The Effect of Reducing Dietary Phytate Intake and Zinc Supplementation on the Iron Status of Elderly Korean Women

To investigate the effects of dietary phytate reduction and zinc supplementation on biochemical iron parameters in elderly Korean women consuming inadequate iron, fifteen healthy women aged 64-75 years were recruited for a feeding study. A high-phytate diet (27.8 phytate:zinc molar ratio) was provided for 9 days, followed by a nine-day low-phytate diet(12.3) and a subsequent 28-day period of unregulated meals with zinc supplementation (22 mg/d as zinc gluconate). Serum iron increased significantly with the low-phytate diet (130.4 $\mu g$/L) but returned to the level observed during the high-phytate diet (113.0 $\mu g$ /L) period when subjects were taking zinc supplements (105.8 $\mu g$ /L). However, serum ferritin in the subjects decreased significantly with the low-phytate diet (73.8 $\mu g$ /L) as well as with zinc supplementation (57.2 $\mu g$ /L), compared to levels following consumption of the high-phytate diet (89.6 $\mu g$ /L). Transferrin receptor and transferrin saturation were unchanged with the treatments. In summary, zinc supplementation might result in deteriorated iron status in elderly Korean women who consume inadequate iron, while there was no significant effect from reducing dietary phytate.