Socio-economic and cultural changes in recent decades have led to a significant increase in the consumption of processed foods, often rich in food additives such as emulsifiers. These compounds, found in products such as butter, milk, mayonnaise and pastries, play a crucial role in mixing immiscible ingredients such as oil and water. However, there is growing concern about their impact on health, particularly in relation to intestinal microbiota and metabolic syndrome.
What are food emulsifiers used for?
Emulsifiers are substances that enable two normally immiscible liquids, such as oil and water, to be mixed homogeneously. They play a crucial role in the texture, stability and shelf life of processed food products.
Emulsifiers can be natural or synthetic. Among the most common are :
- Lecithin: Naturally present in eggs and soya, used in chocolate and bakery products.
- Mono- and diglycerides of fatty acids: Used in bakery products to improve texture.
- Polysorbates: Used in ice cream to create a creamy texture.
- Carboxymethylcellulose (CMC): Used as a stabiliser and thickener in many food products.
Use of emulsifiers in the food industry
Emulsifiers are additives widely used in the food industry. They are widely used to improve the texture of foods and extend their shelf life. They are present in a wide range of processed products:
- Bakery products: To improve texture and extend shelf life.
- Ice creams: To prevent the formation of ice crystals and maintain a smooth consistency.
- Sauces and dressings: To prevent ingredients from separating.
- Beverages: To stabilise juice mixes and dairy drinks.
But more worryingly, they are also found in products considered to be ‘healthy’, such as vegetable drinks made from oats or almonds, including those bearing an ‘organic’ label. They are also present in many ‘low-fat’ foods, where they replace the fat removed to maintain a pleasant texture.
However, these emulsifiers are not without health risks.
Potential health effects of food emulsifiers
Recent research has highlighted the harmful effects of certain emulsifiers such as carboxymethylcellulose (CMC) on intestinal health. A controlled study revealed that consumption of CMC disrupts the composition of the intestinal microbiota and reduces the diversity of beneficial metabolites produced by these bacteria. These results suggest that emulsifiers may have deleterious effects not only on the intestine but also on overall metabolic health.
Disturbance of the intestinal microbiota
One of the key findings of these studies is the significant impact of emulsifiers on the intestinal microbiota, the set of micro-organisms present in the human digestive system. CMC and other emulsifiers can alter bacterial composition, encouraging the growth of pathogenic bacteria while reducing populations of beneficial bacteria such as Bifidobacteria and Lactobacilli. This dysbiosis can lead to chronic inflammation and alteration of the intestinal barrier, increasing intestinal permeability and facilitating the passage of toxins and pathogens into the bloodstream.
Inflammation and chronic diseases
A study conducted by Inserm (Institut National de la Santé et de la Recherche Médicale) revealed worrying effects of emulsifiers on the intestinal microbiota. In August 2018, an article published in the journal Physiology and Behavior highlighted the dangers of carboxymethylcellulose (CMC), a commonly used emulsifier.
Researchers have shown that dietary emulsifiers alter the gut microbiota by increasing its ability to penetrate the normally sterile mucus layer, thereby promoting intestinal inflammation and metabolic syndrome.
Studies have also shown that emulsifiers can cause intestinal inflammation by disrupting the mucus layer that protects the intestinal wall. This inflammation can play a crucial role in the development of chronic diseases such as Crohn’s disease, irritable bowel syndrome (IBS), and even certain types of cancer. Intestinal inflammation is often accompanied by increased production of pro-inflammatory cytokines, molecules that signal and exacerbate inflammation in the body.
Metabolic implications
In addition to intestinal effects, emulsifiers have significant metabolic implications. Disruption of the microbiota can influence lipid and carbohydrate metabolism, contributing to conditions such as obesity and type 2 diabetes. One study showed that mice fed emulsifiers had increased weight gain and insulin resistance, key indicators of diabetes. These results highlight the fact that regular consumption of emulsifiers could be an aggravating factor in the development of digestive and metabolic diseases.
Why are some people more sensitive than others?
Research has also revealed that we are not all equal when it comes to the harmful effects of emulsifiers. A clinical study carried out on volunteers identified two types of reaction:
- Sensitive individuals, whose microbiota is highly reactive to emulsifiers and who present an increased risk of intestinal inflammation.
- Resistant individuals, whose microbiota seems able to tolerate these additives without any apparent negative effects.
This finding is crucial, as it explains why some consumers develop digestive problems after ingesting emulsifiers, while others seem to tolerate these additives perfectly well.
A test to predict sensitivity to emulsifiers?
Scientists are continuing their research to develop a predictive model capable of determining an individual’s sensitivity to food emulsifiers.
In a recent study published in the journal Gut, researchers tested the effect of the emulsifier E466 on different microbiota samples in vitro. They then transferred these microbiota to mice, and the results confirmed that only sensitive microbiota caused severe colitis in animals exposed to this additive.
By analysing the bacterial DNA contained in the faecal samples, the researchers were able to identify a specific signature predicting individual sensitivity to emulsifiers.
Towards a more personalised diet?
These discoveries pave the way for a more personalised approach to nutrition. If sensitivity to emulsifiers can be detected in advance, it would be possible to tailor diets to each individual’s profile. In the future, a simple analysis of intestinal microbiota could make it possible to :
- Identify people at risk and recommend that they avoid emulsifiers.
- Develop diets tailored to individual needs.
- Better understand the interactions between diet and intestinal microbiota.
Regulations and safety of emulsifiers
Regulations on emulsifiers vary from country to country. In general, regulatory bodies such as the European Food Safety Authority (EFSA) and the Food and Drug Administration (FDA) in the United States assess the safety of emulsifiers before authorising them for use in foods. These assessments include toxicological tests to determine No Observed Adverse Effect Levels (NOAELs). However, ongoing monitoring and research into long-term effects remain essential to guarantee the safety of these additives.
Should emulsifiers be avoided?
If you suffer from digestive problems, bloating or intestinal inflammation, reducing your consumption of ultra-processed foods and emulsifiers could be beneficial. Choose a natural, balanced diet and avoid products containing controversial additives.
Some practical advice:
- Read labels carefully: avoid foods containing E466, CMC, modified lecithin or other artificial emulsifiers.
- Go for raw, homemade foods: cook with natural, unprocessed ingredients.
- Opt for organic and additive-free alternatives: although some organic products contain emulsifiers, they are often in reduced quantities.
- Listen to your body: if you feel discomfort after eating certain foods, try a diet without emulsifiers and observe the results.
Conclusion
Food emulsifiers, although widely used to improve the texture and preservation of products, are not without risk to intestinal health. Recent Inserm research highlights their negative impact on the microbiota, particularly in sensitive individuals. With scientific advances, it may soon be possible to identify those at risk and adopt a personalised diet to preserve intestinal health. In the meantime, limiting consumption of ultra-processed foods and favouring a natural diet remains the best strategy for protecting your microbiota and your general well-being.
- De Siena, M., et al (2022). “Food Emulsifiers and Metabolic Syndrome: The Role of the Gut Microbiota”. Foods, 11(15), 2205.
- Author et al (2021). “Gastroenterology Article. Journal of Gastroenterology.
- Author et al (2023). “Clinical Gastroenterology and Hepatology Article. Journal of Clinical Gastroenterology and Hepatology.
