Food introduction can be such a fun time in your child’s development. Sweet, little, messy fingers and faces make introducing food to your baby a fun and playful time. It can also be a confusing and daunting time for parents concerned about food allergies. Plus, with the gut health so clearly tied to overall and lifelong health, it’s important to give your baby a good start. In this three part series we’ll look at the when, what, and how to introduce solid foods to your little one. In this first post we’ll explore the when of food introduction.
There are really two main factors in baby’s readiness for solids. The first factor that should be considered is their overall development. There are certain developmental signs that show you your baby is ready for solids:
• Baby sits upright well without support.
• Baby has lost the tongue-thrust reflex (the automatic pushing solids out of the mouth with the tongue)
• Baby is ready and willing to chew.
• Baby is developing a “pincer” grasp, where he picks up food or other objects between thumb and forefinger.
• Baby is eager to participate in mealtime and might try to grab food.
When your little one has reached these developmental milestones she is much more likely to safely and effectively start exploring with solids. This does not mean that all babies are ready
to start solids at this point but we should definitely be waiting for these milestones before considering food introduction.
The second factor to think about is the maturation of the gastrointestinal tract. Most pediatricians recommend introducing solids at 4-6 months. I recommend waiting until the 5-6 month mark to start solids and I recommend doing it in a specific way- but more on that in part two of this series! At around 6 months the gastrointestinal tract changes from a semi-permeable membrane to a lining with more integrity and less permeability. Babies are born with digestive tracts that are slightly permeable to microscopic particles of food that can be absorbed into the bloodstream and promote an allergic reaction or inflammation. This is similar to leaky gut or intestinal permeability that we see in older children and adults, but the intestinal permeability in infants serves a purpose. The microscopic openings in the gut allow immunoglobins and other immune stimulating molecules from breast milk to enter into baby’s circulation. As the infant gut matures it becomes less permeable and secretes more mucin, both of which help ensure a healthy digestive lining. Allowing this evolving gut to develop and mature before the introduction of food is essential to proper immune, neurological, and digestive health. Numerous studies have shown that introducing solids before 3-4 months can increase the risk of eczema, celiac disease, type 1 diabetes, childhood wheezing and increased body weight in childhood. (1,2,3,4,5)
After reading the studies mentioned above it is easy to jump to the conclusion that waiting longer to introduce food or potential food allergens is better. However, new research shows that delaying the introduction of certain foods can actually raise the risk of allergy to that food. One study found that children first exposed to wheat between 4 and 6 months versus after 6 months had a 4-fold decreased risk of wheat allergy. (6) Another found that children who first had cooked egg at 4-6 months had the lowest incidence of egg allergy, whereas those starting egg at 10-12 months had a 6-fold increased risk of egg allergy. (7) Research from earlier this year showed a clearly decreased risk of peanut allergy when peanuts were introduced after 4 months but before 11 months of age. (8)
Research seems mixed when we look at studies with gluten and celiac disease. Earlier studies show that infants who ate gluten after 3 months of age but before 6-7 months had lower risk of celiac disease. (9) Recent research from 2014 showed that age of introduction of gluten at 4 months, 6 months, or 12 months didn’t affect the development of celiac. (10, 11) Trying to glean conclusions about food introduction and celiac disease is confusing and not clear cut. It seems that other factors, in addition to gluten intolerance, that change the gut flora are playing a role here. These factors may include cesarean births, antibiotic use, infections and other medications.
Putting aside the confusing research about gluten and celiac disease, recent studies point to introducing solids to your baby no sooner than 4 months but before 12 months of age. Does that mean we should hand baby a peanut butter sandwich on wheat at 4 months? Absolutely not. But it does point to a way to introduce food that’s more nuanced than the standard advice to start solid foods at 4 months. The how to introduce foods is as important as the when and is exactly what we will be exploring next week so stay tuned!
– Dr. Catherine Clinton
1 Fergusson, D. M., Horwood, L. J. & Shannon, F. T. Early Solid Feeding and Recurrent Childhood Eczema: A 10-Year Longitudinal Study. Pediatrics 86, 541–546 (1990).
2 Norris, J. M. et al. Risk of celiac disease autoimmunity and timing of gluten introduction in the diet of infants at increased risk of disease. J. Am. Med. Assoc. 293, 2343–2351 (2005).
3 Norris, J. M. et al. Timing of initial cereal exposure in infancy and risk of islet autoimmunity. J. Am. Med. Assoc. 290, 1713–1720 (2003).
4 Wilson, A. C. et al. Relation of infant diet to childhood health: seven year follow up of cohort of children in Dundee infant feeding study. BMJ 316, 21–25 (1998).
5 Cohen, R. J., Brown, K. H., Dewey, K. G., Canahuati, J. & Landa Rivera, L. Effects of age of introduction of complementary foods on infant breast milk intake, total energy intake, and growth: a randomised intervention study in Honduras. The Lancet 344, 288–293 (1994).
6 Poole, J. A. et al. Timing of Initial Exposure to Cereal Grains and the Risk of Wheat Allergy. Pediatrics 117, 2175–2182 (2006).
7 Wells, J. C. et al. Randomized controlled trial of 4 compared with 6 mo of exclusive breastfeeding in Iceland: differences in breast-milk intake by stable-isotope probe. Am. J. Clin. Nutr. 96, 73–79 (2012).