Do Food Emulsifiers Cause Weight Gain and Problems with Gut Health?

Medically reviewed by Abbey Sharp, Registered Dietitian (RD), BASc.

Do food emulsifiers cause weight gain and other problems related to gut health? We dig into the research to uncover the truth about these common food additives.

We’re likely all familiar with the merits of a delicious balsamic and oil vinaigrette, the combination that can only stay together with the help of an emulsifying agent. While food emulsifiers have been our go-to for delicious sauces and dishes, we’ll be exploring the other side of the story – its potential negative effects on our gut health, weight gain and overall wellbeing.

What is an Food Emulsifier?

Remember the saying: “oil and water don’t mix”? Basically, it means these two components will separate and an emulsifier is needed to keep everything together. Emulsifiers are a food additive (which can be natural or artificial) that ensures different ingredients do not separate when combined. They contain hydrophilic (water-attracting) and hydrophobic (lipid/fat-attracting) components. The hydrophobic end surrounds the hydrophilic when shaken, mixed, or whisked well, and are commonly used in ice cream, chocolate, breads, salad dressings, and vegetarian meat products. To help keep the two components together without separating, we need an emulsifier – often, in the case of a homemade dressing, it’s something like mustard. Food emulsifiers are also important in cooking and baking; for example, chefs use the power of egg yolks’ lecithin to ensure their hollandaise sauce doesn’t separate.

While we do have some natural food emulsifiers like eggs and mustard, most of the foods we eat with emulsifiers are added and heavily processed. In fact, the Government of Canada – Health Canada has an entire list of acceptable food additives, including emulsifiers, that can be found and are deemed safe to be used in foods. However, since the publication of a 2015 research study conducted on mice went viral, we’ve witnessed a plethora of concerning emulsifier-bashing headlines. The claim?  Food additives like food emulsifiers are causing chaos to our gut, leading to weight gain and other health problems. Let’s take a deeper dive into the question, “Do Food Emulsifers Cause Weight Gain and Problems with Gut Health?”

Food Emulsifiers and Gut Health

Inflammatory bowel disease (IBD) is a general term referring to conditions like Crohn’s disease (CD) and ulcerative colitis (UC). CD and UC affect gut health by causing gastrointestinal tract inflammation, which has negative effects on dietary intake, uptake of nutrients from food, and optimal bowel function. While it’s suggested that genetics may play a biological role in those who develop IBD, this blog post focuses on the potential environmental impact from food additives. In 2012, roughly 233,000 Canadians had inflammatory bowel disease – suggesting, compared to worldwide rates, Canada has a high number of new cases and those diagnosed with IBD. Within the last 40-50 years in regions like North America, Japan, and Singapore we’ve seen an increase Crohn’s disease cases, which is not well understood. But recent research in Japan has led to a hypothesis that dietary intake of emulsifying-containing products may play a role in Crohn’s disease. It’s also interesting to note that as the rates are rising, Japan’s diet is becoming more in sync with the typical Western diet, which includes a variety of processed foods. While most emulsifiers are digested in the small intestine, it’s suggested that emulsifiers may increase intestinal permeability, meaning the emulsifiers may pass through the small intestine without digestion. The concern is that this may increase the risk of bacterial translocation aka the movement of bacteria from the gut to various parts of the body. With regards to this theory, it’s important to mention that this is solely a hypothesis and has yet to be effectively studied in humans. The researcher behind this theory also cites the rise in Crohn’s and the rise in consumption of emulsifiers as a strong positive correlation, however we all know from our statistics course that correlations do not mean CAUSE and EFFECT. Another thing to point out with regards to emulsifiers and gut health, is that the rise in fast food intake is also associated with a 3 to 4-fold greater risk for developing Crohn’s Disease, which may or may not contain emulsifiers. It’s hard to know if it’s the emulsifiers per se that are responsible for the rise in CD, when there are other factors that may contribute (genetics, smoking, low fibre diet, high fat diet etc.)

