Grape seed extract (GSE) is a by-product of the wine making industry. Extract from the seeds of vitis vinifera grapes can be made into a capsule, tablet or liquid form. Grape seed extract contains substances called oligomeric proanthocyanidins (also known as polyphenols). Oligomeric proanthocyanidins (OPCs) have powerful antioxidant properties.1 It is likely the antioxidant properties of grape seed extract that are effective in treating, for example, conditions such as venous insufficiency (poor blood flow). Grape seed extract has antimicrobial properties, and, by reducing circulating free radicals, may help to prevent or treat some types of cancer. Be aware that grape seed extract is not the same as grape seed oil, or grape oil. The OPCs available in grape seed oil are much less potent than those in grape seed extract.
Growing Grapes for Extract
Some varieties of vitis vinifera contain higher levels of OPCs than others. Koshu grapes are a variety of vitus vinifera grown in Japan. In studies of brain health, Koshu grape seed extract was compared to grape seed extract from the Muscat variety of vitus vinifera. Koshu grape seed extract was found to be effective in promoting neurologic health, whereas Muscat grape seed extract was not effective.2 This is likely due to the Koshu grapes’ higher content of OPCs. More research is needed to determine which variety of grape, and which growing conditions, produce the most effective grape seed extract.
*When buying commercially manufactured products containing grape seed extract, be sure that the grape seed extract is made from grapes of the vitus vinifera species.
Making Grape Seed Extract
Making grape seed extract is a multi-step commercial process, not unlike the extraction process for other substances. In specialised factories:
Grape seeds and skins are separated from crushed grapes and dried.
The dried skins and seeds are then heated at a low temperature (using purified, deionized water) to remove proanthocyanidins from the seeds.
The extract is then concentrated and dried.
The dried extract is ground into a powder for encapsulation.3
Nutritional Benefits of Grape Seed Extract
The beneficial antioxidant properties of grape seed extract’s oligomeric proanthocyanidins are on par with or more potent than, those of green tea, dark chocolate and red grape juice.
Grape seed extract has been found to reduce weight gain, when used in conjunction with lifestyle changes such as diet modification and exercise and is more effective than the extract alone, though, the mechanism for enhanced weight control is not yet fully understood.
Grape seed extract is used as a nutritional supplement in cereals, health bars and fruit juices. The anti-microbial properties of grape seed extract make it an excellent food preservative. Grape seed extract is used for that purpose in mayonnaise (to prevent rancidity) and some dairy products (to prevent spoilage).
Health Benefits of Grape Seed Extract
Grape seed extract helps to prevent and treat cellular and tissue damage from oxidative stress throughout the body.
Grape seed extract may help improve cognition for people with dementia-type conditions, such as Alzheimer’s.4
The antioxidant effects of grape seed extract are protective against various vision-related conditions, such as cataracts and diabetic retinopathy (which can cause blindness).5,6
There is mixed information in the scientific literature about the effect of grape seed extract on cholesterol levels. One study found grape seed extract lowered total cholesterol in people who were obese and had type 2 diabetes. Studies in people without diabetes did not demonstrate a change in cholesterol levels.7 The effects of grape seed extract on triglycerides is not established.
Grape seed extract has been demonstrated to improve blood flow, possibly by reducing the clotting effects of platelets. Improved blood flow could benefit people with peripheral vascular disease, as is common in diabetes.8
Grape seed extract has been used to promote wound healing for hundreds of years. This may be due to the effects it has on increasing blood flow (which speeds healing) or its effects of increasing the density of skin.9
Grape seed extract has been found to inhibit cancer cell growth in vitro. Grape seed extract offers promise as a protective agent against stomach, cervical, colon and breast cancers.10,11,12,13,14
In addition to the possible cholesterol-lowering effect grape seed extract may have for people living with diabetes, grape seed extract has been found to protect the cells of the pancreas that secrete insulin. It may also improve the cells’ sensitivity to insulin (thereby having an insulin-like effect). When taken concurrent with an exercise training program, the combination of grape seed extract and exercise was found to be more effective for weight loss, cholesterol control and control of high blood pressure than either grape seed extract or exercise alone.15,16
As Candida species have become resistant to many anti-fungal medications, there has been growing interest in using complimentary therapies, such as grape seed extract. Grape seed extract has been found to be effective alone, or in combination with, amphotericin B (a potent anti-fungal drug) to treat fungal (yeast) infections caused by Candida sp. When used in combination with amphotericin B, a lower dose of the medication is required.17
Grape seed oil reduces calorie intake, which, over time, leads to weight loss.18
Grape seed extract has the most concentrated amount of polyphenols of all available sources. Grape seed extract has the potential to be an inexpensive and readily accessible therapy, or adjunct therapy, for multiple health and disease related conditions. Safe, effective and inexpensive therapies will be crucial in the near future as growing numbers of people are diagnosed with hypertension, diabetes and obesity. Hypertension, diabetes and obesity increase a person’s risk for more serious conditions such as heart attacks and strokes.
