There is no evidence that giving lactase drops to unhappy babies decreases crying (Hall 2012). There are tests for lactose intolerance (Heyman 2006). Please see your health-care providers if you think your baby is lactose intolerant.
1) Congenital lactase deficiency
A very small number of babies are born unable to make the enzyme lactase. This is called congenital lactase deficiency. This is due to a genetic condition. The highest rates are found in Finland where 1 in 60,000 babies is affected. These babies become very sick soon after starting to breastfeed or take in breast milk.
2) Acquired lactase intolerance
In rare cases, a sick baby may develop lactose intolerance because the small intestine, a part of the gut, is damaged and can’t produce the lactase enzyme. This includes babies who:
- Are under three months old and have severe diarrhea.
- Are ill with parasites.
- Have celiac disease, Crohn’s disease, or other gut abnormalities.
- Are severely malnourished.
Lactose-free infant formula can be bought but is more expensive. It is generally not recommended. Infant formula-fed babies with persistent diarrhea or who have conditions that can cause acquired lactose intolerance may benefit from a two-week period of lactose-free infant formula.
In the past, babies with infectious diarrhea were thought to be unable to digest lactose and breast milk was replaced by juice, broth, tea, rice water, or even flat soda (fizzy) drinks. None of these provide the necessary nutrients to help the bowel heal or the right balance of salt and water to replace the fluids lost.
Otherwise healthy breastfed babies who develop infectious diarrhea should continue to breastfeed (Heine 2017). In addition, babies should be seen promptly by their health-care providers if they:
- Are less than four months of age.
- Have a fever.
- Are also vomiting.
- Are sleepy or weak.
- Have a dry mouth.
- Have peed less than usual.