Here's an interesting thread about the relationship between the brain and the gastro intestinal tract. The gut–brain axis is now considered one of the key factors influencing human behaviours, emotions and health. Your thoughts affect your digestion, and vice versa.

Nineteenth-century doctors accorded stomachs & guts huge importance. Numerous books were published on gut health, aimed at both the public and practitioners. For many, the stomach was the most important of all organs, having a strong influence on physical & emotional well-being.

St. Bartholomew’s Hospital teacher, John Abernethy blamed all bodily & mental disorder on ‘gastric derangement’. He wrote two voluminous books on the subject just to emphasise how bad digestion could make a man go nuts or how a blow to the stomach could make a man lose his mind.

19th century docs associated the stomach with ‘morbid’ emotions, which if left unchecked, could lead to permanent bad temper. The stomachs of women were viewed as weak (as were women themselves) and likely to produce nervous trepidation, fear, ‘sinking’ & a fluttering heart.

In 1826, the Medico-chirurgical review stated that ‘there is no complaint more common in Britain than an imperfect stomach’. Twelve years later, the Dublin journal of medical science famously declared that ‘stomach diseases form the national malady of Britain.

In the 18th century, gastric distress had often been associated with the wealthy. Doctors saw dyspepsia as an outcome of sedentary lifestyles and over-thinking. In a sense, stomach problems were quite fashionable, a symbol of opulence and a lavish lifestyle.

One well-reported case involved Professor James M’Cullagh, a Prof of mathematics, who died in Dublin in 1847 from dyspepsia. His condition was blamed on melancholy, which originated from neglecting health & over-applying the mind to difficult mathematical problems. Maths kills.

Doctors typically depicted incidences of housewives gradually losing their appetite, slowly coming to loathe food and eventually finding solace in the tea cup. Ultimately, she began to suffer from dyspepsia before developing severe nervous & mental problems. Sounds familiar?

Excessive tea drinking was upheld as a major social problem. The government in Ireland was so concerned with rising asylum admissions that it set up an official inquiry. Doctors blamed rising levels of Irish insanity on widespread dyspepsia caused by excessive tea drinking!

"Excessive tea-drinking creates a generation of nervous, hysterical, discontented people, always complaining, scolding their neighbours and sighing. I suspect that over-much tea drinking is acting as a dangerous, revolutionary force amongst us." - Jean Bagnor, an administrator.

World War II experiences seemed to confirm the relationship between stress & stomach disorders. Soldiers at Dunkirk were reported as suffering from disproportionately high levels of perforating duodenal ulcers. Similar problems emerged in areas of London affected by air raids.

In PG Wodehouse's books, Bertie Wooster, who isn't an exceptionally bright lad by any stretch of imagination, comes across as a character with a rather fragile digestive dispensation.

Sylvester Graham might be the prototypical diet guru of today, save that he was born in 1794. Famous for preaching a regimen of abstention, he championed a vegetarian diet of fruits, vegetables, and whole grains well before the rise of modern biomedical science suggested the same

So the next time you order a double cheese burger with a large fizz drink, just consider that it may be the reason why you continuously fling expletives under your breath at your boss.