After my interview with Dr. Cate Shanahan, author of Deep Nutrition: Why Your Genes Need Traditional Food and Food Rules: A Doctor’s Guide to Healthy Eating, I invited Dr. Cate to share a guest post with us on a topic of her choosing. She’s written us a fabulously insightful two part series on iron fortification in infant and toddler foods. I hope you enjoy! And, thanks Dr. Cate!
We hear all the time how iron deficiency is associated with a wide variety of health problems in children and adults. Perhaps the most worrisome is the association with lowered intelligence, which can occur in children who have low iron but won’t show up on blood tests because iron levels are not usually tested until a child is diagnosed with anemia (low blood counts).
To avoid low iron levels, the American Academy of Pediatricians advises doctors to make a blanket recommendation that between ages 6 and 24 months, when iron stores run out and children aren’t getting that much iron in their foods, parents buy iron-fortified formula and cereal. Breastfed babies, who can become deficient even earlier, are to be given supplemental iron after 4 months of age. The assumption behind this widespread practice has been that a little extra iron is harmless to your baby, so why not go ahead and get that extra iron in however you can.
A friend of mine recently prompted me to question that assumption. As a new father to a bouncing baby boy, Patrick Vlaskovits (who runs the popular Paleohacks.com & PaleolithicDiet.com websites), received the usual advice from his pediatrician to fortify his son’s diet with iron.
But the doctor’s recommendation didn’t jibe well with Patrick’s evolutionary approach: if babies are meant to be fed breastmilk and breastmilk is naturally low in iron and even contains chelators that bind to iron so to minimize free iron in the gut, perhaps babies sensitive GI tracts may be harmed by iron. This made him worry that that extra iron, even a little extra iron, might not be so healthy for his little guy, and so asked me if I would be willing to do a little investigating.
I’m glad he did. The results of my investigation has convinced me to withhold any recommendation to parents about feeding their children iron-fortified foods until first checking iron levels. Supplementing iron when iron levels are already normal can lead to serious health problems. Below are five that have the most supporting evidence behind them:
- Lowered IQ. When researchers studied the delayed effects of just a little extra iron in early life (between ages 6-12 months), the results were unmistakable. Half of the babies in the study had been given iron-fortified cereal, while half got unfortified cereal. Most of the children had normal iron levels, and among this majority, at the time of the intervention, their intelligence tests were evenly matched. Ten years after the intervention, however, both groups were given intelligence tests again, and this time members of the iron-fortified group scored an average of 11 points below the children who received no supplementation. (source)
- Bacterial infection. Iron fortified foods have been shown in multiple studies to promote the growth of intestinal pathogens and alter intestinal and systemic immune function. In children with fragile health (i.e. HIV or malaria), iron appears to increase mortality rates. What follows are the most pertinent quotes from the article: “ Iron treatment has been associated with acute exacerbations of infection, in particular, malaria.” “Oral iron supplementation in the tropics in children of all ages … has been associated with increased risk of clinical malaria and other infections including pneumonia.” “In studies of the [prevention] of Pneumocystis carinii in patients with HIV disease, 30 mg of elemental iron daily for 6 mo was shown to be associated with excess mortality” “Parenteral [intravenous] iron treatment is associated with life-threatening sepsis when given in the early neonatal period.” (source)
- Early atherosclerosis, or “fatty streaks.” A Finnish study found that excess iron stores was a stronger risk for heart attack than hypertension or cholesterol levels. (source) We have no comparable data on children because nobody is looking for an association.
- Cancer. One study found a correlation between maternal iron supplementation in pregnancy and the most common childhood cancers: leukemia and lymphoma (source). Several studies show that children with the iron storage disease hemochromatosis, who have only slightly higher-than normal iron levels, suffer significantly higher rates of these cancers. Similar studies in adults have found increased rates of the most common adult cancers: breast and prostate. (source 1 ; source 2).
- Stunted growth. According to an extensive review of the effects of iron on the crucial skeletal developments in early life “iron supplementation in young children without iron deficiency may jeopardize optimal height and weight gains.” (source)
All this sounds rather scary. And you might be wondering how something so simple as a little extra iron could be responsible for so many diverse problems with a child’s health and development. Stay tuned to part 2 of Should You Feed Your Baby Iron Fortified Foods to answer that question and help you make the decision with greater confidence.
(photo by sean dreilinger)
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