Fermented Foods As a Strategy to Reduce Heavy Metal Toxicity in Humans: Mechanistic Insights and Emerging Evidence

Background Chronic exposure to heavy metals remains a major global health concern driven largely by dietary intake from contaminated foods and drinking water. Current mitigation strategies based on source control and pharmacological interventions such as chelation therapy are often impractical for widespread, low-level exposure, highlighting the need for complementary long-term strategies, including dietary interventions that operate within the gastrointestinal tract. Scope and approach Fermented foods may be relevant in this context, as they represent complex biological systems composed of microorganisms, fermentation-derived metabolites, and structurally transformed food matrices that collectively influence metal bioaccessibility and adsorption in the gut, with downstream effects on systemic bioaccumulation and host responses. In addition, recent clinical studies have shown that fermented foods can modulate the gut microbiota and immune system both of which play a role in mitigating heavy metal burden. Key findings and conclusions Experimental evidence from in vitro and animal studies suggests that fermented foods or their associated microorganisms can reduce intestinal metal absorption, enhance fecal excretion of metals, and attenuate oxidative stress and tissue damage associated with metal exposure. Emerging human evidence suggests potential benefits; however, the evidence is very limited. In this review, we outline the mechanisms by which fermented foods may mitigate heavy-metal toxicity and propose that fermented foods may represent accessible, diet-based strategies to mitigate the toxic effects of chronic metal exposure. However, further clinical research is needed to establish efficacy and to identify optimal food matrices, microbial characteristics, and intake levels.