Flaxseed And Flaxseed Oil
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.
Key References
- Colli
MC, Bracht A, Soares AA, et al. Evaluation
of the efficacy of flaxseed meal and flaxseed extract in reducing
menopausal symptoms. Journal of Medicinal Food. 2012;15(9):840-845.
- Flaxseed.
Natural Medicines Web site. Accessed at
naturalmedicines.therapeuticresearch.com on April 8, 2015.
[Database subscription].
- Flaxseed
oil. Natural Medicines Web site. Accessed at
naturalmedicines.therapeuticresearch.com on April 8, 2015.
[Database subscription].
- Pan
A, Yu D, Demark-Wahnefried W, et al. Meta-analysis
of the effects of flaxseed interventions on blood lipids. American Journal of Clinical
Nutrition. 2009;90(2):288-297.
- Pruthi
S, Qin R, Terstreip SA, et al. A
phase III, randomized, placebo-controlled, double-blind trial of
flaxseed for the treatment of hot flashes: North Central Cancer
Treatment Group N08C7. Menopause. 2012;19(1):48-53.
- Simbalista
RL, Sauerbronn AV, Aldrighi JM, et al. Consumption
of a flaxseed-rich food is not more effective than a placebo in
alleviating the climacteric symptoms of postmenopausal women. Journal of Nutrition. 2010;140(2):293-297.
- Thompson
LU, Mason JK. Flaxseed. In: Coates PM, Betz JM, Blackman MR, et al.,
eds. Encyclopedia of Dietary
Supplements, 2nd ed. New York, NY: Informa
Healthcare; 2010:274-287.
-NIH
