Ingredient E466 - CMC cellulose + Why is it very bad for health

Sharyn Carter

Ingredient E466 is Carboxymethylcellulose or CMC for short. 
It is an emulsifier ingredient that appears in a whole host of foods.

How is it made?
CMC is a genetically modified, synthetic by-product made from wood pulp and cotton lint, treated with acid to break it all down to form the cellulose. 

Is E466 safe?
Up until 2015 it was thought to be safe. Since then both animal and human studies have proven that CMC has significant negative health impacts on gut health, obesity and metabolic syndrome. So far only animal studies have linked it to cancer – due to the challenges in ring fencing CMC consumption by humans over a long period of time, in order to draw more firmer conclusions. 


In Europe the Food Safety Council equivalent requested safety data to be presented for CMC and not one single item of data was submitted to prove its safety. Due to the lack of data provided a safety assessment could not be performed so CMCs are banned for consumption by a proportion of the population there.

Is CMC a vegetable gum?
In the case of Queen Fine Food's sugar-free Maple Syrup, CMC is being passed off in ingredients lists, as a much healthier sounding vegetable gum. E466 is not a vegetable gum. It is an unnatural, synthetic, health deteriorating ingredient.  At the time of writing this, it is interesting to note that the Queen Fine Food's own Australian website doesn’t even list the ingredients of the sugar-free maple syrup and the product’s back panel image is completely missing in action.

How does CMC show up on nutritional panels?
CMC is not absorbed or digested, so the FDA allows it to be included with “dietary fiber” on food labels reducing the amount of carbs being declared in products aimed at the health conscious. As dietary fibre is an optionally measured ingredient, there’s no way to know how much E466 you are consuming in a product like the Queens sugar-free maple syrup.

What do the human studies tell us about this ingredient? 
An alarming study of humans in 2015 linkages were proven between CMC to deterioration of gut bacteria, inflammatory bowel disease symptoms and conditions like obesity and metabolic syndrome.

In February 2024 the results of a nearly 7 year duration study of 92,000 French healthy adults linked CMC to significant deterioration of gut bacteria and inflammatory bowel disease symptoms. While the cancer causing part of CMC testing wasn’t conclusive in adult humans, the animal studies that did prove causation of cancer, also shared the studies exact same findings about gut health too. There have also been separate studies linking gut bacteria to the causation of cancers.

What do the animal studies tell us about this ingredient?
Four separate animal studies have also proved linkages between CMC to deterioration of gut bacteria, intestinal inflammatory bowel disease symptoms, obesity and metabolic syndrome symptoms. But in an alarming escalation, the animal studies also linked CMC consumption to increased incidences of cancer (breast, prostate and colon).

How much CMC were the test subjects consuming?
In 2021 a randomised controlled human study found even a 15ml daily portion of E466 consumed over just 11 days, caused significant deterioration and lack of diverse stomach bacteria, leakage through the intestinal gut wall.

References of the important studies for your further reading: 
Animal studies about E466
• Causes chronic intestinal inflammation [58,59].
• Altered intestinal microbiota diversity [20,26,60,61].
• Promotion of carcinogenesis (cancer) demonstrated [20,26,60,61].
• Linkage between cancers and gut health cancers  [23,24

Human studies about E466
A first randomised controlled trial on carboxymethylcellulose (E466) was conducted in 2021 [25] with a dietary intake of only 15g per day over just 11 days. In that time there was:
• increased abdominal discomfort and gut inflammation markers
• weakened the intestinal barrier allowing bacteria to enter a normally almost-sterile inner mucus layer
• reduced gut microbiota diversity, which affects capability and resilience to process food
• altered microbiota composition, which negatively affects protection against pathogens, stimulation of immune response as well as impairing production of vitamins.
These findings are all pre-cursors to the increase in a person’s susceptibility to various forms of cancer. [23,24

In a mass scale study of 92,000 randomised healthy French individuals who were followed over 6.7 years and fed E466 in controlled groups amongst other emulsifiers. This study suggested direct associations between exposures to 7 individual and 3 groups of commonly used food additive emulsifiers and cancer (breast, prostate and colon) risk in a large prospective cohort of French adults. [70],

However, the impact of food additive emulsifiers on cancer risk or progression is yet to be explained and current knowledge is based on scarce, contrasting evidence from experimental studies on animals [2628]. To our knowledge, no epidemiological study has investigated the links between exposure to emulsifiers and cancer risk in humans, due to important challenges in accurate and reliable estimation of exposure to additive emulsifiers. And businesses that don’t even declare it as CMC and instead hide it behind the words vegetable gum don’t help people to identify exactly what is in their food. 

With E466 – should you worry?

Should you be worried when an ingredient is connected to health outcomes that are so bad, that the manufacturers won’t list or show images with the ingredients on their own product website? Queen don’t even have an image of the back of their sugar-free maple syrup bottle, so no nutritional information is shown either.

I was so worried about this ingredient that I fast tracked developing our own zero carb, real food, ingredient Keto Store Maple Syrup. I also wanted to prove that it's just not necessary to manufacture using these nasty emulsifiers at all.  

I invite you to also consider avoiding the Queens or the Lakanto sugar-free maple-flavoured syrup. To me it is simply not worth $5 for poor gut health and a much higher risk of cancer. So no thanks to Queen, and please clean up your product as right now, while it is free of sugar, it is just so not healthy to consume due to other nasty additives.