IBS, Brain Fog, and Nervous System Overload

Brain fog is one of the most dismissed symptoms women with IBS experience. Yet research increasingly confirms that it’s not imagined—it’s neurological.

Studies show that people with IBS often have altered vagal tone, meaning the nervous system struggles to shift out of stress mode.⁴ When this happens, cognitive performance, memory, and mental clarity decline.

Low-grade inflammation plays a major role. Increased intestinal permeability (“leaky gut”) allows inflammatory compounds to circulate, which can interfere with brain signaling and neurotransmitter balance.⁵ This inflammatory signaling has been linked to fatigue, poor concentration, and mood changes.

Sleep disruption further worsens the picture. Poor digestion and blood sugar swings at night impair deep sleep stages that allow the brain to clear metabolic waste. Without this nightly reset, fog accumulates day after day.⁶

Functional medicine addresses brain fog by starting in the gut—reducing inflammation, improving digestion, restoring microbial balance, and supporting parasympathetic (calming) nervous system activity.

When the nervous system feels safe, the brain can think clearly again.

Accompanying article:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6469458/