Habitual tea consumption protects against the inhibitory effects of tea on iron absorption in rats

The hypothesis of this study was that tea inhibits iron absorption in animals unaccustomed to tea onsumption but not in animals habituated to high intakes of tea. Three diets were prepared: 1) annin-free diet; 2) 5% tea solids (tea) diet; and 3) 5% tea solids 6% gelatin (T/G). Gelatin was hosen as a proxy for salivary proline–rich proteins (PRP). Five groups of rats were assigned to the ollowing treatments: 1) control (tannin-free diet throughout), 2) short-term tea (tannin-free except tea iet on day 8, 3) long-term tea (tea diet throughout), 4) short-term T/G (tannin-free except tea with elatin diet on day 8, and 5) long-term T/G (tea with gelatin diet throughout). After 10 days of dietary reatment, iron absorption, measured using Fe, was 41%, 7%, 25%, 7%, and 21% for treatments 1, , 3, 4, and 5, respectively. Rats in groups 3 and 5 showed higher PRP than control. We conclude that ats possess adaptive mechanisms for partially overcoming the inhibitory effects of tannins on iron bsorption possibly by increasing secretion of PRP in saliva. © 2004 Elsevier Inc. All rights reserved.