The gut microbiome exhibits many physiological functions, such as supporting and nourishing gut-lining cells, maintaining intestinal integrity, the production of essential vitamins, and protecting against pathogens. An altered composition or an overgrowth in microorganisms disrupts the body’s homeostasis and can lead to the development of inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and metabolic diseases such as diabetes, obesity and allergies.

Dysbiosis can also lead to small intestinal bacterial, fungal, or yeast overgrowth (SIBO/SIFO/SIYO respectively) and/or large intestinal bacterial (or fungal) overgrowth, and/or a toxic colon, whereas transit is altered and waste materials linger too long inside the bowel, allowing for toxins and detoxified hormones to reenter the blood circulation and participate further in hormone dysregulation and disease progression, such as oestrogen dominance syndrome.

Parasites and heavy metal toxicity can also exacerbate the problem and cause a vicious cycle of damage, deficiencies, and dis-ease.

So now we know how fragile the gut ecosystem is, and unbalances can cause a multitude of health issues, including systemic, liver and brain inflammation. But what do food additives have to do with our gut?

There has been a tsunami of studies that have flooded the medical field of research with incontestable data proving the damaging health effects of certain food additives and their association with obesity and gut disease.

The main culprits: emulsifiers.

What research found?

Research published in Nature back in 2015 already suggested that artificial preservatives commonly used in processed foods may increase the risk of inflammatory bowel diseases and metabolic disorders. Animal studies focused on emulsifiers: chemical additives such as carboxymethylcellulose and polysorbate-80.

Even at one-tenth of the FDA-approved concentration, effects were observed. The study highlights potential connections between emulsifiers, gut inflammation, and changes in metabolism.

Although their diet was not otherwise changed, healthy mice whose water contained the chemicals became obese and developed metabolic problems such as glucose intolerance. In mice genetically engineered to be prone to inflammatory gut diseases, emulsifiers also seemed to increase the severity and frequency with which the animals developed inflammatory bowel disease.

What are emulsifiers?

Emulsifiers, which are added to most processed foods, help mix and stabilise two immiscible substances, such as oil and water (either droplets of oil dispersed in water or droplets of water dispersed in oil), in a uniform and stable emulsion. They also aid in improving texture and extending shelf life and are part of a complete set of food additives specifically designed to make ultra-processed manufactured products palatable (if you knew how they were made you wouldn’t go near it, ever!), more appealing (if you knew how they look like before colourings and other chemicals were added to the recipe, you will be sick in your stomach), and more specifically addictive.

Emulsifyers have both natural and synthetic origins and are commonly used, such as:

• Egg Yolks (contain lecithin, a natural emulsifier)

• Soy (also contains lecithin — Lecithin is often found under the E number: E322)

• Mustard

• Honey (contains proteins that can function as emulsifiers)

• Agar (E406)

• Carrageenan (E407)

• Guar gum (E412)

• Canola oil (typically GMO in the U.S.)

• Alginic acid (E400 — thickener or gelling agent derived from seaweed)

• Sodium alginate (E401 — made from seaweed, it is widely used in cooking as a thickener, emulsifier and texturiser)

• Potassium alginate (E402)

• Ammonium alginate (E403)

• Calcium alginate (E404)

• Propane-1,2-diol alginate or propylene glycol alginate (E405 — a petroleum derivative used as a carrier, emulsifier, stabiliser, thickener in ice cream, confectionery, dressings and more. It is also used in beer to make froth denser and longer lasting)

• Locust bean gum; carob gum (E410)

• Tragacanth (E413 — a natural gum obtained from the dried sap of several species of Middle Eastern legumes of the genus Astragalus)

• Acacia gum; gum arabic (E414)

• Xanthan gum (E415 — used as a thickener, stabiliser and emulsifier, xanthan gum is made when strains of the Xanthomonas campestris bacteria are fed a solution of glucose derived from corn, soy, dairy or wheat. Xanthan gum can have laxative effects and exacerbate gut issues)

• Karaya gum (E416 — made from the sap of trees of the genus Sterculia, which is native to India and surrounding countries, it has a high affinity with water. It may also have laxative effects, but is also found to have many health benefits)

• Tara gum (E417)

• Gellan gum (E418)

• Konjac (E425)

• Soybean hemicellulose (E426)

• Cassia gum (E427)

• Polyoxyethylene sorbitan monolaurate; Polysorbate 20 (E432 — often found to be laden with impurities, due to ethylene oxane, which is used as a pesticide and a sterilising agent, and a known carcinogenic.[1-3]

• Polyoxyethylene sorbitan mono-oleate; Polysorbate 80 (E433)

