Erythorbic acid is a potent enhancer of nonheme-iron absorption.
BACKGROUND
Erythorbic acid, a stereoisomer of ascorbic acid with similar physicochemical properties, is widely used as an antioxidant in processed foods.


OBJECTIVE
The aims of the present study were to evaluate the effect of erythorbic acid on iron absorption from ferrous sulfate at molar ratios of 2:1 and 4:1 (relative to iron) and to compare the effect of erythorbic acid directly with that of ascorbic acid at a molar ratio of 4:1.


METHODS
Iron absorption from iron-fortified cereal was measured in 10 women on the basis of erythrocyte incorporation of stable iron isotopes ((57)Fe or (58)Fe) 14 d after administration. Each woman consumed 4 ferrous-sulfate-fortified test meals (containing 5 mg Fe/meal) with or without added erythorbic or ascorbic acid. The data were evaluated by use of paired t tests, and the results are presented as geometric means.


RESULTS
Iron absorption from the test meal without any added enhancer was 4.1%. The addition of erythorbic acid (at molar ratios of 2:1 and 4:1 relative to iron) increased iron absorption 2.6-fold (10.8%; P < 0.0001) and 4.6-fold (18.8%; P < 0.0001), respectively. The addition of ascorbic acid (molar ratio of 4:1) increased iron absorption 2.9-fold (11.7%; P = 0.0004). At a molar ratio of 4:1, erythorbic acid was 1.6-fold (P = 0.0002) as potent an enhancer of iron absorption as was ascorbic acid.


CONCLUSIONS
Although erythorbic acid is a potent enhancer of iron absorption, its lack of antiscorbutic activity limits its usefulness in iron-fortification programs. However, it may play a major role in enhancing iron bioavailability from mixed diets that include foods preserved with erythorbic acid.
Fidler
Meredith C
MC
Institute of Food Science and Nutrition, Swiss Federal Institute of Technology, Zurich, Rueschlikon, Switzerland.
Davidsson
Lena
L
Zeder
Christophe
C
Hurrell
Richard F
RF
D000328:Adult; D001205:Ascorbic Acid / Q000494:pharmacology*; D002523:Edible Grain; D005260:Female; D005527:Food, Fortified; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D007501:Iron / Q000097:blood / Q000493:pharmacokinetics*; D013237:Stereoisomerism
C005056:isoascorbic acid; D007501:Iron; D001205:Ascorbic Acid