While plenty of recent research has focused on how nutrition during infancy can have lasting effects on health in later life–particularly as it pertains to obesity and chronic disease– new research is suggesting that iron levels during this critical period may influence another key aspect of future health: sleep patterns. A recent review article published in Sleep Medicine suggests that iron deficiency anemia disrupts optimal brain development and leads to altered behaviors in infants that can lead to persistent sleep problems later in childhood.
As many as 1/4 of infants worldwide experience iron deficiency anemia (IDA), or a deficiency in oxygen-carrying red blood cells that results from a diet lacking in iron. Dietary iron intake is particularly important in babies aged 6 to 24 months, the time of critical growth and mental and motor control development in the brain. Though IDA has been linked to cognitive problems such as poor attention span, lack of concentration, and learning difficulties, these researchers were interested in observing how IDA may be related specifically to brain function as it affects sleep patterns.
Iron deficiency affects the organization of sleep, and IDA has been shown to alter patterns of “sleep spindles” – brain waves visible on electroencephalography patterns – which are thought to be indicative of normal cerebral function. Previous research found that, even when simply napping, spindles seem to be important in memory and to the ability to learn. Ample research on adults and in animal models have shown that low levels of spindles are linked to increased muscle tone and motor activity during sleep. Consistent with these findings, this study found that iron deficiency anemia in 6-month-olds was associated with restless nighttime sleep resulting from daytime napping. Specifically, parents of children who had iron deficiencies as infants reported more sleep disturbances, including insomnia, compared to parents of children who never experienced the deficiency. The researchers’ findings suggest that even with correction of iron deficiency through supplementation, early deficiency of the mineral appears to continue to alter sleep patterns into childhood.
A woman’s iron status during pregnancy impacts a newborn’s iron levels and reserves, so many experts recommend choosing a prenatal vitamin that contains iron to help ensure optimal status. Talk to your doctor about an appropriate dose. As complementary foods are introduced to a infant’s diet after 4-6 months of age, experts generally recommend starting off with iron-rich foods first, such as iron-fortified rice cereals or even texture-appropriate pureed meats.
Also, in part to help prevent iron-deficiency anemia, the American Academy of Pediatrics (AAP) recommends delaying introduction of liquid cow’s milk, which is low in iron, until after 12 months of age. Always consult with a doctor before giving your infant a multivitamin or iron supplement, and keep all iron-containing supplements out of reach of children. While it is important to make sure infants are getting the appropriate amount of iron in their diets, it is just as important to remember that too much iron given in the form of supplements can be toxic — and in some cases, fatal.