How Diet and the Microbiome Affect Metabolism with Vanessa Ridaura – EP013

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Ever wonder who might win in a ‘battle of the microbiota’? Would the obese microbiota take over? Or might the lean microbiota prevail? Perhaps you’re not even sure what the microbiome refers to or how it impacts your health. Today’s guest will explain the science behind the bacteria in your gut, and how the microbiome works in conjunction with your diet to affect metabolism.




Vanessa Ridaura received her Ph.D. in Molecular Genetics and Genomics from Washington University in St. Louis, specializing in the effect of the microbiome on human health and disease, with a specific focus on the contributions of human gut microbiome to metabolism and obesity. Vanessa went on to become a Post-Doctoral Fellow at the National Institutes of Health in Bethesda, Maryland, studying the microbiome of the skin and its impact on health.

Today Vanessa explains the details of her research, discussing how diet and the microbiome work together to influence metabolism. Listen to understand the fundamental science of the microbiota, how diet effects the bacteria in your gut, and current developments in microbiome science.

Topics Covered

[1:11] Vanessa’s research regarding gut microbiota’s effect on metabolism

  • Microbiota refers to microbes living in epithelial cavities, protect from pathogenic bacteria
  • Germ-free, genetically identical mice colonized with microbiota from twins discordant for obesity
  • On same diet, mice with lean microbiota lost weight while obese gained
  • Given unhealthy human diet of saturated fats, mice gained regardless of microbiota
  • Conclude that components of healthy diet feed beneficial bacteria in gut while unhealthy destroys it
[5:58] The ‘battle of microbiota’

  • Mice eat each other’s feces
  • Hypothesized that obese microbiota would take over
  • Observed opposite in mice on healthy diet (lean microbiota took over)
  • Not the case in context of mice on unhealthy diet
  • Good bacteria + good diet = higher metabolism
[9:13] The first fecal transplant proven to work

  • diff develops when antibiotics kill healthy microbiota
  • Fecal microbiome transplants give patient healthy, diverse microbiome to displace C. diff
[10:28] What Vanessa learned from her research that has influenced her own diet

  • Little things influence body as whole
  • Simple sugars make easier for bacteria associated with obesity to spread
  • Limit high fat, eat more vegetables
  • No ‘magic bullet’ (must have healthy diet along with lean microbiome)
[12:35] The connection between microbiome and type 2 diabetes

  • Healthy animals receiving obese microbiome had increased branched-chain amino acids
  • Early biomarker for type 2 diabetes
  • Develop within two weeks
[13:55] Vanessa’s study of the skin microbiome

  • Unlike other microbiome, single species of bacteria can colonize locally on skin and affect immunity
  • Certain species of bacteria increased inflammation (psoriasis, atopic dermatitis)
  • Diet high in saturated fats exacerbated skin disease
[17:17] Scientific understanding of the different microbiomes

  • Studied gut for 15-20 years, further ahead
  • Study of skin much newer (only in last five years)
  • Technological advances allow cheap sequencing, mass spectrometry
[18:18] How the microbiome of the mouth affects health

  • Periodontitis in pregnant women can cause low infant weight, premature birth
  • Periodontitis also associated with atherosclerosis
[19:16] The future of microbiome research

  • Continued work with C. diff
  • Cancer studies (how gut microbiome influences cancer therapy)
  • 10-15 years before see strong intervention studies

Learn More About Vanessa Ridaura


New York Times Article

Resources Mentioned

“Cultured Gut Microbiota from Twins Discordant for Obesity Modulate Adiposity and Metabolic Phenotypes in Mice” from Science




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