system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 - Why does untreated diabetes cause parts of limbs to die?
gpt
Your cells need blood/oxygen to survive.

Uncontrolled diabetes/ high blood sugar causes blood vessels to thicken.

Big blood vessels can still have blood going through them. But the problem arises when smaller blood vessels thicken because there won't be blood flowing through. When no blood reaches a said organ, it dies

If the blood vessels in your feet thickens, your feet dies. When blood vessels in your heart thickens, you get a heart attack. When the blood vessels in your brain thickens, you get a stroke. So on and so forth.

That's why diabetes increases mortality because it affects literally every organ.