Stress, Microbiota, and Diets: When Bacteria dance to the rhythm of Calories!

Metabolic and psychological disorders, such as stress and obesity, share complex biological mechanisms regulated by the gut-brain axis. Chronic stress disrupts this balance by altering gut microbiota and reducing the production of key molecules like short-chain fatty acids (SCFAs), which exacerbates inflammation and stress responses.

Low-calorie diets present a promising opportunity to restore this balance by modulating the microbiota and improving stress management. However, their effects on bacterial diversity remain ambiguous. This study investigates the combined impact of caloric restriction and a clinical psychological intervention (CPI) on gut microbiota and mental well-being in overweight or stressed women.

Fewer Calories, Less Stress: Could the Microbiota Hold the Key?

In this study, 41 women were randomly divided into two dietary groups:

• Very Low-Calorie Diet (VLCD)
• F.X. Mayr Diet (FXM), including magnesium supplementation.

Each group was further split into those receiving or not receiving CPI. Blood and stool samples were analyzed before and after two weeks of caloric restriction.

Key findings from the study include:

• Microbial Diversity

Caloric restriction led to a reduction in alpha diversity, indicating a decrease in bacterial species richness. Beta diversity changes, reflecting differences between individuals, were influenced by several factors such as diet type, age, and body mass index.

Taxonomic Changes
Some SCFA-producing bacterial genera, such as Faecalibacterium and Roseburia, significantly decreased following caloric restriction. The FXM diet uniquely increased Oscillibacter, a bacterium associated with psychological improvements, suggesting specific beneficial effects.

• Mental Well-Being
  

Significant improvements in perceived stress scores and other psychological indices were observed, particularly in the FXM group. Conversely, CPI had a negligible effect on the microbiota compared to caloric restriction, reaffirming that diet plays a pivotal role in modulating the microbiota and mental well-being.

Oscillibacter, Faecalibacterium & Co.: In Search of the Perfect Menu for Mind and Body

This study highlights the potential of the FXM diet to favorably modulate gut microbiota, enhance mental well-being, and reduce stress. However, the loss of beneficial bacteria such as Faecalibacterium and Subdoligranulum raises concerns about the long-term effects of low-calorie diets.

These findings encourage the development of targeted dietary approaches, combined with in-depth analysis of specific microbes, to create innovative strategies for optimizing mental and metabolic health.