A new research study conducted by the students and faculty at Binghamton University, State University at New York, has revealed that food packaging could be negatively affecting the way in which our digestive tract operates. Zinc Oxide (ZnO) nanoparticles at doses that are relevant to what might be normally eaten in a meal or in a day, change the way our intestines absorb nutrients or your intestinal cell gene and protein expression.
ZnO nanoparticles are present in the lining of certain canned goods for their antimicrobial properties and to help prevent staining of sulfur-producing foods. In this study, canned tuna, corn, asparagus and chicken were studied using mass spectrometry to estimate how many particles might be transferred to the food. The findings revealed the food contained 100 times the daily dietary allowance of zinc. The researchers then looked at the effect the particles had on the digestive tract.
The researchers looked at how an animal model (chickens) respond to nanoparticle ingestion. The cell culture results are similar to results found in animals and that the gut microbial populations are affected. The effects of nanoparticles on intestinal cells have been looked at before, but the research tended to work with really high doses and looked for obvious toxicity like cell death. The current study looked at cell function which is a more subtle effect and looked at nonparticle doses which are closer to what might people might really be exposed to.
The nanoparticles tend to settle onto the cells representing the gastrointestinal tract and cause loss or remodeling of the microvilli which are tiny projections on the surface of the intestinal absorptive cells that assist in increasing the surface area available for absorption. Loss of surface area tends to result in a decrease in nutrient absorption. Also, some of the nanoparticles cause pro-inflammatory signaling at high doses which can increase the permeability of the intestinal model. An increase in intestinal permeability means that compounds that are not supposed to pass through into the bloodstream might be able to.
The researchers note that it is difficult to forecast what the long-term effects of nanoparticle ingestion are on human health, especially based on results from a cell culture model. The model does show that the nanoparticles do have effects on the in vitro model, and understanding their effect on the gut function is an important area of study for consumer safety. Future studies will focus on the food additive-gut microbiome interactions.
1. Fabiola Moreno-Olivas, Elad Tako, Gretchen J. Mahler. ZnO nanoparticles affect intestinal function in an in vitro model. Food & Function, 2018; 9 (3): 1475 DOI: 10.1039/C7FO02038D