Does introducing complementary foods prior to 4 months old pose risks to infants?

Updated on: Jan 8, 2021

Early introduction (before 4 months old) can be harmful to the baby’s health. Complementary foods should be introduced into the diet only when the baby shows signs that they are ready.   

The development of the baby

At approximately 4 to 6 months of age, the infant reaches a stage of development where solid foods can be introduced as a complement to breastfeeding or commercial formulas. Babies generally show signs of readiness to eat solid foods at around 6 months of age. Nonetheless, some babies may be ready before this age.   

Not all babies develop at the same rate. Be sure to only introduce solid foods when your baby shows signs of being ready to eat them. If the baby is born premature, certain considerations must be taken into account.  

The risks of early introduction 

If solid foods are introduced prematurely into the baby’s diet, that is before 4 months of age, various problems may occur:  

  • The digestive system is not mature enough to properly break down complementary foods. The infant does not produce enough saliva and enzymes to properly digest food.  
  • The immune system is not mature enough, which increases the risk of developing food allergies.  
  • The neuromuscular system is not sufficiently developed to allow proper chewing movements. Before the age of 6 months, the infant can only breastfeed, suck and swallow.  
  • There is the risk that solid foods may take the place of breast milk or formula instead of complementing it. This can have negative effects on the child’s growth.  

The importance of breast milk and commercial formula 

Until about 9 months of age, breast milk or formula should remain the infant’s main source of nutrients. Therefore, breastfeeding should continue according to the baby’s needs. For commercial formulas, the baby should continue to drink at least 750 ml per day. The amount of breast milk and formula should gradually decrease after 9 months of age. At one years old, solid foods should be an essential part of the baby’s diet. 

While it is important not to introduce solid foods too early, it is equally as important not to introduce them too late. Check out our article on how the late introduction of complementary foods (after 6 months old) can negatively affect a baby’s growth and feeding behavior.  


Duryea TK. (2020). Introducing solid foods and vitamin and mineral supplementation during infancy. Uptodate

ESPGHAN Committee on Nutrition : Agostoni, C., Decsi, T., Fewtrell, M., Goulet, O., Kolacek, S., Koletzko, B., et Van Goudoever, J. (2008). Complementary Feeding: A Commentary by the ESPGHAN Committee on Nutrition. Journal of Pediatric Gastroenterology & Nutrition, 46(1), 99-110.

Santé Canada. (2015). Nutrition du nourrisson né à terme et en santé : Recommandation de la naissance à six mois.

Société canadienne de pédiatrie. (2018). Le sevrage de l’allaitement


Doré, N., et Le Henaff, D. (2020). Mieux vivre avec notre enfant de la grossesse à deux ans.


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