Zinc oxide nanoparticles are added to many different types of food packaging. A new study finds that these minute particles might disrupt the way our intestines absorb nutrients.
Nanoparticles are between 1 and 100 nanometers in diameter. To put that into perspective, a human hair is around 75,000 nanometers across, and a red blood cell is roughly 7,000 nanometers across.
Nanoparticles have a relatively large surface area, which makes them more chemically reactive. This increased reactivity gives them unique properties that are utilized by the manufacturers of a vast range of products, including paints, cosmetics, windows, sunscreens, fabrics, and cars.
As nanoparticles are used ever more liberally, some scientists are becoming increasingly concerned about their potential impact on human health. It is very easy for nanoparticles to enter our bodies. They are small enough to pass through cell membranes, potentially disrupting their activity. However, little is known about how they might interfere with biological processes.
Looking to investigate these interactions, researchers from Binghamton University in New York looked at zinc oxide (ZnO) nanoparticles in food packaging in particular. ZnO nanoparticles are included in the packaging of certain food items, such as corn, chicken, tuna, and asparagus, because they have antimicrobial properties. Also, when sulfur-producing foods come in contact with a tin can, it produces a black discoloration; ZnO prevents this reaction, keeping the food fresh-looking.
First, using mass spectrometry, they assessed how much ZnO could realistically be transferred from the packaging into the food. The food was found to contain “100 times the daily dietary allowance of zinc.”
Next they looked at the influence ZnO nanoparticles might have on our intestines. Their results are published in the journal Food and Function. Gretchen Mahler, associate professor of bioengineering, who led the study explains, “We found that [ZnO] nanoparticles at doses that are relevant to what you might normally eat in a meal or a day can change the way that your intestine absorbs nutrients.”
The particles were observed settling on structures on microvilli, potentially reducing the ability of the lining to take on nutrients. “This loss of surface area,” explains Mahler, “tends to result in a decrease in nutrient absorption. “Some of the nanoparticles also cause pro-inflammatory signaling at high doses, and this can increase the permeability of the intestinal model,” she adds.
The authors are quick to note that this study was conducted in the laboratory, rather than in an animal. Thus, at this stage, the findings cannot be extrapolated. To fully understand the long-term health implications, much more research will be needed.
You and I can easily extrapolate from this early study. She is describing malabsorption and leaky gut. This are the two most common digestive issues I see in my practice. Going further, zinc has been implicated in Alzheimer’s when unbound from the nervous system.
The Bottom Line:
Add food packaging to the list of things to avoid at the grocery store. Especially for the items noted in this study. As I continue to research nanoparticles, I’ll try to come up with some nutritional countermeasures in an attempt to reverse some of the potential damage.
Source: April 12, 2018 National Institutes of Health