The relationship between iron and breast cancer is not well understood. Iron is an essential nutrient and its concentration in cells is regulated very closely. However, iron facilitates cell proliferation and growth and can have a role in free radical formation. As such, iron appears capable of contributing to both tumor development and tumor growth.

Iron and breast cancer - the evidence is inconsistent

Studies concerning the relationship between iron and breast cancer have reported the following inconsistent results:

  • Removal of iron from breast cancer cells using iron-chelating agents induces programmed cell death in both (High glycemic load should be avoided in breast cancer diet) MCF-7 and (ER-/ER-) MDA-MB-231 breast cancer cells and increases their sensitivity to Adriamycin (doxorubicin) and cisplatin
  • Relatively high levels of iron in benign breast tissue appears to be related to a modest increase in the risk of breast cancer
  • Based on data from 116,674 postmenopausal participants in the National Institutes of Health-AARP Diet and Health Study, dietary iron is not associated with risk of postmenopausal breast cancer regardless of whether the iron is primarily from meat (heme iron) or from plant sources
  • A large Canadian study of women aged 40 to 59 who were followed for an average of 16.4 years found no link between iron or heme iron intake and risk of breast cancer
  • High dietary iron intake among participants in the Iowa Women’s Heath Study was found to be related to an increased risk of breast cancer in postmenopausal women, especially among drinkers who consumed at least 20g/day of alcohol
  • Polish BRCA1 mutation carriers with relatively high levels of circulating iron have a significantly lower breast cancer rate than those with low levels of plasma iron.
Although the evidence is limited and mixed, to the extent that there is a relationship between iron and breast cancer risk, it appears that iron deficiency might promote breast cancer in young women whereas excess iron might promote it in postmenopausal and older women. It is also possible that iron has a more important role in the metastasis of breast cancer than in its initial development.

Latest research finds iron deficiency promotes metastasis

The study referenced at the beginning of this news story was designed to investigate whether iron deficiency plays a pro-metastatic role in breast cancer in young women (defined as under 45 years of age). To conduct the study, the authors used a mouse model of breast cancer, as well as examining the influence of iron status in young breast cancer patients.

Mice who were raised on an iron-deficient diet were found to have significantly greater tumor volumes and lung metastases compared to mice given normal diets. Correcting the iron deficiency in the iron-deficient mice (by administering iron) reduced primary tumor volume, lung metastasis, and reversed certain cancer markers in the mice. In young breast cancer patients, mild iron deficiency was found to be significantly associated with lymph node invasion. The authors conclude that iron deficiency might contribute to poor prognosis in young breast cancer patients.

Please see our articles on how young breast cancer survivors can avoid a recurrence and breast cancer in very young women for more information.