The increasing use of nanoparticles in personal care and food products poses health and environmental concerns. Nanoparticles, in fact, may exert toxic effects once they are released to the environment or following a direct exposure.

Paul Westerhoff and co-workers, Arizona State University, Tempe, AZ, United States, examined eight commercial dietary supplement drinks containing metallic nanoparticles that were claimed to improve human health. When the researchers exposed these nanoparticles to intestinal cells, they observed a reduction in the number of microvilli, cellular protrusions that absorb nutrients. Metallic-based nanoparticles might thus decrease the absorbing capacity of gut cells and, therefore, cause malabsorption syndromes or diarrhea. The scientists, moreover, demonstrated that, once discharged through the feces, metal-based nanoparticles are likely to enter the environment through water or wastewater treatment plants.

• Caution should be thus taken when consuming metal-based nanoparticles supplement drinks,
  Robert B. Reed, James J. Faust, Yu Yang, Kyle Doudrick, David G. Capco, Kiril Hristovski, Paul Westerhoff,
  ACS Sustainable Chem. Eng. 2014.
  DOI: 10.1021/sc500108m