Mercury is a toxic metal whose compounds can be found in food such as seafood products or mushrooms. The element’s toxicity depends on its chemical form and bioavailability, and it can be influenced by the presence of food components, dietary supplements, or probiotics (beneficial microorganisms).

Vicenta Devesa, Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Valencia, Spain, and colleagues have studied the effect of different strains of Baker’s or Brewer’s yeast, Saccharomyces cerevisiae, on the bioavailability of mercury. The team cultivated eight different strains of yeast and combined them with solutions of inorganic Hg(II) or methylmercury. After incubation, the mercury content of both the cells and the solution was analyzed. Additionally, the researchers used an in vitro model for digestion to evaluate the bioavailability of mercury from seafood (swordfish and tuna) and mushrooms (porcini and Caesar’s mushroom).

The researchers found that yeast can retain mercury and remove up to 89 % of Hg(II) and 83 % of methylmercury from the tested aqueous solutions. Yeast also effectively lowered the bioavailability of mercury from mushrooms (by 77 %), but not from seafood. The team attributes this to the formation of soluble mercury–cysteine or mercury–polypeptide complexes during the digestion of seafood, which could prevent the retention of mercury inside the yeast cells.

• The Use of Saccharomyces cerevisiae to Reduce the Bioaccessibility of Mercury from Food,
  Carlos Jadán-Piedra, Marta Baquedano, Sergi Puig, Dinoraz Velez, Vicenta Devesa,
  J. Agric. Food Chem. 2017.
  DOI: 10.1021/acs.jafc.7b00285