Control blood pressure with flax

Reporter's Notebook: New research shows that eating ground flaxseed can lower your blood pressure

ground flax seeds

One of the interesting side effects of covering agriculture is that influences my eating habits.

I get to hear about the research into food uses and health claims of the crops grown in Western Canada. I eat pulses for the fibre and protein. I use canola oil several times a week. I’m not shy about eating gluten. I occasionally have oats for breakfast (it’s a great option while traveling), and lately I’ve been baking with them.

I’m also a flax fan. So when I saw that Crop Sphere had a session on flax health claims, I had to check it out.

Dr. Grant Pierce presented the results of a year-long clinical trial looking at whether eating ground flaxseed drops blood pressure and cholesterol. Pierce heads research at St. Boniface Hospital and is also a professor at the University of Manitoba.

Cholesterol is certainly bad for your heart health, Pierce said.

“But high blood pressure is four times as important as cholesterol for heart disease. High blood pressure right now leads to 10 million deaths worldwide each year.”

And 19 out of 20 Canadians will develop hypertension if they live an average lifespan.

He told us that, “current approaches are not working as well as they should. And maybe we can complement drug treatment with another therapeutic approach,” Pierce said.

Flax has three things going for it:

  1. Lignins, which are a potent anti-oxidant. Oxidation is an important part of almost every disease out there today, Pierce said.
  2. ALA, an Omega 3 that acts as an anti-inflammatory.
  3. Fibre, which will reduce low-density lipoprotein (“bad cholesterol”).

The study was a double-blinded, placebo-controlled, randomized clinical trial. Pierce explained that’s “fancy jargon meaning it’s the most tightly controlled trial that we can do today, equivalent to any drug trial that’s out there.”

Over a year, 110 patients took part — 52 in the placebo group, 58 in the flax group. All the patients had peripheral arterial disease. The typical participant was a 66-year-old man who had smoked over 20 cigarettes a day for three decades before quitting. He had hypertension. There was a good chance that he also had high cholesterol and/or diabetes.

The flax group consumed 30 grams of milled flax every day. That’s about three heaping tablespoons. Pierce said they worked with Cigi and the Food Development Centre in Portage La Prairie to develop buns, pasta, muffins, and bagels so participants had variety.

Each month the patients would order their carbs. Researchers tracked those orders, so they have a good idea what flavours and products worked for that demographic. “They didn’t like the sun-dried tomato. They loved the cinnamon raisin bagel and that continued throughout the whole study,” said Pierce.

The placebo group got whole wheat instead of flax. Researchers measured the ALA in participants’ blood, just to make sure people from both groups were following the rules. Both groups had low ALA levels in the beginning, but the flax groups’ levels rose through the year.

Flax as good as any drug

Researchers also measured participants’ blood pressure throughout the year. Both groups had the same (high) blood pressure numbers at the beginning of the trial. The flax group saw a significant drop in their blood pressure through the trial. The placebo groups’ blood pressure stayed the same.

Specifically, the flax eaters’ systolic blood pressure dropped about 10 mmHg. Their diastolic blood pressure dropped by seven mmHg. (Systolic is the higher number, and diastolic is the lower number).

Patients who had systolic hypertension reaped the most benefits from the flax. They saw a 15 mmHg drop in systolic blood pressure.

What exactly does that mean? “Flax seed is at least as good as any drug that’s out there today, if not better,” Pierce said. Those numbers represent a big, big drop in stroke and heart attack incidence, he added.

Researchers also looked at cholesterol. Total and LDL cholesterol was the same in both groups at the start. Over 12 months, the flax group saw a 10 to 15 per cent drop in both total and LDL cholesterol. The placebo group stayed the same. Pierce said that anyone eating flax will continue to see cholesterol drops whether or not they’re on cholesterol-controlling drugs.

“And it’s better than if you’re just on the cholesterol-controlling medication.”

You probably don’t need to consume 30 grams of flax a day to see benefits. Pierce said they used 30 grams because they didn’t want to find out part way through that people weren’t getting quite enough flax to see an effect.

Pierce said they saw a blood pressure drop within the first month. That month the flax eaters were only getting 20 grams a day, so they could get used to the extra fibre.

Don’t throw out your medication. But it might be worth a conversation with your doctor. Pierce’s study, along with other research, is available at The site requires users to register, but there is no cost.

About the author

Field Editor

Lisa Guenther

Lisa Guenther is field editor for Grainews based at Livelong, Sask. You can follow her on Twitter @LtoG.



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