Blood Pressure Unaffected By Pine-Bark Extract

Add pine-bark extract to the list of dietary supplements that don't live up to their promises of improved health. A new study from the Stanford University School of Medicine shows that pine-bark extract had no effect in lowering blood pressure or reducing other risk factors for heart disease. 

Senior author Randall Stafford, MD, PhD, said the findings are part of a growing body of evidence that antioxidant supplements don't improve heart function. 

"While there's a good biological basis to presume that antioxidant supplements might have a beneficial effect on heart health, this study is another example that they don't," said Stafford, associate professor of medicine at the Stanford Prevention Research Center. "There's also a broader message that many dietary supplements don't have the data to back up their claims of providing health benefits." 

The study, which will be published in the Sept. 27 issue of the Archives of Internal Medicine, is the largest randomized, placebo-controlled clinical trial to date examining the effects of pine-bark extract on blood pressure and other heart disease risks. 

Pine-bark extract has been reputed to have beneficial properties because it is an antioxidant, meaning that it counters the effects of free radicals - oxygen molecules that can damage cells in the body. While some previous studies linked pine-bark extract to reductions in blood pressure, Stafford said most of those studies were "open-label" (meaning that participants knew they were taking the extract) and didn't have control groups of patients who were given placebos. In some cases, participants took the extract in conjunction with other medication, so it wasn't possible to determine the effects of the pine-bark extract alone. 

For the Stanford study, the researchers recruited 130 overweight individuals who had blood pressure above an optimal level but were not taking medication for it. Stafford said the researchers felt these were the types of people who would be more likely to seek out dietary supplements as an alternative therapy. 

The participants were randomly assigned to take either a Japanese-produced pine-bark extract or a placebo. The extract dosage was 200 mg per day, which researchers said was in the middle range of dosages used in previous studies. 

Blood-pressure readings and blood samples of the participants were taken before the study began, at six weeks and then again at the end of the 12-week study period. Additionally, participants were monitored to ensure that their diets, medications and weight didn't change during the study. 

In analyzing the results, the researchers found that the participants' blood pressure levels - as well as other risk factors for heart disease, including cholesterol, blood glucose, body weight and C-reactive protein levels - remained virtually the same in both groups throughout the study. 

"We conducted additional analyses to see if there were subgroups of patients who might have received a benefit from the supplement, but none of them did," Stafford said. 

The study did confirm that the pine-bark extract was safe for consumption even though it didn't improve heart health, but Stafford said many other dietary supplements haven't undergone the same rigorous safety testing. He pointed to a U.S. Food & Drug Administration decision in 2004 to ban over-the-counter sales of ephedra, an herbal supplement that contained amphetamine-like drugs, because it caused heart problems. 

"Most consumers presume that the supplements on the market are safe, but there isn't rigorous information to back up those presumptions," said lead study author Rebecca Drieling, MPH, research director for the SPRC's Program on Prevention Outcomes and Practices. "That's because federal regulations treat dietary supplements more like food than like drugs. Also chemical composition varies among dietary supplements, making standardized testing difficult." 

Other co-authors include associate professor of medicine Christopher Gardner, PhD, and data analyst David Ahn, PhD. The study was funded by Toyo Shinyaku Co. of Japan, which provided the pine-bark extract along with the placebo tablets. None of the researchers has financial or consulting ties to the supplement company. 


Source: Medical News Today

Are some salts good for your blood pressure?

An increased intake of 'good' potassium salts could contribute significantly to improving blood pressure at the population level. The favourable effect brought about by potassium is even estimated to be comparable with the blood pressure reduction achievable by halving the intake of 'bad' sodium salts (mostly from table salt). Those are the conclusions drawn by Linda van Mierlo and her colleagues at Wageningen University, part of Wageningen UR, and Unilever in their investigation of the consumption of potassium in 21 countries. An article describing their findings appeared in the journal Archives of Internal Medicine on 13 September.

The risk of developing cardiovascular diseases rises as blood pressure increases. In Western countries only 20-30% of the population has 'optimal' blood pressure, with the systolic (maximum) pressure being lower than 120 mm Hg* and the diastolic (minimum) pressure lower than 80 mm Hg. Blood pressure increases with age in most people. Men more often have a higher blood pressure than women.

Diet and lifestyle plays an important role in managing blood pressure. High intakes of sodium and low intakes of potassium have unfavorable effects on blood pressure. Therefore, reducing the consumption of sodium and increasing the consumption of potassium are both good ways to improve blood pressure.

The study carried out by food researchers from the Human Nutrition department at Wageningen University and from the Nutrition & Health department at Unilever demonstrates that the average potassium intake in 21 countries including the US, China, New Zealand, Germany and the Netherlands varies between 1.7 and 3.7 g a day. This is considerably lower than the 4.7 g a day, which has been recommended based on the positive health effects observed at this level of intake.

A hypothetical increase in the potassium intake to the recommended level would reduce the systolic blood pressure in the populations of these countries by between 1.7 and 3.2 mm Hg. This corresponds with the reduction that would occur if Western consumers were to take in 4 g of salt less per day. The intakes of both potassium and sodium are therefore of importance in preventing high blood pressure.

Earlier studies have shown that salt reduction of 3 g per day in food could reduce blood pressure and prevent 2500 deaths per year due to cardiovascular diseases in the Netherlands. In Western countries, salt consumption can be as high as 9-12 g a day whereas 5 g is the recommended amount according to WHO standards. Most household salt is to be found in processed foods such as bread, ready-made meals, soups, sauces and savoury snacks and pizzas. An effective way of increasing potassium intake is to follow the guidelines for healthy nutrition more closely, including a higher consumption of vegetables and fruit. In addition, the use of mineral salts in processed foods - by which sodium is partly replaced by potassium - would contribute to an improved intake of both sodium and potassium.

Sources: Wageningen University and Research Centre, AlphaGalileo Foundation./ Medical News Today