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Vitamin C improves iron absorption

QUERETARO, MEXICO. It is estimated that 2.5 billion people worldwide suffer from iron deficiency and about 1.2 billion have iron deficiency anemia. The problem is particularly acute in countries such as Mexico where the normal diet contains large amounts of cereals and legumes (poor sources of absorbable iron) and limited amounts of meat, poultry and fish (good sources of heme or absorbable iron). Forty per cent of school-age children and 29% of women of childbearing age in Mexico suffer from iron deficiency anemia.

It is well known that ascorbic acid (vitamin C) improves the absorption of iron. Now researchers at the University of Queretaro and Baylor College of Medicine in Houston report that consuming a lime drink (limeade) containing 25 mg of ascorbic acid markedly increases iron absorption. The clinical trial involved 15 non-pregnant, non-lactating, iron-deficient women (ferritin less than 12 micrograms/L). The women were fed a traditional Mexican diet (maize tortillas and beans with vegetables) to which 0.25 mg of a stable isotope of iron had been added. After 2 weeks a blood sample was taken and iron level measured. For the following 15 days the women were fed the same diet, but also consumed limeade to provide an additional 25 mg of ascorbic acid at breakfast and lunch. Iron absorption increased more than 3-fold when limeade was added – from 6.6% to 22.9%. A follow-up test performed 2 months after the beginning of the experiment showed that the average ferritin levels had increased about 33% (from 6.3 to 8.4 micrograms/L). The researchers conclude that consuming 25 mg of ascorbic acid as limeade twice daily with meals improves the absorption of iron and may improve iron status in iron-deficient women over the longer term.
Diaz, Margarita, et al. The efficacy of a local ascorbic acid-rich food in improving iron absorption from Mexican diets: a field study using stable isotopes. American Journal of Clinical Nutrition, Vol. 78, September 2003, pp. 436-40

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