To test whether an allergy to cow's milk was causing
chronic constipation (defined as one bowel movement every
3 to 15 days) in a group of Italian children, the children
received only either cow's milk or soy milk for a two week period
using a double-blind study approach. The children in the study
were all under 6 years old. Those with other
known problems were eliminated. The
study was repeated, with a future cow's milk challenge. The children had
to have at least 8 bowel movements to be considered to have had a response.
There were 65 children, split as evenly as possible into the two groups.
In the first study, 21 of the soy milk children and none of the cow's milk
children had a response. In the second study, 23 of the soy milk children
and again none of the cow's milk children had a response. In addition,
their anal fissures and pain upon defecation also disappeared.
When challenged with cow's milk later, every child developed hard
stools and discomfort after 5 to 10 days on the diet.
First, I need to emphasize one thing: this is a study of milk
allergy not lactose intolerance (LI). You are not likely to
have constipation as a symptom of LI, no matter what your age.
The causes of chronic constipation in children are not very well
known. Doctors have often thought that the problem is psychological,
even though modern research usually shows that the psychological
problems, not unreasonably, are the result rather than the
cause of the constipation. Still, few people would have thought
that cow's milk would be a major cause.
The children in this study were all veterans of doctors and clinics.
They had all been given laxatives with no success. Most had developed
anal fissures and other problems. For two-thirds of them to suddenly
show dramatic improvement is astounding. For all of them to go
back to being constipated when given cow's milk again is equally
dramatic. Seldom do you ever see such clear-cut, one-way results
in a medical study. And this study is a follow-up to an earlier
one by the same group of doctors
("Chronic constipation as a symptom of cow's milk allergy,"
J. Pediatrics, 1995, vol. 126, pp. 34-9) with similar results.
Constipation is a widespread problem, with it affecting
from one-fifth to one-third of young children. Only about one
in 20 children have it as a long-term problem, however. Short-term
constipation can be treated with laxatives.
Serious, long-term constipation needs a better solution. I would
advise parents whose children are suffering in this way to
immediately talk to your pediatrician about taking cow's milk
out of their diets.
I would caution you, however, to remember that while this study
confirms the results of other studies, these are still very
preliminary findings. The children included can't be considered
representative of the general population. However, taking a
child off of cow's milk is so easy, and so much easier on the child
than using drugs and medications, that you should consider it
for any child with severe, chronic constipation.
And in fact, some other researchers cast great doubt on these
findings, in a later issue of the NEJM. See this
NEJM letter for a negative review.