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

Two fold: Even though you can’t digest lactose and turn it into energy or fat stores, the bacteria living in your colon can and break those carbon chemical bonds. This provides energy to the bacteria those causes that carbon to bond with oxygen and form CO2. The excess CO2 causes pain, flatulence and bloating.
Second, sugar is osmotically active meaning that is draws water to itself, causing diarrhea.

Therefore, Lactose intolerance commonly leads to a combination of pain, bloating, flatulence and diarrhea.