What types of gut bacteria are more commonly found in individuals with normal Body Mass Index (BMI)?

Gut Bacteria Associated with Normal BMI

Individuals with normal BMI typically have higher abundance of Bifidobacterium, Lactobacillus, Blautia, Anaerotruncus, Parabacteroides, and Alistipes in their gut microbiota compared to overweight or obese individuals. 1, 2

Key Bacterial Differences Between Normal BMI and Overweight/Obese Individuals

Beneficial Bacteria More Abundant in Normal BMI

• Bifidobacterium: Associated with higher gut microbiota diversity and robustness 1
• Lactobacillus: Often found alongside Bifidobacterium and positively correlated with butyrate-producing bacteria 1
• Blautia and Anaerotruncus: Significantly enriched in lean individuals (LDA score ≥3) 2
• Alistipes and Parabacteroides: Negatively correlated with BMI 2

Bacterial Composition Differences

• Bacteroidetes to Firmicutes Ratio: While historically thought to be important, recent studies show mixed results regarding this ratio 2, 3
• Microbial Diversity: Higher gut microbiota diversity is consistently associated with normal BMI 2
• Butyrate Producers: Normal BMI individuals tend to have more bacteria that produce short-chain fatty acids, particularly butyrate 4

Factors Influencing Beneficial Gut Bacteria

Dietary Factors

• Dietary Fiber: Promotes growth of beneficial bacteria like Bacteroides stercoris, which is associated with lower blood pressure 5
• Whole Grains: Support Bifidobacterium growth, which is important for gut microbiota robustness 1
• Fermented Foods: Enhance populations of Lactobacillus and other beneficial bacteria 4
• Mediterranean/Nordic Diet Patterns: Associated with beneficial microbiota profiles and normal BMI 5

Lifestyle Factors

• Physical Activity: Associated with higher microbial diversity and increased abundance of Akkermansia muciniphilia 4
• Cardiorespiratory Fitness: Linked to beneficial changes in gut microbiota composition 4

Clinical Implications

Microbiome as a Therapeutic Target

• The gut microbiome represents a potential therapeutic target for obesity management 4
• Probiotics containing Bifidobacterium and Lactobacillus may help support a healthier microbiome profile 4
• Dietary interventions that increase fiber intake can promote beneficial bacteria 4

Potential Biomarkers

• Blautia and Anaerotruncus could serve as potential biomarkers for a healthy metabolic state 2
• Decreased abundance of Bifidobacterium may indicate metabolic dysregulation 1

Caveats and Considerations

• Individual Variation: Significant interpersonal variability exists in microbiome composition and response to dietary interventions 4
• Geographic and Cultural Differences: Microbiome composition varies across populations and is influenced by regional dietary patterns 2, 6
• Causality Not Established: While associations between specific bacteria and BMI exist, causality has not been definitively established 5
• Confounding Factors: Age, sex, medications, and other health conditions can influence microbiome composition 4

The evidence strongly suggests that promoting a diverse gut microbiome with specific beneficial bacteria through diet and lifestyle interventions may contribute to maintaining a healthy BMI and metabolic health.