One study did attempt to find out whether food emulsifiers have an impact on increasing the bacteria E-Coli in the body. This in vitro study included cells taken from patients with and without Crohn’s disease. They found that those given the food emulsifier Polysorbate-80 saw an increase in bacterial translocation of E-Coli. Is this a perfect study that we can make definitive conclusions from? Definitely not. They only studied one emulsifier – polysorbate 80 – which severely limits the scope, AND more importantly, they didn’t have a control group (KINDA important). So, more studies are needed to look at specific types and quantity of emulsifiers.

In a 2015 study conducted on mice (with the intention to mirror our gut), researchers looked to see how consuming an emulsifier (carboxymethylcellulose or polysorbate-80) would impact inflammatory gut health and metabolic syndrome. The first (control) group of mice had a healthy, normal gut while the second group (given the emulsifier) had a higher risk of inflammatory bowel disease (IBD). Interestingly, a third group of germ-free mice were transferred the gut microbiota (via feces with contains guts bacteria) from the mice consuming the dietaryfood  emulsifiers. The third group of mice experienced changes in gut bacteria, gut inflammation, signs of metabolic syndrome such as weight gain, and altered blood glucose levels. When mice were exposed to dietary emulsifiers, the protective lining that separates the microbiome and intestinal walls was reduced resulting in inflammation of the gut. If that was complicated and scary, don’t freak out quite yet. Mice studies may be able to give us some clues for where to begin our research, but ultimately, studies conducted on humans are really the key to making any conclusive remarks.

BUT WAIT! The researchers thought the same thing! The same team from the aforementioned mice study conducted a study looking at the role of emulsifiers and gut inflammation in humans… well not REALLY humans. They used this model known as the Simulator of the Human Intestinal Microbial Ecosystem (SHIME), which is a really fascinating piece of equipment that mimics the entire gastrointestinal tract incorporating the stomach, small intestine and specific colon regions. I guess, the next best thing besides a real human being. They examined the two dietary food emulsifiers in the SHIME (polysorbate 80 and carboxymethylcellulose), which revealed that they both acted on the human gut and increased inflammation. Based on the research, they concluded that our guts can be directly affected by these common food additives and may be contributing to gut inflammation which puts us at risk for chronic diseases, such as Crohn’s Disease.

Before we jump on board the anti-additives train, we still cannot confidently make these solid conclusions on the role of emulsifiers on gut health. Remember, these studies haven’t used REAL humans yet… we’re talking about a bunch of mice and a piece of human-like equipment. The human body is a very different beast. We also don’t know the role of all additives, since only a select few were used in this study. For now, the grade of evidence is low and it’s impossible to make sound conclusion.

Final Verdict on Food Emulsifiers and Weight Gain

In no means should this scare you from ever having a scoop of ice cream – everything can be consumed in moderation. In a society where we are moving away from unprocessed, homemade, fresh food, towards a diet based on factory-made, ultra-processed, convenience food, it’s no wonder chronic diseases are rising as well. However, it’s still to early to suggest a direct causation between the consumption of food emulsifiers and the rise of chronic diseases such as inflammatory bowel disease and obesity. There may be other influences from our dietary intake, such as the increase in low nutrient dense processed foods which are often high in fat and sugar, and a decrease in nutrient dense foods. There definitely needs to be more high-quality human research done in this area so we can conclusively understand its role and effect on our gut health. In general, I recommend trying to enjoy the majority of your foods as unprocessed as possible (for reasons beyond gut health), but also recognize that there’s room in the diet to enjoy a little of everything totally guilt free.

Now I want to hear from you: 

What have you heard about emulsifiers? 

What are your thoughts?

Contribution by

Abbey Sharp, RD

Sofia Tsalamlal, MHSc RD

Christina Demirkok #FutureRD

Updated on September 1st, 2022