Flaxseed for Managing High Blood Pressure

woman crushing flaxseeds
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For the one in three American adults with high blood pressure, adding ground flaxseeds to meals may help. Sourced from the Linum usitatissimum plant, flaxseed contains a number of substances, such as alpha-linolenic acid (a type of omega-3 fatty acid), fiber, and lignans.

Flaxseed is available in a number of forms, including whole or ground seeds and flaxseed oil. Sometimes taken in supplement form, flaxseed oil typically contains alpha-linolenic acid (and sometimes lignans). Since whole flaxseed can be tough to digest, the seeds should be ground into a powder prior to eating them.

Why Is Flaxseed Used to Manage High Blood Pressure?

Alpha-linolenic acid is thought to play a key role in flaxseed's possible effects on blood pressure. Indeed, some research has linked alpha-linolenic acid intake with a reduced risk of high blood pressure.

The fiber in flaxseed may also help bring blood pressure down. There's some evidence that fiber intake may help fight high blood pressure in part by protecting against endothelial dysfunction (i.e., abnormalities in the layer of cells lining the blood vessels).

In addition, the lignans in flaxseed may help lower blood pressure. A type of phytoestrogen, lignans are thought to regulate blood pressure in part by producing antioxidant effects.

The Research

Supplementing your diet with flaxseed may lead to a significant decrease in both systolic and diastolic blood pressure, according to a report published in Clinical Nutrition in 2016.

For this report, researchers reviewed 15 previously published clinical trials (with a total of 1,302 participants) which tested the effects of flaxseed supplementation on blood pressure. Their analysis determined that consuming flaxseed for more than 12 weeks had a greater effect on blood pressure than consumption of flaxseed products for fewer than 12 weeks.

The report's authors also found that while the use of flaxseed powder caused a significant reduction in systolic blood pressure (the top number in a blood pressure reading), use of flaxseed oil did not. However, both flaxseed powder and flaxseed oil appeared to significantly reduce diastolic blood pressure (the bottom number on the reading). Lignan extracts did not reduce blood pressure.

In another report, published in the Journal of Nutrition in 2015, researchers reviewed 11 previously published studies and found that flaxseed consumption for more than 12 weeks resulted in a slight reduction in systolic and diastolic blood pressure.

Side Effects

In some people, flaxseed may trigger abdominal pain, bloating, constipation, diarrhea, and nausea, particularly when taken in large amounts or with insufficient fluids (like other fiber supplements).

Since flaxseed may lower blood pressure, if you are taking blood pressure-lowering medication, consult your doctor prior to consuming flaxseed.

Pregnant or breastfeeding women should avoid flaxseeds, as they may have mild hormonal effects.

The NIH cautions that flaxseeds shouldn't be eaten raw or unripe, due to potentially toxic compounds. Some experts suggest limiting consumption to less than 50 grams (or 5 tablespoons of whole flaxseed) per day.

The Bottom Line

There are a number of things you can do to lower your blood pressure naturally, like exercising regularly, managing your salt intake, maintaining a healthy weight, and cutting back on alcohol and caffeine. While more research is needed before flaxseed can be recommended for blood pressure management, it's possible that adding flaxseed to your diet may enhance your health.

In addition to potentially lowering blood pressure, flaxseed may help cut cholesterol and keep blood sugar in check (a factor that may help protect against diabetes). Just be sure to discuss any changes to your regimen with your primary care provider, and note that flaxseed should not be used as a substitute for the standard care of high blood pressure.

To boost your dietary intake of flaxseed, try adding toasted ground flaxseed to such foods as yogurt, soups, salads, smoothies, breakfast cereal, and oatmeal. You can also add them to muffin or bread recipes before baking.

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