Antioxidant effects of cocoa and cocoa products ex vivo and in vivo: is there evidence from controlled intervention studies?

PURPOSE OF REVIEWThere is strong epidemiological evidence that the consumption of flavanol-rich cocoa products contributes to the prevention of cardiovascular diseases mediated partly by their strong antioxidant effects. We reviewed the recent literature to answer the question whether this antioxidant action can be confirmed by intervention studies in healthy study participants and specific patient groups. RECENT FINDINGSIn 19 controlled intervention studies (two in patients with cardiovascular diseases), markers of plasma antioxidant capacity and oxidative stress were analyzed after bolus and/or regular cocoa consumption. In both, healthy study participants and patients, total plasma antioxidant capacity as well as most markers of oxidative stress were not influenced by the intervention. Low-density lipoprotein oxidation ex vivo and in vivo decreased probably due to a direct beneficial effect of cocoa flavanols on lipid and protein oxidation. SUMMARYRecent clinical trials do not provide sufficient evidence for an essential contribution of cocoa products to the overall antioxidant defense. Any recommendations for cocoa intake within preventive and therapeutic measures are presently not reasonable.