Too Much of a Good Thing?
Brown, Valerie J., Environmental Health Perspectives
Pregnant women are famously exhorted to faithfully take their daily prenatal vitamins, which often contain iron and other minerals. But new research suggests that a weekly iron supplement coinciding with the renewal of the small intestine's mucosal lining cells (where nutrient absorption occurs) works better than a daily supplement and prevents problems resulting from too much iron at the wrong times.
Maternal iron deficiency and anemia early in gestation can result in premature birth and low birth weight. These, in turn, can trigger further problems ranging from slow physical growth and motor development to impaired emotional control. In severe cases, both maternal and fetal survival can be threatened at or near birth. Thus, there exists a near-global public health policy of maternal iron supplementation during pregnancy.
The new study appears in the July 2006 issue of Archives of Medical Research. A team including nutritionist and epidemiologist Esther Casanueva of the National Institute of Perinatology Isidro Espinosa de los Reyes (INPerIER) in Mexico City and colleagues elsewhere in Mexico City and California studied 116 women receiving prenatal care at INPerIER. All had come to INPerIER for prenatal care by gestational week 20.
None of the women were anemic at that point, but 66% had low levels of ferritin (the principal form of stored iron), suggesting low iron nutritional status. Half took 60 mg of iron as ferrous sulfate with 200 [micro]g of folic acid and 1 [micro]g of vitamin [B.sub.12] once a day; the others took double this dose once a week. The researchers checked the women's levels of hemoglobin (which transports oxygen) and ferritin every four weeks through the end of pregnancy. …