Eating flaxseed each day might help lower high blood pressure, a new study suggests.
Researchers said it's too early to swap out blood pressure medication for flaxseeds just yet. But if future studies confirm the new results, flax might be a cheap way to treat high blood pressure.
Flaxseed is well known as a plant source the omega-3 fatty acids (called alpha linolenic acid), fibre and lignans, a type of phytochemical.
But so far, its effect on high blood pressure has been better studied among animals than humans. This study is the first to show the cardiovascular benefits of dietary flaxseed in a hypertensive people.
The trial included 110 people who had been diagnosed with peripheral artery disease, in which plaque builds up in arteries in the leg. Patients with the condition often have high blood pressure.
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 four tablespoons or ¼ cup - of milled flaxseed every day for six months.
Those in the comparison group were given foods that tasted similar, but didn't contain any ground flaxseed.
The researchers had participants increase their dose of flaxseed gradually so they could become accustomed to the fibre load.
People who had an initial systolic blood pressure - the top number in a blood pressure reading - 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 - the bottom number - 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," the lead researcher 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.
One expert expressed some concern over 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 - a larger, more controlled trial with out-of-office blood pressure would be needed which is underway.
Source: Hypertension, online October 14, 2013.
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