Ultra-processed food, which comprises up to 60% of the average adult’s daily diet in Western countries, is packed with additives that have nothing to do with nutrition. Now, a growing number of epidemiological studies suggest a link between higher consumption levels of such additives and higher risks of diabetes and other metabolic disorders.
Emulsifiers – often added to processed and packaged foods like certain cakes, cookies, yogurt, ice cream, chocolate bars, industrial bread, margarine, and ready-to-eat or ready-to-heat meals to their appearance, taste, and texture and lengthen shelf life – are among the most commonly used additives. They are listed in the ingredients, or their “E numbers” are given, but few people know what they represent and what harm they might cause. These emulsifiers include, for instance, mono-and diglycerides of fatty acids, carrageenans, modified starches, lecithins, phosphates, celluloses, gums, and pectins.
As with all food additives, the safety of emulsifiers has been previously evaluated by food safety and health agencies based on the scientific evidence available at the time of their evaluation. However, some recent studies suggest that emulsifiers may disrupt the gut microbiota and increase the risk of inflammation and metabolic disruption, potentially leading to insulin resistance and the development of diabetes.
First-time researchers analyze relationship between the dietary intakes of emulsifiers
For the first time in the world, a team of French researchers from the National Research Institute for Agriculture, Food and Environment has studied the relationships between the dietary intakes of emulsifiers, assessed over a follow-up period of maximum 14 years, and the risk of developing type-2 diabetes in a large study in the general population.
They have just published their findings in The Lancet Diabetes & Endocrinology Journal under the title “Food additive emulsifiers and the risk of type 2 diabetes.”
The results are based on the analysis of data from 104,139 adults in France (average age 43 years; 79% women) who participated in the web-cohort study (see box below) between 2009 and 2023.
Participants complete two days of dietary records
The participants completed at least two days of dietary records, collecting detailed information on all foods and drinks consumed and their commercial brands (in the case of industrial products). These dietary records were repeated every six months for 14 years and matched against databases to identify the presence and amount of food additives, including emulsifiers, in the products consumed. Lab assays were also performed to provide quantitative data. This allowed for the measurement of chronic exposure to these emulsifiers over time.
During follow-up, participants reported the development of diabetes (1,056 cases diagnosed), and reports were validated. Several well-known risk factors for diabetes including age, sex, weight (body-mass index), educational level, family history, smoking, alcohol and levels of physical activity, as well as the overall nutritional quality of the diet including their sugar intake were taken into account in the analysis.
After an average follow-up of seven years, the researchers observed that chronic exposure – evaluated by repeated data – to the following emulsifiers was associated with an increased risk of type 2 diabetes:
Carrageenans (total carrageenans and 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 diacetyl tartaric 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)
This study constitutes an initial exploration of these relationships, and further investigations are now needed to establish causal links. The researchers mentioned several limitations of their study, such as the predominance of women in the sample, a higher level of education than the general population, and generally more health-promoting behaviors among the NutriNet-Santé study participants. Therefore, caution is needed when extrapolating the conclusions to the entire French population. The researchers said the study is nevertheless based on a large sample size.
“These findings are issued from a single observational study for the moment and cannot be used on their own to establish a causal relationship. They need to be replicated in other epidemiological studies worldwide and supplemented with toxicological and interventional experimental studies to further inform the mechanisms linking these food additive emulsifiers and the onset of type-2 diabetes. However, 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,” asserted Mathilde Touvier, the research director at Inserm (the French National Institute of Health and Medical Research) and Prof. Bernard Srour, where were lead authors of the study.
To better understand the underlying mechanisms, the research team will look at variations in certain blood markers and the gut microbiota linked to the consumption of these additives, as well as the health impact of additive mixtures and their potential “cocktail effects.” They will also work in collaboration with toxicologists to test the impact of these exposures in in vitro and in vivo experiments, to gather more arguments in favor of a causal link.