Lactose intolerance in infants is highly unlikely.
While babies are sometimes sensitive to dairy products, lactose intolerance in infants is highly unlikely. Here's how to tell.


Spitting up, diarrhea, and vomiting, oh my! If your baby is having trouble calmly digesting your breastmilk, you may be wondering if he's lactose intolerant.

Breastmilk always naturally contains lactose. If your baby is sensitive to lactose, it's not from the milk you are consuming.

Babies produce lactase, an enzyme that breaks down lactose, to digest their mother's milk. Older children and adults can have trouble digesting lactose because the body slowly decreases lactase production as it ages.

It's highly unusual for a baby to be lactose intolerant. Lactose intolerance does not cause vomiting or eczema.

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When the parents are lactose intolerant

Not all lactose intolerance is the same. Most adults have a lactose intolerance which develops in maturity as the body slowly decrease its production of lactase, which breaks down the milk sugar (lactose).

This type of lactose intolerance is not passed down and it's rarely seen before adulthood, never before age 3-5. There is no relationship between lactose intolerance in family members and that seen in babies.

Congenital lactose intolerance

It's very rare to be born with a lactose problem. These metabolic disorders can be inherited, but they are rare and characterized by symptoms severe enough to dehydrate a baby. These include congenital lactose intolerance and the less-severe congenital lactase deficiency.

Some premature babies are temporarily unable to digest lactose because their little bodies aren't making lactase yet. Nursing mothers can supplement breastfeeding with lactase instead of switching to lactose-free formula.

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Acquired lactose intolerance

If your baby was very sick or has had a lot of allergic inflammation, she may have a damaged intestinal lining. As long as you allow time for the gut to heal, the intolerance should be temporary. Human milk will help the baby's gut to heal.

Maybe it's just too much lactose

Lactose overload in babies sometimes occurs when mom has an oversupply of milk. If your baby regularly is not able to empty (or mostly empty) a breast, she may be getting mostly the foremilk, the more watery, lactose-heavy milk that comes out first.

When this happens, the overabundance of lactose can swamp the baby's gut and cause gassiness, discomfort, and green foamy poops.

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If you suspect this is bothering your baby, try expressing a little milk first or letting baby nurse on one side longer. You can also try spacing feedings a bit more and give the baby an 'empty' breast if he wants to nurse before the next feeding.

Cow's milk allergy

It's possible that a baby is allergic to the proteins in cows milk that the breastfeeding mother consumes. If you think your baby is allergic, try eliminating dairy from your diet for 2-3 weeks to see if you notice a difference. It takes that long for the proteins to leave both of your systems.

You can try reintroducing a little bit of dairy to see if the baby has the same reaction, but you may want to wait longer if baby's initial reaction was severe.

Babies usually outgrow their sensitivity by 6-18 months, and almost always by age 3.

It's always best to make an appointment with your child's doctor if you're concerned they may have an intolerance or allergy to lactose.

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