Stanford researchers reveal that consuming 6+ daily servings of fermented foods significantly reduces inflammation and increases gut microbial diversity, according to a new Huberman Lab episode featuring microbiologist Dr. Justin Sonnenburg.
The finding challenges conventional gut health advice that prioritizes fibre intake alone, showing that fermented foods containing live microbes produce measurable reductions in inflammatory markers including Interleukin 6 a key indicator of chronic disease risk.
Key Takeaways
• High fermented food consumption reduces inflammation.
Study participants who ate 6+ servings daily of fermented foods (yogurt, kefir, kimchi) showed increased gut microbial diversity and decreased inflammatory markers including Interleukin 6.
• Gut restoration requires two components:
Access to the right microbes and the proper diet to nourish them. Simply adding fibre or fermented foods may not work without first establishing the right microbial community.
• Avoid processed foods with specific additives.
Artificial sweeteners negatively impact the gut microbiome and can lead to metabolic syndrome. Emulsifiers disrupt the protective mucous layer in the gut barrier.
• Fibre intake effectiveness depends on your existing microbiome.
While 40+ grams daily of plant-based fibre is the goal, severely depleted microbiomes may lack the capacity to degrade fibre, making the intervention ineffective without microbial restoration first.
• Over-the-counter probiotics require scrutiny.
Due to market deregulation, consumers should only use products with independent validation and specific clinical study support.
What They Recommend
Sonnenburg presented research showing that participants consumed 6+ daily servings of unsweetened fermented foods containing live microbes. The study focused on naturally fermented options like yogurt, kefir, and kimchi, specifically avoiding sweetened varieties that introduce detrimental sugars.
The fermented food protocol resulted in measurable increases in gut microbiota diversity and stepwise reductions in multiple inflammatory markers. This indicates a dampening of systemic inflammation associated with chronic disease.
On fiber, the recommendation is 40+ grams daily from diverse plant sources including legumes, whole grains, and vegetables. However, Sonnenburg cautioned that individuals with severely depleted microbiomes common in industrialized populations, may have lost necessary fibre-degrading microbes over generations.
Both experts strongly advised against processed foods, particularly those containing artificial sweeteners and emulsifiers. Sonnenburg compared gut cleanses and fasting without a repopulation strategy to “playing Russian roulette” with your microbial community.
On probiotics, the experts recommended skepticism toward over-the-counter options due to lack of regulation. Consumers should seek products independently validated by specific, well-designed clinical studies.
Sonnenburg’s core insight: “How do we establish new stable states, how do we get back to a healthy microbiota if we have taken a lot of antibiotics or have a deteriorated microbiota it’s probably a combination of having access to the right microbes and nourishing those microbes with the proper diet.”
About the Experts
Dr. Justin Sonnenburg is Associate Professor of Microbiology and Immunology at Stanford University School of Medicine, focusing on how diet shapes the gut microbiome. Stanford Medicine
Dr. Andrew Huberman is Professor of Neurobiology at Stanford and host of the Huberman Lab podcast. hubermanlab.com
Watch the full episode: Essentials: How to Build, Maintain & Repair Gut Health