What’s so bad about the emulsifier E466 or Carboxymethylcellulose (CMC)?

As a nutritionist, I am often asked about food additives and their effects on our health. One such additive that has raised concern over the years is E466, also known as Carboxymethylcellulose (CMC). While it’s commonly used in processed foods as a thickener, stabiliser, and emulsifier, many people are unaware of its potential negative health impacts. In this post, I will take a closer look at what E466 is, how it’s used in our food, and why you might want to reconsider its inclusion in your diet.

What is E466/CMC?

E466, or Carboxymethylcellulose, is a water-soluble polymer made from cellulose, a plant-based substance found in the cell walls of plants. When treated with chemicals, cellulose can be turned into a thickening agent that has multiple uses in the food industry. It’s often added to processed foods like ice cream, baked goods, salad dressings, dairy products, and sauces, to improve texture and shelf life.

On the surface, it might sound harmless. After all, cellulose is naturally found in plants, and many people assume that synthetic derivatives of natural substances are safe. However, the way our body responds to processed versions of these compounds can be quite different from their natural form.

Potential Negative Health Impacts of E466

While Carboxymethylcellulose (CMC) is considered safe for consumption by many food regulatory agencies, there are several potential risks associated with its overconsumption:

1. Digestive Discomfort

One of the most immediate concerns with E466/CMC is its impact on digestion. Research indicates that CMC can disrupt the balance of gut microbiota. This imbalance may result in digestive discomfort, inflammation and in some cases diarrhoea. Some studies also suggest that CMC can thin the protective mucus layer in the gut, increasing susceptibility to irritation and inflammation. For sensitive individuals, even small amounts of CMC may cause bloating, gas, diarrhoea as it passes undigested through the gastrointestinal tract.

Those with pre-existing gastrointestinal conditions, such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD), may be more susceptible so may want to avoid consuming foods containing CMC.

2. Potential Link to Inflammation and Allergies

Carboxymethylcellulose (CMC) has been linked to an increase in inflammation in some animal studies. When consumed in large quantities, it may trigger an immune response, leading to chronic inflammation. Inflammation is a root cause of many health conditions, including heart disease, diabetes, and arthritis. It’s also worth noting that food allergies or sensitivities to CMC can manifest in some individuals, resulting in rashes, hives, and other allergic reactions.

While the research on inflammation and allergies in humans is still developing, the connection between CMC and inflammation in animal studies should not be overlooked. If you are prone to inflammatory conditions or have food sensitivities, it may be best to avoid products containing E466/CMC.

3. Possible Impact on Weight Gain

Some studies have indicated that certain additives, including E466/CMC, might contribute to weight gain over time. This could be due to the fact that thickening agents like Carboxymethylcellulose may cause people to consume larger quantities of processed foods without feeling fully satisfied, which could lead to overeating and, ultimately, weight gain.

Additionally, because E466/CMC is often used in ultra-processed foods—those that are high in sugar, fat, and salt—consuming these foods regularly could contribute to unhealthy weight gain and metabolic dysfunction.

E466 in the Food Industry: Why It’s So Common

So, why is E466/CMC used so widely in processed foods? The answer lies in its cost-effectiveness and functional benefits. Carboxymethylcellulose is relatively cheap to produce and helps extend the shelf life of products by stabilising ingredients and preventing separation. For manufacturers, it’s an easy way to improve texture and viscosity in everything from dressings to coconut milk.

However, as with many food additives, the convenience of using E466 may come at a cost to our health. While small amounts of CMC may not have immediate, severe effects on most people, regular consumption of foods containing this additive may have a cumulative impact on our long-term health.

How to Reduce Your Exposure to E466/CMC

If you’re concerned about the potential negative health impacts of E466/CMC, there are several steps you can take to minimize your exposure:

1. Read Labels Carefully: Start by checking food labels for E466 (Carboxymethylcellulose) or other additives like E415 (Xanthan gum) that may have similar effects. Opt for products with minimal ingredients and fewer additives.
2. Choose Whole, Unprocessed Foods: Whole foods like fruits, vegetables, whole grains, lean proteins, and healthy fats don’t require thickeners or stabilizers, making them a healthier choice.
3. Cook at Home: Preparing meals from scratch allows you to control what goes into your food. When you make your own sauces, soups, and dressings, you can avoid unnecessary additives like E466/CMC.
4. Opt for Natural Alternatives: If you need a thickening agent, consider alternatives like arrowroot, agar-agar, or even chia seeds, which offer natural ways to thicken your meals without the risks associated with synthetic additives.

Final Thoughts

While E466 (Carboxymethylcellulose) may be deemed safe in small quantities, its presence in highly processed foods should be a red flag for health-conscious consumers. Its potential to cause digestive discomfort, inflammation, and even contribute to weight gain makes it worth considering when making food choices. As a nutritionist, I always recommend focusing on whole, minimally processed foods that nourish your body and support long-term health. By being mindful of what you eat and taking steps to avoid unnecessary additives, you can help protect your health and feel your best every day.

Studies used to write this blog:

1. Chassaing B, Compher C, Bonhomme B, Liu Q, Tian Y, Walters W, Nessel L, Delaroque C, Hao F, Gershuni V, Chau L, Ni J, Bewtra M, Albenberg L, Bretin A, McKeever L, Ley RE, Patterson AD, Wu GD, Gewirtz AT, Lewis JD. Randomized Controlled-Feeding Study of Dietary Emulsifier Carboxymethylcellulose Reveals Detrimental Impacts on the Gut Microbiota and Metabolome. Gastroenterology. 2022 Mar;162(3):743-756. doi: 10.1053/j.gastro.2021.11.006. Epub 2021 Nov 11. PMID: 34774538; PMCID: PMC9639366.
2. Costa EM, Silva S, Pereira CF, Ribeiro AB, Casanova F, Freixo R, Pintado M, Ramos ÓL. Carboxymethyl Cellulose as a Food Emulsifier: Are Its Days Numbered? Polymers (Basel). 2023 May 22;15(10):2408. doi: 10.3390/polym15102408. PMID: 37242982; PMCID: PMC10221013.
3. Lock JY, Carlson TL, Wang C-M, Chen A, Carrier RL. Acute Exposure to Commonly Ingested Emulsifiers Alters Intestinal Mucus Structure and Transport Properties. Sci Rep. 2018;8:10008. pmid:29968743
4. Viennois E, Bretin A, Dubé PE, Maue AC, Dauriat CJG, Barnich N, et al. Dietary Emulsifiers Directly Impact Adherent-Invasive E. coli Gene Expression to Drive Chronic Intestinal Inflammation. Cell Rep. 2020;33. pmid:33027647
5. Viennois E, Chassaing B. Consumption of Select Dietary Emulsifiers Exacerbates the Development of Spontaneous Intestinal Adenoma. Int J Mol Sci. 2021;22:2602. pmid:33807577