RESUMO
Objective: To compare the methods of metabolic balance (MB) and fecal monitoring (FM) for evaluating the dietary zinc (Zn) absorption in Tibetan men. Methods: In 14 d field trial on 16 adult Tibetan men, capsules of carmine were given to mark the feces from D4 to D12, and samples of diet, water, feces and urine were collected during the period. In addition, 4.0 mg zinc tracer (enriched with 67Zn) and 1.0 mg recovery indicator ytterbium (Yb) were orally administrated to the subjects in the evening meal of the D5. The ratio of 67Zn/68Zn in fecal samples was determined by inductively coupled plasma mass spectrometry, and then the zinc absorption was calculated based on the principle of isotope dilution. Results: The dietary zinc absorption in Tibetan men was (23.8?3.9) % evaluated by MB and (21.4?4.3) % by FM with significant difference (by paired-samples t test) and linear correlation (Pearson). The unabsorbed zinc tracer and Yb had the similar behavior through the digestive tract, mostly excreted within5 d following the intake. Conclusion: In the 14d metabolic period, the dietary zinc absorption from MB was a little higher than that from FM. Using FM, the metabolic period can be shortened to 4-5 days according to excretion of Yb. Both methods suggested that the dietary zinc absorption in the adult Tibetan men was good.