As anyone who has ever watched a science fiction movie knows, even our best actions can have unintended consequences. The world of child health is rife with examples, such as how lifesaving antibiotics have led to the evolution of antibiotic-resistant infections. When it comes to infant nutrition, I would argue that three positive trends share one major unintended consequence: iron deficiency.

Most people know that the body needs iron to make red blood cells, which carry oxygen from the lungs to everywhere else. Children with very low iron levels may develop a shortage of red blood cells (anemia), which can make them pale, tired, and listless. But anemia is a late effect of iron deficiency. Long before a child becomes anemic, low iron stores in the body may interfere with development, learning, and behavior. Adequate iron levels can even protect children against lead toxicity!

As important as iron is for developing infants, nearly 1 in 5 babies between the ages of 6 and 12 months fall short of the recommended iron intake in their diet, a number that has grown over time. This information comes to us from Nestlé and Gerber, who started conducting huge nationwide studies of infant and toddler nutrition in 2002, called FITS (the Feeding Infants and Toddlers Studies). Nearly 10,000 parents and caregivers of infants and young children under the age of 4 have participated in the studies, which were done in 2002, 2008, and 2016.

Ironically, this decrease in iron intake correlates with some strongly positive trends in infant nutrition. The best of these is the rise in breastfeeding rates, which have jumped from 76% of infants ever breastfed in 2002 to 81% of infants in 2016. Breast milk is the perfect food for infants, and both the World Health Organization (WHO) and the American Academy of Pediatrics (AAP) urge all mother who can nurse their infants to do so, ideally as their only source of nutrition until age 6 months.

Breast milk, however, is comparatively low in iron, so that by age 4 months exclusively breastfed infants run the risk of iron deficiency. For that reason, the AAP advises parents to give breastfed term infants an iron supplement between the ages of 4 and 6 months and then to start first foods that are high in iron (more about that below).

Another trend in the American diet is a move away from refined grains.Iron-fortified baby cereal, however, has been a critical source of iron in the infant diet for decades, with two servings a day providing plenty of the mineral in an easy-to-feed format. Now only about half of infants eat iron-fortified infant cereals. Iron-fortified whole grain infant cereals like brown rice, oatmeal, and barley certainly still deserve a place among babies’ first foods.

Red meat consumption has fallen dramatically in the last 3-4 decades in the US, driven by concerns around both health and the environment. While many welcome this trend, meats serve as readily available iron-rich foods. A carefuly planned vegetarian or vegan diet can provide plenty of iron from sources like beans (of all types), tofu, and leafy green vegetables, especially when paired with fruits and vegetables high in vitamin C. Some parents who are not vegetarian or vegan, however, avoid meats for infants until 9 months of age based on outdated dietary advice.

As a pediatrician and a parent, I love how far we are advancing in our understanding of what constitutes a diet that is healthy both for our infants and for the environment. As for the unintended consequences, they’re easy to iron out by remembering to iron in!

*#Sponsored: Dr. Hill is a consultant to Gerber