Ryan Bradley, ND, MPH is a doctor of naturopathic medicine in San Diego, CA. Diabetes is an area of both research and clinical specialization for Dr. Bradley. He practices integrative care for diabetes and heart health as the Director of the Center for Diabetes & Cardiovascular Wellness at the Bastyr University California.
Pycnogenol®: Easier to Swallow than to Say
Every now and then the “dark side” gets to me- the other side that thinks natural treatments do not deserve further study- and I start questioning the role of natural treatments in diabetes care. And then I learn about a natural substance that re-inspires my belief. One of these inspiring natural treatments is Pycnogenol®. Pycnogenol® is a trademarked supplement derived from the bark of the French Maritime Pine tree, rich in antioxidants called oligomeric procyanidins (or OPCs). Pycnogenol® appears to lower blood glucose and improves diabetic changes to the small blood vessels. Damage to the small vessels due to high blood sugar causes eye damage, kidney damage and nerve damage leading to blindness, renal failure requiring dialysis, ulceration and amputation - so any treatment that may reduce these complications is worth a close look. Does Pycnogenol® really work and how? Keep reading.
What is Pycnogenol®?
Pycnogenol® appears to lower blood glucose and improves diabetic changes to the small blood vessels.
Pycnogenol is a standardized water and alcohol extract from pine bark. It is then dried and pressed into a tablet available as a nutritional supplement. Ultimately it becomes a mixture of flavonoids and phenolic compounds with antioxidant and metabolic activity. Interestingly the antioxidant compounds in Pycnogenol® appear to have affinity for collagen, the protein that forms the basic scaffolding for body structure, including the structure of our blood vessels (Schonlau and Rohdewald. Int. Ophthalmol., 2001).
Pycnogenol® and Small Vessel Disease
Narrowing and fibrosis of the small blood vessels cause considerable problems in diabetes. This microvascular disease impacts the small arteries all over the body, but causes noticeable problems in the circulation to the legs, the eyes, the kidneys and the nerve fibers to the extremities and also to the organs. Although the body is quite good at compensating for small changes in blood flow, ultimately the narrowing and fibrosis that occurs limits blood flow and oxygen delivery to critical tissues resulting in symptomatic conditions like nerve pain and vision problems. Unfortunately not all of the complications have immediate symptoms and so the process continues unchecked. Over time, the narrowing and fibrosis of small vessels causes leakage to occur and bleeding, or hemorrhage, results.
Keeping blood sugar well controlled using diet, exercise and medications is the only way we know with certainty to reduce the risk of developing these complications and also to slow the progression of these complications once they begin.
However, Pycnogenol® has been studied in several microvascular complications with apparent benefit, including diabetic ulcers and retinal disease, by reducing inflammation in vascular tissues (Peng et al, Cell Mol Life Sci, 2000).
...Pycnogenol® has been studied in several microvascular complications with apparent benefit, including diabetic ulcers and retinal disease...
Gizzi et al. reports the results of a small clinical trial evaluating Pycnogenol® in diabetic ulcers (Gizzi et al., Clin Appl Thromb Hemost, 2006). In this study 30 participants with ulcers were randomized to receive either local Pycnogenol®, oral Pycnogenol®, the combination or standard medications. Complete healing was accomplished in 6 weeks in 89% of the combination group, 85% in the oral group, 84% in the local application group and 61% in the standard treatment group. Local treatment involved crushing two - 50mg Pycnogenol® capsules and covering the ulceration with a fine powder and applying a dressing. Oral treatment in this study was 50mg three times daily.
Although clinical studies in retinopathy are not available in English, a review of the studies performed to date is available (Schonlau and Rohdewald. Int. Ophthalmol., 2001). Several clinical trials in approximately 1200 patients have been performed evaluating Pycnogenol in diabetic retinopathy, including two well-controlled trials.
In one of the trials, participants took 120mg Pycnogenol® for 6 days and then 80mg daily for the remainder of the six month trial. Pycnogenol® was compared to a standard treatment called calcium dobesilate during the trial. Both treatments had positive results with Pycnogenol® being comparable to calcium dobesilate. Improvement in the amount of vascular leakage and improvement of the visual field were among the positive results in the study. Pycnogenol® seemed to be more effective in more severe cases than calcium dobesilate, but the study was designed to specifically address this question.
