flaxseed (generic name)
- Auto Immune Conditions
- Bladder & Kidney Health
- Brain & Nervous System
- Care Transitions
- Dental Health
- Emotional Health
- Eye Health
- Falls Prevention
- Financial Planning
- General Safety
- Health Care Basics
- Healthy Living
- Hearing Loss
- Heart Health
- High Blood Pressure
- Life Transitions
- Lung Health
- Men's Health
- Nutrition & Weight Management
- Pain Management
- Preventive Health
- Sexual Health
- Stomach & Digestive Health
- Stress & Anxiety
- Women's Health
TraditionWARNING: DISCLAIMER: The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.
Abdominal pain, acute respiratory distress syndrome (ARDS), allergic reactions, antioxidant, benign prostatic hypertrophy (BPH), bipolar disorder, bladder inflammation, blood thinner, boils, bowel irritation, bronchial irritation, burns (poultice), catarrh (inflammation of mucous membrane), colon cancer, cough (suppression or loosening of mucus), cystitis, depression, diarrhea, diabetic nephropathy, diverticulitis, dry skin, dysentery, eczema, emollient, enlarged prostate, enteritis, eye cleansing (debris in the eye), gastritis, gonorrhea, headache, infections, inflammation, irritable bowel syndrome, liver protection, malaria, melanoma, menstrual disorders, ovarian disorders, pimples, psoriasis, rheumatoid arthritis, skin infections, skin inflammation, sore throat, stomach upset, stroke, ulcerative colitis, upper respiratory tract infection, urinary tract infection, vaginitis, vision improvement.
Adults (over 18 years old)
Flaxseed oil is available in liquid and capsule form, flaxseed powder, flour, and soluble fiber. 10 to 250 grams have been taken by mouth.
Whole or bruised (not ground) flaxseed can be mixed with liquid and taken by mouth. Generally, 1 tablespoon in this form is mixed with 6 to 12 ounces of liquid and taken by mouth up to three times a day. Some studies use doses of soluble flaxseed mucilage/fiber as high as 60 to 80 grams per kilogram (1 kilogram equals 2.2 pounds) of the person's weight. These liquid forms of flaxseed should not be confused with preparations of flaxseed oil.
Anecdotally, 30-100 grams of flaxseed flour can be mixed with warm or hot water to form a moist compress and applied to the skin up to three times a day. It is not clear how long a flaxseed poultice should be used.
Children (under 18 years old)
Not enough information is available to advise use of flaxseed or flaxseed oil in children.
SafetyDISCLAIMER: Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.
People with known allergy to flaxseed, flaxseed oil, or any other members of the Linaceae plant family or Linum genus should avoid flaxseed products. Severe allergic reactions have been reported.
Side Effects and Warnings
There are few studies of flaxseed safety in humans. Flaxseed and flaxseed oil supplements do appear to be well tolerated in the available research, and there is long-standing historical use of flaxseed products without many reports of side effects. However, unripe flaxseed pods are believed to be poisonous and should not be eaten. Raw flaxseed or flaxseed plant may increase blood levels of cyanide, a toxic chemical (this effect has not been reported when flaxseed supplements are taken at recommended doses). Do not apply flaxseed or flaxseed oil to open wounds or broken skin.
Based on animal studies, overdose of flaxseed may cause shortness of breath, rapid breathing, weakness, or difficulty walking, and may cause seizures or paralysis. Theoretically, flaxseed (not flaxseed oil) may increase the risk of cell damage from a reaction called oxidative stress. Studies report conflicting results in this area. Based on one study, flaxseed or flaxseed oil taken by mouth may cause mania or hypomania in people with bipolar disorder. In theory, the laxative effects of flaxseed (not flaxseed oil) may cause diarrhea, increased number of bowel movements, and abdominal discomfort. Laxative effects are reported in several studies of people taking flaxseed or omega-3 acids. People with diarrhea, irritable bowel syndrome, diverticulitis, or inflammatory bowel disease (Crohn's disease or ulcerative colitis) should avoid flaxseed due to its possible laxative effects. Nausea, vomiting, and abdominal pain are reported in two individuals shortly after taking flaxseed products by mouth; these reactions may have been caused by allergy.
Large amounts of flaxseed by mouth may cause the intestines to stop moving (ileus). People with narrowing of the esophagus or intestine, ileus, or bowel obstruction should avoid flaxseed (not flaxseed oil). Individuals with high blood triglycerides should avoid flaxseed and flaxseed oil due to unclear effects on triglyceride levels in animal research. People with diabetes should use caution if taking flaxseed products by mouth, as the omega-3 fatty acids in flaxseed and flaxseed oil may increase blood sugar levels.
One study reports that the menstrual period may be altered in women who take flaxseed powder by mouth daily. Due to the possible estrogen-like effects of flaxseed (not flaxseed oil), it should be used cautiously in women with hormone sensitive conditions such as endometriosis, polycystic ovary syndrome, uterine fibroids, or cancer of the breast, uterus, or ovary. Some natural medicine textbooks advise caution in patients with hypothyroidism, although little scientific information is available in this area. Flaxseed and flaxseed oil may increase the risk of bleeding, based on early studies that show decreased clotting of blood. Caution is advised in patients with bleeding disorders, in people taking drugs that increase the risk of bleeding, and in people planning to undergo medical, surgical, or dental procedures. Dosing of blood-thinning medications may need to be adjusted. In animal studies, flaxseed has increased the number of red blood cells.
Several studies in humans report an increased risk of prostate cancer in men taking alpha-linolenic acid (which is present in flaxseed) by mouth. One small study of men with prostate cancer reports that flaxseed supplements do not increase prostate specific antigen (PSA) levels. Until more information is available, men with prostate cancer or at risk for prostate cancer should avoid flaxseed and alpha-linolenic acid supplements.
Pregnancy and Breastfeeding
The use of flaxseed or flaxseed oil during pregnancy and breastfeeding is not recommended. Animal studies show possible harmful effects, and there is little information in humans. Flaxseed may stimulate menstruation or have other hormonal effects and could be harmful to pregnancy.