Flaxseed may reduce high blood pressure

By Shereen Jegtvig

NEW YORK (Reuters Health) - Eating fiber-rich flaxseed each day might help lower high blood pressure, a new study suggests.

"This is the first demonstration of the cardiovascular effects of dietary flaxseed in a hypertensive population," Grant Pierce told Reuters Health in an email. Pierce is the senior author on the study and executive director of research at St. Boniface Hospital in Winnipeg, Manitoba, Canada.

His team's results were published online October 14 in the journal Hypertension.

The study included 110 people with peripheral artery disease. The participants were randomly assigned to either a flaxseed or comparison group.

People in the flaxseed group ate a variety of foods like bagels, muffins and pasta that contained 30 grams - about one ounce - of milled flaxseed every day for six months. Those in the comparison group were given foods that tasted similar, but didn't contain any flaxseed.

The researchers had participants increase their dose of flaxseed gradually so they could become accustomed to the fiber load.

Still, one in five participants dropped out of each group during the trial. Some of that could have been due to stomach pain from the extra fiber, Pierce said.

People who had an initial systolic blood pressure of at least 140 mm Hg saw that figure drop by 15 mm Hg, on average, after six months of taking flaxseed.

Their diastolic blood pressure also fell by 7 mm Hg. Blood pressure did not change among people with hypertension in the comparison group.

"These decreases in (blood pressure) are amongst the most potent dietary interventions observed and comparable to current medications," Pierce said.

There was no flaxseed-related benefit for people with normal blood pressure, however.

The new study was partially funded by the Flax Council of Canada. It wasn't originally designed to study blood pressure, which means the results have to be interpreted with more caution.

"The study results are indeed surprising - it is actually hard to imagine such huge reductions in blood pressure with flax seed mixed in food stuffs," Dr. William B. White, from the University of Connecticut School of Medicine in Farmington and president of the American Society of Hypertension, told Reuters Health in an email. He was not involved in the new study.

White also expressed some concern that measuring blood pressure changes was not the initial reason for doing the study. And he said the way blood pressure was measured - during a single office visit - isn't as accurate as checking it at multiple points throughout the day.

"The results are preliminary - there is not enough information to justify people taking flax seed for the control of hypertension. A larger, more controlled trial with out-of-office blood pressure would be needed," White said.

According to Pierce, a new study is underway.

SOURCE: http://bit.ly/17A0jXq

Hypertension 2013.