Doctor: Bernard Srour

Title: Food processing and risk of non-communicable diseases : findings from the NutriNet-Santé cohort

Supervisor: Mathilde Touvier

Doctoral school: ED 146 Doctoral school Galilée, University Sorbonne Paris Nord

Date of thesis defense: 11/2019

Jury: Olga Davidenko, Pierre Lombrail

Thesis summary:

During the past decades, diets in many countries have shifted towards an important increase in the degree of food processing and formulation. Several characteristics of ultra-processed foods have led the scientific community to wonder about their potential impact on long-term human health. Ultra-processed foods have in average, a lower nutritional quality than unprocessed or minimally processed foods (higher content of saturated fat, added sugar and salt, along with a lower fiber and vitamin density). They often contain food additives, neoformed compounds created during processes, and are often packaged in materials in contact with food from which contaminants may migrate to the food matrix. We investigated within the prospective French cohort NutriNet-Santé, the associations between the consumption of ultra-processed food and risks of cancer, cardiovascular disease, type 2-diabetes, overweight, obesity, and weight trajectories. More than 100,000 adult participants were included. Dietary intakes were collected using repeated 24 hour dietary records, designed to register participants’ usual consumption of more than 3,500 food items. These foods were categorized using the NOVA classification according to their degree of processing. Participants were followed, and the occurrence of chronic diseases was ascertained using a multi-source strategy including a linkage to medico-administrative databases.The analyses highlighted robust significant associations between the consumption of ultra-processed foods, and increased risks of overall and breast cancers, cardiovascular, cerebrovascular, and coronary heart diseases, type 2-diabetes, overweight, obesity and weight gain. These analyses accounted for a large number of lifestyle, socio-demographic, anthropometric, medical, behavioral, and nutritional factors. The associations remained significant throughout all the sensitivity and stratified analyses. Beyond nutritional aspects, various factors in processing and reformulation might play a role in these associations, and further studies are needed to better understand their relative contributions and to establish a causal link. Meanwhile, public health authorities in several countries have recently started to promote unprocessed or minimally processed foods and to recommend limiting the consumption of ultra-processed foods.


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