Concomitant oral intake of purified clinoptilolite tuff (G-PUR) reduces enteral lead uptake in healthy humans
Karolina Samekova, Christa Firbas, Johanna Irrgeher, Christine Opper, Thomas Prohaska, Anika Retzmann, Cornelius Tschegg, Claudia Meisslitzer, Anastassiya Tchaikovsky, Ghazaleh Gouya, Michael Freissmuth, Michael Wolzt
Abstract
Abstract Lead exposure can cause substantial organ damage. Enteral lead absorption may be reduced by concomitant intake of clinoptilolite tuff, a zeolite from natural sources. This study aimed to assess the effect of purified clinoptilolite tuff (G-PUR) on enteral lead uptake in adults using stable lead isotope 204 Pb as a tracer. In this randomized, placebo-controlled, double-blind, parallel-group study, 42 healthy participants were randomized to receive oral G-PUR 2.0 g, 2 * 2.0 g, or placebo, together with 2.5 µg of 204 Pb in water. The enrichment of 204 Pb caused by the tracer in blood and urine was measured by mass spectrometry. G-PUR was well tolerated. The mean maximum 204 Pb enrichment of 0.505% of total blood lead was significantly higher (p < 0.0001) in the placebo group compared to G-PUR 2.0 g (0.073%) or G-PUR 2 * 2.0 g (0.057%) group. Normalized 204 Pb AUC 0-192 was 86.5, 11.9, and 8.5% * h without and with G-PUR 2.0 g, and G-PUR 2 * 2.0 g, respectively (p < 0.0001 vs. placebo). This smaller 204 Pb exposure was paralleled by a reduced urinary excretion in subjects receiving G-PUR. Concomitant oral intake of purified clinoptilolite tuff reduced enteral uptake of 204 Pb in healthy humans by approximately 90%. The reduced bioavailability is demonstrable by a decrease of 204 Pb tracer enrichment in blood and urine. Trial registration : clinicaltrials.gov identifier: NCT04138693, registered 24/10/2019.