EFFECT OF DIFFERENT LEVELS OF AN ASCORBIC-ACID AND TEA MIXTURE ON NONHEME IRON-ABSORPTION FROM A TYPICAL TUNISIAN MEAL FED TO HEALTHY RATS

The aim of our study was to evaluate the bioavailability of iron from a typical Tunisian meal 'couscous' provided to healthy rats with or wi thout appropriate mixtures of tea plus ascorbic acid and to search for the optimal amount of ascorbic acid able to overcome the inhibitory e ffect of tea prepared under realistic Tunisian circumstances, Our find ings show that a tea decoction (100 mg/ml) reduced nonheme iron absorp tion from couscous by 50%, (16.5 vs. 33.1%; p < 0.01). In contrast, ad ministration of 20 mg ascorbic acid increased nonheme iron absorption from couscous by more than 100% (66.8 vs. 33.1%; p < 0.001). Administr ation of ascorbic acid (20 mg) in a tea decoction (100 mg.ml) complete ly counteracted the inhibiting effect of tea and significantly improve d the nonheme iron absorption from couscous (34 vs, 33% in the control group; NS). The same effect was shown when 10 mg ascorbic acid was ad ded to the tea decoction; however, 5 mg ascorbic acid was not able to overcome the inhibitory effect of tea on nonheme iron absorption from couscous (33.1 vs, 19.4%; p < 0.01). Our findings demonstrate that a m olar ratio of ascorbic acid and tea equal or superior to 0.25 or 0.50 is necessary to overcome the inhibitory effect in rats of tea prepared under Tunisian circumstances, In relation to human nutrition: for Tun isians who regularly drink tea, we suggest a much greater amount of as corbic acid than that normally recommended for normal subjects.