Flaxseed and flaxseed oil (Linum usitatissimum)

Mayo Clinic Health Manager

Get free personalized health guidance for you and your family.

Get Started

Free

E-Newsletter

Subscribe to receive the latest updates on health topics. About our newsletters

  • Housecall
  • Alzheimer's caregiving
  • Living with cancer

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Attention deficit hyperactivity disorder (ADHD)
Preliminary evidence supports the idea that deficiencies or imbalances in certain highly unsaturated fatty acids may contribute to attention deficit hyperactivity disorder (ADHD). Based on one trial, alpha linolenic acid-rich nutritional supplementation in the form of flax oil may improve symptoms of ADHD. More research is needed to confirm these results. 		C
Breast cancer (flaxseed, not flaxseed oil)
There is a lack of information from human studies that flaxseed is effective in preventing or treating breast cancer. 		C
Diabetes (flaxseed, not flaxseed oil)
Human studies on the effect of flaxseed on blood sugar levels report mixed results. Flaxseed cannot be recommended as a treatment for diabetes at this time. 		C
Dry eye syndrome
Taking flaxseed oil capsules by mouth may reduce dry eyes associated with Sjogren's syndrome patients. 		C
Heart disease (flaxseed and flaxseed oil)
People who have had a heart attack are reported to benefit from diets rich in alpha-linolenic acid, which is found in flaxseed. Good studies that examine the effect of flaxseed on heart disease in humans are not available. It is unclear whether flaxseed supplementation alters the course of heart disease. 		C
High blood pressure (flaxseed, not flaxseed oil)
In animals, diets high in flaxseed have mixed effects on blood pressure. One study in humans suggests that flaxseed might lower blood pressure. The evidence in this area is not clear, and more research is needed before a recommendation can be made. 		C
High cholesterol or triglycerides (flaxseed and flaxseed oil)
In laboratory and animal studies, flaxseed and flaxseed oil are reported to lower blood cholesterol levels. Effects on blood triglyceride levels in animals are unclear, with increased levels in some research, and decreased levels in other research. Human studies in this area report mixed results, with decreased blood levels of total cholesterol and low-density lipoprotein ("bad cholesterol") in some studies, but no effect in other studies. Most human research has not been well-designed, and further research is needed before a recommendation can be made. 		C
HIV/AIDS
There is a lack of strong evidence available in this area, and no recommendation can be made without further research. 		C
Kidney disease/Lupus nephritis (flaxseed, not flaxseed oil)
There is a lack of strong evidence available in this area. More research is needed before a firm recommendation can be made. 		C
Laxative (flaxseed, not flaxseed oil)
Early studies in humans suggest that flaxseed can be used as a laxative. However, more information is needed to compare effectiveness and dosing to more commonly used agents. 		C
Menopausal symptoms
There is preliminary evidence from randomized controlled trials that flaxseed oil may help decrease mild menopausal symptoms. Additional research is necessary before a clear conclusion can be drawn and this remains an area of controversy. Patients should consult a doctor and pharmacist about treatment options before starting a new therapy. Overall effects on bone mineral density and lipid profiles remain unclear. 		C
Menstrual breast pain (flaxseed, not flaxseed oil)
Early information from one study in women, the results of which have not been fully reported, suggests that flaxseed may reduce menstrual breast pain. However, further study is needed before a recommendation can be made. 		C
Obesity
There is limited research on the effects of flaxseed flour and its effects in obese patients. 		C
Pregnancy (spontaneous delivery)
It has been proposed that alpha-linolenic acid, provided as flax oil capsules, may delay the timing of spontaneous delivery, but the available evidence does not support this use. 		C
Prostate cancer (flaxseed, not flaxseed oil)
There is limited high quality research of the effects of flaxseed or alpha-linolenic acid (which is in flaxseed) on the risk of developing prostate cancer. This area remains controversial as there is some data reporting possible increased risk of prostate cancer with alpha linolenic acid. Prostate cancer should be treated by a medical oncologist. 		C

Key to grades
A Strong scientific evidence for this use
B Good scientific evidence for this use
C Unclear scientific evidence for this use
D Fair scientific evidence against this use (it may not work)
F Strong scientific evidence against this use (it likely does not work)

Grading rationale

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. 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.

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.

Dosing Synonyms

NS_patient-flaxseed

Portions of this document last updated:

Sept. 1, 2009

THIS EVIDENCE-BASED MONOGRAPH WAS PREPARED BY
THE NATURAL STANDARD RESEARCH COLLABORATION
(www.naturalstandard.com)


Text Size: smaller largerlarger