Consuming High Levels of Zinc Could Make You Susceptible to C. Difficile

According to newly published research in the journal of Nature Medicine, high levels of zinc changes microbiota in the gut decreasing resistance to infections from Clostridium difficile. The study demonstrated susceptibility to C. difficile at lower antibiotic doses in mice models that were fed high-zinc diets. Furthermore, for those mice, the infection was more severe and more often, lethal.

Zinc supplements have been popular with consumers since a study, published in 1984, suggested lozenges containing zinc gluconate shorten the duration of common colds by preventing the virus from multiplying. This lead to the idea that ingesting zinc regularly would prevent illness and reduce the need to take antibiotics.

However, these latest findings suggest that consumers may need to reconsider using cold medicines with high concentrations of zinc. Eric Skaar, PhD, MPH, professor of pathology, microbiology and immunology at Vanderbilt University and one of the authors of the study, said in a news release from Vanderbilt University, “Multivitamins and other supplements are really only needed by those with a particular nutritional deficit in their diet.”

Similar to the way antibiotics kill healthy organisms in the gut, diets high in zinc also change the gut microbiota, giving C. difficile the opportunity to take hold; this reduces the threshold antibiotics need to convert the gut into a microbial community that is sensitive to infection.

Infections from C. difficile have increased over the last decade. Although illnesses resulting from C. difficile are most commonly found in the hospital setting, infections are rising in facilities not typically associated with acute care, such as nursing and assisted living homes. Dr. Skaar and his colleagues believe that this research, “may also partially explain the increasing rates of C. difficile infection in people who haven’t been hospitalized or treated with antibiotics.”

The Centers for Disease Control and Prevention (CDC) estimate that half a million people were infected with C. difficile in 2011. Of those infections, approximately 29,000 people died within 30 days of their initial diagnosis.

For those most affected, older adults who take antibiotics and receive medical care, this research has many implications. Most notable is the discovery that some environmental factors, such as diet, can change the microbiome of an individual. More research is necessary to learn about additional factors that affect and change microbiomes, including the agricultural implications of using zinc supplements to induce the growth of livestock.

“It’s possible that zinc supplementation of livestock is leading to animals that are more susceptible to colonization with C. difficile, and that might be a way that C. difficile is then passed to people,” Dr. Skaar said.

Their investigation also showed that calprotectin—a zinc-binding protein—was critical in fighting C. difficile because it limits the availability of zinc during infections. Dr. Skaar and his colleagues hope these findings will lead to the development of successful therapeutic strategies; they are not alone. Recently, Contagion reported on a possible new treatment for the “superbug” C. difficile in several deworming medications. This Vanderbilt study could be another important step toward counteracting the burden C. difficile infections in the United States.