Researchers in Hawaii monitored the bowel movements of 6790 men from 1971 to 1974, then continued to monitor them for another 24 years to observe which ones developed Parkinson’s.

They found that men who had difficulty producing one bowel movement a day had a 2.7-fold increased risk of developing Parkinson’s disease compared with men who had one movement per day. This rose to a 4.1-fold increase compared with men reporting two bowel movements daily.

The risk was independent of other factors, such as age, cigarette smoking, coffee consumption, diet, exercise and laxative use. The researchers noted the presence of Lewy bodies - the primary central nervous system neuropathological finding in Parkinson’s patients - in both the oesophagus and colon (Neurology, 2001; 57: 456-62).

* More links between the gut and disease were found in a study revealing that non-Hodgkin’s lymphoma is the leading cause of death among coeliacs. Italian researchers found that gluten-intolerant individuals have twice the risk of dying from the disease as those who are not gluten-intolerant, including their own relatives. The risk was highest in those with malabsorption symptoms, but not significant in those who had minor symptoms (Lancet, 2001; 358: 356-61).