Antioxidant May Help Lower Blood Pressure

Supplement May Reduce Dependence on Blood Pressure-Lowering Drugs

From the WebMD Archives

Feb. 20, 2004 -- Taking an antioxidant supplement made from the bark of French pine trees may help people with high blood pressure reduce their dependence on medications taken to keep their blood pressure under control, new research shows.

The study shows that people with high blood pressure who took the supplement, called Pycnogenol, were able to lower their daily dose of blood pressure-lowering medications by more than 30% while still keeping their blood pressure within normal levels.

Researchers say the supplement contains a high concentration of polyphenols, a type of antioxidant also found in foods such as grapes, and flavonoids, such as those found in green tea. Mounting studies have shown that these plant-based antioxidants may have a number of healthy effects, including lowering cholesterol levels and improving circulation.

By lowering the dependence on blood pressure-lowering drugs with natural antioxidants, researchers say it may be possible to reduce the side effects as well as the cost of treating high blood pressure.

Antioxidant Supplement Helps Lower Blood Pressure

In the study, researchers looked at the effects of daily supplementation with 100 milligrams of Pycongenol or a placebo in a group of 58 adults with high blood pressure who were also treated with a calcium channel blocker, nifedipine (sold commercially as Adalat and Procardia).

All of the participants started with a 20-milligram daily dose of the calcium channel blocker and their dosage was either increased or decreased every two weeks until their blood pressure reached normal levels.

After 12 weeks of treatment, those who received the antioxidant supplement in addition to their medication were able to keep their blood pressure within normal levels with a 15-milligram dose of the drug compared with an average dose of 21.6 milligrams per day among those who took the placebo.

Researchers say the blood pressure-lowering effects of Pycongenol appeared to be caused by the antioxidants effect on the endothelium, the innermost layer of arterial blood vessels that expands and contracts in response to blood flow.

"They produced less of the substances that constrict arteries and more of the substances that dilate [expand] the arteries," says researcher Peter Rohdewald, PhD, retired professor of pharmaceutical chemistry at the University of Münster in Germany. "That recovery of the function of the endothelium is probably the most beneficial effect for the patients."

Continued

The study, which appears in the Jan. 2 issue of the journal Life Sciences, showed side effects that were similar in the two groups.

Rohdewald says the most powerful ingredient in the antioxidant supplement appears to be procyanidins, which are bitter tasting compounds that used to be commonly found in many foods.

"My theory is that our food industry and our plant cultivation over past 200 years has nearly eliminated these very useful substance because most people don't like to eat astringent-tasting apples and grapes. They like to have sweet ones," Rohdewald tells WebMD.

"I think for our well-being these procyanidins had been very useful. Now we lack these substances, and we would do better if we take these substances," says Rohdewald, who also serves a consultant to the company that produces Pycnogenol.

New Use for Antioxidants?

Experts say it's not the first time that plant-based antioxidants have been shown to mildly reduce blood pressure levels. But this study is unusual because it looked at the benefits of using antioxidant supplements in combination with conventional medicines.

"What's interesting to me, is that by and large complimentary and alternative medicine have focused on these natural remedies as an alternative to traditional medicines, and in this case they are being a little more integrative, using a natural remedy in combination with a drug remedy," says antioxidant researcher Jeffrey Blumberg, PhD, professor of nutrition at Tufts University in Boston.

Blumberg says previous studies have already shown that antioxidants, such as those found in green tea and vitamin C, have a slight blood pressure-lowering effect when used instead of drugs in treating people with mild high blood pressure. But this study shows antioxidant therapy may also benefit people already on drug therapy for their high blood pressure.

WebMD Health News Reviewed by Brunilda Nazario, MD on February 20, 2004

Sources

SOURCES: Liu, X. Life Sciences, Jan. 2, 2004; vol 74: pp 855-862. Peter Rohdewald, PhD, retired professor, pharmaceutical chemistry, University of Münster, Germany; consultant, research & development, Horphag Research. Jeffrey Blumberg, PhD, professor, nutrition, Friedman School of Nutrition Science and Policy, Tufts University, Boston.

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