Flax

Studies in people

• Benefit

  Heart and blood sugar health²

  Eating flaxseed regularly may improve cholesterol, blood pressure and blood sugar, but scientists do not yet know the best amount.

• Benefit

  Heart disease risk³

  In people, flaxseed may lower a blood fat called Lp(a) that is linked to heart disease.

• Benefit

  Blood clotting in diabetes⁴

  In people with type 2 diabetes, flaxseed oil seemed to lower platelet clumping, but genes made no difference.

• Benefit

  Weight and blood fats⁵

  Overweight adults who ate biscuits with flaxseed meal for 60 days lost more weight and had lower blood fats.

• Benefit

  Blood sugar in diabetes⁶

  In people with diabetes, flaxseed may help lower fasting blood sugar and ease inflammation, though it works alongside regular medicine.

• Benefit

  Breast cancer risk⁷

  Flax may lower breast cancer risk, but scientists do not yet know for sure.

• Benefit

  Heart and blood vessel health⁸

  Flaxseed may modestly lower cholesterol and blood sugar, but its other heart effects are still unclear.

• Benefit

  Fibre versus cadmium¹⁰

  In Danish people aged 15–74, the good effects of flax fibre outweighed the bad effects of cadmium.

• Benefit

  Weight loss in overweight adults¹¹

  In overweight adults, adding milled flaxseed to lifestyle advice led to more weight loss than lifestyle advice alone.

• Benefit

  Heart and blood fats¹²

  In people with high cholesterol, eating roasted flaxseed powder for 3 months improved blood pressure and cholesterol levels.

• Benefit

  Cholesterol and blood sugar¹³

  In people with high cholesterol, flaxseed lignan extract lowered their cholesterol and fasting blood sugar.

• Benefit

  Liver fat in people¹⁴

  In people with fatty liver, 12 weeks of flaxseed powder lowered liver fat and body fat.

• Benefit

  Prostate cancer growth¹⁵

  In men with prostate cancer, eating flaxseed raised enterolignans, which were linked to slower tumor cell growth.

Animal and lab studies only

• Open question

  Bread texture and antioxidants²¹

  In lab studies, adding flaxseed hull to bread raised antioxidants but made loaves smaller and firmer.

• Benefit

  Immune and cancer effects²²

  In lab studies, flax compounds called linusorbs calmed overactive immune cells and triggered self-destruction in some cancer cells.

• Benefit

  Belly fat in rats²³

  In animal studies, flaxseed polysaccharide helped obese rats lose weight and belly fat.

Study type not stated

• Benefit

  Cancer protection¹⁶

  Flax seeds contain compounds that a review of studies says may have anti-cancer properties.

• Open question

  Heart and gut health¹⁷

  Flaxseed contains essential fatty acids, lignans and dietary fiber, which researchers are studying for health benefits.

• Benefit

  Seed compound extraction¹⁸

  Flaxseed lignan may have human health benefits, but the best way to extract it for products is not yet known.

• Benefit

  Cancer and diabetes risk¹⁹

  Flax is one of the richest sources of lignans, which may help lower the risk of cancer and diabetes.

How it’s made and used

• Body weight and energy⁹

  Eating flaxseed or defatted flaxseed flour made people pass more energy and fat in their stools.

• Gut bacteria changes²⁰

  In lab studies, flaxseed changed human gut bacteria and increased the acids they made.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.