Lactobacillus rhamnosus

Fighting heavy metals with yogurt

mother and baby

It’s been touted as a weight loss aide, a calcium-rich bone builder and a tasty dessert. And now, it turns out that spoonfuls of yogurt may deliver the best defense against heavy metals, just not your typical grocery store variety. Yogurt containing special probiotic bacteria has been shown to protect pregnant women and children against absorbing dangerous environmental toxins, researchers have found.

Funded by the Bill and Melinda Gates Foundation, the study by Canadian and Tanzanian researchers focused on the bacterium Lactobacillus rhamnosus, which has an affinity for binding heavy toxic metals. The research team believed that regular consumption of the yogurt strain would prevent the absorption of metals from their diets, and they set about to test their hypothesis.

A research team from the Canadian Centre for Human Microbiome and Probiotics, led by Dr. Gregor Reid, set up a network of community kitchens in Mwanza, Tanzania, which produced a yogurt with the special probiotic. Why Mwanza? Because it sits on the shores of Lake Victoria, which contains toxic metals, including mercury, and pesticides. Researchers gave the Lactobacillus rhamnosus yogurt to a group of pregnant women and a group of children, and measured the baseline and post-yogurt levels of toxic metals.

The pregnant women, all of whom had consumed regularly quantities of the special yogurt, showed that the probiotic provided a significant protective effect against mercury and arsenic. The finding is important because "reduction in these compounds in the mothers could presumably decrease negative developmental effects in their fetus and newborns," according to Dr. Reid.

The results obtained from the children in the study showed benefits and lower toxin levels, but the sample size and duration of treatment did not allow statistical significance.

For the research team, it was very rewarding to learn the potential of basic foodstuffs to provide preventative protection for pregnant women worldwide. They are currently researching lactobacilli with higher and even more specific mechanisms of sequestering mercury.

Wikipedia notes that the use of L. rhamnosus for probiotic therapy has been linked with very rare cases of sepsis in certain risk groups, primarily infants or individuals with an immunodeficiency. Ingestion of L. rhamnosus is, nevertheless, considered to be safe, and data from Finland demonstrate that recent increases in the consumption of L. rhamnosus have not been accompanied by an increase in Lactobacillus bacteraemia cases.

mBio is an open access online journal published by the American Society for Microbiology to make microbiology research broadly accessible. The focus of the journal is on rapid publication of cutting-edge research spanning the entire spectrum of microbiology and related fields. It can be found online at

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(Based on materials obtained from the AAAS (Access original article >>)

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