Food Emulsifiers Linked to Increased Type 2 Diabetes Risk

Emulsifiers in ultra-processed foods may increase the chance of developing type 2 diabetes, according to a new paper.

After analyzing the health data of 104,139 adults over 7 years – and accounting for other risk factors like age and weight – a team from several French research institutes found that those who ate more processed foods containing emulsifiers were more likely to develop secondary diabetes.

While this link was observational – not biochemically proven – the researchers say their findings add to the debate around ultra-processed food regulations.

Other experts, however, say the findings are tenuous and more research is needed before firm conclusions can be drawn.

The paper was published in Lancet Diabetes and Endocrinology.

Goodness gracious, e-muls-ifier

Emulsifiers are added to food to help blend any oil and water, which would otherwise separate. The chemicals are often found in ultra-processed foods such as mayonnaise, ice cream, peanut butter, margarine, processed meats and bread.

As such foods have become staples in Western diets in recent decades, researchers have wondered what effect emulsifiers could be having on population health.

To test whether the chemicals could be influencing the development of type 2 diabetes, the researchers from the French National Institute of Health and Medical Research (INSERM) team analyzed data from an ongoing national survey, the French NutriNet-Santé cohort.

The team looked at the entries of 104,139 adults, who were 42.7 years old, on average, and were mostly (79%) women.

All participants gave at least three days of dietary records on what food and drink they had consumed every six months between 2009 and 2023.

The researchers began by matching these diary entries against food databases and testing the mentioned items to identify which emulsifiers the participants would have consumed and in what volume.

Over the 14-year timeframe of the study, 1,056 cases of type 2 diabetes were diagnosed within the cohort.

The researchers then further compared these cases to the diets of the cohorts using a statistical model that accounted for other diabetes risk factors, such as age, weight, family history, etc.

After an average follow-up of seven years, the researchers found that chronic intake of the following emulsifiers was associated with an increased risk of type 2 diabetes:

• Carrageenans (E407): 3% increased risk per increment of 100 mg per day.
• Tripotassium phosphate (E340): 15% increased risk per increment of 500 mg per day.
• Mono- and diacetyltartaric acid esters of mono- and diglycerides of fatty acids (E472e): 4% increased risk per increment of 100 mg per day.
• Sodium citrate (E331): 4% increased risk per increment of 500 mg per day.
• Guar gum (E412): 11% increased risk per increment of 500 mg per day.
• Gum arabic (E414): 3% increased risk per increment of 1000 mg per day.
• Xanthan gum (E415): 8% increased risk per increment of 500 mg per day.

Despite the study’s limitations – no causational proof, under-representation of men, etc. – the authors say their findings are robust and add to the growing body of evidence that ultra-processed foods are a risk for type 2 diabetes.

“Our results represent key elements to enrich the debate on re-evaluating the regulations around the use of additives in the food industry, in order to better protect consumers,” said Mathilde Touvier, research director at INSERM, and Bernard Srour, a junior professor at the French research institute INRAE. Both were lead authors of the study.

A second opinion

Other dietary experts, however, aren’t as wowed by INSERM’s findings.

Writing in a statement to the UK’s Science Media Centre, Dr. Duane Mellor, a registered dietitian and senior lecturer at Aston University, questioned the reliability of the results, given they were based on the recollections of the participants.

“The way the study estimated intake of emulsifiers needs to be treated with caution, as the study looked at 3 24-hour food recalls and then looked to work back to estimate intakes of emulsifier ingredients which are used in minute quantities in foods,” they said. “This is likely to mean the level of precision suggested in the paper is simply not possible and the paper does not clearly highlight any potential margin of error.”

Mellor also noted that the broad range of emulsifiers listed in the study could blur the specific effects different emulsifiers may be having on the body.

“What this paper does not fully consider is the difference in how the human body might process and manage emulsifiers – lecithins are a common emulsifier (which was not linked to risk of type 2 diabetes in this study) and is found naturally in egg yolks and is used to make mayonnaise from oil and water, which when mixed is an emulsion!” Mellor said. “Lecithins contain a range of compounds including choline, which in our body can be used to make acetylcholine which nerves use to transmit messages through our nervous system and for some people their bodies struggle to make enough of it and may require dietary sources of choline. This is very different to polysorbates which have no function in our bodies and in mechanistic studies have been linked to metabolic changes in rodents. So, it is important not to consider all emulsifiers as being the same.”

Dr. Sarah Berry, a reader at King’s College London’s Department of Nutritional Sciences, concurred that, while the study had merit, the anecdotal nature of the research limited its conclusions.

“This type of large-scale epidemiological study is a vital part of the scientific process,” Berry said. “However, these studies cannot prove that emulsifiers cause type 2 diabetes. Because products that contain emulsifiers often contain a multitude of other ingredients, disentangling the effects of each compound is challenging.”

“However, while emulsifiers are individually carefully checked for safety, few studies investigate how cocktails of these chemicals impact our health. So, this type of study should inform future, more tightly controlled clinical trials.”

“With that said, existing evidence shows that a diet rich in the types of foods that contain emulsifiers, which have typically been heavily processed, is linked to poorer health outcomes. So, cutting down on these foods is likely a healthy choice.”

Reference: Salame C, Javaux G, Sellem L, et al. Food additive emulsifiers and the risk of type 2 diabetes: analysis of data from the NutriNet-Santé prospective cohort study. Diabet. & Endocrin. 2024. doi: 10.1016/S2213-8587(24)00086-X