The ANTIATERO-ALIM study was a randomized, parallel design nutritional trial testing functional food (FF) diets against the usual diet recommended in the metabolic syndrome. Functional meals included balsamic vinegar from apples and honey and grape juice enriched with polyphenols from seeds of red grapes. 300 patients with metabolic syndrome were randomized into 4 groups: gr.1: FF + Ω-3 supplements, gr.2: FF, gr.3: Ω-3 supplements, gr.4: control. IRHOMA insulin resistance, plasma lipids and oxidative stress were assessed at inclusion and at 6 months. After 6 months there was a very significant decrease of oxidative stress in group 3, followed by a significant decrease in groups 1 and 2.