin resistance explain the health improvements.
Source: Brigham and Women’s Hospital
The health benefits of the Mediterranean diet have been reported in multiple studies, but there is limited long-term data of its effects in U.S. women and little understanding about why the diet may reduce risk of death.
In a new study that followed more than 25,000 initially healthy U.S. women for up to 25 years, researchers from Brigham and Women’s Hospital, a founding member of the Mass General Brigham healthcare system, found that participants who had greater Mediterranean diet intake had up to 23% lower risk of all-cause mortality, with benefits for both cancer mortality and cardiovascular mortality.
The researchers found evidence of biological changes that may help explain why: they detected changes in biomarkers of metabolism, inflammation, insulin resistance and more.
Results are published in JAMA.
“For women who want to live longer, our study says watch your diet! 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 US and globally,” said senior author Samia Mora, MD, a cardiologist and the director of the Center for Lipid Metabolomics at the Brigham.
The Mediterranean diet is a plant-based diverse diet that is rich in plants (nuts, seeds, fruits, vegetables, whole grains, legumes). The main fat is olive oil (usually extra virgin), and the diet additionally includes moderate intake of fish, poultry, dairy, eggs, and alcohol, and rare consumption of meats, sweets, and processed foods.
The current study investigated the long-term benefit of adherence to a Mediterranean diet in a U.S. population recruited as part of the Women’s Health Study, and explored the biological mechanisms that may explain the diet’s health benefits. The study investigators evaluated a panel of approximately 40 biomarkers representing various biological pathways and clinical risk factors.
Biomarkers of metabolism and inflammation made the largest contribution, followed by triglyceride-rich lipoproteins, adiposity, insulin resistance. Other biological pathways relate to branched-chain amino acids, high-density lipoproteins, low-density lipoproteins, glycemic measures, and hypertension have smaller contribution.
“Our research provides significant public health insight: even modest changes in established risk factors for metabolic diseases—particularly those linked to small molecule metabolites, inflammation, triglyceride-rich lipoproteins, obesity, and insulin resistance—can yield substantial long-term benefits from following a Mediterranean diet.
“This finding underscores the potential of encouraging healthier dietary habits to reduce the overall risk of mortality,” said lead author Shafqat Ahmad, PhD, an associate professor of Epidemiology at Uppsala University Sweden and a researcher in the Center for Lipid Metabolomics and the Division of Preventive Medicine at the Brigham.
The current study identifies important biological pathways that may help explain all-cause mortality risk. However, the authors note some key limitations, including that the study was limited to middle aged and older well-educated female health professionals who were predominantly non-Hispanic and white.
The study relied on food-frequency questionnaires and other self-reported measures, such as height, weight and blood pressure. But the study’s strengths include its large scale and long follow up period.
The authors also note that as the concept of the Mediterranean diet has gained popularity, the diet has been adapted in different countries and cultures.
“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. Public health policies should promote the healthful dietary attributes of the Mediterranean diet and should discourage unhealthy adaptations,” said Mora.
Authorship: In addition to Ahmad and Mora, Brigham authors include M. Vinayaga Moorthy, I-Min Lee, Paul M. Ridker, JoAnn E. Manson, Julie E. Buring, and Olga V. Demler.
Disclosures: Mora reported being coinventor on a patent for examining glycoprotein acetylation in relation to colorectal cancer risk licensed to LabCorp and on a patent application for amethod for prediction of future cardiovascular disease risk via analysis of IgG glycome, assigned to GENOS d.o.o. and the Brigham and Women’s Hospital, Inc. Additional disclosures can be found in the paper.
Funding: The Women’s Health Study is supported by the NIH (grant Nos. CA047988, HL043851, HL080467, HL099355, and UM1 CA182913). Dr Ahmad was supported through a career-starting research grants from Swedish Research Council (2022-01460) and FORMAS (2020-00989) and also research grant from the EpiHealth, Sweden. Dr Demler was supported by a K award from the NHLBI of the NIH under award No. K01HL135342-02.
Dr Mora was supported by the research grants from the National Institute of Diabetes and Digestive and Kidney Diseases (grant No. DK112940); NHLBI (grant Nos. R01HL160799, R01HL134811, R01HL117861 and K24 HL136852); American Heart Association (grant No. 0670007N); and the Molino Family Trust.
In addition, LabCorp provided the LipoProfile IV results to the study at no additional cost.
About this diet and mortality research news
Author: Cassandra Falone
Source: Brigham and Women’s Hospital
Contact: Cassandra Falone – Brigham and Women’s Hospital
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Mediterranean Diet Adherence and Risk of All-Cause Mortality in Women” by Samia Mora et al. JAMA Network Open
Abstract
Mediterranean Diet Adherence and Risk of All-Cause Mortality in Women
Importance
Higher adherence to the Mediterranean diet has been associated with reduced risk of all-cause mortality, but data on underlying molecular mechanisms over long follow-up are limited.
Objectives
To investigate Mediterranean diet adherence and risk of all-cause mortality and to examine the relative contribution of cardiometabolic factors to this risk reduction.
Design, Setting, and Participants
This cohort study included initially healthy women from the Women’s Health Study, who had provided blood samples, biomarker measurements, and dietary information. Baseline data included self-reported demographics and a validated food-frequency questionnaire. The data collection period was from April 1993 to January 1996, and data analysis took place from June 2018 to November 2023.
Exposures
Mediterranean diet score (range, 0-9) was computed based on 9 dietary components.
Main Outcome and Measures
Thirty-three blood biomarkers, including traditional and novel lipid, lipoprotein, apolipoprotein, inflammation, insulin resistance, and metabolism measurements, were evaluated at baseline using standard assays and nuclear magnetic resonance spectroscopy.
Mortality and cause of death were determined from medical and death records. Cox proportional hazards regression was used to calculate hazard ratios (HRs) for Mediterranean diet adherence and mortality risk, and mediation analyses were used to calculate the mediated effect of different biomarkers in understanding this association.
Results
Among 25 315 participants, the mean (SD) baseline age was 54.6 (7.1) years, with 329 (1.3%) Asian women, 406 (1.6%) Black women, 240 (0.9%) Hispanic women, 24 036 (94.9%) White women, and 95 (0.4%) women with other race and ethnicity; the median (IQR) Mediterranean diet adherence score was 4.0 (3.0-5.0).
Over a mean (SD) of 24.7 (4.8) years of follow-up, 3879 deaths occurred. Compared with low Mediterranean diet adherence (score 0-3), adjusted risk reductions were observed for middle (score 4-5) and upper (score 6-9) groups, with HRs of 0.84 (95% CI, 0.78-0.90) and 0.77 (95% CI, 0.70-0.84), respectively (P for trend < .001).
Further adjusting for lifestyle factors attenuated the risk reductions, but they remained statistically significant (middle adherence group: HR, 0.92 [95% CI, 0.85-0.99]; upper adherence group: HR, 0.89 [95% CI, 0.82-0.98]; P for trend = .001). Of the biomarkers examined, small molecule metabolites and inflammatory biomarkers contributed most to the lower mortality risk (explaining 14.8% and 13.0%, respectively, of the association), followed by triglyceride-rich lipoproteins (10.2%), body mass index (10.2%), and insulin resistance (7.4%).
Other pathways, including branched-chain amino acids, high-density lipoproteins, low-density lipoproteins, glycemic measures, and hypertension, had smaller contributions (<3%).
Conclusions and Relevance
In this cohort study, higher adherence to the Mediterranean diet was associated with 23% lower risk of all-cause mortality. This inverse association was partially explained by multiple cardiometabolic factors.
