The main objective is to develop and validate new endothelial function markers discriminating and reproducible by assessing the ability to reveal changes in endothelial function in response to positive and negative nutritional stimuli.

The study will be randomized (on the order of taking the products: a single dose of lipids or a single dose of flavonoids), single-blinded, cross-over for each population (healthy and metabolic syndrome).

Inclusion Criteria:

• - 40 to 65 years old
• male
• non-smokers

Specific inclusion criteria for healthy subjects :

• Healthy subjects should not take antihypertensive or statin.
• Healthy subjects should not present metabolic syndrome but one criterion of the metabolic syndrome will be tolerated.

Specific inclusion criteria for subjects with metabolic syndrome :

- subjects with metabolic syndrome must have at least 3 of the 5 criteria associated with the metabolic syndrome.

Exclusion Criteria:

• treatment vasodilator nitric oxide liberating,
• diabetes and coronary artery disease,
• chronic alcoholism,
• severe hepatic impairment,
• end stage renal failure or dialysis,
• neurological tremor,
• cancer, mental illness or other severe disease which can impact informed consent and / or results,
• Refusal to be registered in the National File of Volunteers
• Person in exclusion of the National Volunteer File