For ease of reference, figures in brackets refer to the reference numbers appended to this document.
You're right to be wary of certain words that we find incomprehensible when reading the ingredients of a processed product. Several food additives are safe for your health and come from natural sources. These include vitamins C and E, sodium and curcumin. Enhancing flavor, taste and color, allowing for better preservation, we shouldn't point the finger at all these substances added by industry. Some, however, have negative effects on digestive health and the intestinal microbiota, effects which can induce local inflammation, mediating cardio-metabolic problems (cardiovascular disease, type 2 diabetes, obesity, hepatic steatosis, etc.) (1).
First and foremost, Health Canada defines a food additive as «Any chemical substance added to a food during preparation or prior to storage, which becomes part of the food or modifies its characteristics to achieve the desired technical effect. Alternatively, it may be added to food to preserve its nutritional value, increase its shelf life or enhance its appearance, to facilitate processing, packaging or storage».». (2)
The industry is fond of these food additives, and although Health Canada is the regulator, we don't know whether the permitted doses have been validated for all health problems. For example, the permitted amount of certain emulsifiers has been based on cancer studies, but does not take into account their impact on the mucus layer that protects the intestinal barrier. We also ignore the cumulative effect of several doses deemed acceptable, consumed in the same day, over several weeks and years.
More details on acceptable doses
To date, 400 additives are authorized.
The safety of food additives is regulated by a multi-stage process, which determines the inactive dose of an additive, i.e. the dose at which no «perceptible» negative effects have been observed in animal studies.
This inactive dose is then divided by a hundred to obtain the admissible daily dose for humans. This provides the industry with guidelines for long-term daily consumption with no adverse health effects.
Please note that we're talking about ONE additive here. Given that we consume several foods a day, we need to take into account the sum of additives and the potential interactions between them. No scientific data has been able to clearly establish the repercussions of accumulated consumption of several additives simultaneously.
Impact on the digestive system
Thickening, gelling and stabilizing additives and emulsifiers
Cellulose, agar-agar, all gums (xanthan gum, guar gum, locust bean gum), polysorbates, carrageenan and pectin have a direct effect on food texture.
- Cellulose is commonly found in the form of methylcellulose or cellulose gum (carboxymethylcellulose) as a filling agent in frozen products, to thicken various products or to act as an anti-caking agent for grated cheese. As cellulose is an insoluble and indigestible fibre, it can cause constipation, diarrhoea and bloating.. (4) (5) (6)
- Agar-agar, also known as the «vegetable gelatine» par excellence, is harmless, although it can be used in a variety of applications. in high doses, it causes digestive discomfort ranging from bloating to diarrhea. (4) (7)
- Polysorbates are commonly used as emulsifiers, notably in sauces, condiments, creams, cheeses, margarines and prepared dishes. They could potentially negatively modify the intestinal microbiota, thereby favoring the development of inflammatory bowel disease (IBD). (4)
- Studies have also shown that carboxymethylcellulose and polysorbates can directly reduce the mucus layer protecting the intestinal barrier, thereby contributing to the gradual development of local inflammation in the intestinal lumen. (9)
- Pectins are generally extracted from fruit. They are commonly used to thicken jams and spreads. We're talking here about soluble fiber promotes satiety and metabolic health. However, in certain cases of intestinal disorders, their fermentation by intestinal bacteria can cause serious health problems. gas, bloating and intestinal discomfort. (5) (6) We need to adapt our consumption to the symptoms we are experiencing and to our current health condition.
- Visit carrageenan, a very common thickening agent derived from red algae, is controversial, being suspected of being the cause of inflammatory diseases. In fact, the degraded form of this polysaccharide would be likely to create lesions in the intestinal barrier and, therefore, could more easily cross it.. (4) (8) (9) Damage to the barrier implies intestinal permeability correlated with certain metabolic disorders that originate in intestinal inflammation.
For further information on intestinal permeability, please refer to the article «Permeability or «leaky gut», what's important to know!»
Filling agents
Maltodextrin is becoming increasingly popular as it is categorized as a «new fiber», but it is a product that contains carbohydrates and calories. With its slightly sweet taste, it is used to replace some of the sugar in food products, enabling companies to increase the number of grams of fiber in their products without reducing their sweetness.
In the presence of maltodextrin, the intestinal bacteria produce fewer short-chain fatty acids (AGCC) beneficial, (9) Propionic acid is also reduced. This SCFA plays an important anti-inflammatory role in the prevention of inflammatory bowel disease, while increasing the number of favorable bacteria such as Bifidobacteria. (9) (10) (11)
In short, this new sweetening agent results in the reduction of molecules that play a central role in maintaining the impermeability of the intestinal membrane and in the composition of the intestinal microbiota. (9) (11)
Inulin
Inulin is a soluble fiber extracted from chicory root. It is used in a variety of food products to boost fiber content. Interesting at first glance, since it acts as a prebiotic, a food enabling beneficial bacteria to grow and produce anti-inflammatory metabolites.
However, being part of the large family of fermentable carbohydrates containing FODMAP, its consumption, even in small quantities, can be a source of serious health problems. gas and severe intestinal discomfort for a certain segment of the population, people with FODMAP intolerance. (5) (6)
Sweeteners
Sweeteners are very popular because of their sweetness, which is more than a hundred times greater than table sugar (sucrose), with little or no increase in calorie intake (12).
