Gut Bacteria's Role in Obesity Varies by Gender, Says Research

Recent research suggests that gut bacteria play a crucial role in the onset and progression of obesity, with notable distinctions between men and women, potentially impacting the metabolism of various nutrients and the presence of bioactive molecules in the gut that influence metabolic disease development. The findings were published in the 'European Association for the Study of Obesity' journal.

The gut microbiota comprises a complex community of microorganisms, including bacteria, viruses, fungi, and protozoa, residing in the gastrointestinal tract. Disruptions in this community, known as dysbiosis, significantly affect metabolic health and influence the risk of certain diseases, including obesity. However, identifying which bacterial species contribute to obesity and their impact on metabolic health remains unclear.

To delve deeper, researchers analyzed metagenomic and metabolomic data from a Spanish population to understand how these microorganisms contribute to obesity development. They focused on the faecal metabolome, which encompasses the diverse collection of metabolites produced by gut bacteria during food metabolism and impacting health.

The study included 361 adult volunteers (251 women and 110 men) from the Spanish Obekit study, a randomized trial investigating the relationship between genetic variants and the response to a hypocaloric diet. Researchers ensured that participants in the LOW and HIGH obesity index groups were matched for sex and age.

Genetic microbiota profiling identified the types, composition, diversity, and relative abundance of bacteria present in the participants' stool samples. Analysis revealed that individuals with a HIGH obesity index had significantly lower levels of Christensenella minuta, a bacterium associated with leanness and health.

In men, greater abundance of Parabacteroides helcogenes and Campylobacter canadensis species correlated strongly with higher BMI, fat mass, and waist circumference. Conversely, in women, greater abundance of Prevotella micans, Prevotella brevis, and Prevotella sacharolitica species was highly predictive of higher BMI, fat mass, and waist circumference, but not in men.

Untargeted metabolomics analyses showed variation in the abundance of certain metabolites, particularly higher levels of bioactive lipids such as phospholipids and sphingolipids, in participants with a HIGH obesity index. These lipids are implicated in metabolic disease development and insulin sensitivity modulation.

Lead author Dr. Paula Aranaz from the Centre for Nutrition Research at the University of Navarra in Spain highlighted the study's significance, emphasizing the role of distinct bacterial groups in obesity development with notable sex differences. She stressed the need for tailored interventions targeting gut microbiota to prevent obesity, particularly considering the differences between men and women. Further research is required to pinpoint the timing for effective interventions.

Dr. Aranaz concluded by advocating for the combined use of metagenomics and metabolomics to study metabolic disease mechanisms with confidence. She suggested that this comprehensive approach could aid in developing precision nutrition strategies for weight loss by modulating specific bacterial strains or bioactive molecule levels.

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