NutrImmune: Precision Nutrition to Improve Immunity in Individuals With Obesity

Obesity is a complex health condition defined by the World Health Organization (WHO) as an excess of body weight that may be harmful to health. It leads to other diseases such as type 2 diabetes or cardiovascular diseases, commonly referred to as "co-morbidities." Among these, it is known that obesity increases the risk of developing infectious diseases and of these diseases progressing to severe stages. During the COVID-19 pandemic and the 2009 H1N1 influenza epidemic, a rise in severe infection cases was observed in people with obesity. A part of people with obesity exhibits certain markers on the surface of their immune cells, which are known to cause immunosuppression when present in high numbers, thus increasing the risk of developing infectious diseases. Investigator teams found that after bariatric surgery and a calorie-restricted diet for weight loss, patients with obesity can improve the levels of these immunity-related markers. Moreover, the choice of foods consumed contributes to strengthening the immune system and immune functions of individuals, both directly by influencing inflammation and indirectly through the microbiota. However, to date, there are no dietary recommendations specifically designed to help people with obesity improve their immune response. Therefore, this study aims to compare different dietary recommendations intended to improve immune status, with or without calorie restriction, during 3 months, in individuals with obesity (BMI ≥ 30 kg/m²) and impaired immunity. Over 6 months (3 months of nutritional intervention and 3 months of follow-up), investigators will collect extensive information through biological samples, measurements and questionnaires to compare the different dietary interventions studied and to understand the mechanisms behind the results obtained.