The NutriNet-Santé study is an ongoing investigation into the relationship between nutrition and health. In this Special Feature, we look at some of the project’s findings and speak with Principal Investigator Dr. Mathilde Touvier, who has been involved in the study since its inception.

A range of factors influences health, including genetics, lifestyle, environmental factors, and diet. Unraveling the complex relationships between these factors is a challenge.

For many reasons, it is incredibly difficult to investigate the role of nutrition in health and disease. For instance, no two people eat the exact same diet, and very few people eat the exact same food 2 days in a row.

As it is neither feasible nor ethical to ask thousands of people to follow a strict diet for 10 years to see what happens, researchers have to find other ways of unpicking the links between diet and disease.

The best way to tackle any difficult health-related question is to generate as much good quality data as possible, and this is the NutriNet-Santé study’s raison d’etre.

Beginning in 2009, the NutriNet-Santé study was the first internet-based study of its kind. By the start of 2021, the team was regularly collecting data from 171,000 people aged 15 years and older, making it the largest ongoing nutrition study in the world.

Now running in France and Belgium, the team is also seeding similar projects in Canada, Mexico, and Brazil.

Specifically, the researchers set out with the following aims:

Investigate the relationship between nutrition, health, lifestyle factors, and mortality.
Examine the factors that influence dietary patterns, such as economic and cultural factors.
The researchers keep a biobank of serum, plasma, and urine from about 20,000 people. They also collect stool to monitor and analyze gut bacteria.

Alongside questions about food intake, the NutriNet-Santé team collects information about food packaging, cooking practices, mode of production, physical activity, tobacco, drugs, environmental factors, and domestic and professional exposures.

Importantly, data from the NutriNet-Santé study are linked with medical and insurance records to improve accuracy regarding medications, diagnoses, and long-term sick leave. The study is financed entirely by public institutions.

Ultra-processed foods
In recent years, ultra-processed foods have become a nutritional pariah, and the NutriNet-Santé study has played no small part in this.

Over recent years, data from the NutriNet-Santé study have revealed associations between diets high in ultra-processed foods and an increased risk of cancer, cardiovascular disease, mortality, depressive symptoms, type 2 diabetes, obesity, and gastrointestinal disorders.

As an example, one paper based on data from the NutriNet-Santé cohort, which appeared in the BMJ in 2018, concluded:

“In this large prospective study, a 10% increase in the proportion of ultra-processed foods in the diet was associated with a significant increase of greater than 10% in risks of overall and breast cancer.”

Another study using their data, which also appeared in BMJ, concludes:

“[H]igher consumption of ultra-processed foods was associated with higher risks of cardiovascular, coronary heart, and cerebrovascular diseases.”

Yet more research, which appeared in BMC Medicine in 2019, investigated ultra-processed foods and their links with depression. The authors write:

“Overall, [ultra-processed food] consumption was positively associated with the risk of incident depressive symptoms, suggesting that accounting for this non-nutritional aspect of the diet could be important for mental health promotion.”

More… What we have learned from the world’s largest nutrition study – MNT