- What other names is Flaxseed known by?
- What is Flaxseed?
- How does Flaxseed work?
- Are there safety concerns?
- Are there any interactions with medications?
- Dosing considerations for Flaxseed.
People use flaxseed for many conditions related to the gastrointestinal (GI) tract, including ongoing constipation, colon damage due to overuse of laxatives, diarrhea, inflammation of the lining of the large intestine (diverticulitis), irritable bowel syndrome (IBS) or irritable colon, sores in the lining of the large intestine (ulcerative colitis), inflammation of the lining of the stomach (gastritis), and inflammation of the small intestine (enteritis).
Flaxseed is also used for disorders of the heart and blood vessels, including high cholesterol, "hardening of the arteries" (atherosclerosis), high blood pressure (hypertension), and coronary artery disease.
Flaxseed is also used for acne, attention deficit-hyperactivity disorder (ADHD), kidney problems in people with a disease called systemic lupus erythematosus (SLE), symptoms of menopause, and breast pain. It is also used for diabetes, obesity and weight loss, HIV/AIDS, depression, bladder infections, malaria, and rheumatoid arthritis.
Other uses include treatment of sore throat, upper respiratory tract infections (URTI), and cough.
Some people use flaxseed to lower their risk of getting weak bones (osteoporosis) and to protect against breast cancer, lung cancer, colon cancer, and prostate cancer.
Flaxseed is sometimes applied to the skin for acne, burns, boils, eczema, psoriasis, and to soothe inflammation.
Possibly Effective for...
- Diabetes. Research shows that taking a specific flaxseed product (FlaxEssence, Jarrow Formulas) three times daily for 3 months lowers hemoglobin A1C, a measure of average blood sugar level, in people with type 2 diabetes. Other clinical research shows that taking flaxseed powder for one month can reduce fasting blood glucose in people with type 2 diabetes, and taking flaxseed for 3 months can reduce blood sugar levels in people with glucose-intolerance. However, taking milled flaxseed does not seem to lower fasting blood sugar, insulin levels, or blood fats in people with type 2 diabetes.
- High cholesterol. Research shows that various flaxseed preparations, including ground flaxseed, partially defatted flaxseed, and flaxseed bread and muffins, seem to reduce total cholesterol and the "bad cholesterol," low-density lipoprotein (LDL) cholesterol, in people with normal cholesterol levels and in men and pre-menopausal women with high cholesterol. However, flaxseed does not have much effect on "good cholesterol," high-density lipoprotein (HDL) cholesterol. Most flaxseed preparations do not affect triglyceride levels. However, partially defatted flaxseed (flaxseed without as much alpha-linolenic acid content) can increase triglycerides.
- Autoimmune disorder (systemic lupus erythematosus, SLE). Taking flaxseed by mouth seems to improve kidney function in people with SLE.
Possibly Ineffective for...
- Osteoporosis. Research shows that consuming 40 grams of ground flaxseed daily for up to one year does not improve bone density in women. Similar findings were found for older men and women who took flaxseed extract.
Insufficient Evidence to Rate Effectiveness for...
- Enlarged prostate (benign prostatic hyperplasia; BPH). Early research shows that taking a specific flaxseed product (Beneflax) daily for 4 months reduces urinary tract symptoms associated with BPH and improves quality of life.
- Breast cancer. Early research shows that eating a muffin containing 25 grams of flaxseed daily for about 40 days reduces tumor cell growth in women recently diagnosed with breast cancer. However, it is unclear if this effect significantly improves overall breast cancer outcomes. There is inconsistent evidence regarding the effects of dietary flaxseed on breast cancer development.
- Heart disease. Research suggests that dietary intake of lignans, which are found in flaxseed and other foods, does not reduce the risk of heart disease.
- Colorectal cancer. Research on the effect of flaxseed on colorectal cancer risk is inconsistent. Some research shows that consumption of lignans, which are in flaxseed, is not associated with a reduced risk of colorectal cancer. However, other research suggests that it is.
- Constipation. Flaxseed is a good source of dietary fiber. Eating flaxseed-containing muffins seems to increase bowel movements in young adults, while eating flaxseed-containing yogurt seems to increase bowel movements in elderly people.
- Endometrial cancer. Research suggests that blood levels of lignans, which are found in flaxseed and other foods, are not associated with endometrial cancer risk.
- High blood pressure. Early research shows that taking flaxseed extract three times daily for 6 months reduces blood pressure in men but not in women.
- Irritable bowel syndrome (IBS). Early research shows that taking 24 grams of flaxseed daily for 4 weeks does not improve quality of life or the severity of IBS symptoms in people with IBS.
- Lung cancer. Research suggests that people who eat more phytoestrogens, such as those found in flaxseed, might have a lower risk of developing lung cancer than those who eat less.
- Breast pain (mastalgia). In early research, eating a flaxseed muffin each day for 3 months reduced breast pain associated with the start of the menstrual cycle. The muffins each contained 25 grams of flaxseed.
- Menopausal symptoms. It is not clear if flaxseed works for reducing symptoms of menopause such as hot flashes. Some research has found that it might modestly reduce symptoms. However, other studies show that it does not work any better than taking a sugar pill placebo. The difference in effectiveness might be due to the dose of flaxseed used.
- Metabolic syndrome (a condition that increases risk for diabetes and heart disease). Evidence on the use of flaxseed for metabolic syndrome is inconsistent. Early research shows that taking flaxseed extract reduces the risk of metabolic syndrome. However, other research shows that taking flaxseed does not improve markers of metabolic syndrome in people also following lifestyle modifications compared to those who just follow lifestyle modifications.
- Prostate cancer. Early research suggests that taking flaxseed and following a low-fat diet can lower prostate-specific antigen (PSA), a marker for prostate cancer, in men who have a precancerous prostate condition. However, in men who have prostate cancer, adding flaxseed to the diet does not lower PSA, but it does seem to lower levels of the hormone testosterone and slow the rate at which cancer cells multiply.
- Weight loss. Research in young adults who are not obese suggests that taking flaxseed fiber before a meal might reduce appetite and food intake. However, other research suggests that taking 40 grams of flaxseed daily for 12 weeks does not reduce body weight or mass in obese adults.
- Stomach upset.
- Bladder inflammation.
- Skin irritation.
- Attention deficit-hyperactivity disorder (ADHD) .
- Other conditions.
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).
Next: How does Flaxseed work?
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Get breaking medical news.