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Flaxseed and Flaxseed Oil

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This fact sheet provides basic information about flaxseed and flaxseed oil—common names, usefulness and safety, and resources for more information.

 

Common Names:  flaxseed, flax, linseed

Latin Name: 
Linum usitatissimum

Background

  • Over the thousands of years it’s been cultivated, flaxseed has had a variety of health and industrial uses. Around 500 B.C., Hippocrates wrote about flaxseed being a laxative, and pioneers in North America made flaxseed dressings for cuts and burns. Fiber from the plant is made into linen, and oil from the seed is used in paints, among other products.
  • Today, flaxseed and flaxseed oil are used as dietary supplements for constipation, diabetes, cholesterol, cancer, and other conditions.
  • Flaxseed is made into tablets, extracts, powder, and flour. The oil is also put in capsules.

How Much Do We Know?

  • There have been a number of studies in people of flaxseed and flaxseed oil, including their effect on hot flashes.

What Have We Learned?

  • Flaxseed contains fiber, which generally helps with constipation. However, there’s little research on the effectiveness of flaxseed for constipation.
  • Studies of flaxseed and flaxseed oil to lower cholesterol levels have had mixed results. A 2009 research review found that flaxseed lowered cholesterol only in people with relatively high initial cholesterol levels.
  • Flaxseed doesn’t decrease hot flashes, studies from 2010 and 2012 suggest.
  • NCCIH is funding preliminary research on the potential role of substances in flaxseed for ovarian cancer, cardiovascular disease, metabolic syndrome, diabetes, asthma, and inflammation.

What Do We Know About Safety?

  • Don’t eat raw or unripe flaxseeds, which may contain potentially toxic compounds.
  • Flaxseed and flaxseed oil supplements seem to be well tolerated in limited amounts. Few side effects have been reported.
  • Avoid flaxseed and flaxseed oil during pregnancy as they may have mild hormonal effects. There’s little reliable information on whether it’s safe to use flaxseed when nursing.
  • Flaxseed, like any fiber supplement, should be taken with plenty of water, as it could worsen constipation or, in rare cases, cause an intestinal blockage. Both flaxseed and flaxseed oil can cause diarrhea.

Keep in Mind

  • Tell all your health care providers about any complementary or integrative health approaches you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.

NCCIH Clearinghouse

The NCCIH Clearinghouse provides information on NCCIH and complementary and integrative health approaches, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.

Toll-free in the U.S.: 
1-888-644-6226
TTY (for deaf and hard-of-hearing callers): 
1-866-464-3615

PubMed®

A service of the National Library of Medicine, PubMed® contains publication information and (in most cases) brief summaries of articles from scientific and medical journals. For guidance from NCCIH on using PubMed, see How To Find Information About Complementary Health Approaches on PubMed.

Office of Dietary Supplements (ODS), National Institutes of Health (NIH)

ODS seeks to strengthen knowledge and understanding of dietary supplements by evaluating scientific information, supporting research, sharing research results, and educating the public. Its resources include publications (such as Dietary Supplements: What You Need to Know), fact sheets on a variety of specific supplement ingredients and products (such as vitamin D and multivitamin/mineral supplements), and the PubMed Dietary Supplement Subset

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Key References

This publication is not copyrighted and is in the public domain. Duplication is encouraged.

NCCIH has provided this material for your information. It is not intended to substitute for the medical expertise and advice of your health care provider(s). We encourage you to discuss any decisions about treatment or care with your health care provider. The mention of any product, service, or therapy is not an endorsement by NCCIH.
NCCIH Publication No.: 
D313
Updated: 
September 2016

This publication is not copyrighted and is in the public domain. Duplication is encouraged.


NCCIH has provided this material for your information. It is not intended to substitute for the medical expertise and advise of your primary health care provider. We encourage you to discuss any decisions about treatment or care with your health care provider. The mention of any product, service, or therapy is not an endorsement by NCCIH.


U.S. Department of Health & Human Services, National Institutes of Health, National Center for Complementary and Integrative Health

nccih.nih.gov

This page last modified November 30, 2016