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 dark side to these substances, from polysorbate-80 to carrageenan. Evidence connects emulsifiers with disturbed intestinal microbiome, inflammationand various conditions, from heart attacks to breast cancer.
What‘more, emulsifiersmafia boss‘It doesn’t necessarily equate to junk food. Such substances are found in many foods that are often considered healthy, such as some low-fat Greek yogurt, trail mix bars or oat milk.
There are more than 100 different emulsifiers that can be added to foods. They prevent the separation of oil and water and improve the texture. a 2023 study found emulsifiers in as many as 95% of British pastries and cakes in supermarkets, 55% of bread and 36% of meat products.
Certain goods containing emulsifiers may not fit neatly into traditional food categories. Dairy products with reduced fat content are a good example of this Benoit Chassaing, PhD, microbiologist at the French National Institute of Health and Medical Research (INSERM). “Like [producers] remove fat, they should replace it with something else. So if you buy fat-free or low-fat cream or cream cheese, it’s often packed with dietary emulsifiers,” he said.
From a health perspective, that is bad news. In 2024, Chassaing and his colleagues published a study based on 92,000 French adults who provided detailed data about the foods they ate, including brand names. The results showed that people who ate the highest levels of emulsifiers had a significantly increased risk of cancer. For carrageenans, which are emulsifiers derived from seaweed, increased the risk of breast cancer by 32%. Another type of emulsifier, mono- and diglycerides of fatty acids, increased the risk of prostate cancer by 46%. A related one 2023 study linked dietary intake of emulsifiers to an increased risk of cardiovascular disease. The worst offenders included Micrystalline cellulose and carboxymethylcellulose (CMC), which can be found in ice cream or processed cheese.
Although population studies suggest a link between food emulsifiers and poor health, they do not prove that the additives directly cause the negative health outcomes. What can help are laboratory studies. For such experiments, researchers often use a human intestinal simulator, a machine that can do that resemble a row of old-fashioned milk bottles connected via pipes to a telephone exchange. The bottles contain gut microbiota from human feces, to which scientists add various emulsifiers (admittedly, the lab can be quite smelly). In one such study published in 2024Researchers from Belgium have shown that polysorbate 80, a synthetic emulsifier commonly used in dairy products and salad dressings, reduces the number of friendly gut bacteria, such as Faecalibacterium prausnitziiwhile the number of people associated with inflammation increases.
Andreas Gewirtz, PhD, a microbiologist at Georgia State University, said emulsifiers have long been considered safe for consumption because many are not absorbed by the body. It was “assumed that therefore they cannot possibly do anything negative,” he said. This view began to change when we recognized the importance of the gut microbiota for health. The fact that emulsifiers could reach the intestines virtually unchanged made them “prime suspects involved in disrupting the microbiota,” Gewirtz said.
When you eat something that contains emulsifiers, the nutrients and water in the food are absorbed through your digestive tract. However, several additives remain relatively intact. “We think they can reach a higher concentration in the intestines,” Chassaing said. Once there, some emulsifiers can composition and function of the microbiota change, causing intestinal bacteria to release pro-inflammatory molecules. This in turn could lead to a variety of chronic inflammatory diseases diabetes Unpleasant cardiovascular disease.
One of the strongest arguments for the negative effects of food emulsifiers came from a 2022 trial executed by Gewirtz, Chassaing, and their colleagues. For that experiment, 16 volunteers were randomized to eat either a diet without an emulsifier or a diet with high doses of CMC. For 11 days, the participants were housed in a local hospital and fed an identical diet, with one exception: some of them were given desserts made with CMC. The results showed that eating the emulsifier was associated with increased complaints of abdominal pain, as well as the loss of health-promoting metabolites released by gut microbes, such as the short-chain fatty acids.
“It confirmed the idea that emulsifiers influence the gut microbiota, changing species composition,” Gewirtz said.
