Q And A Clearinghouse
1st Quarter, 1999
Updated April 1, 1999
This page answers the
questions that arrived in the first quarter of 1999.
Send your questions to me, Steve Carper, at SteveCarper@CS.com.
Remember, I personally answer all questions that you send me, no
matter what. The ones that are of sufficiently general interest
get posted here, where I hope they can do the most good.
If you don't spot your question here, be sure to check my
Q and A Quick Finder Index.
Q. a) Do eggs contain lactose?
b) When I drink beer, I have some
of the same symptoms as when I drink
milk. Is there some sort of dairy
product in beer?
Q. I have heard that black males
experience LI at a much higher rate than white males.
Is this true, and if so why?
This is a yes and no thing. In general, the only peoples in
the world who are _not_ lactose intolerance are northern
Europeans (or descended from people originally from northern
Europe). All others are.
The brief explanation is that the first farmers to arrive
in northern Europe about 10,000 years ago lacked a good way
of getting and processing calcium in their bodies. Those who
could drink milk had a slight reproductive advantage over
those who couldn't. (Women were more likely to survive
childbirth, men were more likely to be healthy enough to
father healthy babies.) The northern Europeans happened to
be the ones who colonized America, so most people grew up
thinking that the ability to drink milk was normal. Africans,
as well as Asians and Native Americans, either had other
sources of calcium, or could use the abundant sunlight to
manufacture vitamin D in their bodies to help them process
the calcium, so they didn't need to adapt to milk drinking.
The situation is far more complicated than I can describe
here, of course. There are African peoples who because of
local conditions had the same dilemma as the Scandinavians
and solved it the same way, by natural selection favoring
those who drink milk. There is nothing about skin color
that inherently determines whether you are LI or not.
It's all a function of what your ancestors ate 10,000 years ago.
Q. Have you heard of a
dairy allergy with no other symptoms at all, except a
badly upset stomach?
Yes. There are two types of allergy. A "true" allergy is
mediated by one particular antibody. All the others, or
hypersensitivities, are mediated by other antibodies.
Hypersensitivities to milk in children are likely to
manifest themselves as gastrointestinal problems rather
than as classic respiratory and skin problems. So it
could be a reaction to the dairy protein rather than
to the milk sugar. Your doctor should be able to test for this.
Q. Can wheezing and a
stubborn dry cough be a symptom of lactose intolerance?
Not a chance. It's barely possible that the wheezing could be
due to a dairy allergy (some people beleive that a dairy
allergy can cause _any_ symptom), but that would really
be reaching. Sometimes a cough is just a cough. If it lasts
and lasts, see your doctor.
Q. What is whey? I heard it was
the byproduct or waste water from cottage cheese. I've noticed that cookies
or items with whey seem to bother me more than others.
Milk separates into lactose (milk sugar), whey proteins, casein proteins, water,
fat, and a few vitamins and minerals. Most cheeses, not just cottage and other soft
cheeses, are predominantly hardened casein. The remaining liquid is known
as whey. It has some of the milk's proteins and almost all of the sugar.
Commercial bakers love whey because it is indeed a cheap waste product,
but one that gives a product many of the same nutritional and taste benefits
of whole milk. Most commercial whey is dried, meaning that it is roughly
50-75% pure lactose and the rest mostly whey protein. If you are lactose
intolerant, whey is one of the worst ingredients to encounter on a label.
Most allergies seem to be to casein, but many people are allergic to the
whey proteins as well. And of course, since the majority of the world's
population is LI, by sheer chance many of them have protein allergies as
well. It's not clear which is your problem, but you should avoid whey on
a package label.
SuperGuide to Dairy Products for more info on dairy.
Q. If my wife is pregnant
with a child with lactose intolerance, how dangerous can it be?
For your wife, not at all. There is absolutely no danger
to the pregnant mother at any time, in any way.
As for the child, the only possible problem would be in the extremely
rare case that the baby could not digest milk at all. Those babies
will not thrive, and must be put onto a soy (or other non-dairy)
formula immediately after birth to prevent starvation and dehydration.
This is so incredibly rare, however, that most doctors have never seen
a case. For all other babies, absolutely nothing would happen.
All humans, just like all mammals, are genetically programmed to
be able to drink their mother's milk. Human milk happens to be
highest in lactose of all milks, about 7%. But all babies, even
those who will become LI later in life, can drink it just fine.
Q. Why does the lactase
that is in me when I am born, decrease when I grow older?
Here's what one researcher had to say:
"Speculation as to why the lactose gene 'turns off' is a fascinating
topic. One theory suggests that lactase deficiency evolved early in
mammalian history, perhaps 75 million years ago, as a means to
facilitate weaning and shorten the dependence of the child on
the parent for lactation. The gas and diarrhea produced by lactose
malabsorption would stimulate the child to become weaned. One
competing theory suggests that lactose malabsorption in adults
prevents competition of adults with infants for food (who can
only digest milk early in life), and another theory proposes
that lactose intolerance evolved as a defense mechanism against
In other words, nobody knows for sure.
Q. My 80-year-old mother
has been diagnosed as being LI. I've heard that it was
unusual to have this happen so late in life. What
do you know about this?
It is unusual, but hardly unknown. Different people are
genetically programmed to lose their ability to make
lactase at different ages, that's all. (Unless she had some
sort of intestinal disease or surgery that might have
damaged her intestines. That can cause LI at any age.)