Doctors can observe how we swallow food by performing a Barium Swallow test.
A drink containing mildly radio-active Barium is administered. Standing in front of an X-ray scanner, you drink the liquid and the scanner watches its progress through the oesophagus. Normal transit would be about 5 seconds but if there is poor peristalsis or nutcracker oesophagus, the liquid may take longer or even flow backwards at some stage. A Barium Swallow will also reveal existence of any oesophageal pouches where the liquid pools.
A Barium Meal is administered to look at the efficiency of the stomach to empty. It is administered lying down with the X-ray scanner monitoring the stomach.
In a recent paper published in Gastroenterology and Endoscopy news in September 2015, researchers at Nottingham University Hospital question the necessity of performing a Barium test declaring an endoscopy to be a better diagnostic procedure whereby detection of cancer (if present) could be dealt with immediately. [t-iv]