Impact pattern of heavy metals on gut microbiota in the polluted city of Tehran.

BACKGROUND AND

OBJECTIVES

This article focuses on the effects of six heavy metals on gut microbiota, which plays a key role in human health. Gut microbiota plays a key role in metabolism, immunity, and maintaining homeostasis. Heavy metals can affect microbiota composition and function, with health consequences. Consuming large amounts of heavy metals may have harmful impacts, including alteration in microbial composition and bacterial population changes.

MATERIALS AND

METHODS

Six heavy metals-cadmium, chromium (toxic metals), copper, zinc, iron, and selenium (beneficial trace elements)-were detected in peripheral blood, serum, or urine, while feces were used for 16S rRNA sequencing. Serum samples from 100 volunteers from Tehran (polluted area) and Firoozkooh (clean city) were collected. Subjects were analyzed for the presence of Escherichia coli, Bacteroides fragilis, Bifidobacterium longum, Lactobacillus acidophilus, Clostridium clostridioforme, Faecalibacterium prausnitzii and Akkermansia muciniphila to evaluate correlations between metals and microbial composition using biochemical, microbial, and molecular methods.

RESULTS

Escherichia coli and Bifidobacterium longum levels in polluted areas were not significantly different from those in unpolluted areas. Bacteroides fragilis in polluted areas was significantly higher compared to non-polluted locations. Clostridium, Akkermansia, Faecalibacterium, and Lactobacillus acidophilus were significantly lower in polluted areas, amounting to less than half the levels in clean areas. Heavy metal concentrations showed no gender differences in either location.

CONCLUSION

Some heavy metals change intestinal microbiota composition and metabolic profiles, potentially resulting in metabolic diseases and environmental risks.