Although clinical studies in retinopathy are not available in English, a review of the studies performed to date is available...
The second study included in the review by Schonlau and Rohdewald compared Pycnogenol® to a placebo, also studying diabetic retinopathy. Participants were randomized to receive either placebo or Pycnogenol® for two months. Participants in the Pycnogenol® group took 50mg three times daily (150mg total per day). Improvements were noted in vascular stability and structure of the blood-retina barrier in the Pycnogenol® group, but not in the placebo group. In the Pycnogenol® group, 53% were rated as having a “very good” or “good” response, with the remaining 47% having a “moderate” response.
Although not well studied in the United States, Pycnogenol® is available and appears to be a viable option for diabetic retinopathy and ulcerations. Less is known about the application of Pycnogenol® to diabetic kidney disease or nerve damage, however given the similarity in the pathogenesis of these complications to retinopathy and the established mechanism of Pycnogenol®, it is a reasonable treatment to consider in my opinion.
Pycnogenol® and High Blood Pressure
In addition to the research on Pycnogenol® in small blood vessel complications in diabetes, Pycnogenol® has also been studied in high blood pressure, or hypertension. A small clinical trial of Pycnogenol® in 58 participants suggests that Pycnogenol® improves the functioning of the thin inner lining of the large arteries (the endothelium); 100mg of Pycnogenol® per day allowed dose reductions of standard blood pressure lowering medications (Liu et al. Life Sci.2004).
Although not well studied in the United States, Pycnogenol® is available and appears to be a viable option for diabetic retinopathy and ulcerations.
Another study evaluated Pycnogenol® in eleven participants in a double-blind, cross-over design (Hosseini et al. Nutr Research, 2001). In this study 100mg Pycnogenol® per day significantly reduced average systolic (the top number) blood pressure from 140mmHg to 133 mmHg. Although this is not a huge reduction, the study was quite small and a few points of blood pressure reduction correlates to a greater reduction in risk of blood pressure-related cardiovascular events like heart attacks and strokes. From a clinical perspective, a 7-point blood pressure reduction can influence my decision on whether or not to recommend an additional medication for blood pressure lowering.
Pycnogenol® Effects on Blood Glucose
Pycnogenol® has not been well studied for its effect on blood sugar in people with diabetes. However, one small study suggests benefit. Liu et al. published a small dose-finding study in 30 participants with diabetes demonstrating significant reductions in hemoglobin A1c, fasting and post-meal blood sugars (Liu et al. Diabetes Care, 2004). The study compared doses of 50, 100, 200 and 300mg of Pycnogenol® per day. Hemoglobin A1c reduced significantly from 8.02% to 7.37% on average; statistical significance was achieved after 9 weeks on treatment. The optimal dose per this study for blood glucose reduction and improvement in various biomarkers appeared to be 200mg per day.
Too Good to Be True?
Apparently not. Pycnogenol® has been studied by multiple researchers, in multiple countries, and while it does not appear to be a panacea for diabetes, it does appear to offer significant protection and improvement in function for people with diabetes, and especially people with known small vessel complications like retinopathy and ulcerations.
Pycnogenol® has not been well studied for its effect on blood sugar in people with diabetes.
The results have not been specifically extended to neuropathy or nephropathy, but given the same physiologic process is at play in these complications, it is worth trying (and asking your doctor to evaluate objectively). Pycnogenol® has not been specifically studied for the prevention of these complications, but in my opinion this is a study that should be performed. Given diabetes is still the leading cause of adult blindness and non-traumatic amputation in the United States, Pycnogenol® deserves the attention of clinicians, researchers and funding agencies. In the meantime, Pycnogenol® is standardized and available to those willing and in need of more effective treatments that those currently being offered.
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High blood pressure and venous insufficiency is common in people with diabetes, often limiting activity due to pain and swelling. Gotu Kola, or Centella asiatica, is a botanical medicine indigenous to the Indian subcontinent. A standardized extract of Centella has also been evaluated for its effects on swelling and edema caused by chronic venous insufficiency and high blood pressure with benefit. 60mg twice daily of a standardized tablet for 8 weeks resulted in reductions in pain and swelling symptoms and reduced capillary filtration (Cesarone et al. , Angiology,2001).