Eating combinations of common food additives may be tied to a slightly increased risk of Type 2 diabetes, according to a study published Tuesday in the journal PLOS Medicine.
A growing body of evidence has linked certain food additives to cancer, diabetes, heart disease and changes to the gut microbiome. Many of these studies, however, were focused on single ingredients.
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WATCH HERE“In real life, we ingest a mixture of additives,” said Mathilde Touvier, director of the nutritional epidemiology research team at Université Sorbonne Paris Nord. Touvier holds the same role on the French National Institute of Health and Medical Research, the new study's co-author.
Touvier and her team looked at about eight years of data from more than 108,000 adults from the French NutriNet-Santé cohort, a long-running study that looks at the links between food and health.
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SIGN UP Poring over the participants’ reported diets, the researchers identified five mixtures of additives people commonly consumed together. The combinations don’t look unlike an ingredient list you might find on the label of an ultra-processed food.
- Mixture 1: Sodium carbonates; diphosphates; glycerol; ammonium carbonates; potassium carbonates; sorbitol
- Mixture 2: Modified starches; pectins; guar gum; carrageenan; polyphosphates; potassium sorbate; curcumin; xanthan gum
- Mixture 3: Magnesium carbonates; riboflavin; alpha-tocopherol; ammonium carbonates
- Mixture 4: Ammonium carbonates; sodium carbonates; diphosphates; alpha-tocopherol; DATEM; magnesium carbonates; lecithins
- Mixture 5: Citric acid; sodium citrates; phosphoric acid; sulphite ammonia caramel; acesulfame K; aspartame; sucralose; arabic gum; malic acid; carnauba wax; paprika extract, capsanthin, and capsorubin; anthocyanins; guar gum; pectins
“It’s relatively uncommon for all of them to appear in a single product, however, it’s entirely possible to consume all of them across different foods throughout the day, especially when eating a variety of processed or ultra-processed foods,” said Mengxi Du, a research associate at the Harvard T.H. Chan School of Public Health who studies nutrition and health and wasn’t involved with the study.
Carrageenan and potassium sorbate, two additives in Mixture 2, are found together in sweetened condensed milk. Xanthan gum is commonly found in mayonnaise and gluten-free prepared foods. Pectin is in cream cheese.
“These are pretty common products in someone’s fridge and a lot of times we combine them,” Du said.
Two groups — Mixture 2 and Mixture 5 — were linked to an increased risk of Type 2 diabetes, the researchers found. People with more of these combinations in their diet were more likely to develop the disease, regardless of how healthy their diet was overall.
Mixture 2 was heavy in emulsifiers and thickening agents, including carrageenans, which are found in plant-based milks and processed meats, and modified starches, which thicken and stabilize packaged sauces, soups and baked goods. Mixture 5 contained ingredients commonly found in sugary and artificially-sweetened drinks, and included artificial sweeteners, natural dyes and acidifiers.
Still, the study was observational, meaning it doesn’t show cause and effect. Studies that require participants to recall their diets are also notoriously tricky. The limitations make it difficult to draw strong conclusions from the study, which Touvier and her team said will require more research.
“The additives may be markers of something else, rather than causing Type 2 diabetes themselves,” said Dr. Tom Rifai, an internal and lifestyle medicine doctor in Cleveland Clinic’s department of endocrinology, diabetes and metabolism. Rifai owns a lifestyle coaching company that includes nutrition counseling. “These could be a marker for what we call calorie density.”
Food additives are ubiquitous in ultra-processed foods, which usually pack in many more calories in much smaller amounts of food than minimally and unprocessed foods.
“At the very least, these additives are markers of ultra-processing, which we know makes people eat more without realizing they are taking in a lot more calories,” Marion Nestle, a professor emerita of nutrition, food studies and public health at New York University, said in an email.
The same is true for the three groups of additives that were not found to be linked to diabetes risk. Nestle said that while the study cannot show causation, the results are consistent with “present thinking that additives may well be anything but benign.”
Some food additives do play an important role in food safety. Potassium sorbate, for example, stops yeast and fungus from growing in packaged food. Others — including emulsifiers, which create certain textures, and artificial dyes — have come under scrutiny.
Last month, Health and Human Services Secretary Robert F. Kennedy Jr. directed the Food and Drug Administration to review its rule on “generally recognized as safe,” or GRAS, ingredients. The rule allows manufacturers to add certain additives to food without FDA review. It was originally intended for common ingredients such as salt or vinegar but has come to cover an expansive range of additives.
In 2023, California became the first state to ban four food additives: brominated vegetable oil, potassium bromate, propylparaben and Red Dye No. 3. In March, West Virginia banned seven food dyes.
In the first three months of this year, 20 states — including Illinois, Missouri, New York, Oregon and Pennsylvania — introduced similar bans, but not on any of the additives included in the new study.
It’s too early to tell whether food additives, when eaten together, can have a synergistic effect, Du said. It’s possible that one ingredient, safe on its own, may be linked to health problems when combined with other ingredients, for example. Or an ingredient’s mild health effects could be amplified when mixed with other additives.
Given that ultra-processed foods account for more than half of the calories an average American eats in a day, research that further investigates such an effect is worthwhile, she said.
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