The Lost Microbe?
The “Lost Microbe” L. reuteri: What Science Says About the 96% Claim and Reported Benefits An estimated 96% of people in modern industrialized societies no longer carry detectable levels of Limosilactobacillus reuteri (formerly Lactobacillus reuteri ), a bacterium once common in the human gut. Proponents, including Dr. Eric Berg (a chiropractor, not an MD), link its disappearance—driven by antibiotics, highly processed diets, sanitation, and reduced breastfeeding—to higher rates of anxiety, depression, poorer sleep, accelerated physical aging, and related issues. Restoring it, they say, has been associated with increased muscle mass, thicker hair, younger-looking skin, improved libido, lower cortisol, and better mood. The core observation about declining prevalence is real. Multiple lines of evidence show L. reuteri is now rare in Western populations (often estimated around 4–10% or lower with detectable levels in fecal samples) while remaining more common in some non-industriali...