The most common are sucralose, stevia, aspartame, acesulfame K and saccharin.
To date, their consumption in the diet is considered safe. The number of human studies is limited, there is no evidence that sweeteners affect intestinal health for human use doses.
The majority of current studies have been carried out on animals, and at doses far in excess of what is consumed by humans. (12) The hypotheses that non-nutritive sweeteners may disrupt intestinal flora are still highly controversial, but there is no doubt that research must continue into the impact of large doses on the animal model, and that the scientific literature will eventually be more consensual regarding their long-term effects.
However, some people report that sucralose has a laxative effect when consumed in higher doses. (12) In the same vein, we find polyalcohols (sugar-alcohol): sorbitol, xylitol, erythritol, mannitol. They are found in many low-carbohydrate and low-fat products, as well as in gums for their anti-caries effect.
They should be avoided by the vast majority of people suffering from digestive problems, because their consumption is strongly correlated with digestive discomforts such as gas, flatulence and diarrhea.
If these symptoms are affecting your day-to-day life and you would like to receive support in this area, make an appointment with one of our clinic nutritionists.
In conclusion, it should be remembered that certain additives play a noble role in the products offered at the grocery store. In particular, they help preserve nutritional qualities and extend shelf life, thereby reducing food waste.
However, considering the numerous negative impacts of some of them on intestinal health, it would be important to prioritize the following as much as possible fresh, unprocessed foods and cook our own meals and snacks. Reading the list of ingredients is our best tool for limiting recurrent exposure to these additives.
In short, these molecules are numerous, and to this day, many of them are new to the food market. It's easy to get lost and let your guard down. As the saying goes, «moderation tastes best», so it's best to err on the side of caution!
Find out more about the intestinal microbiota and discover our recipes specially designed for intestinal health, it is possible to subscribe to our monthly newsletter.
References :
(1) Chassaing et al. (2022) Randomized Controlled-Feeding Study of Dietary Emulsifier Carboxymethylcellulose Reveals Detrimental Impacts on the Gut Microbiota and Metabolome. Gastroenterology Mar;162(3):743-756. Chen et al (2021) Role and Mechanism of Gut Microbiota in Human Disease. Front Cell Infect Microbiol Mar 17;11:625913.
(2) https://www.canada.ca/fr/sante-canada/services/aliments-nutrition/salubrite-aliments/additifs-alimentaires/listes-autorises.html
(3) https://www.canada.ca/fr/sante-canada/services/aliments-nutrition/rapports-publications/politique-differenciation-additifs-alimentaires-agents-technologiques-2008.html
(4) Chancerelle, R. (2019). The new pocket guide to additives. Édition Poche Leducs. Paris (France).
(5) O'Grady J, O'Connor EM, Shanahan F. Review article: dietary fibre in the era of microbiome science. Aliment Pharmacol Ther. 2019; 49:506-515. https://doi.org/10.1111/apt.15129.
(6) https://www.jandonline.org/article/S2212-2672(16)31187-X/fulltext#back-bib123
(7) https://www.quechoisir.org/comparatif-additifs-alimentaires-n56877/e406-agar-agar-p223609/
(8) https://www.quechoisir.org/comparatif-additifs-alimentaires-n56877/e407a-carraghenane-semi-raffine-algue-eucheuma-transformee-pes-p223617/
(9) Gerasimidis, K., Bryden, K., Chen, X., Papachristou, E., Verney, A., Roig, M., Hansen, R., Nichols, B., Papadopoulou, R., & Parrett, A. (2020). The impact of food additives, artificial sweeteners and domestic hygiene products on the human gut microbiome and its fibre fermentation capacity. European journal of nutrition, 59(7), 3213-3230.
(10) Zangara, M. T., Ponti, A. K., Miller, N. D., Engelhart, M. J., Ahern, P. P., Sangwan, N., & McDonald, C. (2022). Maltodextrin Consumption Impairs the Intestinal Mucus Barrier and Accelerates Colitis Through Direct Actions on the Epithelium. Frontiers in immunology, 13, 841188. https://doi.org/10.3389/fimmu.2022.841188
(11) https://www.biolineaires.com/les-bacteries-propioniques-leur-role-essentiel-sur-la-muqueuse-intestinale/
(12) Ruiz-Ojeda, F. J., Plaza-Díaz, J., Sáez-Lara, M. J., & Gil, A. (2019). Effects of Sweeteners on the Gut Microbiota: A Review of Experimental Studies and Clinical Trials. Advances in nutrition (Bethesda, Md.), 10(suppl_1), S31-S48. https://doi.org/10.1093/advances/nmy037
(13) https://www.quechoisir.org/comparatif-additifs-alimentaires-n56877/e385-edta-calcio-disodique-ethylene-diamine-tetra-acetate-calcio-disodique-p223577/
(14) https://www.quechoisir.org/comparatif-additifs-alimentaires-n56877/e320-butylhydroxyanisol-bha-p223461/
(15) https://www.quechoisir.org/comparatif-additifs-alimentaires-n56877/e321-butylhydroxytoluene-bht-p223465
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