Breast Cancer and Flaxseeds
WHAT IS THE NEWS STORY
The Use of Flaxseed for breast cancer cure and prevention.
WHY THE STORY HAS MISINFORMATION
During the 1980s, breast cancer incidence rose greatly probably due to increased mammography screening and awareness in society. Its incidence stabilized during the decade of 1990 only to decline early in the 2000s, and even though mammography screening rates fell somewhat over this same time period, evidence shows us that these changes were not likely the cause. This appears to be related to a diminishing use of postmenopausal hormone supplementation that happened as a consequence of the Women's Health Initiative study and the evidence offered to the medical community through it.
Since 2004, the incidence of breast cancer has been almost stable and breast cancer prevention efforts are being focused more and more on dietary modifications. The reason for this is due to the potential of these modifications to be successful due to their ease of implementation and wide acceptance. Flaxseed is one of the elements that is being integrated into the diet of cancer patients, and even though it may contribute to lower cancer risk, research is too limited at this moment to recommend it for this purpose. Doubts arose regarding the use of flaxseed for this purpose since the interpretation of research studies regarding phytoestrogen intake and breast cancer risk concluded that its use is hampered by many factors, including the retrospective nature of much of the research in this area.
Some information exists in medical literature regarding the impact of dietary flaxseed on tumor cell growth and proliferation in postmenopausal breast cancer patients. For instance, one randomized controlled trial (RCT) suggested that 25 grams of flaxseed intake per day reduced cell proliferation, increased apoptosis, and reduced c-erbB2 expression of human breast cancer cells in biopsy tissue between time of diagnosis and time of definitive breast surgery, but there was no definitive evidence. No RCTs have specifically studied whether phytoestrogen supplementation reduces the risk of breast cancer recurrence. Data regarding the role of phytoestrogens in breast cancer prevention is conflicting and there is a need for proper study of it until it is deemed safe, especially when considering that food-drug interactions are possible and that the action of lignans on aromatase could be dampened, making it an unsafe choice against breast cancer.
A revision of the use of flaxseed done by the Mayo clinic points out that even though flaxseed (not flaxseed oil) contains lignans that may alter estrogen activity and that these effects may improve symptoms of breast pain, it was still deemed as a grade C level (unclear scientific evidence for this use) in medicine based on evidence. Also, they expressed concerns about the security of using this medical supplement, with potentially dangerous side effects such as lowering blood sugar or blood pressure levels, increasing the risk of bleeding, and increasing the risk of complications in patients with diverticulitis, amongst others. This information, along with differences in dietary measurement, lack of standardization of supplemental sources, and differences in metabolism amongst individuals makes it a potentially dangerous choice in treatment.
In the face of this evidence regarding dietary lignans and breast cancer risk, clinicians find themselves once again recommending the unexciting balanced diet that includes plenty of whole grains, fruits, and vegetables. Nonetheless, until a trial of lignan intake/supplementation and disease end points quantify the risks and benefits of such an intervention, the prudent clinician should be wary of recommending high doses of any dietary compound solely on the basis of laboratory and observational epidemiological studies. This leaves one sole conclusion: Flaxseed’s effects need more studies performed in order for the supplement to be deemed safe for breast cancer patients.