Multidimensional Phenotyping Towards Personalized Preventive Nutritional Support for Elderly People

There is high inter-individual variability in the response to feeding, which is determined by multiple interacting factors such as age, sex, genotype, gut microbiota, eating behaviors, physical activity or even socio-demographic factors. Original studies have recently demonstrated the possibility of predicting the postprandial response to the diet of healthy individuals on the basis of in-depth phenotyping, and of offering them foods adapted to their own metabolic capacities according to their belonging to different groups of individuals defined on the basis of the similarity of their metabolic capacities. Due to different life trajectories, inter-individual variability could be amplified upon entry into the aging period, which could explain at least in part why traditional strategies for managing chronic age-related pathologies are insufficient. The investigators aim is to propose a new strategy to better understand inter-individual variability in the response to food in the elderly based on deep phenotyping.

During a first phase of the project, the investigators defined all the parameters that could be measured to realize a deep phenotyping of 150 volunteers to establish "metabotypes" and have a better understanding of the variability in the response to food. These parameters include: kinetics of change in postprandial blood glucose over a period of 4 hours following home consumption of four types of test meals (composite nutritional test); and measurement of several blood parameters either in the post-absorptive state, or in the post-prandial state, either after test meals at home, or after a fat meal in the research facility: triglycerides, insulin, C-Reactive-Protein, metabolites through open metabolomics, albumin, fatty acids, cytokines, different gene expression. Through questionnaires or tests the investigators will also assess:

food habits and preferences (with a special focus on polyphenols), olfactory and taste abilities, physical activity, muscle functionality, body composition, peripheral endothelial function and microvascular stiffness, blood pressure, oral status, cognitive function, stress and depression status, intestinal function, psycho-socio-economic status. Finally, the investigators will constitute a collection of blood, white cell, plasma, serum, saliva, urine and stool samples.

Eligibility Criteria:
Inclusion Criteria:

* - Subject with grip strength (assessed with a dynamometer) ≥16kg for women and ≥26 kg for men.
* 21 ≤ BMI ≤35
* Participant living in a rural or peri-urban area or city dweller, according to the population density grid of the Territorial Observatory (categories 3, 2 or 1 respectively).
* Cognitively able to perform tests and answer questionnaires according to the judgment of the recruiting doctor and on the basis of the Mini-Mental State Examination (MMSE)
* Available to carry out the entire protocol
* Biological assessment considered by the investigator as compatible with participation in the study,
* Subject agreeing to give written consent, and registration in the national file of volunteers who lend themselves to research
* Person subject to a social security system.

Exclusion Criteria:

* - Diabetes treated
* Sub-acute pathology (flu, gastroenteritis, bacterial infection, etc.) or trauma (fracture, surgical intervention, etc.) in the 30 days preceding inclusion.
* Hepatocellular insufficiency,
* Heart failure with decompensation,
* Renal insufficiency (clearance \<30 ml/min)
* Chronic anti-inflammatory treatment, long-term corticosteroid therapy \> 1 month, infiltrations
* Antibiotic treatment within 30 days prior to recruitment
* Progressive pathology at the time of inclusion (cancer, etc.)
* Gastrointestinal pathology deemed incompatible with the protocol
* Eating habits incompatible with the protocol (allergies, test food intolerances/aversions, vegan diets, ketogenic diets, etc.)
* Unstabilized thyroid diseases
* Intense physical activity (activity causing shortness of breath and sweating) \> 10 hours per week
* Person who is in a period of exclusion on the National File of Healthy Volunteers
* Subject presenting a psychiatric pathology or cognitive disorders making them incapable of giving informed consent.
* Subject under guardianship, curatorship, deprived of freedoms or under the protection of justice