Buy grape seed extract, and other supplements from a reliable source to ensure purity and quality.
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2. Narita, K, Hisamoto, M, Okuda, T, et al. Differential neuroprotective activity of two different grape seed extracts. Plos One. 2011; doi 10.1371/journal.pone.0014575
3. GRAS Notice 000124: Grape seed extract. 2003
4. Ferruzzi, MG, Lobo, JK, Janie, EM, et al. Bioavailability of gallic acid and catechins from grape seed polyphenol extract is improved by repeated dosing in rats: implications for treatment in Alzheimer’s disease. Journal of Alzheimer’s Disease. 2009. 18(1): 113-124. DOI: 10.3233/JAD-2009-1135
5. Sun, Y, Xiu, C, Liu, W, et al. Grape seed proanthocyanidin extract protects the retina against early diabetic injury by activating the Nrf2 pathway; Experimental and Therapeutic Medicine 2016 11:1253-1258.
6. Jia, Z, Song, Z, Zhao, Y, et al. Grape seed proanthocyanidin extract protects human lens epithelial cells from oxidative stress via reducing NF-KB and MAPK protein expression; Molecular Vision 2011; 17:210-217.
7. Preuss HG, Wallerstedt D, Talpur N, et al. Effects of niacin-bound chromium and grape seed proanthocyanidin extract on the lipid profile of hypercholesterolemic subjects: a pilot study. J Med. 2000;31(5-6):227-246.
8. Vitseva O, Varghese S, Chakrabarti S, et al. Grape seed and skin extracts inhibit platelet function and release of reactive oxygen intermediates. J Cardiovasc Pharmacol. 2005;46(4):445-51.
9. Brooker S, Martin S, Pearson A, et al. Double-blind, placebo-controlled, randomised phase II trial of IH636 grape seed proanthocyanidin extract (GSPE) in patients with radiation-induced breast induration. Radiother Oncol. 2006;79(1):45-51.
10. Hsu CP, Lin YH, Chou CC, Zhou SP, Hsu YC, Liu CL, Ku FM, Chung YC. Mechanisms of grape seed procyanidin-induced apoptosis in colorectal carcinoma cells. Anticancer Res. 2009;29(1):283-9.
11. Kaur M, Agarwal R, Agarwal C. Grape seed extract induces anoikis and caspase-mediated apoptosis in human prostate carcinoma LNCaP cells: possible role of ataxia telangiectasia mutated-p53 activation. Mol Cancer Ther. 2006;5(5):1265-74.
12. Kaur M, Agarwal C, Argarwal R. Anticancer and cancer chemopreventive potential of grape seed extract and other grape-based products. J Nutr. 2009;139(9):1806S-12S.
13. Kaur M, Mandair R, Agarwal R, Agarwal C. Grape seed extract induces cell cycle arrest and apoptosis in human colon carcinoma cells. Nutr Cancer. 2008;60 Suppl 1:2-11.
14. Waffo-Teguo P, Hawthorne ME, Cuendet M, et al. Potential cancer-chemopreventive activities of wine stilbenoids and flavans extracted from grape (Vitis vinifera) cell cultures. Nutr Cancer. 2001;40(2):173-179.
15. Kar P, Laight D, Rooprai HK, Shaw KM, Cummings M. Effects of grape seed extract in Type 2 diabetic subjects at high cardiovascular risk: a double blind randomized placebo controlled trial examining metabolic markers, vascular tone, inflammation, oxidative stress, and insulin sensitivity. Diabet Med. 2009;26(5):526-31.
16. Badavi, M, Abedi, HA, Dianat, M, et al. Exercise training and grape seed extract co-administration improves lipid profile, weight loss, bradycardia and hypotension of STZ-induced diabetic rats. International Cardiovascular Research Journal. 2013, Dec; 7(4) 111-117.
17. Han, Y. Synergic effect of grape seed extract with amphotericin B against disseminated cadidiasis due to Candida albicans. Phytomedicine. 2007 Nov;14(11):733-8. Epub 2007 Oct 3. DOI: 10.1016/j.phymed.2007.08.004
18. Décordé K, Teissèdre PL, Sutra T, Ventura E, Cristol JP, Rouanet JM. Chardonnay grape seed procyanidin extract supplementation prevents high-fat diet-induced obesity in hamsters by improving adipokine imbalance and oxidative stress markers. Mol Nutr Food Res. 2008 Nov 26.