Blocking toxins with bacteria: Probiotics may fight off mercury while increasing nutrient absorption

19 Jun 2023 --- Probiotics can potentially block mercury absorption in the gut, according to researchers in Pennsylvania, US. They say that with the help of probiotics, the human gut could be harnessed to block the absorption of toxic metals while supporting the nutritional intake function of iron and other minerals.

Daniela Betancurt-Anzola, the study’s lead author, explains that methylmercury, a neurotoxin, is “particularly worrisome.”

She details that it has various toxic effects and is detrimental to neurological development during pregnancy and childhood, particularly in communities heavily reliant on fish-based diets. Most methylmercury exposure is through fish or shellfish, but it can also be found in other foods. 

Probiotics to the rescue?
The research team started analyzing thousands of genomes from gut bacteria and focused on genetic determinants that interact with metals in the gut. Betancurt-Anzola explains that many genes are resistant to metals, and therefore, the group focused on those that can convert mercury to be less toxic with the help of bacteria.

They used the findings to create a probiotic that specifically can detoxify harmful mercury commonly found in the human diet, using genes that are known for their high resistance to methylmercury Bacillus megaterium and put it into strains of the genus of lactic acid bacteria Lacticaseibacillus.

“It’s a perfect probiotic for this because we have previously shown it works in humans and now we are engineering it to make it even better,” Betancurt-Anzola underscores.

“It is inside the gut, it grabs the methylmercury and then it goes out.”

The researchers created a probiotic that can detoxify harmful mercury commonly found in the human diet.In the future, the researchers will investigate other metals. The “ultimate goal” is to develop interventions to reduce levels of mercury and other dangerous metals while boosting the body’s ability to absorb what it needs.

Betancurt-Anzola emphasizes that they are interested in studying how the entire microbial community reacts to different metals. 

Action on mercury
Last year, the US Food and Drug Administration launched an independent study to investigate the role of seafood consumption in child growth. 

The agency stressed that seafood contains many critical nutrients needed during pregnancy, breastfeeding and early childhood for proper development of the brain, immune system and spinal cord. Meanwhile, it is also the primary dietary source of mercury.

“It accumulates in living things, plants and fish,” says Betancurt-Anzola. “We eat those things, and it accumulates in us.”

Many popular baby foods on the market have also been shown to contain chemical toxins, a US-based study recently found high levels of arsenic, lead, mercury and cadmium.

The researchers of the baby food study stressed that when toxic elements are ingested with food or water, they get absorbed in the gastrointestinal tract, which allows them to enter the bloodstream. This is concerning, as the toxic elements can be found in infant formula, breast milk, water, fruits, vegetables and homemade and commercial purees.

Edited by Beatrice Wihlander