September 28/Washington/Asian News International (ANI) -- A new study has suggested that use of pine bark does not have any positive effect on the heart as previously thought.

The study has indicated that use of pine bark extract, at a dose of 200mg per day, appears safe but did not improve risk factors for heart disease.

"A substantial population seeks alternative therapies, including various dietary supplements, to lower cardiovascular disease risk," the authors wrote.

Rebecca L. Drieling of the Stanford University and colleagues conducted a randomized, placebo-controlled, double-blind clinical trial of pine bark extract supplements.

A total of 130 individuals at increased risk for cardiovascular disease were randomly assigned to take either 200mgs of pine bark extract or a placebo once per day for 12 weeks.

Participants were asked not to lose weight, change their diet or begin taking any other medications or supplements during the study. Blood pressure and other risk factors were assessed at the beginning of the study and at six and 12 weeks.

Baseline risk factors for heart disease were the same in the pine bark and placebo groups.

Over the course of the study, blood pressure decreased by 1mm of mercury in patients taking pine bark and 1.9mm of mercury in patients taking placebo.

Other risk factors-including body mass index, blood cholesterol levels, liver enzyme test results, size of cholesterol particles and levels of insulin, lipoprotein(a), fasting blood glucose and the inflammatory marker C-reactive protein-also did not differ significantly between the two groups.

The researchers assessed blood pressure levels among subgroups of participants with higher risk for cardiovascular disease and still found no differences between those who took pine bark and those who took placebo.

Although it is biologically plausible that pine bark extract could reduce blood pressure through its ability to relax blood vessels constricted by stress hormones epinephrine and norepinephrine, the extract tested in this study was safe but did not improve blood pressure or other heart disease risk factors, the authors noted.

"Although a different dosage or formulation might produce different results, our findings argue against recommending this pine bark extract to improve cardiovascular disease risk factors," they concluded.

The study was published in the Archives of Internal Medicine, one of the JAMA/Archives journals.

From the October 4, 2010, Prepared Foods E-dition