High levels of dietary iron linked to increased cancer risk

31/03/05 High-protein diets that include a lot of iron-containing foods, may not be the best choice for everybody, according to a new study out of the Medical University of South Carolina. Analyzing population-based data from U.S. National Health and Nutrition Examination Surveys, Mainous and colleagues found that people with elevated levels of serum transferrin saturation - an indicator of iron overload - who consume high levels of dietary iron, have an increased risk of cancer and cancer mortality.

Specifically, they found that people with elevated levels of transferrin saturation 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. The authors point out that a substantial proportion of adults in the United States - approximately 7 percent of the adult U.S. population - has transferrin saturation levels greater than 41 percent, and are at increased risk.

The authors suggest that simple dietary restrictions may help to reduce the cancer risk associated with high transferrin saturation. They add that these findings call into question the strategy of the addition of iron to food by manufacturers.