The effects of dietary and fecal phytate associated with fecal minerals: Calcium, copper, iron, and zinc, relative to colonic polyp recurrence

Colorectal adenomatous polyps are recognized as precursor lesions in most cases of colorectal cancer. Phytate, found in most plants, is considered by many to be an antinutrient, because it binds divalent cations thus impairing absorption into the body. This study analyzed the levels of phytate and minerals in stored fecal samples to discover whether dietary and fecal phytate in the presence of fecal minerals (Ca, Cu, Fe, and Zn) were related to polyp recurrence in humans. The objectives of the study were to compare and explore the relationships of dietary phytate, and fecal phytate, the fecal phytate:mineral molar ratios (calcium, copper, iron and zinc), to the recurrence of adenomatous polyps. Procedures consisted of retrieval of frozen fecal samples from 50 of the volunteers recruited in the Polyp Prevention Trial (PPT). The fecal samples, the Food Frequency Questionnaire (FFQ), Four-Day Food Records (4DFR), and adenoma recurrence data were provided by the National Cancer Institute. High Performance Liquid Chromatography (HPLC) and Induction Coupled Plasma Emission Spectroscopy (ICP-ES) were used for measuring the levels of dietary and fecal phytate, and minerals (calcium, copper, iron and zinc) in stool samples, respectively. The fecal phytate and mineral data were compiled using descriptive statistics: means, standard deviations, and frequency distributions. The Wilcoxon Rank-Sum test for continuous variables and the chi-square test for categorical variables were used to analyze the results. No significant differences in dietary and fecal phytate relative to the recurrence of colonic polyps and/or higher concentrations of fecal calcium, fecal copper, fecal iron, and fecal zinc relative to fecal phytate concentration were found. In addition, significant relationships between the recurrence of colonic polyps and higher phytate:mineral(s) molar ratios was not observed. All statistical differences were determined at the p ≤ 0.05.