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quarta-feira, 20 de maio de 2015

Nanoparticles & Food: Vitamins

by Ese Ehimiaghe
For decades, Americans have spent billions of dollars on vitamin and mineral supplements,1and despite concerns about effectiveness and safety,2 a 2013 Gallup poll found that half of Americans take a supplement regularly.3 As nanoparticles have made their way into medicine and pharmaceuticals, they have also moved  into the health supplement industry. In this post, I will explore how nanoparticles are being used in vitamins and supplements.
Vitamins!                        image source
People take vitamins for many different reasons but most often to compensate for compounds whose daily dose they typically cannot meet. While these supplements are supposed to provide the vitamins and nutrients people need, a number of studies have found that some of them can be futile or even harmful.2 Anti-supplement proponents argue that the content of the pills often cannot be absorbed by the body and used for its desired purpose. In the end the compound of interest (in the pill) is filtered through the renal system and ends up in urine.
This concern is one of the reasons nanoparticles are advantageous for the pharmaceutical industry. As mentioned in previous posts (such as here and here), nanoparticles’ shapes can be modified, which means you can make nanotubes or spheres. Those special shapes can carry vitamins and minerals that are often difficult for the body to absorb through traditional mechanisms. The nanoparticles can carry the desired compound through the body so that it gets to its proper location and can be absorbed instead of secreted. This is called increasing the bio-accessibility of the compound.4
In spite of all the good that can come from using nanoparticles in this way there is a certain amount of caution and wariness surround nanoparticles. This is a sensitive topic for two main reasons. First, nanoparticles cannot be seen or tasted in vitamins or supplements. Second,companies in this country are not mandated to label their products that contain nanoparticles. This lack of knowledge makes it difficult for people to take ownership of what goes into their bodies, which makes a lot of people uneasy.5 The lack of openness about nanoparticles also makes people distrustful of the food and drug industry and their motives.
The second major concern with nanoparticles in the food industry relates to the fact that not enough research has been done that looks at how nanoparticles react inside the human body and in the environment. As mentioned above, many people take vitamins and supplements to make up for things they cannot get from their diet or environment. This often means prolonged use of the supplements. However, this leads to important questions about potential use of nanoparticles, such as: Do they change over time? Do they bind to organ lining? Do they react with metals and other chemical species present in the body?
No matter how much we increase the efficiency of supplemental pills, there is still the possibility that the body will excrete some of the materials. This means that we must also ask questions about the environment, like what will happen when the excreted nanoparticles enter our water system? Will the nanoparticles be filtered out during water processing? Will they negatively affect the wildlife and ecosystems around us? How can we track the passage of nanoparticles through different sites and systems?
While there are definitely potential benefits of using nanoparticles in food supplements, there are still many unanswered questions. These are some of the questions that drive the scientific community – including the Center for Sustainable Nanotechnology – to continue our research.

REFERENCES
  1. National Institutes of Health (2013) “Multivitamin/Mineral Supplements” fact sheet for health professionals.
  2. Offit, P. (2013) The Vitamin Myth: Why We Think We Need SupplementsThe Atlantic.
  3. Swift, A. (2013) Half of Americans Take Vitamins RegularlyGallup. 
  4. Liu, Q., Zhang, J., Sun, W., Xie, Q. R., Xia, W., & Gu, H. (2012). Delivering hydrophilic and hydrophobic chemotherapeutics simultaneously by magnetic mesoporous silica nanoparticles to inhibit cancer cells. International Journal of Nanomedicine, 7, 999-1013. doi: 10.2147/IJN.S28088
  5. Kessler, R. (2011). Engineered Nanoparticles in Consumer Products: Understanding a New Ingredient. Environmental Health Perspectives, 119(3), A120-A125. doi:10.1289/ehp.119-a120