Overview

Flax (Linum usitatissimum) is a food and fiber crop. Flaxseeds are a good source of dietary fiber and omega-3 fatty acids, including alpha-linolenic acid.

Flaxseeds also contain phytoestrogens called lignans, which are similar to the hormone estrogen. The fiber in flaxseed is found in the seed coat. When taken before eating, it seems to make people feel less hungry. It might also help limit how much cholesterol the body absorbs from food.

Flaxseed is used for constipation, diabetes, high cholesterol, obesity, and swelling of the kidneys in people with lupus. It is also used for many other conditions, but there is no good scientific evidence to support most of these other uses.

Flaxseed and flaxseed oil have different effects. For information about the oil, see Flaxseed Oil.

Uses & Effectiveness ?

Possibly Effective for

  • Constipation. Flaxseed is a good source of dietary fiber. Eating flaxseed in muffins or other foods seems to increase bowel movements in young adults and people with diabetes.
  • Diabetes. Taking flaxseed by mouth might slightly improve blood sugar control in people with type 2 diabetes. Benefits seem to be greatest with ground flaxseed and when used for at least 12 weeks.
  • High cholesterol. Taking flaxseed by mouth seems to help reduce total cholesterol and low-density lipoprotein (LDL or "bad") cholesterol. It seems to work the best in people with high cholesterol and in people who are overweight. It's unclear if taking flaxseed improves triglyceride levels. Taking flaxseed doesn't seem to improve high-density lipoprotein (HDL or "good") cholesterol levels.
  • High blood pressure. Taking flaxseed by mouth may slightly reduce blood pressure in people with high blood pressure.
  • Breast pain (mastalgia). Eating a flaxseed muffin daily for 3 months or taking flaxseed powder by mouth daily for 2 months seems to reduce breast pain that occurs at the start of the menstrual cycle.
  • Obesity. Taking flaxseed by mouth may help reduce body weight, body mass index (BMI), and waist size in adults who are overweight or obese. Taking at least 30 grams of flaxseed daily for at least 12 weeks seems to work best. Flaxseed mucilage may also help to reduce weight, although flaxseed lignan extract doesn't seem to help.
  • Swelling (inflammation) of the kidneys in people with lupus. Taking whole or ground flaxseed by mouth seems to improve kidney function in people with SLE.

Possibly Ineffective for

  • Weak and brittle bones (osteoporosis). Taking flaxseed by mouth doesn't seem to help bone density in people with osteoporosis.
There is interest in using flaxseed for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.

Side Effects

When taken by mouth: Flaxseed is likely safe for most adults. Adding flaxseed to the diet might increase the number of bowel movements each day. It might also cause side effects such as bloating, gas, stomachache, and nausea. Higher doses are likely to cause more side effects.

Taking flaxseed extracts that contain lignans is possibly safe. Flaxseed lignan extracts can be used safely for up to 6 months.

Taking raw or unripe flaxseed by mouth is possibly unsafe. It might be poisonous.

When applied to the skin: Flaxseed is possibly safe when used in a cloth on the skin.

Special Precautions and Warnings

When taken by mouth: Flaxseed is likely safe for most adults. Adding flaxseed to the diet might increase the number of bowel movements each day. It might also cause side effects such as bloating, gas, stomachache, and nausea. Higher doses are likely to cause more side effects.

Taking flaxseed extracts that contain lignans is possibly safe. Flaxseed lignan extracts can be used safely for up to 6 months.

Taking raw or unripe flaxseed by mouth is possibly unsafe. It might be poisonous.

When applied to the skin: Flaxseed is possibly safe when used in a cloth on the skin.
Pregnancy: Taking flaxseed by mouth during pregnancy is possibly unsafe. Flaxseed can act like the hormone estrogen. Some healthcare providers worry that this might harm the pregnancy. But there is no reliable clinical evidence about its effects on pregnancy. Until more is known, stay on the safe side and avoid use.

Breast-feeding: There isn't enough reliable information to know if flaxseed is safe to use when breast-feeding. Stay on the safe side and avoid use.

Hormone-sensitive cancers or conditions: Because flaxseed might act somewhat like the hormone estrogen, it might make hormone-sensitive conditions worse. Some of these conditions include breast and ovarian cancer. Until more is known, avoid taking large amounts of flaxseed if you have one of these conditions.

High triglyceride levels (hypertriglyceridemia): Partially defatted flaxseed, which contains less alpha linolenic acid content, might increase triglyceride levels. If your triglyceride levels are too high, don't take this type of flaxseed.

Surgery: Flaxseed might increase the risk of bleeding during and after surgery. Stop using it at least 2 weeks before a scheduled surgery.

Interactions ?

    Moderate Interaction

    Be cautious with this combination

  • Medications for diabetes (Antidiabetes drugs) interacts with FLAXSEED

    Flaxseed might lower blood sugar levels. Taking flaxseed along with diabetes medications might cause blood sugar to drop too low. Monitor your blood sugar closely.

  • Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs) interacts with FLAXSEED

    Flaxseed might slow blood clotting. Taking flaxseed along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

  • Antibiotic drugs interacts with FLAXSEED

    Bacteria in the intestine convert some of the chemicals in flaxseed into lignans, which are thought to be responsible for many of the possible benefits of flaxseed. However, because antibiotics kill these bacteria, lignans might not be formed as usual. This might alter the effects of flaxseed.

  • Estrogens interacts with FLAXSEED

    Flaxseed can act like the female hormone estrogen. It might compete with drugs that contain estrogen. Flaxseed might make these estrogen-containing drugs less effective.

  • Medications for high blood pressure (Antihypertensive drugs) interacts with FLAXSEED

    Flaxseed might lower blood pressure. Taking flaxseed along with medications that lower blood pressure might cause blood pressure to go too low. Monitor your blood pressure closely.

Dosing

Flaxseed has most often been used by adults in doses of 20-30 grams by mouth daily. Flaxseed is often mixed with foods and used in baked goods, such as muffins, breads, and snack bars. Speak with a healthcare provider to find out what type of product and dose might be best for a specific condition.
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CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.
© Therapeutic Research Faculty 2020.