Q: My child could not tolerate milk as an infant and I have lactose intolerance as an adult. Are these two connected?
A: Intolerance to milk in infants is almost always related to milk allergy.
Cow milk protein allergy occurs in about 1%-2% of babies. It may present in a variety of ways including vomiting, diarrhea, blood in the stool, poor weight gain, rashes, eczema and low hemoglobin. This could occur in formula fed babies, or those who are breast fed (due to dairy ingestion by the mother and the milk protein coming through the breast milk).
In most cases, the allergy tends to subside by one year of age. There will be children who may take longer to overcome the allergy, especially if their allergy is of the IgE-mediated form.
You will notice that I mention protein. Milk intolerance in babies is an allergy to the protein component of the milk. Very rarely do older children and adults develop milk allergy as a new condition.
More often than not, babies and infants do not have allergies to other food items.
However, some do develop, especially if there is a strong family history, but many of the food allergies resolve by the time the child is 3-to-4-years-old. Children with multiple food allergies need to be monitored closely by their pediatricians, or an allergist, gastroenterologist and nutritionist to ensure adequate nutrition, growth and prevention of other complications.
Babies with milk protein allergy need a special formula, or if they are being breast-fed, the mother needs to avoid all dairy in any form and amount. It is estimated that about 30% of them will also have allergy to soy and that needs to be avoided as well.
The formulas that are used for milk allergy are soy- free. Soy-based formulas can be used above the age of 6 months (if there is no soy allergy).
As mentioned, most overcome their allergy by the time they are one year old. This means that the baby food that is started between 4-to-6-months of age should also be dairy- and soy-free till they are one year old. As this is an allergy, even small amounts of the offending protein can result in clinical symptoms and damage.
Lactose intolerance on the other hand is very common and can start after 5 years of age. Many adults have varying degrees of lactose intolerance. It tends to run in some families. Here the intolerance is to the carbohydrate in the milk called lactose.
It occurs as there is a decrease in the amount of lactase enzyme that is produced in the intestinal lining. The lactase enzyme helps breakdown the lactose to two simple sugars, glucose and galactose, that are easily absorbed. If the lactose molecule does not get broken down, it results in abdominal discomfort, cramping, bloating, flatulence or diarrhea. It is an intolerance, short-lived after the consumption of lactose containing milk, food or other beverages, and does not result in a permanent damage.
In this case, the problem is the carbohydrate, not the protein. And it is not an allergy. Hence, consuming small amounts of lactose will not cause any problem to a majority of people who have lactose intolerance.
This means that yogurt consumption should be fine, low-lactose cheese will be fine, milk in your coffee or tea will be fine, a scoop of ice-cream will be fine, but if you take large amounts of milk or cheese or ice cream, you will get the symptoms. Lactose-free milk may be consumed without any problems.
Administration of the lactase enzyme prior to consumption of dairy will also help alleviate the symptoms. Consuming dairy with other food items also helps in improving tolerance.
To answer your question – milk protein allergy in the baby is not connected to lactose intolerance in the older age group, though both can run in families. They are two very different conditions.
For the allergy part, complete avoidance of the protein is important, while for the latter, dairy with less amounts of lactose can be consumed without a problem. Milk allergy in infants resolves with time, while lactose intolerance does not improve. Lactose intolerance allows the individual to consume dairy albeit within limits of tolerance of lactose intake.
Pankaj Vohra is a Pediatric Gastroenterologist at UNM. Please send your questions to firstname.lastname@example.org.