Breast Feeding and Lactase Deficiency

Could Transient Lactase Deficiency Be Causing My Baby’s Colic Symptoms?


Your baby is fussy and gassy most of the time. You spend hours listening to Intense crying, you and your baby get no sleep, and you feel helpless. Colic is defined as "prolonged and uncontrollable crying and irritability in an otherwise healthy infant", and is typically attributed to pain in baby’s developing digestive tract. But what causes that pain? And more importantly, what can parents do to relieve it?

One possible theory of colic in some babies is a condition called transient lactase deficiency, although the link is unproven. Lactase is the enzyme that is needed to digest lactose, the sugar found in all mammalian milks. When someone cannot digest lactose, the result is often gas, bloating, abdominal cramps, and in babies, fussiness and bouts of prolonged crying.

While lactose intolerance caused by primary lactase deficiency is fairly common among adults, it’s not seen very often in babies since by definition a baby’s diet consists primarily of breastmilk. When the condition does show up in newborns, it’s called transient lactase deficiency, because it is only temporary. For some babies who do not have enough of the lactase enzyme, symptoms improve when they start producing it around four months of age.

For the breastfeeding baby, it might seem like there’s no choice but to wean. But breastfeeding still remains best for these babies. If we consider the way that lactase works, it needs slow digestion in order to break down lactose. And the best way to slow digestion is with a high fat and low carbohydrate diet. This is something a mother has control over when breastfeeding. Carb levels are highest at the beginning of a nursing session, and the fat content of the milk increases the longer the baby nurses. So, basic breastfeeding management can make a difference. If baby comes off the breast too soon, he will have a high carb, low fat feeding that is more likely to lead to problems digesting the lactose, thus more colic like symptoms. Breastfeeding moms should let baby finish the first side before switching breasts, allowing baby to determine how long the nursing session lasts.

Sometimes the transient lactase deficiency is caused by an insult to the gut – perhaps by solids introduced too early, an allergy to something in breastmilk or formula, medications, or a bout of diarrhea or gastroenteritis. In this case, the levels of lactase are low temporarily until the gut has a chance to heal, after which time the deficiency will resolve itself, and the colic-like symptoms will subside.

If you suspect that an allergy to something in your diet is causing your breastfed baby’s symptoms, the most likely culprit is cow’s milk protein. This is an allergy rather than intolerance to lactose, and it can be treated by eliminating all dairy from mom’s diet.

The most important thing to keep in mind with transient lactase deficiency is that it’s temporary. Most babies will outgrow these issues, and will eventually be able to digest milk sugars normally.

*Colic Calm is not intended to treat the underlying condition of transient lactase deficiency (TLD). For the treatment of TLD many parents use lactose drops or switch to a soy based or lactose free formula.


  2. Riordan J , Wambach K. (2010) Breastfeeding and Human Lactation, 4th ed. Boston: Jones & Bartlett.
  3. Mohrbacher, N. (2010) Breastfeeding Answers Made Simple. Amarillo, TX: Hale Publishing.