What are emulsifiers, and are they safe?

Emulsifiers are food additives that manufacturers add to a huge number of products — from bread and cake to cocktail mixers and beer. 

In this feature, we’ll explain what they are, how they work, where they’re found, and whether they affect your health.

What do emulsifiers do?

In short, emulsifiers help mix together compounds in food that wouldn’t normally mix. 

A common example is oil and water. If you put droplets of oil into water, the oil will stay in separate blobs. If you whisk or stir it, they’ll mix but eventually separate back out.

For instance, manufacturers use emulsifiers in mayonnaise to ensure that it doesn’t separate into layers of oil and vinegar. 

Emulsifiers also stop foods from being sticky, giving them a smoother texture and flavor.

How do they work?

Although, chemically, they can be very different, emulsifiers all have something in common. 

Each has two distinct ends. One loves water but hates oil — and so it's called hydrophilic. The other end loves oil but hates water, and so it's called hydrophobic.

One end of each emulsifier molecule ends up facing the oil in a substance, and the other end faces the water.

This stops the blobs of oil from joining back together and keeps them evenly distributed through the mixture. And so, an emulsion is born.

Where are they used?

Here are just some of the many places where food manufacturers use emulsifiers:

• bread, to increase volume, softness, and shelf life

• chocolate, to help it mold and keep it from turning white if it’s stored somewhere warm

• ice cream, frozen yogurt, sorbet, etc., to make it smoother, keep it from melting too quickly, and help it thaw and refreeze 

• margarine, to help with stability, texture, and taste 

• processed meat, to keep proteins, water, and fat from separating

What are emulsifiers?

Many different compounds act as emulsifiers. In the food industry, they’re either natural — made from plants or animals — or synthetic but similar to the natural ones.

And in the United States, the Food and Drug Administration (FDA) has approved 171 “emulsifiers or emulsifying salts.”

Here are some common examples of those used in the U.K. and U.S. The codes that start with “E” appear on food labels in the European Union and U.K.

• lecithin (E322), a fatty substance often derived from soybeans and sunflowers

• alginic acid (E400), isolated from seaweed

• agar (E406), extracted from the cell walls of algae

• carrageenan (E407), also made from seaweed

• carob bean gum (E410), extracted from carob tree seeds

• guar gum (E412), extracted from guar beans

• xanthan gum (E415), created by fermenting sugar with a particular species of bacteria

• methyl cellulose (E461), derived from cellulose in plant cell walls

• hydroxypropyl cellulose (E463), also made from cellulose 

• sodium carboxymethyl cellulose (E466), derived from cellulose, too

• mono- and diglycerides of fatty acids (E471), a mixture of fatty acids and an alcohol called glycerol

• castor oil (E1503), extracted from the castor oil plant

How much do we consume?

Regional bodies, like the FDA and FSA, set the acceptable daily intake (ADI), which is the amount of something you can consume daily before it starts presenting a health risk.

But measuring how much people consume on average is tricky. And we all eat different amounts of different foods, so we all have different levels of exposure. 

One study looked at the intake of a handful of additives, including some emulsifiers, in the U.K., Italy, France, and Ireland. The researchers found that children and adults do exceed the ADI of some emulsifiers.

Meanwhile, research in the U.S. assessed the intake of 7 of the 171 emulsifiers in use. And it concluded that most people didn’t go over the ADI.

Do emulsifiers impact health?

Like all food additives in the U.S., E.U., and U.K., emulsifiers have to be deemed safe by the relevant regional organization. 

However, all of the research used to calculate these ADIs was conducted in animals.

Some emulsifiers don’t have an ADI, including lecithins, mono- and diglycerides of fatty acids, and guar gum.

This is because even very high doses didn’t seem to cause any concerning health effects in studies.

Gaps in the research

Most relevant studies focus on cancer and genotoxicity — a compound’s ability to damage your genetic information. Other possible effects, like those on your gut or metabolic health, receive less attention.

But before we dig into the details, it’s worth remembering that most of the studies below were conducted on animals or in a lab. So, we can’t assume that the results apply to us.

