Comparison of ferrous sulfate and ferrous glycinate chelate for the treatment of iron deficiency anemia in gastrectomized patients.

OBJECTIVES: Postgastrectomy iron deficiency anemia has a variable prevalence and occurs in 20-50% of patients. Food fortification reports examining ferrous glycinate chelate have shown that it can be 2.5-3.4 times more bioavailable than ferrous sulfate, with minimal gastrointestinal symptoms. The present study was designed as a controlled experimental study including 18 gastrectomized patients with iron deficiency anemia to compare the effects of ferrous sulfate and ferrous glycinate chelate in the treatment of anemia and to evaluate the presence of side effects. METHODS: Patients were divided in two groups: group 1 received ferrous sulfate (200 mg twice a day, corresponding to 80 mg of elemental iron) and group 2 received ferrous glycinate chelate (250 mg/d, corresponding to 50 mg of elemental iron) for 4 mo. Laboratory measurements were performed at baseline and after 2 and 4 mo. RESULTS: Group 1 showed an apparent recovery in laboratory parameters, with increases in medium corpuscular hemoglobin (P = 0.02), serum iron (P = 0.02), and ferritin (P = 0.04), and a decrease in transferrin (P = 0.002) after 4 mo. Individualized analysis showed that only one patient using ferrous sulfate had anemia at the end of the study in contrast to six patients using ferrous glycinate. In addition, ferritin levels increased above 20 microg/L at the end of the study in seven patients using ferrous sulfate in contrast to one patient using ferrous glycinate. CONCLUSION: Patients with iron deficiency anemia after gastrectomy treated with ferrous sulfate had better results in hematologic laboratory parameters than those who used ferrous glycinate chelate.

Bioavailability of iron bis-glycinate chelate in water.

Iron amino acid chelate is being increasingly considered in programs for iron fortification of foods. The bioavailability of iron bis-glycinate chelate given in water was studied using a double-isotopic method in a group of 14 women. Iron absorption from aqueous solutions of 15 mg/L of elemental iron as either iron bis-glycine chelate or ferrous ascorbate was not significantly different (34.6% and 29.9% respectively). Standardized iron absorption of the iron bis-glycinate was 46.3% (standardized to 40% absorption of the reference dose). There was a significant correlations between (ln) iron absorption of iron bis-glycinate chelate with (ln) serum ferritin (r = -0.60, p < 0.03) and with (ln) iron absorption from ferrous ascorbate (r = 0.71, p < 0.006), suggesting that iron bis-glycinate chelate absorption is indeed regulated by the iron stores of the body.

The absorption and metabolism of iron amino acid chelate.

This paper summarizes several studies which describe significant increases in the intestinal absorption of iron from iron amino acid chelate compared to inorganic iron salts. While these increased uptakes of iron from the amino acid chelate into mucosal tissue are highly significant, this paper also demonstrates that there is a mechanism in the mucosal tissue which controls the quantity of iron from the amino acid chelate that is transferred to the plasma. For example, the higher the hemoglobin value, the less iron transferred. When considered together these studies demonstrate that iron amino acid chelate is both a safe and effective source of iron for treatment of iron deficiencies.

Effectiveness of treatment of iron-deficiency anemia in infants and young children with ferrous bis-glycinate chelate.

Forty infants, 6 to 36 mo old, with iron-deficiency anemia (hemoglobin < 11 g/dL) were matched and assigned to two groups. One group received FeS0(4) and the other received ferrous bis-glycinate chelate at a dose of 5 mg of Fe daily per kilogram of body weight for 28 d. Both groups had significant hemoglobin increases (P < 0.001), but only the group treated with ferrous bis-glycinate chelate had significant increases (P < 0.005) in plasma ferritin. Apparent iron bioavailabilities were calculated at 26.7% for FeS0(4) and 90.9% for ferrous bis-glycinate chelate. Regression analysis indicated that absorption of both sources of iron were similarly regulated by the body according to changes in hemoglobin. We concluded that ferrous bis-glycinate chelate is the iron of choice for the treatment of infants with iron-deficiency anemia because of its high bioavailability and good regulation.

Milk inhibits and ascorbic acid favors ferrous bis-glycine chelate bioavailability in humans.

The chemical properties of ferrous bis-glycine chelate allow for its use as a fortificant in fluid, high fat vehicles. This chemical form may also protect iron from the inhibitory or enhancing effects of the diet on iron absorption. Alternatively, iron bis-glycine chelate may be absorbed by a mechanism independent of an individual's iron stores. To test these hypotheses, the bioavailability of iron bis-glycine chelate added to water and milk was studied using a double-isotopic method in two groups of 14 women. Iron absorption from aqueous solutions of 0.27 mmol/L (15 mg/L) of elemental iron as either iron bis-glycine or ferrous ascorbate was not significantly different (34.6 and 29.9%, respectively). There were significant correlations between (log) iron absorption of iron bis-glycine with (log) serum ferritin (r = -0.60, P < 0.03) and with (log) iron absorption from ferrous ascorbate (r = 0.71, P < 0.006), suggesting that iron bis-glycine chelate bioavailability is indeed affected by iron stores. Iron absorption of iron bis-glycine given in milk was significantly lower (P < 0.002) than when given in water, with values of 11.1 and 46.3%, respectively (standardized to 40% absorption of the reference dose). With the addition of 0.57 mmol/L ascorbic acid (100 mg/L), iron absorption of iron bis-glycine given in milk increased significantly from 11.1 to 15.4% (P < 0.05). These findings show that milk and ascorbic acid affect iron bis-glycine chelate bioavailability and also demonstrate that iron stores may influence its bioavailability as well. The good bioavailability of iron bis-glycine makes this compound a suitable alternative to be considered in iron fortification programs.