Iron absorption in normal subjects and patients with idiopathic haemochromatosis: relationship with serum ferritin concentration.

Abstract

SUMMARY In 52 normal subjects there was an inverse relationship between serum ferritin concentration and iron absorption. In 21 measurements in 15 patients with idiopathic haemochromatosis there was a similar inverse relationship but absorption was higher in relation to iron stores at all levels. Haemochromatotic patients with normal serum ferritin levels had abnormally high values for desferrioxamine chelatable iron and there was no correlation between chelatable iron and iron absorption.Iron balance is maintained by the regulation of iron absorption. The precise mechanism is poorly understood (Jacobs, 1973) and one of the outstanding problems is the relationship of iron stores to absorption. Heinrich (1970) (Bentley and Williams, 1974).More recently, the concentration of ferritin in serum has been shown to relate closely to iron stores in normal subjects and in those with iron deficiency or overload (Jacobs, Miller, Worwood, Beamish, and Wardrop, 1972;Walters, Miller, and Worwood, 1973a;Siimes, Addiego, and Dallman, 1974). The assay of ferritin can be carried out in a reproducible manner on a small serum sample, and a preliminary study indicated an inverse relationship between serum ferritin concentration and iron absorption in normal subjects (Walters, Thompson, Jacobs, and Wood, 1973b). This assay has been used in the present study to confirm the relationship between iron stores and iron absorption in normal subjects and to compare it with data from patients with haemochromatosis.Received for publication 17 October 1974. SubjectsFifty-two healthy adults (22 women and 30 men) were studied. In all cases the serum iron concentration was above 70 jig per dl and the transferrin saturation above 16%. Haemoglobin concentration was above 12-5 g per dl in women and 13-0 g per dl in men.Fifteen patients with primary idiopathic haemochromatosis (one woman and 14 men) were studied; all met the same haematological criteria as the normal subjects. Six of the patients were studied on two occasions giving a total of 21 observations in this group. Three patients were investigated before venesection therapy, nine during and nine after the completion of a course of venesection. Patients studied during treatment were not bled for a minimum of one month before the absorption measurement.All subjects gave their fully informed consent to the investigations. MethodsIron absorption was measured by whole body counting using a flat bed scanning technique. The whole body counter consists of four uncollimated Nal (T1) crystals 10-2 cm thick and 15-2 cm in diameter arranged symmetrically on a vertical metal ring. The subject lies on a fixed bed and the detectors traverse the entire length of the bed. The detectors are connected to a multichannel analyser with 188 on 9 May 2018 by guest. Protected by copyright.

Erythrocyte Incorporation of Ingested 58-Iron by Infants

“…Thus, in our study there was greater likelihood of inhibition of iron absorption by mixing of the dose with formula or formula components in the stomach or upper small intestine. Studies of adult subjects given oral doses of radioisotopes of iron under standardized, fasting conditions have demonstrated a significant inverse relationship between percentage of the dose of 59Fe absorbed and serum femtin concentration (17)(18)(19)(20)(21)(22). As would be expected, the correlation is higher when the population studied includes both normal and iron-deficient subjects.…”

“…Even when the analysis is restricted to iron-suficient subjects, the correlation is significant. In iron-sufficient adult subjects, Walters et al (18) reported a correlation coefficient of -0.398 ( p < 0.005) for the regression of percent absorption on serum ferritin concentration and Heinrich et al (20) reported a correlation coefficient of -0.356 ( p < 0.01) for the regression of log serum femtin concentration on percent absorption. Neither Walters et al (1 8) nor Heinrich et al (20) calculated the regression on a sex-specific basis, although there was a significant sex-related difference in serum concentration of femtin among the subjects studied by Walters et al (18) and probably among the subjects studied by Heinrich et al (20).…”

Duodenal iron proteins in idiopathic hemochromatosis.

“…The central disturbance in IH is excessive absorption ofdietary iron despite expanded body iron stores (25)(26)(27). By simultaneously labeling the nonheme and heme iron compartments of the hamburger meal used in this study, it is possible to obtain quantitative estimates of total absorbed dietary iron.…”

Defective iron homeostasis in beta 2-microglobulin knockout mice recapitulates hereditary hemochromatosis in man.

“…The capacity to reduce or increase absorption of iron in response to increased or reduced iron stores is well documented. In HH, patients fail to decrease their iron absorption despite the accumulation of iron in the body (30)(31)(32).…”