The FDA requires immunotoxicity testing only for food contact substances with high daily exposure. As a result, the immunotoxicity of many food additives and food contact substances is largely unknown. The effects of immunotoxicity can result in hypersensitivity, chronic inflammation, immunosuppression, immunostimulation, and autoimmunity.
To test whether a chemical is toxic to humans often requires animal studies which are complex and have significant lead time. Enter ToxCastTM, a means of testing the immunotoxicity of chemicals in the lab without the need for animals.
According to the Environmental Protection Agency (EPA), ToxCast is:
[…] a multi-year effort launched in 2007 that uses automated chemical screening technologies (called “high-throughput screening assays”) to expose living cells or isolated proteins to chemicals. The cells or proteins are then screened for changes in biological activity that suggest potential toxic effects. These innovative methods have the potential to limit the number of required laboratory animal-based toxicity tests while quickly and efficiently screening large numbers of chemicals.
Studies are underway comparing the findings of ToxCast with prior animal studies. One recent study whose findings were published in the International Journal of Environmental Research and Public Health analyzed a total of 63 direct food additives present on more than 10 product labels sold in the US between 2018–2020 while also assessing PFAS (polyfluoroalkyl substances)-based chemicals known to migrate from food packaging to food.
Researchers concentrated on those chemicals with the highest number of active ToxCast assays, then focused further analyses on those substances with activity toward multiple immune-related targets and proteins involved in immune response, inflammation, and defense mechanisms.
Strong data from animal studies confirmed by ToxCast indicate that tert-Butylhydroquinone (TBHQ) may cause immune functioning changes.
THBQ is often used by manufacturers to prolong the shelf lives of their products. According to the Environmental Working Group (EWG), the preservative is present in 1200+ processed foods, including Cheez-It crackers, Pop-Tarts, Reese’s Peanut Butter Cups, and Little Debbie Swiss Rolls.
The researchers also concluded that — based on both ToxCast and animal studies — certain chemicals in the PFAS family may also adversely affect immune system functioning.
Said lead study author Dr Olga Naidenko, PhD, EWG’s Vice President for Science Investigations:
The pandemic has focused public and scientific attention on environmental factors that can impact the immune system. Before the pandemic, chemicals that may harm the immune system’s defense against infection or cancer did not receive sufficient attention from public health agencies. To protect public health, this must change.
Added Scott Faber, Senior Vice President for Government Affairs at the EWG:
Food manufacturers have no incentive to change their formulas. Too often, the FDA [allow] the food and chemical industry to determine which ingredients are safe for consumption.
Our research shows how important it is that the FDA take a second look at these ingredients and test all food chemicals for safety.
- Guidance for Industry: Preparation of Food Contact Notifications for Food Contact Substances (Toxicology Recommendations) — FDA
- Can a common food preservative harm the immune system? — Medical News Today
- Toxicity Forecaster (ToxCastTM) — Environmental Protection Agency
- Investigating Molecular Mechanisms of Immunotoxicity and the Utility of ToxCast for Immunotoxicity Screening of Chemicals Added to Food — International Journal of Environmental Research and Public Health
- PROCESSED FOODS WITH THE PRESERVATIVE TBHQ — Enviromental Working Group