Pine bark extract may boost diabetic eye health
Visual acuity, or the clearness of vision, was found to improve from 14/20 to 17/20 in people with early stage retina damage associated with diabetes (diabetic retinopathy) following daily supplements of the pine bark extract, Pycnogenol, for two months.
Forty-six diabetics participated in the randomised controlled study with the findings published in the Journal of Ocular Pharmacology and Therapeutics.
“Our study suggests that Pycnogenol taken in the early stages of retinopathy may enhance retinal blood circulation accompanied by a regression of oedema, which favourably improves vision of patients,” said lead researcher Dr Robert Steigerwalt. “Pycnogenol may be particularly beneficial for preventing this complication in diabetic patients, based on the large number of individuals who were diagnosed when the disease had already significantly progressed.”
An estimated 19 million people are affected by diabetes in the EU 25, equal to four per cent of the total population. This figure is projected to increase to 26 million by 2030.
In the US, there are almost 24 million people with diabetes, equal to 8 per cent of the population. The total costs are thought to be as much as $174 billion, with $116 billion being direct costs from medication, according to 2005-2007 American Diabetes Association figures.
According to the National Institute of Health, between 40 and 45 percent of Americans diagnosed with diabetes already have some stage of diabetic retinopathy, a major cause of blindness in people with diabetes and is one of the most feared diabetic complications.
Pine bark potential
Researchers from G D’Annunzio University in Italy and Horphag Research, the company behind the pine bark extract, randomly assigned 24 subjects to receive a daily dose of 150 mg of Pycnogenol and 22 subjects to receive placebo for to months. All subjects had been diabetic for at least four years and showed early signs of retinopathy characterised by capillaries in the eye leaking fluid into the retina causing swellings.
At the end of the study, 75 per cent of participants in the Pycnogenol group subjectively perceived improvements in their visual acuity. Tests showed a significant improvement in visual acuity from 14/20 to 17/20 after two months of Pycnogenol supplementations. No improvements were recorded in the placebo group, said the researchers.
Commenting on the potential mechanism, the researchers noted that the pine bark extract may improve endothelial function by stimulating nitric oxide synthase, which leads to the production of the potent vasodilator nitric oxide. This would improve blood flow by dilating the blood vessels. The researchers also noted that Pycnogenol may inhibit matrix metalloproteinases (MMPs) that are involved in causing changes to the permeability of blood vessels.
“Retinal oedema has been ascribed to cause blurred vision, therefore, the reduced oedema found in our patients was expected to improve vision,” they added.
The authors acknowledge financial support from Horphag Research, manufacturers of Pycnogenol. The company has been very active in sponsoring and supporting studies into the potential health benefits of the pine bark extract. The first research was conducted on the ingredient 35 years ago.
Source: Journal of Ocular Pharmacology and Therapeutics
Published online ahead of print, doi:10.1089/jop.2009.0023
“Pycnogenol Improves Microcirculation, Retinal Edema and Visual Acuity in Early Diabetic Retinopathy”
Authors: R. Steigerwalt, G. Belcaro, M.R. Cesarone, A. Di Renzo, M.G. Grossi, A. Ricci, M. Dugall, M. Cacchio, F. Schonlau