ATLANTANew clinical research indicates that a widely used food additive, carboxymethylcellulose, alters the intestinal environment of healthy persons, perturbing levels of beneficial bacteria and nutrients.These findings, published in GastroenterologyThese data demonstrate the need for further research on the long-term effects of this food ingredient on health.
A team of scientists from Georgia State Universitys led the research. Institute for Biomedical SciencesINSERM (France), and the University of Pennsylvania. Researchers at Penn State University (USA) and Max Planck Institute Germany (Germany) also contributed key contributions.
Carboxymethylcellulose (CMC) is a synthetic member of a widely used class of food additives, termed emulsifiers, which are added to many processed foods to enhance texture and promote shelf life. CMC has not yet been extensively tested in humans, but it has been used more frequently in processed foods since 1960. CMC is not absorbed and is therefore safe to ingest. Scientists have begun to question this assumption, recognizing the health benefits of bacteria that live in the colon and interact with non-absorbed additives. CMC and other emulsifiers altered the gut bacteria in mice, causing more severe disease in a variety of chronic inflammatory conditions including colon cancer, metabolic syndrome, and colitis. However, it was not known if these results could be applied to humans.
The team conducted a controlled-feeding study on healthy volunteers. Participants, housed at the study site, consumed an additive-free diet or an identical diet supplemented with carboxymethylcellulose (CMC). Because CMC can cause diseases in mice that take years to develop in humans, researchers focused their attention on intestinal bacteria as well as metabolites. CMC consumption altered the composition of the colon bacteria, reducing certain species. CMC-treated patients also showed a dramatic decrease in beneficial metabolites, which are believed to be essential for maintaining a healthy colon.
The researchers also performed colonoscopies of subjects at the beginning and the end of the study. They found that a subset had CMC consumption and had gut bacteria invading the mucus. This was previously seen to be a characteristic of inflammatory bowel disease and type 2 diabetes. While CMC did not cause any disease in this two-week study per se, the results from the animal studies support the conclusion that long-term CMC intake might lead to chronic inflammatory diseases. Therefore, further research on this additive is warranted.
It definitely disproves that it just passes by argument used to justify a lack of clinical studies on additives, stated Dr. Andrew Gewirtz from Georgia State University, one of the senior authors. Beyond supporting the need for further study of carboxymethylcellulose, the study provides a general blueprint to carefully test individual food additives in humans in a well-controlled manner, said co-senior author Dr. James Lewis, of the University of Pennsylvania, where the subjects were enrolled.
Dr. Benoit Chassaing (research director at INSERM University of Paris, France), was the lead author. He noted that such studies must be large enough to account to a high level of subject heterogeneity. Our results show that CMC and other food additives responses are highly personalized. We are currently developing methods to predict which individuals might be sensitive, Chassaing stated.
This study was supported by the National Institutes of Health (NIH), the European Research Council (ERC), the Max Planck Society (MPS), the INSERM, and the Kenneth Rainin Foundation.
Visit the following link to read the study https://www.gastrojournal.org/article/S0016-5085(21)03728-8/fulltext.