A Series on Food Additives - Titanium Dioxide

So much to think about when it comes to food additives!

Recently, I have become very interested in the topic of food additives, as they have popped up in mainstream media, bringing attention to them regarding diet and how they affect our health.

Titanium dioxide (aka E 171) is one food additive that is widely used in food products, pharmaceuticals, and health and hygiene products. It is used mainly as a coloring agent and opacifying agent to improve the appearance and taste of processed foods. It is found in over 900 food products including pastries, sauces, icing, candies, beverages, and chewing gum.

It is estimated that dietary exposure to titanium dioxide may be as much as 1 to 4 micrograms per kilogram of body weight per day. Amounts consumed may be even higher in children than in adults due to dietary patterns.

Titanium dioxide is listed in the FDA Center for Food Safety and Applied Nutrition as Generally Recognized As Safe (GRAS), however, the European Food Safety Authority (EFSA) no longer endorses titanium dioxide as safe as a food additive. Current research suggests that nanoparticle (very small particle size) titanium dioxide is able to easily pass through cells in our bodies, possibly affecting our health.

So how does titanium dioxide affect our health? 

Recent concerns have been raised in regard to the capacity of titanium dioxide to act as a genotoxic substance, meaning it has the ability to cause DNA damage. This has led to suspicion that it is also a carcinogenic substance- possibly leading to cancer. In regards to gut health, some cell studies and animal studies have demonstrated possible negative health effects of titanium dioxide nanoparticles.

Possible ways titanium dioxide impacts gut health leading to dysbiosis:

- Alter gut microbiota composition

- Alter the activity of the microbiota

- Promote inflammation leading to compromised gut integrity (weakened gut barrier)

- Reduce immune response in hosts that already have inflammatory diseases such as colitis or colon cancer

Animal studies have identified that titanium dioxide might lead to compositional changes in the gut bacterial profile resulting in an offset of the firmicutes to bacteroidetes ratio, reduction of lactobacillus (good bacteria), and increase in proteobacteria (harmful bacteria). 

Beneficial gut bacteria like lactobacillus produce short chain fatty acids which are a critical component of metabolism in healthy individuals while proteobacteria have been shown to increase in individuals with inflammatory bowel diseases. This could lead one to speculate that titanium dioxide therefore might contribute to these issues.

As previously addressed, gut microbiota aids in gut integrity (keeping our gut strong). Several studies have identified that titanium dioxide can cross the gut epithelium (gut lining). This could be related to titanium dioxide exposure possibly aiding in a reduction of short-chain fatty acids, a decrease in goblet cells, and reduction in mucus production (all these are needed to keep the gut strong) leading to a weakened gut barrier.

Titanium dioxide is also linked to inflammation and reduced immune function. 

Cell studies have identified that after titanium dioxide exposure there was an increase in inflammatory markers such as interleukins and other pro-inflammatory cytokines as well as a decrease in T-reg cells which are known to reduce gut inflammation and prevent food allergy development.

Cell studies and animal studies are still working to understand how titanium dioxide specifically impacts human health but there is enough evidence to suggest risk with ingestion. With the high consumption of processed foods in the western diet and the increase in overall disease, it is important to identify the potentially harmful effects of food additives such as titanium dioxide and work to reduce exposure to these chemicals.

For now, we know the best is to choose whole foods vs processed foods. Talk with a dietitian to find ways to make simple and economic steps to reduce processed foods in your diet. 

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2. _{Pinget, G., Tan, J., Janac, B., Kaakoush, N. O., Angelatos, A. S., O'Sullivan, J., Koay, Y. C., Sierro, F., Davis, J., Divakarla, S. K., Khanal, D., Moore, R. J., Stanley, D., Chrzanowski, W., & Macia, L. (2019). Impact of the Food Additive Titanium Dioxide (E171) on Gut Microbiota-Host Interaction. Frontiers in nutrition, 6, 57. https://doi.org/10.3389/fnut.2019.00057} 
3. _{Rinninella, E., Cintoni, M., Raoul, P., Mora, V., Gasbarrini, A., & Mele, M. C. (2021). Impact of Food Additive Titanium Dioxide on Gut Microbiota Composition, Microbiota-Associated Functions, and Gut Barrier: A Systematic Review of In Vivo Animal Studies. International journal of environmental research and public health, 18(4), 2008. https://doi.org/10.3390/ijerph18042008} 

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