Date of Award:

1997

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Nutrition, Dietetics, and Food Sciences

Department name when degree awarded

Nutrition and Food Sciences

Advisor/Chair:

Deloy G. Hendricks

Abstract

Common methods for determining mineral absorption by the body are invasive and frequently utilize radioisotopes. In experiment one. rats were given a dose of radiolabeled ferrous sulfate. Relative absorption was estimated by changes in serum iron and by appearance of the radiotracer in the serum. There were no differences in relative absorption determined by the methods, although the low overall absorptions by the iron-replete rats may have decreased the sensitivity.

In experiments two and three. iron and magnesium supplements were given orally to 12 women age 19-25. Each subject received iron and magnesium supplements once each week for 5 weeks. Blood samples were taken via venous catheter every 30 minutes for 2 hours and 30 minutes following dosing, and a urine sample was taken following the collection time period. Samples were analyzed for serum iron, serum magnesium, hematocrit, ferritin, urinary magnesium, and urinary creatinine. The increase in serum iron was evaluated from both the peak increase in serum iron and from the integrated increase in serum iron over the blood collection time. The data for each supplement were compared by analysis of variance. For the iron supplements. the taste-free iron supplement increased serum iron less than either the Ferrochel or the ferrous sulfate supplements. When the iron absorption was then compared to ferritin stores (low, medium, and high), the relative absorption of Ferrochel was higher in the low ferritin range (0-15 ng/ml) than in the upper ranges (P=.00l for peak and P=.0002 for area). Relative absorption from Ferrochel iron was also higher than the other supplements for subjects with low ferritin stores.

Neither serum nor urinary magnesium values differed significantly among the three compounds examined. Serum magnesium values are stable in healthy individuals, and the urinary magnesium data were not evaluated over 24 h as in typical magnesium load tests.

In summary, both the ferrous sulfate and Ferrochel supplements were absorbed more efficiently than the taste-free iron supplement. The Ferrochel was also absorbed more efficiently in individuals with low iron stores, demonstrating better regulation by the body than with the other supplements examined.

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Nutrition Commons

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