Proanthocyanidins

Also indexed as: Grape Seed Extract, Oligomeric Proanthocyanidins (OPCs), Procyanidolic Oligomers (PCOs)

What do they do? Proanthocyanidins—also called "OPCs" for oligomeric procyanidins or "PCOs" for procyanidolic oligomers—are a class of nutrients belonging to the flavonoid family.

Proanthocyanidins have antioxidant activity and they play a role in the stabilization of collagen and maintenance of elastin—two critical proteins in connective tissue that support organs, joints, blood vessels, and muscle.1 2 Possibly because of their effects on blood vessels, proanthocyanidins have been reported in double-blind research to reduce the duration of edema after face-lift surgery from 15.8 to 11.4 days.3 In preliminary research, proanthocyanidins were reported to have anti-mutagenic activity (i.e., to prevent chromosomal mutations).4

Proanthocyanidins have been shown to strengthen capillaries in double-blind research using as little as 100 mg per day.5 In another double-blind trial, French researchers reported that women with chronic venous insufficiency had reduced symptoms using 150 mg per day.6 In another French double-blind trial, supplementation with 100 mg taken three times per day, resulted in benefits within four weeks.7

Proanthocyanidins (200 mg per day for five weeks) have improved aspects of vision (visual performance in the dark and after exposure to glare) in healthy people.8 9 A product that is high in proanthocyanidins has been shown to prevent and reverse abnormal blood clotting in smokers.10

Where are they found? Proanthocyanidins can be found in many plants, most notably pine bark, grape seed, and grape skin. However, bilberry, cranberry, black currant, green tea, black tea, and other plants also contain these flavonoids. Nutritional supplements containing proanthocyanidins extracts from various plant sources are available, alone or in combination with other nutrients, in herbal extracts, capsules, and tablets.

Proanthocyanidins have been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating Health Concerns
3Stars Chronic venous insufficiency
2Stars Capillary fragility
Retinopathy
1Star Pancreatic insufficiency
Varicose Veins
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

Who is likely to be deficient? Flavonoids and proanthocyanidins are not classified as essential nutrients because their absence does not induce a deficiency state. However, proanthocyanidins may have many health benefits, and anyone not eating the various plants that contain them would not derive these benefits.

How much is usually taken? Flavonoids (proanthocyanidins and others) are a significant source of antioxidants in the average diet. Proanthocyanidins at 50–100 mg per day is considered a reasonable supplemental level by some doctors, but optimal levels remain unknown.

Are there any side effects or interactions? Flavonoids, in general, and proanthocyanidins, specifically, have not been associated with any consistent side effects. As they are water-soluble nutrients, excess intake is simply excreted in the urine.

At the time of writing, there were no well-known drug interactions with Proanthocyanidins.

References:

1. Mitcheva M, Astroug H, Drenska D, et al. Biochemical and morphological studies on the effects of anthocyans and vitamin E on carbon tetrachloride induced liver injury. Cell Mol Bio 1993;39:443–8.

2. Maffei F, Carini M, Aldini G, et al. Free radical scavenging action and anti-enzyme activities of procyanidines from Vitis vinifera. A mechanism for their capillary protective action. Arzneimittelforschung 1994;44:592–601.

3. Baroch J. Effect of Endotelon in postoperative edema. Results of a double-blind study versus placebo in 32 female patients. Ann Chir Polast Esthet 1984;29:393–5 [in French].

4. Liviero L, Puglisis E. Antimutagenic activity of procyanidins from vitis vinfera. Fitother 1994;65:203–9.

5. Dartenuc JY, Marache P, Choussat H. Resistance Capillaire en Geriatrie Etude d’un Microangioprotecteur. Bordeaux Médical 1980;13:903–7 [in French].

6. Delacroix P. Etude en Double Avengle de l’Endotelon dans l’Insuffisance Veineuse Chronique. Therapeutique, la Revue de Medicine 1981;27–28 Sept:1793–802 [in French].

7. Thebaut JF, Thebaut P, Vin F. Study of Endotelon in functional manifestations of peripheral venous insufficiency. Gazette Medicale 1985;92:96–100 [in French].

8. Corbe C, Boissin JP, Siou A. Light vision and chorioretinal circulation. Study of the effect of procyanidalic oligomers. J Fr Ophtalmol 1988;11:453–60.

9. Boissin JP, Corbe C, Siou A. Chorioretinal circulation and dazzling; use of procyanidolic oligomers. Bull Soc Ophtalmol Fr 1988;88:173–4, 177–9 [in French].

10. Puetter M, Grotemeyer KHM, Wuerthwein G, et al. Inhibition of smoking-induced platelet aggregation by aspirin and pycnogenol. Thromb Res 1999;95:155–61.