Medical Attributes of Linum usitatissimum - Flaxseed

By Sarah Witkowski and Khushbu Desai
Wilkes University, Wilkes-Barre, PA

July, 2007
Flaxseed or linseed is obtained from the flax plant, Linum usitatissimum, which belongs to the Linaceae or Flax family (Dodds et al. 2006).  L. usitatissimum is an erect annual plant with slender stems, alternate leaves, and flowers having five blue petals (Wikipedia contributors 2007).  This species grows in Belgium, Britain, China, Egypt, Germany, India, Iraq, Kurdistan, Mexico, Peru, Spain, Turkey, Venezuela, and the United States (Plants For a Future 2000).

Flaxseed was originally used by Egyptians in foods and medicines. Also, they cultivated flax to obtain linen (American Cancer Society 2007). Later, flaxseed was mentioned by Hippocrates in his writings as an abdominal pain reliever (Klimaszewski, 2000). Native Americans also used flax as a cough and cold remedy (Moerman, 2007). Plants that are rich in fiber, such as flax, have been commonly used as a laxative and a regular dietary supplement for its health advantages (Giacco et al. 2000).

Many of the medicinal qualities of flaxseed are attributed to the high concentrations of lipid alpha-linolenic acid (LNA), an omega-3 fatty acid (Harper et al. 2006). Omega-3 fatty acids are not produced by the human body and need to be gained from dietary sources (Logan, 2004). LNA is a simple fatty acid that is converted into other fatty acids that are proven to support cardiac health (Harper et al. 2006). The body uses these simple fatty acids as a template to produce necessary and more complex molecules. When combined with a low fat diet, LNA and other fatty acids can reduce the effects of high cholesterol and lessen the occurrence of non-fatal coronary infarctions (Dodin et al. 2005). Cholesterolemia, or the presence of elevated LDL cholesterol, the bad form of cholesterol which is responsible for heart disease and other health risks, in the blood has shown to be decreased by supplementation with flax (Dodin et al.  2005). Flax is also a good source of other omega 3-fatty acids, which among other qualities are natural blood thinners and help prevent clotting. Flax is thus a valuable supplement for good cardiac health.

Omega 3-fatty acids are also known to reduce the risk of prostate cancer as found by Demark-Wahnefried et al. in 2001, in the study of flaxseed supplementation and fat restriction. They conducted the study on twenty five men, varying in age, with prostate cancer waiting for prostatectomy. The results showed that flaxseed diet along with strict fat restriction decreased the hormonal levels of testosterone, androgen, and cholesterol, leading to decreased proliferation and increased apoptotic cancer cell death (Demark-Wahnefried et al 2001).

Omega-3 and omega-6 fatty acids, obtained from flaxseed oil, have also been associated with good mental health. These fatty acids are shown to be required by a developing nervous system, in both fetal and adolescent systems, and decrease the occurrence of mental depressive disorders (Logan 2004). In patients suffering from depressed moods, low levels of omega fatty acids were found in the blood (Logan 2004). Many studies have shown a negative correlation between depression and a diet supplemented with higher levels of omega fatty acids (Logan 2004).

Supplementation with flax has also been shown to increase the metabolism of postmenopausal women (Brooks et al. 2004). This could help decrease the effect of menopause and eliminate the needs for hormone replacement therapy with costly drugs such as Premarin. Flax has been found to be a good source for phytoestrogens, a group of lignin, or highly aromatic compounds derived from the cell walls of plants, that are metabolized in the body like estrogenic compounds or serve as precursors to the hormones. Phytoestrogens interfere with estrogen metabolism in postmenopausal women and retard the progression of breast cancer and osteoporosis. Studies indicate that the fecal and urinary excretion levels of phytoestrogenic lignin in postmenopausal women taking flax are higher than those who do not (Kurzer et al. 1995). This indicates the supplementation with flax raises the body’s levels of such compounds that are usually lowered following menopause.

Flaxseed’s lignin, secoisolariciresinol diglycoside, was tested for its ability to reduce tumor growth in postmenopausal breast cancer patients. After days of flaxseed diet, women showed an increase in urinary lignin which caused reduced expression of c-erbB2, usually found in aggressive breast cancers. The study concluded that flaxseed changes the phenotype of the cancer cells to a less aggressive form and thus delays the progression of breast cancer (Thompson et al. 2005).

Flax is high in fiber, both insoluble fiber to support fecal binding and soluble fiber to promote digestive motility (Demark-Wahnefried 2001). Foods high in fiber have also been known to slow the body’s absorption of sugar into the blood stream. This allows the body to better regulate blood sugar levels and insulin secretions, leading to a decrease in hypoglycemia (Giacco et al. 2000). Because Flax is a good source of fiber, flax supplementation may help those who are hypoglycemic, diabetic, and those with insulin intolerance a way to better control their blood glucose and insulin levels. The addition of fiber to one’s diet is also thought to lower blood pressure and cholesterol (Giacco et al. 2000).When incorporated into a diet, flax can increase the amount of fiber and beneficial dietary lipids (Dodin et al. 2005).

