Ramen

I had an argument with someone at work that it is more odd for someone to be able to digest dairy products as an adult and not odd for someone to be unable to digest dairy as an adult. My reasoning was that milk was meant as a food for babies (human or other mammals). My friend from work gave me some argument about hops and beer, which I said was not analogous since the specific purpose of milk is to feed babies. No other animal would drink milk as an adult unless they are feeding on milk given to them by humans or taken from humans.

So is it "normal" for an adult to have the ability to digest dairy products or is it "normal" for an adult to be lactose intolerant?

Undercurrent

It depends. Normalcy is defined by majority. Among mammals, it is very wierd. Among western european human populations, not really.

Just another one of those beneficial mutations that never, ever, ever happen.

Roland98

Indeed. You'll see that those of European descent are some of the few mammals that are able to digest lactose. Among Asians, for example, on the order of 95% of adults are intolerant to lactose. On the whole, it is indeed not "normal."

anthrosciguy

Of course, using that criteria for "normal", a whole lot of things aren't "normal". Being six feet tall, for instance. Or Canadian.

Undercurrent

Maybe not normal, but those six-foot-tall Canadians have got to be the sexiest people on the planet. Especially those six-foot-tall Canadian vegetarian mathematicians.

Jet Black

well we non-lactose intolerant people have an enzyme that can digest lactose. It is nothing to do with being a baby or not. I knew a girl who was lactose intolerant and her family bought a goat, because she could not drink cows milk. I think that one suggestion for this is that Europeans domesticated cows for milk before anyone else did, and hence the people who were selected for were the people with the lactase (at a guess) gene. Alternatively people in the East might have always heated their milk before they drank it, breaking down the lactose (like my girlfriend does, she is chinese)

my main point for contributing to this thread was this: Under no circumstances must you ever feed cheese to a lactose intolerant volcano god.

Walross

Well, both are pretty normal around here .

Guitar Dog

Being lactose intolerant myself I've learned a bit about it.

here are some web sites:
http://lactoseintolerant.org/
http://www.lactose.co.uk/
http://my.webmd.com/content/article/18/1689_51849
http://www.research.medsch.ucla.edu/...FacultyKey=422



The gene that codes for lactase is usually switched off as you age, the mutation keeps it on.

I think lactase activity typically declines after childhood for most people anyway.

The default is to be lactose intolerant as an adult, certain populations have evolved to digest lactase as an adult, that is the new allele- the switch keeping the lactase enzyme production turned on.

here is the abstract if you are curious:
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

Yangja Isuko

i'm a mutant. where's senator kelly?

Shake

My mother was lactose intolerant for several years and then it went away!

I also have a co-worker who claims that lactose intolerance can be brought on by (certain) antibiotics* which wipe out all kinds of enzymes in your stomach. He further claims that this sort of thing can be cured by eating plain (non-homogenized maybe?) yogurt which puts back some of the good enzymes that allow you to process dairy.

*I'm pulling this from memory, so it may have been some other type of drug, but antibiotics stick out in my mind for some reason