Answers to Questions from Readers, part 9

Q. Do you think taking lactase artificially in tablet form would induce the body's natural mechanism to decrease its natural production. In other words do I become dependent on this tablet forever?

There is no evidence that using (or not using) lactase tablets has any effect whatsoever on the body's natural supply of lactase. For most people, the lactase-making ability declines with age. Nothing is known that will slow it down; nothing (other than actual damage to the intestines) is known that will speed it up.

You may need to use lactase tablets forever, but that is only because your natural amount of lactase will be forever insufficient.

Q. What mutations if any cause lactose intolerance and what chromosome are they on?

Sorry, you have it the wrong way around. No mutations cause LI. LI is the normal state of humanity. It is the ability to continue to produce the enzyme lactase all one's life that is the mutation. The gene is on chromosome 2.

Q. I may need to soon begin taking a medicine that contains lactose. Would this be a problem for my son since it is dairy? Or maybe not because breast milk already has lactose?

If your son can tolerate your breast milk, he should be able to tolerate anything you eat containing lactose. Lactose does not travel to breast milk in any case; it's only the milk proteins (which are not found in pills) that you have to worry about.

And the amount of lactose in any given pill is so small that only a tiny few exceptionally sensitive people ever react. However, a lactase tablet will help even those.

Q. Does being allergic to mother's milk necessarily mean being allergic to cow milk? What's the best way to tell if a 5 month old is allergic?

As far as I know, no infants are ever allergic to mother's milk itself. The allergy is to something in the milk. It is possible, if the mother is drinking cow's milk, for some of the proteins to filter through into the milk. The cow's milk itself is the true culprit. Of course, some other contaminant may be to blame, anything from corn to onions or about a zillion others.

The way to tell if an infant is allergic depends very much on the specifics of the allergy. However, in many cases an allergic infant will react with a rash or welt if you simply put a few drops of milk on an arm. In other cases, you will have to notice a pattern of reactions to drinking the milk itself. If you're really concerned, a formal allergy test can be done.

Q. Do lactose intolerant people get their reactions with an hour of eating the food that they are intolerant to or are the cramping and diarrhea a much longer-delayed reaction?

I wish I could give you a better answer, but I'm stuck with "it depends." Some people seem to feel the effects right away. At other times, and in other people, it can be delayed several hours.

However, if you regularly have cramping and diarrhea an hour after every meal with lactose and not after meals that have none, then I'd have to say lactose intolerance is a good bet. In any case, I'm glad you're seeing your doctor. There is a very accurate test for lactose intolerance that your doctor can arrange. Of course, most doctors will try to rule out the more serious diseases with similar symptoms first, so don't be surprised if you're asked to take other tests in the beginning.