For its number of medicinal uses, flaxseed has achieved recognition in complementary and alternative medicine for ages. More recently, the National Center for  Complementary and Alternative Medicine is funding additional studies to evaluate or discover other medicinal values of flaxseed (NCCAM 2006). Flax, like many herbal supplements, does not have its origins in traditional Westernized medicine. However, it is now gaining more scientific and medical evidence to verify its benefits.

LITERATURE CITED

American Cancer Society. 2007. Flaxseed. http://www.cancer.org/. Accessed July 08, 2007.

Brooks  JD, W.E. Ward, J.E. Lewis, J. Hilditch, L. Nickell, E. Wong, and L.U. Thompson. 2004. Supplementation with flaxseed alters estrogen metabolism in postmenopausal women to a greater extent than does supplementation with an equal amount of soy.  The American Journal of Clinical Nutrition 79: 318-325.

Demark-Wahnefried W, D.T. Price, T.J. Polascik, C.N. Robertson, E.E. Anderson, D.F. Paulson, P.J. Walther, M. Gannon, and R.T. Vollmer. 2001. Pilot study of dietary fat restriction and flaxseed supplementation in men with prostate cancer before surgery: Exploring the effects on hormonal levels, prostate-specific antigen, and histopathologic features. Urology 58(1): 47-52.

Dodds, P.N., G.J. Lawrence, A.M. Catanzariti, T. Teh, C.I.A. Wang, M. Ayliffe, B. Kobe, and J.G. Ellis. 2006. Direct protein interaction underlies gene-for-gene specificity and coevolution of the flax resistance genes and flax rust avirulence genes. Proceedings of the National Academy of Sciences of the United States of America 103(23): 8888-8893.

Dodin, S, A. Lemay, H. Jacques, F. Legare, J.C. Forest, and B. Masse. 2005. The effects of flaxseed dietary supplement on lipid profile, bone mineral density, and symptoms in menopausal women: A randomized, double-blind, wheat germ placebo-controlled clinical trial. The Journal of Clinical Endocrinolgy and Metabolism 90 (3): 1390-1397.

Giacco, R., A. Gaicco, M. Parillo, L. D’Episocopo, A. Riverllese, G. Riccardi, and G. Lasorella.  2000. Long term dietary treatments with increased amounts of fiber-rich low-glycemic index natural foods improves blood glucose control and reduces the number of hypoglycemic events in Type I diabetic patients. Diabetes Care 23: 1461-1466.

Harper, C.R., M.J. Edwards, A.P. DeFilipis, and T.A. Jacobson. 2006. Flaxseed oil increases the plasma concentrations of cardioprotective (n-3) fatty acids in humans. The Journal of Nutrition 136: 83-87.

Kurzer, M.S., J.W. Lampe, M.C. Martini, and H. Adlercreutz. 1995. Fecal lignan and isoflavonoid excretion in premenopausal women consuming flaxseed powder. Cancer Epidemiology, Biomarkers, and Prevention 4: 353-358.

Klimaszewski, A. 2000. Flax for Health. http://www.fatsforhealth.com. Accessed July 01, 2007.

Logan, A.C. 2004. Omega-3-fatty acids and major depression: A primer for the mental health professional. Lipids in Health and Disease 3: 25.

Moerman, D.  American Indian uses for flax. University of Michigan.  http://herb.umd.umich.edu/. Accessed June 20, 2007.

National Center for Complementary and Alternative Medicine. 2006.  Herbs at a Glance. http://nccam.nih.gov/. Accessed July 01, 2007.

Plants for a Future. 2000.  Linum usitatissimumhttp://www.ibiblio.org/pfaf/. Accessed July 08, 2007.

Thompson, L.U., J.M. Chen, T. Li, K. Strasser-Weippl, and P.E. Goss. 2005. Dietary flaxseed alters tumor biological markers in postmenopausal breast cancer. Clinical Cancer Research 11(10): 3828.

Wikipedia contributors. 2007.  Flax. Wikipedia, The Free Encyclopedia. http://en.wikipedia.org/w/index.php?title=Flax&oldid=144818631.  Accessed 17 July 2007.
This paper was developed as part of the BIO 368 - Medical Botany course offered at Wilkes University during the summer of 2007. Course instructor was Kenneth M. Klemow, Ph.D. (kklemow@wilkes.edu). The information contained herein is based on published sources, and is made available for academic purposes only. No warrantees, expressed or implied, are made about the medical usefulness or dangers associated with the plant species in question.

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This page posted and maintained by Kenneth M. Klemow, Ph.D., Biology Department, Wilkes University, Wilkes-Barre, PA 18766. (570) 408-4758, kklemow@wilkes.edu.