• Polyoxyethylene sorbitan monopalmitate; Polysorbate 40 (E434)

• Polyoxyethylene sorbitan monostearate; Polysorbate 60 (E435)

• Polyoxyethylene sorbitan tristearate; Polysorbate 65 (E436)

• Pectins (E440)

• Ammonium phosphatides (E442 — synthetic lecithins used in chocolate production and confectionery)

• Brominated vegetable oil (E443 — banned un Europe)

• Sucrose acetate isobutyrate (E444 — added to cocktail mixers, beer, malt beverages, or wine coolers, as a potential replacement for brominated vegetable oil. An intake of over 2 grams a day is shown to be carcinogenic and has reproductive and developmental studies in animal studies).

• Glycerol esters of wood resins (E445 )

• Cellulose (E460)

• Methylcellulose (E461)

• Ethylcellulose (E462)

• Hydroxypropyl cellulose (E463)

• Hydroxypropyl methylcellulose (E464)

• Ethyl methylcellulose (E465)

• Carboxymethylcellulose (E466)

• Crosslinked sodium carboxy methyl cellulose (E468)

• Enzymatically hydrolysed carboxy methyl cellulose (E469)

• Sodium, potassium and calcium salts of fatty acids (E470a)

• Magnesium salts of fatty acids (E470b)

• Mono- and diglycerides of fatty acids (E471)

• Acetic acid esters of mono- and diglycerides of fatty acids (E472a)

• Lactic acid esters of mono- and diglycerides of fatty acids (E472b)

• Citric acid esters of mono- and diglycerides of fatty acids (E472c)

• Tartaric acid esters of mono- and diglycerides of fatty acids (E472d)

• Mono- and diacetyltartaric acid esters of mono-and diglycerides of fatty acids (E472e)

• Mixed acetic and tartaric acid esters of mono-and diglycerides of fatty acids (E472f)

• Sucrose esters of fatty acids (E473)

• Sucroglycerides (E474)

• Polyglycerol esters of fatty acids (E475)

• Polyglycerol polyricinoleate (E476)

• Propane-1,2-diol esters of fatty acids (E477)

• Thermally oxidised soya bean oil interacted with mono­ and diglycerides of fatty acids (E479b)

• Sodium stearoyl-2-lactylate (E481)

• Calcium stearoyl-2-lactylate (E482)

• Stearyl tartrate (E483)

• Sorbitan monostearate (E491)

• Sorbitan tristearate (E492)

• Sorbitan monolaurate (E493)

• Sorbitan monooleate (E494)

• Sorbitan monopalmitate (E495)

• Invertase (E1103 — an enzyme that breaks down sucrose into fructose and glucose)

These are only a few of one class of additives added to processed food products, and many can be found together in any one product. It is suspected it is the combination of those substances, how often and how much that is the issue.

Many of these substances are also added to products like cosmetics and personal care products, so we may be exposed to excessive levels of man-made chemicals every day of our lives the more unhealthy we eat and the more unnatural products we apply to our skin, many of which are direct derivatives of petroleum, which could potentially be contaminated with polycyclic aromatic hydrocarbons (PAHs).

Many other additives, such as parabens, mineral oils, phthalates, colourings, fragrances, nitrates and nitrites, potassium bromate, titanium dioxide (added to anything white to make it more white), butylated hydroxyanisole and butylated hydroxytoluene (preservatives found in cereals, chewing gum, potato chips, and vegetable oils to prevent the food from changing colour or become rancid), have been found to be serious health hazards, even more so when found in combination of other additives, such as emulsifiers.

What is IBD?

Inflammatory Bowel Disease (IBD) is a chronic condition that involves inflammation of the gastrointestinal tract. There are two main types: Crohn's disease and ulcerative colitis.

In IBD, the immune system mistakenly attacks the digestive tract, causing persistent inflammation and various symptoms. These may include abdominal pain, diarrhoea, weight loss, and fatigue.

The exact cause is not fully understood but likely involves a combination of genetic, environmental, and immune factors.

Conventional treatment aims to manage inflammation, alleviate symptoms, and improve the patient's quality of life through medications, lifestyle adjustments, and, in some cases, surgery.

What is Metabolic Syndrome?

Metabolic syndrome is a cluster of very common obesity-related disorders that can lead to type 2 diabetes, cardiovascular disease, and liver disease (e.g., NAFLD).

The main components of metabolic syndrome include:

• Abdominal Obesity and an excess of visceral fat around the waist.

• Consistently elevated Blood Pressure

• Insulin resistance or elevated fasting blood glucose levels.

• Elevated levels of triglycerides in the blood.

