summary: Adherence to the Mediterranean diet reduces the risk of all-cause mortality by 23% in US women aged 25 years and older. Benefits of the diet include reduced mortality from cancer and cardiovascular disease, which are linked to improved metabolism, inflammation, and insulin resistance. Researchers analyzed biomarkers to understand these health improvements. The study highlights the diet’s potential to have long-term health benefits.
Key Facts:
- The Mediterranean diet reduces the risk of all-cause mortality in U.S. women by 23%.
- Benefits include reduced mortality from cancer and cardiovascular disease.
- Favorable changes in metabolism, inflammation, and insulin resistance explain the improved health.
sauce: Brigham and Women’s Hospital
Although the health benefits of the Mediterranean diet have been reported in several studies, long-term data on its effects in US women are limited, and little is known about why this diet may reduce mortality risk.
In a new study that followed more than 25,000 initially healthy American women for up to 25 years, researchers at Brigham and Women’s Hospital, a founding member of the Massachusetts General Brigham Health System, found that participants who consumed more of the Mediterranean diet had up to a 23 percent lower risk of all-cause mortality, with benefits for both cancer mortality and cardiovascular disease mortality.
The researchers found evidence of biological changes that might help explain why: They detected changes in biomarkers of metabolism, inflammation, insulin resistance, and more.
Result is In the way.
“Our study says that women who want to live longer would do well to watch what they eat. The good news is that following a Mediterranean dietary pattern reduced mortality risk by about a quarter over 25 years, potentially conferring benefits on both cancer and cardiovascular disease mortality, the leading causes of death for women (and men) in the U.S. and around the world,” said lead author Samia Mora, MD, a cardiologist and director of the Brigham’s Center for Lipid Metabolism.
The Mediterranean diet is a diverse, plant-based diet that is rich in plants (nuts, seeds, fruits, vegetables, whole grains, and legumes). The main fat is olive oil (usually extra virgin). The diet includes moderate consumption of fish, poultry, dairy products, eggs, and alcohol, and rarely eats meat, sweets, and processed foods.
The current study investigated the long-term benefits of the Mediterranean diet in a U.S. population recruited as part of the Women’s Health Study and explored biological mechanisms that may explain the health benefits of this diet. Study researchers evaluated a panel of approximately 40 biomarkers representing a range of biological pathways and clinical risk factors.
Metabolic and inflammatory biomarkers made the largest contributions, followed by triglyceride-rich lipoproteins, obesity, and insulin resistance. Other biological pathways related to branched-chain amino acids, high-density lipoproteins, low-density lipoproteins, blood glucose measurements, and hypertension made smaller contributions.
“Our study provides important public health insights, as even small changes in established risk factors for metabolic disease, particularly those related to small molecule metabolites, inflammation, triglyceride-rich lipoproteins, obesity and insulin resistance, may confer significant long-term benefits from continuing a Mediterranean diet.”
“This finding highlights the possibility that encouraging healthier eating habits may reduce overall mortality risk,” said lead author Shafqat Ahmad, PhD, an associate professor of epidemiology at Uppsala University in Sweden and a researcher in the Center for Lipid Metabolism and Department of Preventive Medicine at Brigham Health.
Although the study identifies important biological pathways that may help explain all-cause mortality risk, the authors point out several important limitations, including that it was limited to a sample of mostly non-Hispanic and white, middle-aged, highly educated, female health care workers.
The study relied on food frequency questionnaires and self-reported measures of height, weight, blood pressure, etc. However, the strengths of the study are its large size and long follow-up period.
The authors also note that as the concept of the Mediterranean diet has gained popularity, the diet has been adopted by different countries and cultures.
“The health benefits of the Mediterranean diet are recognised by medical experts and our study provides insight into why this diet is so beneficial. Public health policies should promote the healthy eating properties of the Mediterranean diet and discourage unhealthy adaptations,” said Mora.
author: In addition to Ahmad and Mora, Brigham authors include M. Vinayaga Murthy, I-Ming Lee, Paul M. Ridker, Joan E. Munson, Julie E. Burling and Olga V. Demler.
