- Indications with possible efficacy:
Effentials fatty acids source - omega 3, alpha-linolenic acid (popular use)
Hypercholesterolaemia (popular use)
- Indications with possible, but poorly documented efficacy:
- Other indications with no proof of efficacy:
Colon damage due to laxative abuse
Gastritis and enteritis
Irritable bowel syndrome
Skin inflammation - topical
- Risk of Drug Interactions: Moderate
- Adverse Effects: Rare
Flax is a herbaceous plant that grows around the Mediterranean basin. It is now cultivated widely in temperate and tropical climates. While it is sometimes white, the flower is usually blue. The leaves are grey-green and the plant can reach 1,5m high. Seeds are harvested after flowering, before they ripen and fall to the ground.
Flaxseeds are a good source of fibre and omega-3 fatty acids. They are used to treat several gastrointestinal disorders, to slightly lower cholesterol levels, to prevent or delay the progression of certain types of cancer. They can also be used as a poultice to treat skin inflammation. Apparently, seeds can be placed in eyes to help remove foreign objects.
The seeds can be used to produce flaxseed oil, but usually whole seeds are used.
Direction of use
- Chronic constipation:
Some sources recommend soaking the seeds until they release their mucilage, while others consider that they should do so in the intestine to be effective. Whole flaxseeds are not advisable for people with intestinal diverticula. It can take 18 to 24 hours before the onset of the laxative effect, so flaxseeds should be taken for 2 to 3 days.
Usual doses: 10 g (1 tablespoon) to 45 g (4.5 tablespoons) per day of whole or crushed seeds mixed in a glass of water (at least 150 mL) in 2 to 3 doses.
Taking the recommended dose appears to reduce total cholesterol levels by 5 to 9% and "bad" cholesterol by 8 to 18%.
Usual doses: 30 to 50 g of flaxseeds daily (taken whole or crushed, or mixed in muffin batter).
- Menopause symptoms:
To reduce mild menopausal symptoms.
Usual doses: 40 g of flaxseed per day
- Systemic lupus erythematosus nephritis:
Usual doses: 15 g of crushed seeds twice a day, mixed with cereals, tomato or orange juice.
There is insufficient reliable information to conclude that this plant is effective in any other indication.
- Side effects
When taken with lots of water, flaxseeds are not associated with any serious adverse effects. Nonetheless, doses should be increased gradually. Cases of flatulence, bloating, abdominal pain and diarrhea have been reported. Taking flaxseeds with an insufficient amount of liquid can result in intestinal blockage.
Flaxseeds should be avoided in people with intestinal obstruction.
Because flaxseeds can impair the absorption of certain drugs, they should be taken 2 hours before or after taking medications. Before taking flaxseeds, check with your pharmacist to make sure that there are no interactions with your regular medication.
- Pregnancy and breastfeeding
There is insufficient information about its use during pregnancy and breast-feeding.
In 2004, Canada adopted new regulations that control the manufacturing, packaging, labeling and importing of natural health products. The new regulations also include an adverse reaction reporting system. Products that conform to the regulation's criteria are identified with a natural product number (NPN) and can be legally sold in Canada. This number indicates that the product meets specific criteria for safety and purity, not that it is effective for any indication.
Medicinal plant contents vary naturally from plant to plant - just as fruits from the same package may vary in taste and texture. There is no standard to measure the active content of each plant. Thus, efficacy of natural products should be expected to vary from brand to brand as well as from bottle to bottle of the same brand.
For more information about the Natural Health Products Regulations, or to check if a product has been assessed, visit the Health Canada website at www.hc-sc.gc.ca/dhp-mps/prodnatur/index-eng.php.
- Blumethal M et al. The Complete German Commission E monographs, 1998
- Natural Medicines Comprehensive Database, Therapeutic Research Faculty, 2010
- Passeportsanté.net. Lin. www.passeportsante.net
- Herbal Companion to AHFS DI, American Society of Health-System Pharmacists, 2001
- Taylor J. CE: Phytomedicinals: Uses, precautions, and drug interactions. Drug Topics 2003;1:79
- Natural Therapeutics Pocket Guide, 2000-2001
- The Review of Natural Products, 6th Edition, 2010
- Health Canada, Natural Products Database
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The patient information leaflets are provided by Vigilance Santé Inc. This content is for information purposes only and does not in any manner whatsoever replace the opinion or advice of your health care professional. Always consult a health care professional before making a decision about your medication or treatment.