Even more intriguingly, nerve cells in the colons of Parkinson's sufferers who are constipated contain structural abnormalities known as Lewy bodies, which are a hallmark of the affected brain tissue in people with Parkinson's.
The reason a colonoscopy is recommended for those over 50 is because, with age, we are more likely to have these pre-cancerous polyps in our colons just as we are more likely to find pre-cancerous growths on our skin.