Disclosure: Mora reported that he is a co-inventor on a patent investigating glycoprotein acetylation in relation to colorectal cancer risk, licensed to LabCorp, Inc., and a patent application on methods for predicting future cardiovascular disease risk by analysis of the IgG glycome, assigned to GENOS doo, Inc., and 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 numbers CA047988, HL043851, HL080467, HL099355, and UM1 CA182913). Dr. Ahmad is supported by a Career Start Research Grant from the Swedish Research Council (2022-01460) and FORMAS (2020-00989), and a research grant from EpiHealth, Sweden. Dr. Demler is supported by a K Award from the NHLBI of the NIH under grant number K01HL135342-02.
Dr. Mora has received research grants from the National Institute of Diabetes and Digestive and Kidney Diseases (grant number DK112940), NHLBI (grant numbers R01HL160799, R01HL134811, R01HL117861, K24 HL136852), the American Heart Association (grant number 0670007N), and the Molino Family Trust.
In addition, LabCorp provided LipoProfile IV results to the study at no additional cost.
About this diet and mortality study
author: Cassandra Fallone
sauce: Brigham and Women’s Hospital
contact: Cassandra Fallone – Brigham and Women’s Hospital
image: Image courtesy of Neuroscience News
Original Research: Open access.
“Adherence to a Mediterranean diet and risk of all-cause mortality in womenSamia Molla et al. JAMA Network Open
Abstract
Adherence to a Mediterranean diet and risk of all-cause mortality in women
Importance
Higher adherence to the Mediterranean diet has been shown to reduce the risk of all-cause mortality, but there are limited data on the underlying molecular mechanisms in long-term follow-up studies.
the purpose
Objective: To examine adherence to a Mediterranean diet and risk of all-cause mortality and to examine the relative contribution of cardiometabolic factors to this risk reduction.
Design, Setup, and Participants
This cohort study included initially healthy women enrolled in the Women’s Health Study who provided blood samples, biomarker measurements, and dietary information. Baseline data included self-reported demographic information and a validated food frequency questionnaire. Data collection period was from April 1993 to January 1996, and data analysis was conducted from June 2018 to November 2023.
Exposure
A Mediterranean diet score (range, 0–9) was calculated based on nine dietary components.
Main findings and evaluation
Thirty-three blood biomarkers, including traditional and novel lipids, lipoproteins, apolipoproteins, inflammation, insulin resistance, and metabolic measures, were assessed at baseline using standard assays and nuclear magnetic resonance spectroscopy.
Mortality and causes of death were determined from medical and death records. Cox proportional hazards regression was used to calculate hazard ratios (HRs) between adherence to the Mediterranean diet and risk of death, and mediation analysis was used to calculate the mediating effects of different biomarkers to understand this association.
result
Among 25,315 participants, mean (SD) baseline age was 54.6 (7.1) years, there were 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 of other races or ethnicities. The median (IQR) Mediterranean diet adherence score was 4.0 (3.0-5.0).
During a mean (SD) follow-up of 24.7 (4.8) years, 3879 deaths occurred. Compared with low adherence to the Mediterranean diet (score 0-3), those with medium (score 4-5) and high (score 6-9) adherence had reduced adjusted risks, with HRs of 0.84 (95% CI, 0.78-0.90) and 0.77 (95% CI, 0.70-0.84), respectively (P trend < .001).
After further adjustment for lifestyle factors, the risk reduction was attenuated but remained statistically significant (moderate adherence group: HR, 0.92 [95% CI, 0.85-0.99]; High adherence group: HR, 0.89 [95% CI, 0.82-0.98]; P Of the biomarkers examined, small molecule metabolites and inflammatory biomarkers contributed most to reduced mortality risk (explaining 14.8% and 13.0% of the association, respectively), followed by triglyceride-rich lipoproteins (10.2%), body mass index (10.2%), and insulin resistance (7.4%).
The contributions of other pathways, including branched-chain amino acids, high-density lipoprotein, low-density lipoprotein, blood glucose, and hypertension, were small (<3%).
Conclusions and relevance
This cohort study showed that higher adherence to the Mediterranean diet was associated with a 23% lower risk of all-cause mortality, an inverse association that was partially explained by multiple cardiometabolic factors.
