Nutrient interrelationship of ascorbic acid and iron in rats and guinea pigs fed cereal diets

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 (k 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.