Dietary and lifestyle factors influencing iron stores in Australian women: an examination of the role of bio-available dietary iron

Research to date has not been able to adequately describe the relative impact of dietary and lifestyle variables on iron status. While total iron intake appears unrelated to iron sta- tus, bio-available dietary iron should correlate with iron stores, after adjustment for iron losses. Therefore, the objective of this study was to examine dietary and lifestyle variables that are important in the determination of iron status for Australian women of child-bearing age. Serum ferritin was measured in 52 iron-deficient and 24 iron-replete women. Dietary data were col- lected using seven-day weighed food records and bio-available dietary iron calculations were performed using the algorithms developed by Monsen et al., Monsen and Balintfy, and Tseng et al. Self-reported data on demographic characteristics, parity, breastfeeding, oral contraceptive pill, intrauterine device and hormone replacement therapy use, menstruation, smoking, alco- hol intake, exercise, dieting, vitamin and mineral supplement use and blood donation were collected. Multiple linear regression was used to examine dietary and lifestyle factors associated with serum ferritin. Current oral contraceptive pill use and alcohol intake were positively associated (P = 0.01 and P =0 .001 respectively) and phytate intake was negatively associated (P = 0.05) with serum ferritin. Total iron, haem iron and bio- available dietary iron intakes were not associated with iron stores. Bio-available dietary iron estimates were well below the recommended intakes for menstruating women, suggesting pos- sible problems with either the algorithms or the assumptions built into the current Australian recommended dietary intakes. Further work to accurately determine bio-available dietary iron estimates for Australian women is needed. (Aust J Nutr Diet 2001;58:107-113)