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Description
We examined the use of stool as an alternative, non-invasive way to assess Persistent Organic Pollutants (POPs) exposures in healthy adults while also attempting to reduce body burden through diet intervention trials. The concentrations of 13 POPs were measured in matched plasma and stool samples collected from 30 adults (aged 50-70) in San Diego. Initially, 45 participants were randomly assigned to three groups to be given three different interventions: Olestra (Non-Fat PringlesTM) (n=15), Nuts (combination of almonds and walnuts) (n=15), and standard vegetable oil chips (regular PringlesTM) (n=15) and given to the participants at intake rates of 14.7, 18, and 17.4 in grams of fat/day respectively. Following 4-6 days after intervention began, stool samples were collected. The return rate used to match plasma and stool samples was n=11 in the Olestra group, n=9 for vegetable oil, and n=10 in the nuts group. POPs were extracted using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS), gel permeation chromatography (GPC) and silica Solid Phase Extraction (SPE). Extracts were run on an Agilent 7890 gas chromatography/5977 mass spectrometer (GC/MS) and analyzed by its software program, Chemstation. Statistical analyses were done on IBM SPSS Statistics for Windows (version 25.0). Comparisons using parametric and nonparametric tests on pre-intervention concentrations of plasma and stool samples in lipid and wet weights yielded significantly different results for 11 and 9 out of the 13 compounds respectively. However, further analysis of linear regression showed a significant(p<0.05) relationship between plasma and stool. Results suggest that stool may be used as an alternative matrix to plasma if a proper conversion is calculated. Intervention resulted in significant changes for only two compounds, trans- and cis-Nonachlor, after Olestra intervention and no significant difference was observed in the other trial groups. The results may suggest that high fat diet did not excrete POPs quickly. Further analysis of linear regression between pre-intervention and post-intervention stool samples concentrations in lipid and wet weights, however, found that there was a significant positive relationship between pre- and post-concentrations, suggesting excretion rate of POPs was consistent. To determine the dietary intervention effect, we conclude that additional measurements are necessary. A CD-ROM, Appendices C and D to this thesis, is available for viewing at the Media Center in the SDSU Library.
