Clinical Relevance of OPCs from Grape Seeds
Daily antioxidant intake from our diet is necessary, because it is known that reactive oxygen and nitrogen radicals (free radicals) are generated by many metabolic and physiologic processes. Free radicals attack cellular proteins, lipids and DNA, inducing changes in cell structure and function leading to physiological and, eventually, pathological changes and aging. Dietary antioxidants found in many of the plant foods we eat, neutralize these free radicals. High antioxidant intake supports healthy cellular function and normal physiological function.*
While grapes themselves have many health-supporting properties, the seeds of the grapes contain powerful oligomeric proanthocyanidin complexes or OPCs. Findings from a 2007 review published in the Journal of Agricultural and Food Chemistry described OPCs ability to help reduce free radical production and oxidative stress. These naturally occurring plant metabolites have also been shown in clinical studies to exert high antioxidant activity.*
A 2017 mini review published in the journal Antioxidants explained various mechanisms of action associated with grape seed extract, which includes the improvement of antioxidant capacity.* The researchers conclude, “The health benefits of grape seed consumption are thought to arise mainly from bioactivities of their polyphenols.”
A 2015 clinical human trial published in the Nutrition Journal looked at the ability of grape seed extract to increase antioxidant status in healthy volunteers. This study featured 46 non-smoking adults (20 men and 26 women) with an average age of 34 years. On the first day of the study, the volunteers ate eight biscuits that did not contain grape seed extract and on the second day, the volunteers ate eight biscuits that contained grape seed extract providing a total dose of 250 mg of grape seed polyphenols. An overnight urine sample was provided by the volunteers each night. The grape seed extract resulted in a significant reduction in urine redox potential (33%) which actually reflects an increase in antioxidant capacity.*
A 2017 review in Nutrition Journal reveals that grape seed extract appears to have a unique quality which supports healthy collagen and elastin structure and vascular tissue.* As a potent antioxidant, grape seed extract also supports healthy inflammatory response.* This insight helps explain why animal and human studies consistently show that OPCs can support heart health.* A 2011 meta-analysis of randomized controlled trials evaluating the effect of grape seed extract on cardiovascular function concluded that grape seed extract supports healthy blood pressure and heart rate.*
Far from being passé, scientific interest in grape seed extract and other OPC’s is increasing, with the body of new research growing annually. It’s now very clear that OPCs have a place in clinical practice when it comes to supporting human antioxidant capacity.* New areas of research include investigation into potential metabolic support for glucose intolerant individuals, menopausal support and the potential photoprotection of topical applications.
Fujii H, Nakagawa T, Nishioka H, et al. Journal of Agricultural and Food Chemistry. 2007;55(4):1525-1531.
Grases F, Prieto RM, Fernandez-Cabot RA, et al. Nutrition Journal. 2015;14:94.
Ma ZF, Zhang H. Antioxidants. 2017;6(3):71.
Terauchi M, Horiguchi N, Kajiyama A, et al. Menopause. 2014;21(9):990-996.
Wahner-Roedler DL, Bauer BA, Loehrer LL, et al. Journal of Dietary Supplements. 2014;11(2):184-197.
Weseler AR, Bast A. Nutrition Journal. 2017;16:5.
Feringa HH1, Laskey DA, Dickson JE, Coleman CI. J Am Diet Assoc. 2011 Aug;111(8):1173-81. doi: 10.1016/j.jada.2011.05.015.
The effect of grape seed extract on cardiovascular risk markers: a meta-analysis of randomized controlled trials.