Herbs & Supplements:
OPCs (Oligomeric Proanthocyanidins)
Supplement Forms / Alternate Names
•
Procyanidolic Oligomers (PCOs), Grape Seed Extract, Pine Bark Extract, Pycnogenol
Principal Proposed Uses
•
Strengthening Blood Vessels/ Reducing Inflammation, Varicose Veins, Hemorrhoids, Edema (Swelling) Following Injury, Edema (Swelling) Following Surgery, Easy Bruising
Other Proposed Uses
•
Asthma, Aging Skin, Cancer Prevention, Diabetic Neuropathy, Diabetic Retinopathy, Atherosclerosis Prevention, Macular Degeneration, Allergies, Impaired Night Vision, Lupus, Hypertension, Liver Cirrhosis
One of the bestselling herbal products of the early 1990s was an extract of the bark of French maritime pine. This substance consists of a family of chemicals known scientifically as oligomeric proanthocyanidin complexes (OPCs) or procyanidolic oligomers (PCOs). Similar (but not identical) substances are also found in grape seed.
The modern use of OPCs is closely linked to an event in 1534, when a French explorer and his crew were trapped by ice in the Saint Lawrence River. Many of the men were saved from scurvy by a Native American who suggested they make tea from the needles and bark of a local pine tree. Over 400 years later, Jacques Masquelier of the University of Bordeaux came across this story and decided to investigate the constituents of pine trees. In 1951, he extracted OPCs from the bark of the maritime pine, and found that they could duplicate many of the functions of vitamin C. Later, he found another source of OPCs in grape seed.
Some evidence suggests that OPCs can reduce the discomfort and swelling of varicose veins and decrease the edema (swelling) that often follows injury or surgery. OPCs are also marketed for preventing heart disease, revitalizing aging skin, treating allergic conditions and reducing the tendency toward easy bruising, but there is little meaningful evidence as yet that they are effective for these purposes.
Sources
OPCs aren't a single chemical, but a group of closely related compounds. Several food sources contain similar chemicals: red wine, cranberries, blueberries, bilberries, tea (green and black), black currant, onions, legumes, parsley, and the herb hawthorn. However, most OPC supplements are made from either grape seed or the bark of the maritime pine. These two OPC sources lead to products that are not necessarily identical in function, although there do seem to be many similarities. In the discussion of scientific studies below, we indicate the source of the OPCs used.
Therapeutic Dosages
For the treatment of varicose veins and swelling following injury, studies have used doses of 150 to 300 mg daily. For use as a general antioxidant, 50 mg of OPCs daily are often recommended; however, there is no evidence that this dose provides any health benefits.
Therapeutic Uses
The best-documented use of OPCs is to treat varicose veins and chronic venous insufficiency. In these closely related conditions, blood pools in the legs, causing aching, pain, heaviness, swelling, fatigue, and unsightly visible veins. Fairly good preliminary evidence suggests that OPCs can relieve leg pain and swelling.8–12 However, no studies have evaluated whether regular use of OPCs can make visible varicose veins disappear, or prevent new ones from developing.
On the basis of their use in the treatment of varicose veins, OPCs are often recommended as a treatment for hemorrhoids as well, but there is no direct evidence to support this use.
OPCs may reduce the swelling that often follows injuries or surgery.13,14,15
Some evidence suggests that OPCs work by protecting and strengthening collagen and elastin.20–25 These proteins are found in blood vessels as well as cartilage, tendons, skin and muscle. The net effect may be to strengthen blood vessels, thereby reducing leakage of fluid and blood.
OPCs could theoretically also help aging skin through their effects on elastin and collagen. However, there is no solid evidence as yet for this use.
