Herbs & Supplements:

FlaxSeed Oil (Flax Seed Oil)

Supplement Forms / Alternate Names
  • Linseed Oil
Principal Proposed Uses
  • · There are no well-documented uses for flaxseed oil
Other Proposed Uses
  • Heart Disease Prevention, Rheumatoid Arthritis, Bipolar Disorder, Cancer Prevention

Note: Flaxseed oil contains alpha-linolenic acid.

Flaxseed oil is derived from the hard, tiny seeds of the flax plant. It has been proposed as a less smelly alternative to fish oil. Like fish oil, flaxseed oil contains omega-3 fatty acids, a type of fat your body needs as much as it needs vitamins.

However, it's important to realize that the omega-3 fatty acids in flaxseed oil aren't identical to what you get from fish oil. Flaxseed oil contains alpha-linolenic acid (ALA), while fish oil contains eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The effects and potential benefits may not be the same.

Flaxseeds contain another important group of chemicals known as lignans.Lignans are being studied for use in preventing cancer. However, contrary to some reports, flaxseed oil has no lignans.¹

Requirements/Sources

Flaxseed oil contains both omega-3 and omega-6 fatty acids, which are essential to health. Although the exact daily requirement of these essential fatty acids is not known, deficiencies are believed to be fairly common.² Flaxseed oil may be an economical way to ensure that you get enough essential fatty acids in your diet.

The essential fatty acids in flax can be damaged by exposure to heat, light, and oxygen (essentially, they become rancid). For this reason, you shouldn't cook with flaxseed oil. A good product should be sold in an opaque container, and the manufacturing process should keep the temperature under 100 degrees Fahrenheit. Some manufacturers combine the product with vitamin E because it helps prevent rancidity.

Therapeutic Dosages

A typical dosage is 1 to 2 tablespoons of flaxseed oil daily. It can be taken in capsule form or made into salad dressing. Some people find the taste pleasant, although others would politely disagree.

For whole flaxseed, a typical dose is 1 tablespoon of the seed (not ground) with plenty of liquid 2 to 3 times daily.

Therapeutic Uses

The best use of flaxseed oil is as a general nutritional supplement to provide essential fatty acids. There is little evidence that it is effective for any specific therapeutic purpose.

Flaxseed oil has been proposed as a less smelly alternative to fish oil for the prevention of heart disease. Although fish oil is much better studied, there is some evidence that flaxseed oil or whole flaxseed may reduce LDL ("bad") cholesterol, perhaps slightly reduce hypertension, and, overall, slow down atherosclerosis.^3,4,5

In addition, one study found that a diet high in ALA (from sources other than flaxseed oil) was associated with a reduced risk of heart disease.⁶ However, there were so many other factors involved that it is hard to say what caused what.⁷

Although fish oil appears to be effective for reducing symptoms of rheumatoid arthritis, flaxseed oil does not seem to work.⁸

One very preliminary study suggests that flaxseed oil may be helpful for controlling bipolar disorder when combined with conventional medications.⁹

Finally, although flaxseed or flaxseed oil are sometimes recommended as prevention or treatment for cancer, the evidence is still extremely preliminary.^10–13

Safety Issues

Flaxseed oil appears to be a safe nutritional supplement when used as recommended.

Last reviewed March 2002 by Medical Review Board

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