Manganese retention

On the whole, manganese retention in the intestinal wall is far less affected by iron than its transport (47,91), which suggests that the binding sites for manganese (or iron) transport are not the same as for their retention in the mucosa. In other wards, the transport binding sites are more sensitive to iron deficiency. Nothing, of course, can be said about actual molecular differences between the two types of binding sites. 

From then on it sharply decreases in the iron-pretreated animals to attain in the third week as much as 50 percent lower values than in control animals (109). The abrupt diminution of manganese retention (as well as that of iron-59 in identical experiments, (110) in iron-pretreated animals between the 17th and 21st day of life is likely to be due to the alterations taking place in the intestinal tract of the rat at that age. Having in mind that that is also the time of weaning, one is impelled to take into account the type of food consumed by the animals. However, our weanling rats switched over from mother s to cow s milk and not to the standard laboratory food. 

Tea drinking resulted in an increase in fecal manganese excretion approximately equal to that added to the diets in the form of tea. Hence, no significant improvement in manganese retention occurred as the result of tea drinking. This suggests that either the polyphenols or other constituents of tea rendered the manganese in tea essentially unusable to the human (Table V). 

All patients requiring prolonged IVN, especially those who have cholestasis, should be monitored for evidence of manganese retention. 

Davidsson L, Cederblad A, Lonnerdal B, et al. 1989a. Manganese retention in man A method for estimating manganese absorption in man. Am J Clin Nutr 49 170-179. 

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