DHA is not the only critical substance for developing babies’ brains. Researchers have known for some time that iron is also key, but recently they have been discovering just how long the effects of a deficiency can last. Babies are born with a solid store of iron, but by 5 or 6 months they’ve used much of it up and can’t get enough from breast milk to sustain their ever-growing bodies: they need to take it in from the outside world in food or supplements. Studies show that being deficient at points within the 5- to 12-month age block irrevocably slows academic, social and emotional development. Even if children are fortified with iron soon after the deficiency is detected, they never catch up, and can still show signs of cognitive delay even 10 years later.
Iron is not only needed to transport oxygen to the brain in the bloodstream, but it also helps myelinate, or insulate, nerve fibers so signals travel faster—and helps create the neurotransmitters that relay signals between neurons. Until the early 1970s when manufacturers began adding iron to formula, more than 30 percent of infants were iron-deficient; since fortification, that number has plummeted. (At last count, about 7 percent of toddlers were iron-deficient.) But with the rise in breastfeeding, exclusively breast-fed infants are now at risk, especially as they’re transitioning to solid foods. Breast milk is still the best food (bar none) for infants, but physician groups recommend using rice cereal fortified with iron or supplementing with a vitamin drop during and after that critical transition to solid foods around 5 or 6 months.
With irreversible brain delay churning through my gray matter (and after consulting the pediatrician), I drove to the drugstore and bought a multivitamin with iron for my son, who at 7 months was still breastfeeding but beginning to discover the delights of runny rice cereal and mushy peas.