if you’re lactose intolerant, why does the lactose cause bowel distress instead of passing through inertly?

Question

I get that lactase is needed to break it down into galactose and glucose, but why does the two monosaccharides’ glycocidic linkage cause so much pain and problems during digestion if it’s isn’t broken apart?

In: 104

Answer 1

In addition to fermentation, if the amount of unabsorbed lactose in the gut is high enough it raises the osmotic pressure, attracting water into the bowels, so water flows in and this influx of water is what leads to diarrhea.

That’s why for me if I eat like a meal with cream it just makes me gassy and my stool smell very sour, but if I drink like a glass of milk on an empty stomach I will have diarrhea within 30 minutes.