Things got particularly bad for two of the participants: Their gut bacteria invaded the normally sterile inner mucus layer of the intestine, a condition that can lead to Crohn’s disease or U.S.lcerative inflammation A follow-up study from 2024 revealed that this was likely due to the composition of the two participants’ gut microbiome.
They had “microbiota that were very sensitive to the disturbance,” Chassaing said. If you transfer intestinal bacteria from such patients to mice, “you can cause very strong colitis,” he said. However, the trial was small, and, like Aaron BancilM.D., a gastroenterologist from King’s College London said the participants were given quite high doses of CMC: 15 grams per day. While some people do ingest these types of doses through their regular diet, “it’s not going to be something that’s consumed frequently,” he said.
Meanwhile, other research suggests that emulsifiers may have a direct impact on the human intestines. When researchers from Italy applied nutritional emulsifiers to human cells derived from colon cancer, they did just that found it that it caused such cells to multiply faster. This could indicate a role of emulsifiers in cancer of the gastrointestinal tract, confirming the results of the French population studies. Emulsifiers can also act as a gateway for other potentially harmful chemicals. In experiments performed on both human cell lines and rats, polysorbate 80 damaged the intestinal mucus barrier, leading to increased permeability — the infamous ‘leaky gut’. This helped phthalates, chemical compounds often added to plastics that, once ingested, can be metabolized to endocrine disruptorsto be more easily absorbed by the body.
Animal research shows that consuming emulsifiers can also lead to anxiety. Mice fed CMC and polysorbate 80 showed changes in the… areas of the brain responsible for stress response, such as the amygdala. And are fed to mice as emulsifiers during the pregnancysuch effects can also be passed on to their offspring. But according to Bancil, while animal models are informative, “we can’t fully translate those things to humans.”
Furthermore, not all emulsifiers appear to be equally harmful. When Chassaing, Gewirtz and their colleagues tested 20 common dietary emulsifiersthey discovered that some, like carrageenans, guar gum and xanthachewing gum had notable harmful effects, while others, such as lecithin, were less harmful. Lecithin is a natural emulsifier, usually derived from eggs and soy. As such, Gewirtz said, it does not reach the intestines unabsorbed the way synthetic emulsifiers do. On the other hand, “polysorbate 80, carrageenansand also a lot of the gums, xanthan gum and guar gum, which are really very aggressive to the microbiota,” Chassaing said.
There may be ways to protect the gut microbiome from the harmful effects of dietary emulsifiers. When researchers fed mice mucus-strengthening bacteria, Akkermansia muciniphila, it prevented the damage caused by eating CMC and polysorbate 80. Still, Gewirtz cautioned that doesn’t mean we should all rush to stock up on supplies. akkermansia pills, because such supplements ‘just haven’t been tested really well’.
The safest bet for keeping your gut healthy is to eat home-cooked foods and avoid emulsifiers altogether. However, Bancil said this can be difficult for some people, especially those with busy lifestyles. Therefore, checking labels may be a better approach. “Very often there is an alternative,” says Chassaing. “You have a lot of food emulsifiers in ice cream, but you can find some brands that make emulsifier-free ice cream,” he said.
Counterintuitively, cheaper foods sometimes contain fewer emulsifiers than more expensive options. “There can be a branded ketchup, and there can be a supermarket’s own brand. The branded product, which may be more expensive, may contain emulsifiers, but the private label may not contain emulsifiers,” Bancil said.
The same goes for foods marketed as healthy, he said Megan Rossi, PhD, nutritionist at King’s College London. “Let’s be careful and not automatically assume they’re better for you,” she said.
Yet studying labels is not without challenges. That’s because “emulsifiers can be labeled 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 mossEucheuma extract, or E407.
According to Gewirtz, given the results of animal and in vitro studies, as well as preliminary human trials, the food industry should be encouraged to look for safer alternatives, especially to synthetic emulsifiers. Chassaing hopes that “in the future we will be able to select and promote additives that are much better tolerated by the microbiota.” But according to him, that is not yet the case.