Cancer
Too much iron may raise breast cancer risk
By David Liu
Oct 7, 2007 - 12:19:08 PM

SUNDAY October 6, 2007 (Foodconsumer.org) -- High levels of free iron either released from iron reservoirs in the body or from dietary intake may increase risk of developing breast cancer, according to a review article published in the October 2007 issue of Cancer Causes Control.

In the review of 83 research reports, Drs Geoffrey C. Kabat and Thomas E. Rohan from Albert Einstein College of Medicine proposed that iron overload and disruption of iron homeostasis resulting in an increase in free iron may increase the oxidative stress and cause damages that eventually lead to breast cancer.

The carcinogenicity of iron has been demonstrated in early animal and laboratory studies, but less so in epidemiologic studies, according to the authors.   The role iron may potentially play in development of breast cancer was not clear although researchers have gained substantive understanding of the possible mechanism that supports the proposal by Kabat and Rohan.

According to Drs Kabat and Rohan, stored ferric iron (Fe3+) can be reduced to ferrous iron (Fe2+) in the presence of superoxide radical and hydrogen peroxide. Ferrous iron can in turn catalyze the formation of the hydroxyl radical (*OH), which promotes a myriad reactions including lipid peroxidation, mutagenesis, DNA strand breaks, oncogene activation, and tumor suppressor inhibition, increasing the risk of breast cancer.

Additionally, free iron at high levels may potentiate the cancer-causing effects of estradiol, ethanol, and ionizing radiations such as x-ray - three major established risk factors for breast cancer, Drs. Kabat and Rohan state in their report.

The proposed role of iron in the breast carcinogenesis in part explains the early finding that high intake of red meat (with high iron) was linked with elevated risk of breast cancer.

Editor's note:  We thank DR. Kabat for sending us a reprint of his article.  More details on the issue will be published in a booklet later on breast cancer prevention.