Also, the researchers only investigated one emulsifier at a time, for relatively short periods. So, the results can’t help us understand the cumulative effects of consuming cocktails of emulsifiers daily over a lifetime.

Altered gut microbiome

A study in mice found that the emulsifier polysorbate-80 reduced the diversity of the small intestine’s microbiome. 

Another study, also in mice, found that the emulsifier glycerol monolaurate caused an imbalance in the gut microbiome, as well as inflammation and metabolic syndrome.

Metabolic syndrome is a collection of obesity-related changes to blood pressure, blood sugar, blood fat, and cholesterol levels.

In particular, the scientists write, “Carboxymethylcellulose and polysorbate-80 induced a lasting, seemingly detrimental impact on microbiota composition and function.” 

Introducing IBD

Inflammatory bowel disease (IBD) is an umbrella term for conditions that cause long-term gut inflammation. The two most common forms of IBD are Crohn’s disease and ulcerative colitis.

Symptoms can include ongoing diarrhea, abdominal pain, weight loss, rectal bleeding, and fatigue. These tend to fluctuate over time, worsening then improving. This process is called remission and relapse.

In a healthy gut, a mucous barrier protects the gut’s lining. It stops gut bacteria from reaching the lining and triggering an immune response. 

In people with IBD, this barrier is deficient, so it’s easier for bacteria to reach the lining and trigger inflammation.

They wonder if emulsifiers might disturb the mucous lining, making it less effective. So, let’s look at some of the research.

Emulsifiers and IBD

One study focused on the common emulsifier carboxymethylcellulose. 

Looking at the effects in mice susceptible to an IBD-like condition, the team found that carboxymethylcellulose caused gut inflammation and an overgrowth of bacteria.

The study’s authors conclude that carboxymethylcellulose “is an ideal suspect to account for the rise of IBD in the 20th century.” 

Another study that used a mouse model of IBD found that the emulsifier methylcellulose worsened the condition.

A review of research into emulsifiers and IBD outlines the results of 26 studies, including lab studies on cells and studies in mice, rats, rabbits, guinea pigs, and pigs.

All the studies found increased inflammation, worsening IBD, IBD-like symptoms, changes to the gut lining, or changes in gut bacteria. 

But as many of the studies' authors note, there needs to be more research in humans. We aren’t mice, rats, rabbits, guinea pigs, pigs, or clumps of cells. 

What about human IBD studies?

Very few studies have looked at the effects of emulsifiers in humans with IBD. Those that exist are very small. We’ll cover two below.

Removing carrageenan

One study focused on the emulsifier carrageenan. The scientists investigated whether cutting it from the diet would extend the time before IBD symptoms returned.

Three of five participants taking the carrageenan capsule had a symptom relapse within a year. None of the seven participants in the placebo group did. 

Low-emulsifier diet

Another study tested mice and humans, and the scientists recruited 20 participants with Crohn's disease. 

The participants followed a low-emulsifier diet for 14 days. At the end of this period, they had fewer IBD symptoms and more perceived control over their condition.

Wrapping up

The evidence we’ve outlined above seems quite damning, but we must interpret the results cautiously. 

First, although animal studies can shed a certain amount of light, we can’t extrapolate the findings to humans.

Still, as evidence mounts that emulsifiers might influence our gut microbiomes, inflammation levels, and metabolic health, some health organizations have pricked up their ears.

For instance, in 2017, the European Food Safety Authority identified “food emulsifiers, the gut microbiome, and long-term health effects” as an emerging risk.

Not everyone shares their concerns, however.

Also in 2017, the FDA completed a review on sodium carboxymethylcellulose and polysorbate-80. It concluded that “Emulsifiers remain safe at the levels currently consumed and that claims suggesting these ingredients are harmful are not valid.”

What should you do?

In the real world, avoiding emulsifiers is nearly impossible, and it’s probably not necessary. 

At ZOE, no food is off the table. But we believe that having a varied, plant-based diet likely leads to a reduced intake of food additives and better overall health.

If you’d like to learn about the bacteria in your gut and how to eat for your body, start by taking our free quiz.