There is growing evidence that nutritional intervention with dietary polyphenols can positively modulate the gut microbiota to improve cardiometabolic health. Whether the beneficial effects of blueberries on obesity and the metabolic syndrome can be linked to their potential impact on the gut microbiota and intestinal integrity remains speculative at this time. Moreover, the mechanisms of action underlying health benefits associated to blueberry consumption are still unknown. The investigators are thus proposing to combine the study of metagenomics, transcriptomics and metabolomics to test whether a prebiotic activity of highbush blueberries can play a role in the prevention of obesity-linked metabolic syndrome in a clinical setting.

Inclusion Criteria:

• Men and premenopause women in good health
• Caucasians
• At least one of the following : BMI between 25 and 40 kg/m2 or Waist circumference ≥ 80 cm for women and ≥ 94 cm for men
• At least one of the following : TG ≥ 1.35 mmol/L or fasting insulinemia ≥ 42 pmol/L

Exclusion Criteria:

• Metabolic disorders (hypertension, diabetes, hypercholesterolemia)
• Regular use of medication affecting study parameters
• Use of natural health product in the last 3 months
• Use of antibiotics in the last 3 months
• Nicotine users
• Allergy or intolerance for blueberries
• Blueberry taste aversion
• More than 2 alcohol drinks par day
• Particular dietary habits (vegetarism, gluten-free diet, cetogenic diet...)
• Weight change of more than 5% in the last 3 months
• Surgery in the last 3 months or planed during the study