Extra iron can help infant motor development
© 2016 Roy Benaroch, MD
A randomized, controlled study from China might be able to teach us something about infant nutrition in the US: iron isn’t just to prevent anemia. It’s essential for motor development, too. And breastfed babies, especially, might not be getting enough.
It’s a clever study. They started with a group of women, who had already been randomized to get either extra iron or a placebo during their pregnancies. After their babies were born, the infants were randomized again to get either an iron supplement or placebo from age 6 weeks to 9 months. So there were really 4 groups, in the end, sorted by whether they had iron during pregnancy/infancy: placebo/placebo, iron/placebo, placebo/iron, and iron/iron. That design was chosen to figure out just when iron supplementation made a difference to infant motor development. The authors postulated that the more iron, taken for longer, the better. They were wrong, but that doesn’t mean we can’t learn from their missed guess.
The babies then had multiple tests of motor development performed. There were about 300 babies in each of the four groups, and the results were consistent among various ways of measuring the babies’ motor skills. Bottom line: iron supplementation during infancy improved motor skills by a considerable margin; iron supplementation during pregnancy didn’t make much difference.
The amount of iron given was smaller than what we’d typically give using a common infant multivitamin with iron in the United States. There were no adverse effects from the iron, which is expected. It is a myth that the ordinary doses of iron given to babies in formula or as a supplement causes constipation or any other problems. I think moms believe that myth because they get constipated during pregnancy, when they’re on higher doses of iron (typically 300 or 325 mg a day), but those doses are way way higher than what babies get (less than 10 mg a day.)
Another important caveat: the study was done in a poor area of rural China, in the Hebei province. Most of the babies, including the once who received iron supplementation, were still iron deficient on their blood tests; 80% of them were breastfeeding at 9 months. So the population isn’t really the same as what we’d see in the developed world. Still, when a safe, cheap, and easy intervention makes a big difference, that’s something to notice.
With this study in mind, should all babies just get a little extra iron? Formula-fed babies probably don’t need an extra supplement, unless they were premature or have other health issues that put them at risk for insufficient iron. But breastfed babies – they almost certainly need extra iron, especially by 4-6 months of age when their storage iron from birth starts to run down. Some complementary foods offer good iron, like fortified cereals, meats, and eggs, but some four month old infants don’t seem quite ready for those kinds of meals yet (many do, though—give it a try!) There’s also some evidence that you can prevent iron deficiency in infants by delaying clamping of the umbilical cord for a few minutes after birth. Will that help improve motor development, as seen with the supplements used in this study? Maybe.
There are really no important down sides to giving an iron supplement to infants. In fact, the only one I can think of is that they might stain teeth, so rinse the mouth or wipe teeth afterwards. A typical dose is one dropper of an iron-containing infant vitamin once a day, but check with your doctor for the best dose for your baby. And remember, with those improved motor skills, Junior might be able to get the cap off herself. So keep iron, vitamins, and all other meds well away from the reach of children.