Emulsifiers are one of the many food additives helping to hold together the modern food supply, quite literally. Their job is to ensure that mixtures of oil- and water-based ingredients stay combined. They help improve shelf life, texture, taste and convenience.
Without emulsifiers, your salad dressing would separate into noticeable layers and your loaf of supermarket bread would go stale faster than you can say “toasted sandwich”.
At a chemical level, emulsifiers act like the diplomats of the food world: they help bring together ingredients that wouldn’t usually get along. Most have both a water-loving (hydrophilic) and an oil-loving (lipophilic) end, enabling them to bind oil and water into a uniform mixture, preventing the mixture from separating.
They’re commonly found in processed foods such as bread, margarine, mayonnaise, ice-cream, chocolate and many low-fat or low-sugar products that require extra stabilisation to mimic the creaminess of their full-fat variants. In bread, emulsifiers help keep the crumb soft and extend shelf life. Cheaper loaves that contain fewer emulsifiers will go stale more quickly.
Like all food additives permitted for use in New Zealand, Food Standards Australia New Zealand assesses emulsifiers for safety before authorising them. Only those safe at specific levels of use make it into our food supply.
Some emulsifiers, such as lecithin (E322), are naturally found in foods such as egg yolks and soybeans. Others are derived from natural compounds such as citric acid, found in citrus fruits (although typically manufactured via fermentation).
But some others, not extracted from natural sources, have recently attracted scrutiny for their potential health effects.
A 2024 review, published in Nature Reviews Gastroenterology & Hepatology, highlighted concerns about food additives commonly found in ultra-processed foods (UPFs), including emulsifiers, sweeteners and colours, along with micro- and nano-sized food additives.
Preclinical studies suggest these additives can affect gut health by altering the microbiome, intestinal permeability and inflammation. Such studies have featured two common emulsifiers, carboxymethylcellulose (466) and polysorbate 80 (433). Studies in mice found they promote bacterial overgrowth in the small intestine, possibly resulting in chronic inflammatory disease.
Emerging human studies also raise concerns, with a greater emulsifier intake positively associated with increased inflammatory markers, and a human clinical trial finding carboxymethylcellulose consumption produced abdominal discomfort and negatively affected the intestinal microbiome.
The 2024 review authors concluded the effect of emulsifiers on the gut may be “implicated in the rapid increase in the incidence of chronic inflammatory disease since the mid-20th century”.
But with much of the concerning evidence coming from animal or cell-based studies, more investigation on the role of emulsifiers in human gut health is needed – particularly because they are so prevalent, with six emulsifiers among the 10 most common food additives in UPFs.
The broader issue here is most likely the company emulsifiers keep in UPFs (see Is cutting back on ultra-processed foods the key to ageing well?) – food products that typically have undergone multiple stages of industrial processing and include ingredients you wouldn’t find in a home kitchen. High intakes of UPFs have been linked to several chronic health conditions, and while emulsifiers may play a supporting role, it’s more likely the cumulative effect of the whole ultra-processed package that’s to blame.
And whereas a 2014 Yale University study concluded “a diet of minimally processed foods close to nature, predominantly plants” is decisively associated with better health outcomes, it’s also true that many busy households rely on some ultra-processed foods to get a meal on the table.
A helpful way to frame emulsifiers is that they’re a marker of a more industrialised food product – not necessarily something to avoid at all costs.
As always, it’s the overall pattern of your diet that counts. If emulsifiers occasionally sneak into your jam, chocolate, supermarket bread or vegetable-based pasta sauce, that’s perfectly okay.
But if UPFs start crowding out fresh whole foods day after day, it might be time to mix things up.
