Overview of potential adverse health effects of oral exposure to nanocellulose

Abstract

Nanocellulose is an emerging material for which several food-related applications are foreseen, for example, novel food, functional food, food additive or in food contact materials. Nanocellulose materials can display a range of possible shapes (fibers, crystals), sizes and surface modifications. For food-related applications in the EU, information on the safety of substances must be assessed. The present review summarizes the current knowledge on (possible) adverse health effects of nanocellulose upon oral exposure, keeping EU regulatory aspects in mind. The overview indicates that toxicity data, especially from in vivo studies, are limited and outcomes are not unambiguous. The hazard assessment is further complicated by: the diversity in morphologies and surface modifications, lack of standard reference materials, limited knowledge about intestinal fate and absorption, analytical difficulties in biological matrices, dispersion issues, the possible presence of impurities and interferences within biological assays. Two subchronic in vivo toxicity studies show no indications of toxicity for two specific nanocellulose materials, even at high doses. However, these studies may have missed certain early or nano-specific toxic effects, such as inflammation potential, for which other, subacute studies provide some indications. Most in vitro studies show no cytotoxicity; however, several indicate that effects on oxidative stress and inflammatory responses depend on differences in size or surface treatments. Further, too few studies assessed genotoxicity of nanocelluloses. Therefore, immunotoxicity, oxidative stress and genotoxicity require further attention, as do absorption and effects on nutrient uptake. Recommendations for future research facilitating the safety assessment and safe-by-design of nanocellulose in food-related applications are provided.

Keywords:

• Food
• cellulose nanocrystals
• cellulose nanofibers
• bacterial nanocellulose
• risk assessment

Acknowledgements

The authors thank Jacqueline Castenmiller of the Netherlands Food and Consumer Product Safety Authority (NVWA-BuRO) for support and fruitful discussions. Corinne Sprong, Hedwig Braakhuis and Jacqueline van Engelen (all from RIVM) are acknowledged for their useful comments on the manuscript before submission. Apostolos Petrislis is acknowledged for the initial literature review on the impact of nanocellulose on human health after oral exposure, during his internship at the Division of Toxicology of Wageningen University, performed at RIVM.

Disclosure statement

The authors declare that they have no competing interests.

Additional information

Funding

The research was commissioned and financed by the Netherlands Food and Consumer Product Safety Authority (NVWA-BuRO).