Take a drive through wine country in late summer and early fall and you’ll see vines laden with grapes, ready to burst.

These are not your ordinary seedless grapes from the grocery store. If you bite into these grapes, you’ll be greeted with a tingling sweetness and slightly tangy flavor. Bite too hard and you might get an unpleasant crunch – bitter seeds that release acerbic tannins that clash with the juicy sweet and slightly tangy fruit.

If you’ve ever had vine-ripened grapes, then you know you just spit the seeds out. But it turns out the compounds that produce that tannic flavor have vast potential as antioxidants.

Grapes, like many other colorful fruits and vegetables in our diets, contain flavonoids (a subgroup of polyphenols) that have been studied widely for their beneficial effects on human health. Perhaps you’ve heard the popular axiom that drinking a glass of red wine a day can be heart healthy; much of the flavor and color in red wine comes from these health-promoting flavonoids. In the common grape, flavonoids are found in both the skin and the seeds.

The polyphenols that grape seeds contain are oligomeric proanthocyanidins, or OPCs. OPCs can also be found in many other plants, including apples, blueberries, cranberries, pine bark, and cocoa beans.

Grape seed extract benefits

Antioxidant. OPCs have potent antioxidant effects.* Because flavonoids, including OPCs, are not typically well-absorbed, OPCs can be complexed with phospholipids for enhanced absorption; the technical name of such a complex is a phytosome.

In a 2008 study, to test its antioxidant potential, 20 young adults were given either 300 mg grape seed phytosome or a placebo daily for five days. After a two-week washout period, both groups began the opposite treatment. Total antioxidant capacity was significantly increased in both groups after supplementation of the grape seed phytosome compared to the placebo.1

UV protection. An important mechanism of action of antioxidants is their ability to mitigate damage to the skin from UV rays.* As an antioxidant, research shows that OPCs can enhance the skin’s naturally protective response to UV exposure.*

Some natural sunscreens use grape seed extract for topical photo-protective effects on the skin. A 2019 study found that sunscreen with a grape seed extract content of just three percent by weight was enough to increase its sun protection factor (SPF) rating by five units.2

A study on the oral supplementation of OPCs derived from pine bark tested the extent that OPCs protect skin after exposure to UV light sufficient to produce a reddening of the skin. The participants (n=21) supplemented OPCs (amount based on body weight) daily for four weeks before UV exposure and again afterward at a higher amount. The researchers found the higher amount resulted in nearly double the exposure time needed for UV exposure to produce a reddening of the skin.3 In other words, it took longer for an individual’s skin to redden when they took the higher amount of OPCs.

Cardiovascular. Grape seed extract has the potential to support circulation – in veins, arteries, and the lymphatic system.* It has been shown to support lymph flow in women after breast cancer surgery, for example.*4 

It has been used in Europe for decades to support healthy venous circulation.* Studies show it supports healthy vein function and tone and decreases associated nighttime leg discomfort.*5,6 

OPCs also support endothelial function in arteries by increasing nitric oxide production, which in turn supports healthy circulation by relaxing the arteries.*7 

There’s also evidence that grape seed extract might help maintain healthy blood pressure.* A review of studies on grape seed extract found that, particularly in individuals who were overweight or had a metabolic disorder, consuming grape seed extract in a range of 100-400 mg daily over a 16-week period maintained healthy blood pressure.*8

A review of studies by the National Institutes of Health suggests grape seed extract helps maintain healthy cholesterol levels.*9 Meanwhile, a separate study found that combining grape seed extract with a chromium supplement also promoted healthy cholesterol levels.*10

We started out talking about a trip to wine country – so what about wine? Does drinking a glass of wine offer any of these same benefits? In a 2005 study, 17 healthy men consumed 400 mL (equivalent to 2.66 glasses of wine) of either red or white wine daily with meals for two weeks. At the end of the two weeks, antioxidant effects of decreased lipid peroxidation were seen with red but not white wine drinkers (who actually had increased lipid peroxides). HDL cholesterol (the good one) was also increased in the red wine drinkers.11 The fact that red, but not white, wine provided benefit indicates it’s not the alcohol but the polyphenols that provided the positive effects in this study. You don’t have to drink two or three glasses of wine a night to get the benefits.

Add grape seed extract to your supplement routine

As you can see, grape seed extract and its OPCs are a powerful partner in building health and wellness that lasts. Luckily, you don’t need to search for specialty grapes at the grocery store and endure the seeds’ bitter flavor. Thorne’s Grape Seed Extract (formerly O.P.C.-100) contains 100 mg of grape seed extract phytosome in each capsule. The phytosome complex bonds grape seed extract from Vinis vinifera, the common wine grape, with phospholipids to enhance absorption.

Need something more filling with grape seed support? Then try Thorne’s MediClear-SGS or MediClear Plus powders, each with 50 mg of grape seed phytosome per serving. Thorne’s MediClear suite begins with a plant-based protein and adds a complete multi-vitamin/mineral profile. MediClear-SGS is available in chocolate and vanilla flavors and MediClear Plus is unflavored, perfect to mix with your favorite flavor to fit your daily routine.

Have you tried Thorne's Grape Seed Extract? What do you think about Thorne’s MediClear powders? Write a review about your experience and share your feedback with others.

References

  1. Nuttall SL, Kendall MJ, Bombardelli E, Morazzoni P. An evaluation of the antioxidant activity of a standardized grape seed extract, Leucoselect®. J Clin Pharm Ther 2008 Oct 09. 23(5):385-389. 
  2. Yarovaya L, Khunkitti W. Effect of grape seed extract as a sunscreen booster. Songklanakarin J Sci Technol 2019. 41(3):708-715. doi:10.14456/sjst-psu.2019.
  3. Saliou C, Rimbach G, Moini H, et at. Solar ultraviolet-induced erythema in human skin and nuclear factor-kappa-B-dependent gene expression in keratinocytes are modulated by a French maritime pine bark extract. Free Radic Biol Med 2001 Jan 15;30(2):154-160. doi: 10.1016/s0891-5849(00)00445-7.
  4. Pecking A. Oligomeric proanthocyanidins (Endotelon®) in the treatment of post therapeutic lymphoedema of the upper limbs. Association de Lymphologyie de Lange Francaise HospitalSaint-Louis, Paris 1989;69-73. [Article in French].
  5. Delacroix P. Double-blind study on Endotelon in chronic venous insufficiency. Rev Med (Paris) 1981;1793:27-28.
  6. Thebaut JF, Thebaut P, Vin F. Study of Endotelon in functional manifestations of peripheral venous insufficiency. Results of a double-blind study on 92 patients. Gaz Med (Montr) 1985;92:12.
  7. Fitzpatrick DF, Fleming RC, Bing B, et al. Isolation and characterization of endothelium dependent vasorelaxing compounds from grape seeds. J Agric Food Chem 2000;48:6384-6390.
  8. Zhang H, Liu S, Li L, et al. The impact of grape seed extract treatment on blood pressure changes: A meta-analysis of 16 randomized controlled trials. Medicine (Baltimore). 2016;95(33):e4247. doi: 10.1097/MD.0000000000004247. 
  9. Grape Seed Extract. National Center for Complementary and Integrative Health. 2020 Aug. https://www.nccih.nih.gov/health/grape-seed-extract [Accessed August 11, 2023]
  10. 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. 
  11. Fuhrman B, Lavy A, Aviram M. Consumption of red wine with meals reduces the susceptibility of human plasma and low-density lipoprotein to lipid peroxidation. Am J Clin Nutr 1995;61:549-554.