in lactose intolerance why cant lactose pass easily through the intestinal wall without lactose?

Question

without lactase, lactose remains unabsorbed, lactose cannot pass easily through the intestinal wall why? is it to do with water potential?

Answer 1

so far the answers are correct - lactase is needed to break lactose down to simple sugars. Lactose is a combination of 2 different sugar molecules. Your intestines are only able to absorb certain types of simple sugars - so anything else cannot be absorbed. Lactose isn't one of these simple sugars and must be broken down into (glucose and galactose) in order to be absorbed.

If you lack lactase, you can take the enzyme as a pill and it will break the lactose down - causing you to lactose tolerant again.

Answer 2

Lactase breaks down lactose. Anything with an -ase ending in biology is an enzyme (a protein that speeds up organic chemical reactions) and obviously lactase breaks down lactose.

Since it breaks it down it either becomes smaller in size or less reactive so passing through the intestional wall would become an easier process for lactose (or what it breaks down into) if the lactose-intolerant person had more lactase.

Answer 3

Absorption in the gut isn't down to water potential (if you've seen a colonoscopy, you'll know why), this only concerns absortion in the blood. Lactase breaks the lactose into smaller molecules which can then be easily absorbed.

Answer 4

If you are lactose intolerant, you do not have enough lactase, which breaks lactose into smaller, easily absorbed particles. Without lactase, lactose is not broken down so cannot be absorbed.

Answer 5

From what I remember the body needs salt and sugar (lactose is milk sugar). Without both the body cannot absorb liquids and they will pass right through the body.
I remember a story about kids in Africa dying of dehydration, they drank, milk and water but they still were dehydrated/ they finally realized that they needed to add salt to the milk or water for the body to absorb it.