A double-blind pilot study suggests that OPCs from pinebark might help reduce asthma symptoms.42 OPCs are also often recommended for allergies, but an eight week double-blind trial of 49 individuals found no benefit with grapeseed extract.19
One study suggests that while OPCs alone may not reduce levels of cholesterol, when taken in combination with chromium some benefits may occur.18
OPCs are strong antioxidants. Vitamin E defends against fat-soluble oxidants and vitamin C neutralizes water-soluble ones, but OPCs are active against both types.5,6,7 For this reason, regular use of OPCs has been proposed as a measure to prevent cancer, diabetic neuropathy and diabetic retinopathy (side effects of diabetes), heart disease and macular degeneration. In addition, OPCs have been tried as a treatment for impaired night vision, retinopathy,45lupus (systemic lupus erythematosus),44easy bruising,16,17high blood pressure43 and liver cirrhosis. However, more research needs to be performed to discover whether any of these potential benefits are real.
What Is the Scientific Evidence for OPCs (Oligomeric Proanthocyanidins)?
Most double-blind studies of OPCs have used the grape seed rather than the pine bark source.
Venous Insufficiency (Varicose Veins)
There is fairly good preliminary evidence for the use of OPCs to treat people with symptoms of venous insufficiency.
A double-blind placebo-controlled study of 71 subjects found that grape seed OPCs, taken at a dose of 100 mg 3 times daily, significantly improved major symptoms, including heaviness, swelling, and leg discomfort.27 Over a period of 1 month, 75% of the participants treated with OPCs improved substantially. This result doesn't seem quite so impressive when you note that significant improvement was also seen in 41% of the placebo group; nonetheless, OPCs still did significantly better than placebo.
A 2-month double-blind placebo-controlled trial of 40 individuals with chronic venous insufficiency found that 100 mg 3 times daily of pine bark OPCs significantly reduced edema, pain, and the sensation of leg heaviness.28 A similar study of 20 individuals also found OPCs from pine bark effective.29
A placebo-controlled study (blinding not stated) that enrolled 364 individuals with varicose veins found that treatment with grapeseed OPCs produced statistically significant improvements as compared to baseline.30 There was a lesser response in the placebo group, but whether this difference was statistically significant was not stated.
Finally, a double-blind study of 50 people with varicose veins of the legs found that doses of 150 mg per day of grapeseed OPCs were more effective in reducing symptoms and signs than another natural treatment: the bioflavonoid diosmin, widely used in Europe for this condition.31
Edema After Surgery or Injury
Breast cancer surgery often leads to swelling of the arm. A double-blind placebo-controlled study of 63 post-operative breast cancer patients found that 600 mg of grapeseed OPCs daily for 6 months reduced edema, pain, and peculiar sensations known as paresthesias.32 Also, in a double-blind placebo-controlled study of 32 "face-lift" patients who were followed for 10 days, edema disappeared much faster in the group treated with grape seed OPCs.33
Another 10-day double-blind placebo-controlled study enrolling 50 participants found that grape seed OPCs improved the rate at which edema disappeared following sports injuries.34
Atherosclerosis
Although there are no reliable human studies, animal evidence suggests that OPCs can slow or reverse atherosclerosis.37–40 This suggests (but definitely does not prove) that OPCs might be helpful for preventing heart disease.
Safety Issues
OPCs have been extensively tested for safety and are generally considered to be essentially nontoxic.41 Side effects are rare, but when they do occur they are limited to occasional allergic reactions and mild digestive distress. However, maximum safe dosages for young children, pregnant or nursing women, or those with severe liver or kidney disease have not been established.
OPCs may have some anticoagulant properties when taken in high doses, and should be used only under medical supervision by individuals on blood-thinner drugs, such as Coumadin (warfarin), heparin, Plavix (clopidogrel), Ticlid (ticlopidine), Trental (pentoxifylline), or aspirin.
Interactions You Should Know About
If you are taking Coumadin (warfarin), heparin, Plavix (clopidogrel), Ticlid (ticlopidine), Trental (pentoxifylline), or aspirin, high doses of OPCs might cause a risk of excessive bleeding.
View References
Last reviewed March 2002 by Medical Review Board
Back to Top
