© Mathilde Touvier/Inserm
Emulsifiers are among the additives most widely used by the food industry, helping to improve the texture of food and extend its shelf life. Researchers from Inserm, INRAE, Université Sorbonne Paris Nord, Université Paris Cité and Cnam, as part of the Nutritional Epidemiology Research Team (CRESS-EREN), have undertaken to study the possible links between the dietary intake of food additive emulsifiers and the development of cancer. They analysed the health data of 92 000 adults participating in the French NutriNet-Santé cohort study, specifically evaluating their consumption of this type of food additive. The results of this research, published in PLoS Medicine, suggest an association between the intake of certain emulsifiers and an increased risk of cancer – particularly of the breast and prostate.
In Europe and North America, 30 to 60% of dietary energy intake in adults comes from ultra-processed foods. An increasing number of epidemiological studies suggest a link between high intakes of ultra-processed foods with higher risks of obesity, cardiometabolic diseases and certain forms of cancer.
Emulsifiers are among the most commonly used additives in these foods. They are often added to processed and packaged foods such as certain industrial cakes, biscuits and desserts, as well as ice creams, chocolate bars, breads, margarines and ready meals, in order to improve their appearance, taste and texture and lengthen shelf life. These include mono- and diglycerides of fatty acids, carrageenans, modified starches, lecithins, phosphates, celluloses, gums and pectins.
As with all food additives, the safety of emulsifiers had already been evaluated based on the scientific evidence available at the time. However, some recent studies suggest that emulsifiers may disrupt the gut microbiota and increase the risk of inflammation, potentially increasing susceptibility to some types of cancer. For the first time at an international level, a team of French researchers has studied the relationships between the dietary intake of emulsifiers and the risk of several forms of cancer in a large study in the general population.
The results are based on the analysis of data from 92 000 adults in France (average age 45 years; 79% women) who participated in the NutriNet-Santé cohort study (see box below) between 2009 and 2021.
The participants completed at least 3 days of online dietary records of all food and drink consumed and their brand (for industrial products), with the possibility of updating their dietary intake data every 6 months. These records were matched against databases in order to identify the presence and level of food additives (including emulsifiers) in the products consumed. Laboratory assays were also performed in order to provide quantitative data.
During the follow-up, the participants reported the onset of any cancer (2 604 cases diagnosed), which was validated by a medical committee following examination of their medical records. Several well-known risk factors for cancer, including age, sex, weight (BMI), educational level, family history, smoking, alcohol and levels of physical activity, as well as the overall nutritional quality of the diet (e.g. sugar, salt, energy intakes) and menopausal status were taken into account.
After an average follow-up of 7 years, the researchers found that higher intakes of mono- and diglycerides of fatty acids (E471) were associated with increased risks of cancer overall (a 15% higher risk among those consuming the most – 3rd tertile – compared with those consuming the least – 1st tertile), breast cancer (a 24% higher risk), and prostate cancer (a 46% higher risk). On the other hand, women with higher carrageenan intakes (E407 and E407a) had a 32% higher risk of developing breast cancer, compared with the group with lower intakes.
Given that this is the first observational study in this area, it cannot establish causality on its own, and the authors acknowledge it to have certain limitations. For example, the high proportion of women, the higher average level of education and the generally more health-conscious behaviours among the NutriNet-Santé study participants compared with the general French population, which may limit the generalisation of the results
That being said, the study sample was large and the authors were able to consider a wide range of potentially confounding factors, while using detailed and unique data on exposures to food additives, down to the brand of the products consumed. In addition, the results remained unchanged after multiple sensitivity analyses, thereby strengthening their robustness.
‘While these findings need to be replicated in other studies worldwide, they bring new key knowledge to the debate on re-evaluating the regulations around the use of additives in the food industry, in order to better protect consumers,’ explains Mathilde Touvier, Research Director at Inserm, and Bernard Srour, Junior Professor at INRAE, lead authors of the study.
NutriNet-Santé is a public health study coordinated by the Nutritional Epidemiology Research Team (CRESS-EREN, Inserm/INRAE/Cnam/Université Sorbonne Paris Nord/Université Paris Cité) which, thanks to the commitment and loyalty of over 170 000 participants (known as Nutrinautes), advances research into the links between nutrition (diet, physical activity, nutritional status) and health. Launched in 2009, the study has already given rise to over 270 international scientific publications. In France, a drive to recruit new participants is still ongoing in order to continue to further public research into the relationship between nutrition and health.
By devoting a few minutes per month to answering questionnaires on diet, physical activity and health through the secure online platform etude-nutrinet-sante.fr, the participants contribute to furthering knowledge, towards a healthy and more sustainable diet.