This post is for anyone who’s struggled with gut problems that seem to defy logic—and especially for those who think they’re eating healthily, but still feel unwell.
Introduction
For six decades, I have lived ‘on and off’ with quite severe digestive issues —mostly severe bloating and diarrhoea. It has generally been labelled as Irritable Bowel Syndrome (IBS) and I have had a sensitivity to several food components known as FODMAPS. FODMAPS are different types of sugars that are found in many fruits and vegetables and research from Monash University has now produced Tables and an online App that can be used as a very informative guide to safe food choices.
Nevertheless, despite my attention to my food selection, I was still having problems. So, there was something else that wasn’t on their list that was causing me problems (mostly from about 1 to 2.30 a.m. in the morning) and being very sleep-deprived, I needed to figure out what it was!
I had already decided some months ago that the ‘middle of the night disturbed gut issue’ must have something to do with bread, which I generally ate at lunchtime, so I tried eating Sourdough and then Gluten-free bread. I was pleased to discover that some Sourdough breads seemed to reduce the problem but I soon found that not all bread labelled sourdough ‘worked’? I wondered whether some breads called ‘sourdough’ weren’t genuine sourdough and have since learnt that ‘real’ Sourdough bread does remove the problem but not, (let’s call them) ‘Supermarket Sourdoughs’. Nevertheless, at the time still doubting my conclusion, I started eating Gluten-free bread and found that this did not seem to help me until I found a small article online that recommended eating ‘Helga’s Gluten-free bread’. To my amazement, Helga’s Gluten-free did work! But why, and what could I tell people who might not be able to buy this bread?
So, after lunch today, I decided to research the ingredients in Helga’s Gluten free bread versus another well-known GF free bread, which I knew from my recent tests, didn’t work.
Interestinly, the ingredients in the two breads were identical except for one of those numbers that I usually overlook! The different number was ‘466’ and it turns out that this is a thickener called carboxymethyl cellulose (CMC)—usually just labelled as 466! So, expecting another ‘dead-end’ I looked up additive 466 and here was my answer to today’s question and at least part of the explanation for my GI problems of 60 years!
The Hidden Chemistry of Modern Food
Since the 1960s and 1970s, the food industry has transformed. In pursuit of longer shelf lives and smoother textures, manufacturers began using synthetic additives—many of which were never part of our ancestral diets. These include emulsifiers, thickeners, preservatives, and stabilizers, now common in bread, sauces, ice cream, and even some yogurt.
These compounds may help factories produce beautiful, uniform food—but they can interfere with our gut’s natural rhythms and some people seem to be more susceptible to their secondary effects than others.
What Is Thickener 466 (CMC)?
Carboxymethyl cellulose is a synthetic polymer derived from cellulose (plant fibre), chemically modified to act as a stabilizer and thickener. It’s added to:
- Industrial bread (to retain moisture and softness)
- Ice cream (to prevent crystal formation)
- Sauces and dressings (to create a smooth, creamy texture)
Though previously thought to be completely “safe,” recent studies suggest otherwise. CMC has been shown to disrupt the gut microbiota, damage the mucus barrier, and promote inflammation in animal models. For sensitive individuals, this disruption may manifest as IBS-like symptoms. So, for anyone who is sensitive like me, it is crucial to look at the fine print on labels to avoid CMC (466). It could be a good idea for everyone to avoid it as it probably affects everyone’s gut microbiota to some extent?
A Personal Turning Point: Real Sourdough vs. Supermarket Bread
I had already noticed that traditional sourdough bread didn’t cause digestive issues—but “supermarket sourdough” did. But more specifically, Helga’s ‘Gluten -free’ bread that is the bread that people with IBS can enjoy does not use Thickener 466. Discovering this has been my eureka moment.
When I changed my bread, my gut improved dramatically, and I no longer had hours of discomfort in the middle of the night. It was the clearest result I’ve ever had from any dietary change.
Other Additives That Can Trigger Gut Symptoms
CMC isn’t the only culprit. Many additives now common in “normal” food can disturb the gut:
- Polysorbates (e.g., polysorbate 80): These are Emulsifiers that are linked to increased gut permeability.
- Carrageenan: A thickener extracted from seaweed has been associated with inflammation in some studies.
- Modified starches: Industrially processed carbohydrates that can irritate sensitive guts.
- Sorbitol and mannitol: These sugar alcohols that ferment in the gut, often trigger bloating and diarrhea. These are listed in the FODMAPS foods because they are common in many different fruits and vegetables but possibly the worst ‘food’ for acute exposure to sorbitol is CHEWING GUM.
The Illusion of Natural: Food That Looks Familiar but Isn’t
Today’s processed bread may resemble the loaves our grandparents ate, but chemically it’s very different.
Many of us assume store-bought bread is wholesome, but even “health” loaves are often filled with:
- Emulsifiers (E471, E472e)
- Thickeners (E466)
- Preservatives (calcium propionate)
- Added sugars and gums
The Power of Observation: Becoming Your Own Researcher
When medicine and standard dietary advice fail, your own symptoms are data. My breakthrough came not from a lab test, but from reading labels, running mini-elimination trials, and listening to my body. It has been a very long journey but at the risk of seeming to be overly ‘picky’ about what I eat, I am hopeful that I can stay well.
Tips for Others on This Path:
- Read ingredient lists carefully (watch for codes like E466, E471, E433) and be rigorous in avoiding those that you can’t tolerate.
- Stick to minimally processed foods whenever possible.
- Try real sourdough or traditional flatbreads with few ingredients.
- Keep an ongoing food and symptom journal if you start to feel unwell.
Conclusion: You’re Not Imagining It
If you’ve been dismissed or told your symptoms are “just IBS,” don’t give up. The food industry has changed significantly —and your body might be reacting to things it was never designed to process. Removing a single additive like CMC might not solve everything—but it could be the missing piece you’ve been searching for.
References:
- Chassaing B, et al. Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Nature (2015). Aug;66(8):1414-1427. doi: 10.1136/gutjnl-2016-313099. Epub 2017 Mar 2017
- Naimi S et al. (2021) Direct impact of commonly used dietary emulsifiers on human gut microbiota. Microbiome Mar 22;9(1):66. doi: 10.1186/s40168-020-00996-6.
Let your symptoms guide your curiosity—and remember, sometimes the smallest changes make the biggest difference.
If you would like to contact me about this blog or follow-up in any way, please contact me by email at dr.judy.ford@gmail.com. I would be happy to speak with groups about this or any other topics I have addressed in my blogs at https://www.drjudyford.com.