The Mediterranean diet and exercise reshape the gut microbiome, aiding weight loss

In a recent study published in The American Journal of Clinical Nutrition, Researchers are investigating the health benefits of Mediterranean diet (MedDiet) and physical activity interventions in overweight and obese participants by measuring changes in faecal and gut metabolic microbiota.

Study: Effect of a one-year lifestyle intervention with a reduced-energy Mediterranean diet and physical activity promotion on gut metabolism and microbiota: A randomized clinical trial. Image credit: Valentyn Volkov / Shutterstock.com

The health benefits of the MedDiet

Characterized by a high intake of healthy vegetables, legumes, fruits, whole grains and nuts, a moderate intake of seafood, a low intake of dairy products and processed meats, as well as olive oil being the main source of fat, the traditional MedDiet has developed. in worldwide popularity.

Previous studies have explored the health benefits of the MedDiet, which include significant cardiovascular disease (CVD), obesity, neurological, and all-cause mortality risk reductions compared to suboptimal dietary patterns such as the Western diet.

The high concentrations of dietary fiber and anti-inflammatory nutrients in the MedDiet have also been associated with the promotion and maintenance of beneficial gut microbiota. To date, the metabolic consequences of these associations remain unknown.

Investigating blood metabolism provides important insights into how gut microbiota-derived metabolites correlate with cardiometabolic diseases. Through the use of plasma metabolomics and 16S sequencing, researchers can elucidate how diet, circulating metabolites, and gut microbiota affect cardiovascular health.

Understanding the effect of dietary interventions on both gut microbial composition and metabolic profiles may support clinical recommendations for adherence to the MedDiet and other healthy diets, particularly in high-risk patients. Furthermore, these data may provide fundamental insights for future studies investigating the indirect effects of nutrition on other non-cardiovascular body systems.

About the study

In the present study, researchers used data from the PREvención con DIeta MEDiterránea (PREDIMED)-Plus randomized trial to investigate the effects of one year of intensive lifestyle intervention on faecal metabolites, gut microbiota and cardiovascular risk factors, particularly in overweight and obese patients. . The study included 400 people aged between 55 and 75 years from Alicante, Barcelona, ​​Reus and Valencia who were randomly divided between the intervention group (IG) and the control group (CG).

Data collection included dietary and lifestyle information obtained through the er-MedDiet questionnaire, a 17-item derivative of the 14-item Mediterranean Diet Adherence Screener (MEDAS) questionnaire. Blood and stool samples were also collected during baseline assessments and routine follow-up. Anthropometric measurements and demographic data were further obtained from medical and government records.

The researchers encouraged all study participants to increase their usual levels of physical activity to include at least 45 minutes a day of brisk walking or a similar activity. All study participants were also encouraged to perform specific exercises that increase their balance, strength and flexibility to eventually complete 150 minutes or more of moderate to vigorous physical activity each week.

Changes in physical activity levels were quantified using questionnaires that assigned metabolic equivalent of tasks (MET) min/week counts to physical activity status and MET h/day to sedentary behavior. The study intervention included lifestyle recommendations for physical activity and diet and personal behavioral support by a licensed dietitian for the IG group. Instead, he underwent CG treatment ad libitum with regular MedDiet, which was the only intervention.

Outcomes of interest were measured using liquid chromatography-tandem mass spectrometry (LC-MS) for metabolomic identification, characterization and quantification and 16S amplicon sequencing for gut microbiome assessments. Linear regression models and weighted gene co-expression network analysis (WGCNA) were used to identify differences between groups and metabolomic sub-networks, respectively.

Study findings

The present study highlights the combined health benefits of a dietitian-led MedDiet along with physical activity compared to ad libitum MedDiet.

Overweight and obese participants in the IG cohort showed a mean weight reduction of 4.2 kg and 4.4 cm lower waist circumference than their CG counterparts. Body mass index (BMI) and total energy intake estimates of the IG group were 1.5 kg/m² and 113.9 kcal lower than controls, thus explaining the observed 0.1% reductions in glycated hemoglobin values ​​compared to controls.

Faecal metabolomic analysis revealed a total of 532 faecal metabolites, four of which were significantly different between IG and CG after one year. These four metabolites included 4,7,10,13,16-eicosapentaenoic acid (DPA) and adrenic acid, both of which decreased after the intervention, as well as oleic acid and 3-methyl-adipic acid (3-MAA) , both of which increased after the intervention. While preliminary analyzes suggested an additional 56 metabolites of interest, these were non-significant after false discovery rate (FDR) corrections.

Network analyzes clustered the 532 identified metabolites into 16 subnetworks ranging in size from Grey60 to brown. The Black, Midnight Blue, Pink, and Salmon subnetworks differed significantly between the IG and CG cohorts after one year of the study.

The Black sub-network contained ceramides and sphingosines, while the Midnight blue sub-network consisted of purines. Metabolites of the Pink subnetwork included fatty acids and carnitines, while the Salmon network included bile acids.

Compared to CG, IG showed reduced levels of the Black, Midnight Blue, and Pink subnetworks. In comparison, the IG showed increased levels of the Salmon subnetwork compared to the CG.

Gut microbial analysis determined that the IG Shannon and Chao1 alpha diversity indices were significantly higher than the CG indices by the end of the study, with the top two principal coordinate analysis (PCoA) axes explaining 36% of the observed differences.

The Eubacterium hallii The group showed a significant reduction in population size in the IG compared to the CG. Reduced abundance Dorea was also observed but to a lesser extent than in Eubacterium hallii club.

conclusions

The present lifestyle intervention-based clinical trial highlights the benefits of strict dietary supervision and physical activity for at-risk overweight and obese individuals, even compared to equal-risk individuals consuming a similarly healthy diet. The MedDiet reduced energy and physical activity intervention in the IG, compared to a ad libitum The MedDiet for CG significantly reduced weight measurements, including waist circumference and BMI.

Even with similar healthy dietary patterns, high intensity of dietary intervention and weight loss intervention components such as caloric restriction and physical activity could have significant benefits on CVD risk factors, possibly through modification of microbiota and stool metabolism. Public health policies and interventions can be tailored to individual microbiome profiles, enabling more precise and effective strategies for the prevention and management of cardiometabolic diseases.”