Iron overloads may be linked to cancer risk
risk of cancer, suggests new US research, which raises questions
about fortifying foods with the mineral.
Researchers at the Medical University of South Carolina analyzed population-based data from the US National Health and Nutrition Examination Surveys.
People with elevated levels of serum transferrin saturation - an indicator of iron overload - who consume high levels of dietary iron had an increased risk of cancer and cancer mortality, they report in the March/April issue of the Annals of Family Medicine (issue 3, pp131-137).
Transferrin saturation of more than 60 per cent has previously been identified as a cancer risk factor but the researchers wanted to find out whether dietary iron intake increases the risk of cancer among individuals with transferrin saturation of less than 60 per cent.
They found that people with transferrin saturation of more than 45 per cent who ingest more than 18 mg of iron per day have a 2.24 times greater relative risk of cancer than those who have normal transferrin saturation levels and report low dietary iron intake.
Having high transferrin saturation with a normal diet did not carry increased risk, they said. Intake of dietary iron was essentially uncorrelated with transferrin saturation.
The authors note that a substantial proportion of adults in the United States - approximately 7 per cent - has transferrin saturation levels greater than 41 per cent, and are at increased risk.
Simple dietary restrictions may help to reduce the cancer risk associated with high transferrin saturation, say the researchers, adding that their findings call into question the strategy of the addition of iron to food by manufacturers.
