What Is Flaxseed?
Flax is a plant that grows throughout Canada and the northwestern United States. Its seed, also known as linseed, contains soluble fiber, omega-3 fatty acids, and lignans (naturally occurring chemicals with estrogen-like effects).
Flaxseed is sold whole and in powder form. Derived from flaxseed, flaxseed oil is available in liquid and capsule form. It should be noted that flaxseed oil preparations lack lignans.
Health Benefits of Flaxseed:
Although research on flaxseed's health effects is limited, studies suggest that flaxseed products may be beneficial for people with the following health problems:
1) High Cholesterol
A number of human studies have shown that flaxseed can significantly reduce total and LDL ("bad") cholesterol levels, according to a research review published in 2009. However, flaxseed did not appear to considerably alter levels of HDL ("good") cholesterol. What's more, flaxseed's cholesterol-lowering effects were more apparent in females (especially postmenopausal women) and people with higher cholesterol levels.
2) Hot Flashes
Study results are mixed on whether flaxseed can cool hot flashes. For instance, a pilot study published in 2007 found that six weeks of daily crushed-flaxseed consumption decreased hot flash activity in women not taking estrogen therapy. However, a more recent study concluded that regular intake of flaxseed is no more effective than a placebo for reducing hot flashes.
A 2005 study of 26 healthy young adults found that daily flaxseed intake produced a laxative effect, suggesting that flaxseed may be useful in the treatment of constipation.
Flaxseed and Cancer
Although preliminary research is promising, there is a lack of evidence from human-based studies that flaxseed is effective in preventing or treating cancer.
Uses for Flaxseed
Flaxseed is purported to offer a number of health benefits, including treatment or prevention of these conditions:
- high cholesterol
- menopausal symptoms
- premenstrual syndrome
- periodontal disease
How to Use Flaxseed
Flaxseed should be taken with plenty of water; otherwise, it could worsen constipation or, in rare cases, even cause intestinal blockage.
Since whole flaxseeds may pass through your intestine undigested, nutrition experts often suggest grinding flaxseed (in a coffee grinder, for instance) before adding it to cereals, smoothies, and other foods.
The fiber in flaxseed may lower the body's ability to absorb medications that are taken by mouth. Flaxseed should not be taken at the same time as any conventional oral medications or other dietary supplements.
If you're considering the use of any flaxseed product in the management of a specific health condition, make sure to consult your physician before beginning treatment.
Flaxseed Side Effects
Although flaxseed and flaxseed oil supplements are generally considered safe, their intake may lead to increased bowel movements and/or flatulence.
Dahl WJ, Lockert EA, Cammer AL, Whiting SJ. "Effects of flax fiber on laxation and glycemic response in healthy volunteers." J Med Food. 2005;8(4):508-11.
National Center for Complementary and Alternative Medicine. "Flaxseed and Flaxseed Oil." NCCAM Publication No. D313. Created May 2006. Updated April 2008.
Pan A, Yu D, Demark-Wahnefried W, Franco OH, Lin X. "Meta-analysis of the effects of flaxseed interventions on blood lipids." Am J Clin Nutr. 2009 90(2):288-97.
Pruthi S, Thompson SL, Novotny PJ, Barton DL, Kottschade LA, Tan AD, Sloan JA, Loprinzi CL. "Pilot evaluation of flaxseed for the management of hot flashes." J Soc Integr Oncol. 2007 5(3):106-12.
Simbalista RL, Sauerbronn AV, Aldrighi JM, Arêas JA. "Consumption of a Flaxseed-Rich Food Is Not More Effective Than a Placebo in Alleviating the Climacteric Symptoms of Postmenopausal Women." J Nutr. [Epub ahead of print]
Thompson LU, Chen JM, Li T, Strasser-Weippl K, Goss PE. "Dietary flaxseed alters tumor biological markers in postmenopausal breast cancer." Clin Cancer Res. 2005 15;11(10):3828-35.