Can arsenic in drinking water damage your gut bacteria and cause inflammation?

What's actually in it

Arsenic is a naturally occurring element that contaminates groundwater in many parts of the world. It also concentrates in rice, which absorbs it from paddy water, and shows up in apple juice, chicken, and some seafood. Private wells are especially at risk since they aren't always tested for arsenic.

Low-level arsenic exposure from food and water often goes unnoticed because it doesn't cause immediate symptoms. But it accumulates in tissues over time.

What the research says

A 2026 study in Ecotoxicol Environ Saf showed that subchronic (months-long) arsenic exposure caused gut microbiota dysbiosis and intestinal inflammation. The damage followed a specific molecular path.

Arsenic activated the NF-kB signaling pathway, a master switch for inflammation in the gut. This led to increased production of pro-inflammatory cytokines that damaged the intestinal lining. At the same time, arsenic wiped out beneficial bacteria like Lactobacillus and Bifidobacterium, replacing them with bacteria linked to inflammation and disease.

The weakened gut barrier allowed bacteria and toxins to leak into the bloodstream, creating inflammation far beyond the gut. The study noted that these effects happened at environmentally relevant doses, not extreme levels.

If you use well water, get it tested for arsenic. For rice, rinse it thoroughly and cook with extra water (then drain it), which removes up to 60% of arsenic. A home water filter rated for arsenic removal adds another layer of protection.