• Low levels of high-density lipoprotein (HDL) cholesterol, which is often referred to as "good" cholesterol.

Having three or more of these conditions qualifies as metabolic syndrome. The syndrome is associated with lifestyle factors such as sedentary behaviour, unhealthy diet, and obesity.

The link between emulsifiers, IBD and metabolic Syndrome

incidence of IBD and metabolic syndrome has been markedly increasing since the mid-20th century.

The researchers leading the study cited at the beginning of this article suggest emulsifiers might be partially responsible for the disturbance and the increased incidence of these diseases. This what they have to say:

Chasaaing and Gewirtz hypothesised that emulsifiers might affect the gut microbiota to promote these inflammatory diseases and animal studies gave the answers.

The team fed mice two very commonly used emulsifiers (carboxymethylcellulose and polysorbate-80) at doses seeking to model the broad consumption of the various emulsifiers that are found in almost all processed foods. They observed that emulsifier consumption altered the composition of the gut microbiota into a more pro-inflammatory. Certain bacteria had the enhanced capacity to digest and infiltrate the dense mucous layer that lines and protects the intestines from the outside environment. The dense mucous layer is typically void of bacteria. Subsequently, it activated pro-inflammatory gene expression by the immune system.

Such transformation triggered chronic colitis in mice genetically prone to this disorder, as a result of immune hyperresponsiveness. Oppositely, in mice with normal immune systems, emulsifiers induced low-grade or mild inflammation and metabolic syndrome, characterised by increased food consumption, obesity, hyperglycaemia, and insulin resistance.

Most surprisingly, the effects of emulsifier consumption were absent in germ-free mice (they do not have a microbiota). But that’s not all. Transplant of microbiota from emulsifier-treated mice to germ-free mice was sufficient to transfer some parameters of low-grade inflammation and metabolic syndrome, indicating a central for the microbiota in mediating the adverse effects of emulsifiers.

The team is now investigating a larger list of emulsifiers and designing experiments to investigate how emulsifiers affect human health. If similar results are obtained, we may expect to find a role for this class of food additive in driving the epidemic of obesity, its inter-connected consequences and a range of diseases associated with chronic gut inflammation.

While many other players are at play, and the detailed mechanisms underlying the effect of emulsifiers on metabolism are still under study, the team recommends avoiding excess food consumption, as well as that of processed food products.

The researchers have also noted that the results suggest that current means of testing and approving food additives may not be adequate to prevent the use of chemicals that promote diseases driven by low-grade inflammation or be a cause of problems in susceptible individuals.

References:

1. U.S. Environmental Protection Agency (EPA). (2018). Ethylene Oxide. Available at: https://www.epa.gov/sites/default/files/2016-09/documents/ethylene-oxide.pdf. Last accessed: 9th November 2023.

2. CDC. (2022). Ethylene Oxide. Available at: https://www.cdc.gov/niosh/topics/ethyleneoxide/default.html. Last accessed: 9th November 2023.

3. UK Health Security Agency. (2022). Ethylene oxide: General information. Available at: https://www.gov.uk/government/publications/ethylene-oxide-properties-and-incident-management/ethylene-oxide-general-information. Last accessed: 9th November 2023.

Cox, S. et al. (2021). Food additive emulsifiers: A review of their role in foods, legislation and classifications, presence in food supply, dietary exposure, and safety assessment. Nutrition Reviews. 79(6), pp. 726-41

De Siena, M. et al. (2022). Food emulsifiers and metabolic syndrome: The role of the gut microbiota. Foods. 11(15), 2205. doi:10.3390/foods11152205

EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), Mortensen, A. et al. (2017). Re‐evaluation of E440i and E440ii as food additives. EFSA Journal. 15(7), e04866.

EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), Mortensen, A. et al. (2017). Re‐evaluation of E 322 as a food additive. EFSA Journal. 15(4), e04742.

Food Standard Agency. (2022). Approved additives and E numbers. Available at: https://www.food.gov.uk/print/pdf/node/847

Hasenhuettl, GL. Hartel, RW. (Eds.). (2008). Food emulsifiers and their applications (Vol. 19). New York: Springer.

Laudisi, F. Stolfi, C. Monteleone, G. (2019). Impact of food additives on gut homeostasis. Nutrients. 11(10), 2334. doi:10.3390/nu11102334

Raoul, P. et al. (2022). Food additives, a key environmental factor in the development of IBD through gut dysbiosis. Microorganisms. 10(1), 167. doi:10.3390/microorganisms10010167

Zeisel, SH. (1981). Dietary choline: Biochemistry, physiology, and pharmacology. Annual Review of Nutrition (USA).