Emulsifiers Make Food Appetizing yet Bring Health Dangers

April 12, 2024 — Creamy, thick, and velvety: Without emulsifiers, your favorite ice cream or muffin might not taste the same. Yet research warns that there is a darker side to these substances, from polysorbate-80 to carrageenan. Evidence links emulsifiers with upset gut microbiome, inflammation, and several conditions, from heart attacks to breast cancer. 

What’s more, emulsifiersdon’t necessarily equal junk food. Such substances can be found in many foods that are often considered healthy, such as some low-fat Greek yogurts, trail mix bars, or oat milk. 

There are over 100 different emulsifiers that can be added to foods. They prevent separation of oil and water, improving texture. A 2023 study found emulsifiers in as many as 95% of British supermarket pastries and cakes, 55% of breads, and 36% of meat products. 

Certain goods that contain emulsifiers may not fit neatly into traditional dietary categories. Reduced-fat dairy products are a good example, said Benoit Chassaing, PhD, a microbiologist at the French National Institute of Health and Medical Research (INSERM). “If [producers] remove fat, they need to replace it with something else. So very often, if you buy fat-free or low-fat cream or cream cheese, it will be loaded with dietary emulsifiers,” he said. 

Andrew Gewirtz, PhD, a microbiologist at Georgia State University, said emulsifiers have long been considered safe for consumption because many of them pass through the body unabsorbed. It was “presumed that therefore they can’t possibly do anything negative,” he said.  This view began to shift as we recognized the importance of gut microbiota for health. Now the fact that emulsifiers could reach the gut almost unchanged made them “prime suspects involved in perturbing the microbiota,” Gewirtz said. 

When you eat something that contains emulsifiers, the nutrients and water in the food will be absorbed along your digestive tract. Various additives, however, will stay relatively intact. “We think that they can reach higher concentration in the gut,” Chassaing said. Once there, some emulsifiers can change microbiota composition and function, prompting gut bacteria to give off pro-inflammatory molecules. This, in turn, could lead to a variety of chronic inflammatory diseases, from diabetes to cardiovascular disease.

One of the strongest arguments for the negative effects of food emulsifiers came from a 2022 trial conducted by Gewirtz, Chassaing, and their colleagues. For that experiment, 16 volunteers were randomized to either eat an emulsifier-free diet or one containing high doses of CMC. For 11 days the participants were housed at a local hospital and fed an identical diet, with one exception: some of them received desserts made with CMC. The results showed that eating the emulsifier was linked with more complaints of abdominal discomfort, as well as the loss of health-promoting metabolites released by gut microbes such as the short-chain fatty acids. 

Other research suggests, meanwhile, that emulsifiers may impact human gut directly. When researchers from Italy applied dietary emulsifiers to human cells derived from colon cancer, they found that it made such cells proliferate faster. This could point to a role of emulsifiers in cancers of the gastrointestinal tract, confirming the results of the French population studies. Emulsifiers could also act as a gateway for other potentially harmful chemicals. In experiments conducted on both human cell lines and on rats, polysorbate 80 damaged the mucus barrier in the intestine, leading to its increased permeability — the infamous “leaky gut.” This helped phthalates, chemical compounds that are commonly added to plastics and which, once ingested, can be transformed into endocrine disruptors, to be easier absorbed by the body.

The safest bet to keep your gut healthy would be to eat homemade foods and shy away from emulsifiers altogether. However, Bancil said, for some people, especially those with a busy lifestyle, this may be tricky to do. As such, checking out labels might be a better approach. “Very often there is an alternative,” Chassaing said. “You have a lot of dietary emulsifiers in ice cream, but you can find some brands that will be doing emulsifier-free ice cream,” he said. 

Counterintuitively, cheaper foods are sometimes less loaded with emulsifiers than are pricier options. “There might be a branded ketchup, and there might be a supermarket’s own brand. The branded one, which might be more expensive, might have emulsifiers in it, but the own brand might not have emulsifiers,” Bancil said. 

Same goes for foods marketed as healthy, said Megan Rossi, PhD, a nutritionist at King’s College London. “Let’s just be cautious and not automatically assume that they’re better for you,” she said. 

Yet studying labels is not without its challenges. That’s because “emulsifiers might be labelled as different things,” Bancil said. So carboxymethylcellulose could appear on a label as CMC, cellulose gum, modified cellulose or, in Europe, as E466. Carrageenan could be called Irish moss, Eucheuma extract, or E407.

According to Gewirtz, considering the results of animal research and in vitro studies, as well as of the preliminary human trials, the food industry should be encouraged to look for safer alternatives, particularly to synthetic emulsifiers. Chassaing hopes that “in the future we’ll be able to select and to favor the use of additives that are much more well tolerated by the microbiota.” However, he said, “this is not yet the case.”