Grapeseed Extract

You have probably heard about resveratrol, a powerful antioxidant found in grapes. But did you know that extracts from grape seeds also have very high levels of another powerful antioxidant? These disease-fighting compounds are called oligomeric proanthocyanidins (also known as OPCs), and are a combination of polyphenols.¹ Polyphenol antioxidant activity is believed to be the source of their many health benefits.² It was documentation about Native American use of tea from pine tree bark and needles from French explorers who used it to treat scurvy in the 1500s that culminated in research to extract the biologically active OPC compounds hundreds of years later.³ In 1970 these same scientists extracted OPCs from grape seeds,³ and later studies confirmed that the grape seed waste (pomace) from wineries is an abundant raw material source of multiple good quality OPCs and other beneficial polyphenols.⁴ Agricultural and nutritional experts continue to explore the best methods and solvents to extract the greatest yield of these powerful antioxidant compounds from grape seeds.⁵

Scientists have conducted many experiments on grape seed extract (GSE), both in vitro and in vivo (animals and human), that suggest an astounding array of benefits for a variety of health conditions. Even though there has been some question about the bioavailability of OPCs in grape seed extract,⁶ in vivo studies have demonstrated that GSE’s antioxidant protection from free radicals is actually better than other well-known antioxidants—including vitamins C and E.³ The three most important antioxidant mechanisms² of OPCs are:

• free radical scavenging²
• preventing metals naturally in the body, like copper and iron, from reacting with other substances and forming harmful hydroxyl radicals^2,7
• inhibition of enzymes that form free radicals^2,8

Some of the antioxidant benefits that grape seed extract may provide include:

• Alzheimer’s disease: GSE has neuro-protective effects that may help prevent Alzheimer’s; in vivo studies with rats suggest that the OPCs from GSE were bioavailable in the brain with repeated dosing.⁹
• Cancer: Research continues to show that GSE exhibits cancer chemopreventive activity,¹⁰ including inhibiting proliferation while promoting death of prostate cancer cells¹¹, bladder cancer,¹² and non-small cell lung cancer.¹³
• Cardiovascular Disease: As fats in our diets are digested and oxidize, they can cause physiological reactions that promote cardiovascular disease. In vivo and in vitro experiments demonstrated that GSE added to meat inhibited oxidized lipid production during digestion of that meat, suggesting a preventive effect from cardiovascular disease.¹⁸
• HIV: GSE OPCs have been shown to inhibit the receptors that allow entry of the HIV virus into cells.²¹
• Liver Health: GSE antioxidants seemed to provide enhanced antioxidant protection of liver cells against free radical damage produced by high blood sugar in one in vivo animal study.¹⁵
• Obesity: An in vivo study with hamsters suggests that GSE can help prevent obesity, even in a high-fat diet, probably due to helping prevent the insulin resistance, higher blood glucose levels, and increased abdominal fat found in test subjects not given GSE.¹⁴
• Oral Health: Based on comparative measurements of antioxidants and free radicals in the saliva of patients with periodontal diseases in one study, researchers linked these diseases to an imbalance between oxidants and antioxidants;¹⁶ in vitro studies suggest that GSE’s antioxidant and antimicrobial properties can help prevent periodontitis.¹⁷
• Rheumatoid Arthritis: Interleukin 17 (IL-17) and tumor necrosis factor alpha (TNF-α) are both inflammatory cytokines involved in the development of rheumatoid arthritis.¹⁹ An animal study of rats with collagen-induced arthritis showed that those injected with grape seed extract had much lower levels of both IL-17 and TNF-α, suggesting possible therapeutic uses for rheumatoid arthritis in humans.²⁰

The Best Way to Ingest Grape Seed Extract

Grape seed extract is most commonly available in capsule, tablet, or liquid form. When buying grape seed extract supplements, look for a formula that is labeled as having at least 95% OPCs; recommended dosage is 25 - 150 mg up to 3 times a day. As for drinking your grape seed extracts in the form of wine, scientists are still unsure whether it is the flavonoids, the alcohol, or the combination of both that offers the most protective and preventative results. Since alcoholic beverages may represent health risks to some, it is important to discuss the risks and benefits of drinking wine with your health care provider, especially if you are pregnant, breastfeeding, or trying to become pregnant.²²

Possible Risks Associated with Grape Seed Extract Consumption

Grape seed extract is generally well tolerated by most individuals when taken in an oral form. Rare cases of side effects may involve headache, itchiness, dizziness, and/or nausea.²³ Due to the action of proanthocyanidins, which reduce blood platelet adhesion, this extract may increase the clotting time for blood. Interactions between grape seed extract and allopathic medicines have not been carefully studied, so as with any supplement, always consult with a doctor before taking grape seed extract, especially if you are currently taking any other form of medication.²²

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