Linseed oil is an alternative name for flaxseed oil, which comes from the seeds of the plant Linum usitatissimum. Preliminary evidence suggests that flaxseed itself may play a beneficial role in the treatment or prevention of certain types of cancer. However, the oil derived from flaxseed has different chemical properties and may not provide any anti-cancer benefits.
Basics
Flaxseed oil contains an omega-3 fatty acid called alpha-linolenic acid, or ALA. When you consume foods or supplements that contain ALA, your body converts some of this substance into two other omega-3s, called docosahexaenoic acid, or DHA, and eicosapentaenoic acid, or EPA. Flaxseed itself contains substances called lignans. When you consume lignans, bacteria in your small intestine convert them into substances called phytoestrogens, which weakly mimic the effects of the hormone estrogen. Phytoestrogens can also halt or interfere with the actions of estrogen inside your body.
Oil's Effects
Omega-3 fatty acids from flaxseed oil or other sources may suppress the onset of certain cancers in animals, or hinder the growth of these cancers after they form, according to the American Cancer Society, or ACS. Cancers that have responded to the effects of omega-3s in animal testing include pancreatic, colon, prostate and breast cancer. However, human studies of omega-3s don't consistently support their anti-cancer properties, and a review of 40 years of research indicates that the use of flaxseed oil or other omega-3s will not reduce cancer-related risks.
Lignans' Effects
The phytoestrogens that come from the lignans in flaxseed meal, flour and seeds may help prevent breast cancer and other cancers that grow in the presence of estrogen, ACS reports. In a laboratory setting, these lignans seem to hinder breast cancer cells' ability to grow or spread inside your body. Laboratory testing also showed similar lignan-related benefits for inhibiting the onset, growth and spread of prostate cancer and a form of skin cancer called melanoma. Use of flaxseed may also increase the benefits of a breast cancer drug called tamoxifen.
Considerations
The majority of evidence for flaxseed oil and flaxseed as cancer treatments comes from either animal studies or studies of isolated cell cultures, not human studies, ACS notes. In limited human studies of prostate cancer, flaxseed --- but not flaxseed oil --- appears to reduce cancer risks and slow the growth of cancer cells when consumed in combination with a low-fat diet. However, the anti-cancer benefit in these cases may come from dietary changes rather than flaxseed. Some studies indicate that the ALA content in flaxseed oil can actually increase your risks for the onset of prostate cancer. Before you consider taking flaxseed oil or flaxseed for cancer treatment or prevention, seek your doctor's advice and consent.
References
- American Cancer Society: Flaxseed
- MayoClinic.com: Flaxseed and Flaxseed Oil (Linum usitatissimum)
- University of Maryland Medical Center: Alpha-Linolenic Acid
- Oregon State University - Linus Pauling Institute: Lignans; Jane Higdon, Ph.D.; June 2004
- American Cancer Society: Omega-3 Fatty Acids
- MayoClinic.com: Flaxseed; Does It Affect Risk of Prostate Cancer?; Erik Castle, M.D.; October 24, 2009
