Relationships between fecal phytate and mineral excretions depend on the dietary phytate and age

Abstract

The study was done to determine the effect of dietary phytate and age on the relationships between fecal phytate and mineral excretions. Fourteen young and 14 elderly women were fed two experimental diets, high phytate (HP) and low phytate (LP), for 10 days each with a washout period. Duplicate diet samples from two different menus and complete fecal samples were collected for 5 days during each diet period to analyze phytate and mineral contents. Fecal phytate excretion (319 vs. 177 mg/d, p<0.05) and degradation rate of dietary phytate (80 vs. 74%, p = 0.002) increased significantly during the HP diet compared to the LP diet in young women. There was a positive relationship between fecal phytate and mineral excretions such as calcium, copper, iron and zinc in both HP and LP diet in young women (p<0.05). The linear relationship was greater during LP diet compared to the HP diet. However, no association was found in elderly women. Fecal phytate had a positive relationship with mineral excretion suggesting the negative effect of un‐degraded phytate on mineral absorption. The inhibitory effect of phytate on mineral absorption was affected by dietary phytate and age. Supported by Korea Research Foundation