Soy Isoflavone Supplementation Not Effective In Breast Cancer Protection

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Main Category: Breast Cancer
Also Included In: Complementary Medicine / Alternative Medicine
Article Date: 08 Feb 2012 - 10:00 PST


A study published in Cancer Prevention Research, a journal of the American Association for Cancer Research, reveals that breast cancer cell proliferation was not lowered with soy isoflavone supplements in a randomized human trial. Isoflavone are components of soy foods believed to have anti-estrogen activity.

Results of the study are consistent with findings from earlier investigations that were designed to examine cancer prevention benefits of dietary supplements, according to lead researcher Seema A. Khan, M.D., professor of surgery at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.

Khan explains:

"Simply put, supplements are not food. Although soy-based foods appear to have a protective effect, we are not seeing the same effect with supplementation using isolated components of soy, so the continued testing of soy supplements is likely not worthwhile."

Furthermore, Khan states that in lung cancer prevention studies, selenium-supplementation and beta-carotene have been demonstrated to lack benefit.

He continues:

"Foods are very complex and there are likely traveling companions that we haven't identified that are protecting against cancer."

98 women were randomly assigned by Khan and colleagues to receiver either placebo or mixed soy isoflavones supplement.

Over 4,000 breast cancer epithelial cells were identified in the participants, by fine needle aspiration biopsy. Levels of Ki-69, an established protein marker of cancer cell growth, were assessed by the team at six months.

The researchers observed no difference at six months in women receiving mixed soy isoflavones supplement or those receiving placebo. Although, the researchers found that the level of Ki-67 rose from 1.71 to 2.18 among pre-menopausal women, indicating a negative effect of the supplementation.

Khan says:

"This was a small finding, but one that should suggest caution."

Written by Grace Rattue
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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