As a Woman The Gut–Hormone Connection: Fiber, Microbiome & Fertility | Will Bulsiewicz, MD
Jan 13, 2026
Will Bulsiewicz, MD, a gastroenterologist and bestselling author specializing in the gut microbiome, explains how gut health and inflammation influence hormones and fertility. He talks about fiber’s role, microbial short-chain fatty acids, fermented foods, and the estrobolome. Practical tips include plant variety, meal timing, and daily rhythms to support gut-driven hormonal balance.
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Gut Microbiome Acts Like A Hidden Organ
- The gut microbiome is a physiologically active organ that influences immunity, hormones, metabolism, mood, and gene expression.
- Will Bulsiewicz explains ~38 trillion microbes live in the intestines and 70% of the immune system resides in the gut lining, so gut health ripples systemwide.
Celiac Diagnosis After Years Of Dismissal
- Natalie Crawford shares her personal journey: celiac disease diagnosed after age 40 and years of being told symptoms were 'nervous gut.'
- She uses this to illustrate how women's gut symptoms often get dismissed and the need for better advocacy and testing.
Fiber Is Microbes' Fuel And Hormone Protector
- Fiber is the microbiome's primary fuel and is drastically lacking: ~95% of Americans are fiber deficient.
- Bacteria convert fiber into anti-inflammatory short-chain fatty acids (acetate, propionate, butyrate) that protect the gut barrier and influence fertility and hormones.
