Infant Lactose Intolerance: Congenital Lactase Deficiency and Milk Allergy

True infant lactose intolerance generally exists in the form of congenital lactase deficiency. This form of lactose intolerance is present from birth and is a genetic condition passed down from the parents (from both parents). Congenital lactase deficiency is a lack of adequate production of the enzyme lactase which is necessary to break down the milk sugar lactose. Lactose needs to be broken down into its two components parts, glucose and galactose, in order to be absorbed and used by the body. If lactose is not broken down properly it can provide food for the bacteria in our intestines and these bacteria can produce more than the normal amount of gases and other irritating by-products.

It is also possible for infants to have temporary intolerance to lactose if they are born premature, need to have intestine surgery, or have a virus that causes severe diarrhea, such as rotavirus. This is a fairly common way for infant lactose intolerance to be seen in babies although it usually reverses itself quickly.

Congenital lactase deficiency, being present from birth, will rear its ugly head from early on, showing itself in the form of severe diarrhea and bloating when the infant is given anything containing lactose, including breast milk and formula produced from cow's milk. Often infant lactose intolerance has symptoms that are confused with milk allergy but they are quite different from each other.

Milk allergy is a reaction of the immune system to the proteins in milk. This is different from the digestive condition of infant lactose intolerance. Milk allergy often has the additional symptoms of vomiting, itchy and red skin, watery eyes and nose, and other symptoms associated with allergic reactions to something.

There is a lot of controversy brewing about whether a fussy baby with lots of gas, diarrhea, and a failure to thrive might be lactose intolerant or have a milk allergy. The best way to test that is to remove all sources of lactose from the baby's diet for two or three weeks. If the symptoms disappear but then reappear after reintroducing lactose, then the problem was likely a lactose problem. One important thing to remember is that lactose is found in other places besides just dairy products. Any food that contains whey, dry milk solids, or nonfat dry milk powder will have lactose in them. This includes some breads, soups, salad dressings, pancake mixes and breakfast cereals.

If you are unsure about whether your infant is intolerant to lactose in the form of congenital lactase deficiency or whether the symptoms are being caused by an allergy to milk proteins, consult your pediatrician. If your infant is already on a lactose-free diet, remember not to change that diet unless you are under medical advice. Your baby could be the one to suffer for it.