Synthetic Antioxidants in Packaged Foods: A Closer Look at Dietary Exposure and Health Risks

A study revealed that synthetic antioxidants in packaged foods are present at high levels, particularly in foodstuffs, with dietary intake posing a more significant health risk than dermal contact. The research highlights the need for further investigation into the long-term health implications of these compounds.

Researchers from Shandong University, Qilu University of Technology, and the Chinese Academy of Sciences have conducted a pivotal study exploring the prevalence and potential health risks of synthetic antioxidants (AOs) found in packaged foods. These AOs, including synthetic phenolic antioxidants (SPAs) and organophosphite antioxidants (OPAs), are widely used in a range of consumer and industrial products, primarily to prevent oxidative deterioration. Despite their extensive use, there has been limited documentation of their presence in food packaging and packaged foods, as well as their potential impact on human health through ingestion or skin contact. This study represents a significant step in filling that knowledge gap.

High Levels of Antioxidants Detected in Food Samples

The research involved analyzing 23 synthetic antioxidants and six of their transformation products across various food samples and their corresponding packaging materials. The results were striking, revealing that AOs are present in packaged foods at concentrations significantly higher than those found in both the outer and inner packaging materials. Specifically, the concentrations in food ranged from 1.30 × 103 to 1.77 × 105 nanograms per gram (ng/g), surpassing the levels detected in the outer packaging (6.05 × 102–3.07 × 104 ng/g) and inner packaging (2.27 × 102–1.09 × 105 ng/g). Among the most commonly detected AOs in food were tris(2,4-di-tert-butylphenyl) phosphate (AO168O), butylated hydroxytoluene (BHT), and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (AO1076). These three compounds collectively accounted for 95.7% of the total AOs found in the foodstuffs, underscoring their prevalence and potential impact on human health.

Dietary Intake: The Primary Exposure Route

The study also conducted a preliminary assessment of human exposure to these synthetic antioxidants, focusing on two primary routes: dietary intake and dermal contact with food packaging. The findings indicated that dietary exposure is a significantly more important pathway for human exposure to AOs than dermal contact. The median estimated daily intake (EDI) of AOs through food consumption was calculated at 2.55 × 104 ng per kilogram of body weight per day (ng/kg bw/day) for children and 1.24 × 104 ng/kg bw/day for adults. In contrast, the exposure through dermal contact with packaging materials was found to be minimal, especially when compared to the intake through food consumption. Notably, BHT emerged as a critical compound in this analysis, accounting for 76.8% and 67.6% of the total BHT intake for children and adults, respectively. This suggests that food consumption is a significant source of BHT exposure, raising concerns about the potential long-term health effects of this synthetic antioxidant, particularly given its widespread use as a food additive.

Health Risks and Toxicity Concerns

The study's findings align with previous research that has highlighted the potential health risks associated with synthetic antioxidants. For instance, BHT has been shown to influence hormone homeostasis, contribute to obesity, and even exert carcinogenic effects in some studies. Additionally, transformation products of BHT, such as BHT-Q, have been found to possess enhanced toxicity, leading to further concerns about the safety of these compounds when consumed over extended periods. Similarly, AO1076, another commonly detected antioxidant in this study, has been associated with reproductive and developmental toxicity in experimental animals. These findings suggest that the health risks associated with these synthetic antioxidants may be more significant than previously understood, particularly given their widespread presence in the food supply.

The Need for Further Investigation

Despite these concerns, the study also found that the estimated daily intakes of AOs via food consumption were within the acceptable daily intake (ADI) limits recommended by health authorities. For example, the European Food Safety Authority (EFSA) has set the ADI for BHT at 250 micrograms per kilogram of body weight per day (μg/kg bw/day), which is several orders of magnitude higher than the EDI observed in this study. However, the researchers caution that these estimates are preliminary and come with several uncertainties. For instance, the dietary exposure assessments did not account for differences in diet composition between children and adults, which could lead to slight biases in the calculations. Moreover, the lack of specific data on the transfer of AOs from packaging materials to food, as well as the absorption rates through human skin, adds further uncertainty to the exposure assessments. In conclusion, while the study suggests that the current levels of dietary intake and dermal contact with food packaging materials may pose relatively low health risks, the potential for long-term exposure to synthetic antioxidants in packaged foods warrants further investigation. The findings underscore the need for more comprehensive research to fully understand the health implications of these compounds, particularly in light of their ubiquitous presence in the food supply. As our understanding of the toxicological effects of synthetic antioxidants evolves, it may become necessary to reassess current regulatory standards to ensure that they adequately protect public health. This study serves as an important reminder of the hidden risks that may be present in everyday consumer products and the importance of continued vigilance in monitoring and assessing these risks.