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This food ingredient can damage your DNA

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By David Liu, PHD

Thursday July 12, 2012 (foodconsumer.org) -- Nanoparticles like titanium oxide, iron oxide, zinc oxide, and  silicon dioxide - which are commonly used in processed food, dietary supplements, cosmetics and personal care products may actually damage cells and DNA potentially leading to serious health conditions.

One study published in the Oct 2011 issue of  Toxicology in Vitro found synthetic amorphous silica nanoparticles or otherwise known as silica and sillicon dioxide cause toxicological effects in cultured human hepatoma cells including causing morphological changes, reducing cell viability and cytomembrane integrity, increasing DNA damage, cell cycle distribution, and apoptosis.

Y. Li of Jilin University in Jilin China and colleagues, authors of the study, also found the nanoparticles cause cell injuries at least by increasing the levels of intracellular reactive oxygen species, which are highly reactive and damaging to cellular components like proteins and DNA.  DNA damages cause genetic mutations, which in turn can lead to the development of cancers.

The researchers reported the damages are size-dependent.  In the study, they exposed cells to four sizes of silica, 498 nm, 68, 43, and 19 nm for a period of 24 hours, and found silica dioxide nanoparticles in smaller sizes cause greater damages. 

The researchers cautioned although increased ROS should be one possible damage pathway, it may not be responsible for all the toxic effects produced by silica nanoparticles.

A similar study led by C. Gong of Zhengzhou University  in Zhengzhou, China and colleagues and published in the April 2012 issue of Molecular Biology Reports found similar results.

Cong et al. tested micro-sized silicon dioxide particles and nanoscaled particles in sizes 15, 30 and 100 nm in cultured human epidermal Keratinocyte cells and found the nanoparticles caused a series of toxic reactions, including reduced cell viability, altered cell morphology, increased reactive oxygen species, increased DNA damage and cell deaths or apoptosis.

The authors found toxic effects of silicon dioxide are not only size-dependent, but also concentration-dependent, meaning that nanoscaled particles and greater exposure to them can cause greater damages.

These two studies are not the only ones available to the public to reveal the potential harm that nanoparticles may cause to humans, animals and plants.  The problem with nanoparticles is that they do not dissolve in water.  The damage caused by one type of nanoparticles can also be caused by another. The cells injured by nanoparticles may eventually find a way to cause health problems.

A study released in 2009 in the journal Cancer Research showed titanium dioxide nanoparticles found in many household goods caused systemic genetic damage in mice. 

The comprehensive study led by researchers at UCLA's Jonsson Comprehensive Cancer Center found the TiO2 nanoparticles induced single- and double-strand DNA breaks and also damaged chromosome, promoted inflammation, all of which raise the risk of cancer.

These titanium dioxide nanoparticles after ingestion accumulate in various organs because the body can't get rid of them.

These nanoparticles are considered safe because they do not get into chemical reactions. But Robert Schiestl, a professor of pathology, radiation oncology and environmental health sciences at UCLA said these particles can cause genetic damages through surface interactions.

In the study, mice were fed drinking water with the titanium dioxide nanoparticles (the size of particles is so small that they can be dispersed in water and become invisible) and genetic damages were observed on the fifth day, equivalent to 1.6 years in humans.

Titanium dioxide is used in many products including paint, cosmetics, sunscreen and vitamins, toothpaste, food colorants, nutritional supplements and hundreds of other personal care products.

Schiestl said some portion of spontaneous cancers are caused by the exposure to titanium dioxide and suggested it would be prudent to limit intake of the nanoparticles.

The nanoparticles commonly used in foods including colorants and flavors, dietary supplements, and personal care products are silica (silicon dioxide), titanium dioxide, iron oxide and zinc oxide.  All types of nanoparticles should have the same toxic effects.

Those who are health-conscious may want to consider not using processed foods, dietary supplements, cosmetics and other personal care products, with an ingredient whose name ends with oxide or dioxide.

Health is one of your most important savings accounts.  Damage is like cash withdrawals from your account.  It may not result in bankruptcy immediately.  But when enough damage is done, your account gets a zero balance and your health collapses.

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