A. K. MAJUMDER, B. K. NANDI, N. SUBRAMANIAN AND I. B. CHATTERJEE Department of Biochemistry, University College of Science, Calcutta 19, India ABSTRACT Iron at a daily dose of 5 mg per animal was toxic to rats and guinea pigs fed unfortified whole wheat flour and whole rice flour diets. In rats, a species capable of synthesizing ascorbic acid, iron supplementation resulted only in decreased growth. In guinea pigs, iron administration resulted not only in decreased growth but also in high mortality. The apparent toxicity of iron was not observed when wheat flour was fortified with 15% casein. In guinea pigs, administration of ascorbic acid (5 mg per 100 g body weight per day) along with iron not only counteracted the toxic effect of iron, but also led to a greater utilization of iron as revealed by increased hemoglobin and serum iron levels accompanied by decreased spleen iron content. Iron administration, however, resulted in decreased ascorbic acid synthesis (in rats only) and increased ascorbic acid utilization as revealed by lowered urinary, blood, and other tissue levels of the vitamin. J. Nutr. 105: 240-244, 1975. INDEXING KEY WORDS wheat flour • rice flour ascorbic acid synthesis •ascorbic acid utilization
In geographic areas where the diet is made up largely of whole grain cereals, not only subclinical scurvy but also iron deficiency are prevalent. When high cereal diets are eaten, iron is likely to be more or less abundant, but many constituents such as carbonate, oxalate, phosphate, and phytate bind iron to form precipitates that are absorbed poorly ( 1 ). Because ascorbic acid enhances absorption and utilization of iron (2, 3), we were interested to see the effect of ascorbic acid on iron utilization in guinea pigs fed high cereal diets. While ascorbic acid improves iron utilization in the presence of an iron overload, large doses of ascorbic acid disappear without an appreciable rise in blood levels or uri nary excretion of the usual end product of ascorbic acid metabolism (4, 5). There fore, we were interested in studying ascor bic acid metabolism in rats and guinea pigs fed high cereal diets with supplemen tation of iron.
tory colony,2 and young male short hair guinea pigs ( 200 ±5 g ), obtained from the animal supplier, were used throughout the experiment. The animals were fed unforti fied whole grain wheat flour and whole grain rice flour diets as well as a fortified wheat diet with or without supplementa tion of ascorbic acid. The compositions of the unfortified and fortified diets have been described ( 6 ). The diets were fed for 45 days in the case of rats and 10-20 days in the case of guinea pigs. Iron ( 1 mg and 5 mg as 5 mg and 25 mg FeSO4, 7HaO in 0.2 ml of water) and ascorbic acid were administered orally as described before (7). The serum iron was determined by the method described elsewhere (8), and iron contents of tissues were determined by the method of Cameron (9). The hemo globin was determined following the method of Cannan (10). The urinary and tissue levels of ascorbic acid, synthesis of
Received for publication August 20, 1974. 1The work was supported by the PL-480 project no. A7-HN-25. «rant no. FG-In-41C. 2Until these rats were fed the experimental diets, rats (100 ±5 g) of they were fed from weaning fortified wheat diet as raised in our labora previously described (6). 240
EXPERIMENTAL
Young male albino Charles Foster strain,
iron utilization
Downloaded from https://academic.oup.com/jn/article-abstract/105/2/240/4768685 by Tulane University Medical Library user on 21 January 2019
Nutrient Interrelationship of Ascorbic Acid and Iron in Rats and Guinea Pigs Fed Cereal Diets1
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TABLE 2 o/ supplementation of iron on lipid peroxide content in the liver microsomes of rats fed wheat flour, rice flour, and a fortified wheat diet
o£oo oo oo r— o o' O' o' O "H^io gnSS""Sii&&"•ocagei"^
CerealsWheat O O O COCO«CO "O-f-H-H-H-H
O O
-H-rlo o^O o o o
gu
flourRice ironNone5 mg
flourFortified 1•§»1ico•ii§l""i*"toTABLK ironNone5 mg a;-33Ht*Wa>.oHiI
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In geographic areas where the diet is made up largely of whole grain cereals, not only subclinical scurvy but also iron deficiency are prevalent. When high cereal diets are eaten, iron is likely to be more or less abundant, but many constituents such as carbonate, oxalate, phosphate, and phytate bind iron to form precipitates that are absorbed poorly ( 1 ). Because ascorbic acid enhances absorption and utilization of iron (2, 3), we were interested to see the effect of ascorbic acid on iron utilization in guinea pigs fed high cereal diets. While ascorbic acid improves iron utilization in the presence of an iron overload, large doses of ascorbic acid disappear without an appreciable rise in blood levels or uri nary excretion of the usual end product of ascorbic acid metabolism (4, 5). There fore, we were interested in studying ascor bic acid metabolism in rats and guinea pigs fed high cereal diets with supplemen tation of iron.
tory colony,2 and young male short hair guinea pigs ( 200 ±5 g ), obtained from the animal supplier, were used throughout the experiment. The animals were fed unforti fied whole grain wheat flour and whole grain rice flour diets as well as a fortified wheat diet with or without supplementa tion of ascorbic acid. The compositions of the unfortified and fortified diets have been described ( 6 ). The diets were fed for 45 days in the case of rats and 10-20 days in the case of guinea pigs. Iron ( 1 mg and 5 mg as 5 mg and 25 mg FeSO4, 7HaO in 0.2 ml of water) and ascorbic acid were administered orally as described before (7). The serum iron was determined by the method described elsewhere (8), and iron contents of tissues were determined by the method of Cameron (9). The hemo globin was determined following the method of Cannan (10). The urinary and tissue levels of ascorbic acid, synthesis of
Received for publication August 20, 1974. 1The work was supported by the PL-480 project no. A7-HN-25. «rant no. FG-In-41C. 2Until these rats were fed the experimental diets, rats (100 ±5 g) of they were fed from weaning fortified wheat diet as raised in our labora previously described (6). 240
EXPERIMENTAL
Young male albino Charles Foster strain,
iron utilization
Downloaded from https://academic.oup.com/jn/article-abstract/105/2/240/4768685 by Tulane University Medical Library user on 21 January 2019
Nutrient Interrelationship of Ascorbic Acid and Iron in Rats and Guinea Pigs Fed Cereal Diets1
INTERRELATIONSHIP
ö ö
cö
-tì-H& ¿-H-H-H
uj§ I *ops"§
241
TABLE 2 o/ supplementation of iron on lipid peroxide content in the liver microsomes of rats fed wheat flour, rice flour, and a fortified wheat diet
o£oo oo oo r— o o' O' o' O "H^io gnSS""Sii&&"•ocagei"^
CerealsWheat O O O COCO«CO "O-f-H-H-H-H
O O
-H-rlo o^O o o o
gu
flourRice ironNone5 mg
flourFortified 1•§»1ico•ii§l""i*"toTABLK ironNone5 mg a;-33Ht*Wa>.oHiI
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C"3T31"1 £
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