Blood pressure control was achieved in 58 per cent of study participants, and a halving of the use of medication, among 48 participants randomly assigned to daily supplements of the pine bark extract, Pycnogenol, or placebo for 12 weeks.
The results of the new study, published in the May issue of the journal Nutrition Research , is of particular importance for diabetics who are reportedly two to four times more likely to suffer from heart disease than non-diabetics "These data confirm the hypothesis that Pycnogenol improves diabetes control, reduces antihypertensive medicine use, and may favour a reduction in cardiovascular disease risk in individuals with type 2 diabetes," wrote lead author Sherma Zibadi from the University of Arizona.
Indeed, previous studies have reported potential health benefits for the extract, including hypertension, asthma, chronic venous insufficiency, osteoarthritis, deep vein thrombosis, diabetes management, and diabetic leg ulcers.
The new study recruited diabetic subjects with an average age of 60 and randomly assigned them to receive daily supplements of Pycnogenol (125 mg) or placebo for 12 weeks in a randomised, double-blind, placebo-controlled trial with parallel-group design.
All subjects were receiving pharmaceutical anti-hypertension treatment (angiotensin- converting enzyme [ACE] inhibitors).
At the end of the study, Zibadi and co-workers report that 58.3 per cent of subjects in the Pycnogenol group experienced blood pressure control, defined as attaining a stable systolic blood pressure, compared to 20.8 per cent in the placebo group.
Moreover, use of ACE inhibitors was reduced by 50 per cent in the group receiving the pine bark extract Improvements in measures of diabetes control were also recorded, with a 23.7 mg/dL reduction in fasting blood glucose levels in the Pycnogenol group, compared to only 5.7 mg/dL in the placebo group.
Improvements in LDL-cholesterol, a marker of cardiovascular health, were recorded in the pine bark extract-supplemented group.
After eight and 12 weeks of supplementation, decreases of 11.6 and 12.7 mg/dL were observed, respectively, compared with placebo.
Mechanism of action In attempting to understand the benefits of the pine bark extract on cardiovascular health of the diabetics, the researchers noted that the blood pressure lowering effects may be due to a suppression of serum endothelin-1, a protein that restricts blood vessels and reported to be found in higher levels than normal in type 2 diabetics and hypertensives.
On the other hand, the authors could not rule out the potential of an inhibitory effect on ACE, which could improve blood flow and subsequently blood pressure.
Finally, other studies have reported a potential benefit from Pycnogenol on the production of the potent vasodilator, nitric oxide (NO).
Limitations
The authors noted several important factors that would limit the results of the study from being classed as conclusive. "
The first limitation of our study concerns the very restricted inclusion and exclusion criteria (because of the target population being studied) that may limit the generalisability of the findings," wrote Zibadi. "
Another limitation of the study was the relatively small sample size.
Due to the limited size of the study population, we combined patients from different ethnic backgrounds in one group to achieve the required statistical power.
"Another limitation was that we did not differentiate between recently diagnosed diabetic patients and those who were diagnosed many years ago who may have been better controlled." About 22.5 million people are affected by diabetes in the European Union, 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 over 20 million people with diabetes, equal to seven per cent of the population.
The total costs are thought to be as much as $132 billion, with $92 billion being direct costs from medication, according to 2002 American Diabetes Association figures.
Funding 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.
Victor Ferrari, research chief operating officer and executive vice president of Horphag Research, told NutraIngredients in October 2006 that the company ploughs $1.5m - "most of its profits" - into research each year.
Source: Nutrition Research (Elsevier) May 2008, Volume 28, Issue 5, Pages 315-320 "Reduction of cardiovascular risk factors in subjects with type 2 diabetes by Pycnogenol supplementation" Authors: S. Zibadi, P.J. Rohdewald, D. Park, R.R. Watson