Dr John Wright



Dan Brown, The Lost Symbol and Gastroenterology

Dr John P Wright
Updated: 8 October 2009

Having just finished Mr. Brown’s latest, but probably not greatest, tome I was struck by the role of perception in the character’s response to the symptoms presented to them. As a generalization one could say that humans are a superstitious lot of lost souls. Optimists however would say that we all have a built in awareness of the “other” and one day we will all be able to move mountains by thought alone. I will probably miss that day but remain hopeful.

The gastrointestinal tract is imbued with many roles and functions which are often outside of the day to day practice of gastroenterology. Patients try to relate their symptoms to their perceptions of their inner functions. We try to relate symptoms to our understanding of the patho-physiology. Both approaches are open to misinterpretation.


Feeling hungry and eating may have survival advantages but is seldom an appropriate response in our fat society. Why do we do it? Like most biological functions, it makes us feel better. After all we know that true happiness comes from the filling and emptying of our tubes. A dictum that unfortunately reduces us to the level of the machines that we are.

Hunger may be appropriate if our body stores are in need of replenishment but often we eat for pleasure even if we do not really like what we are eating. This is a strange habit.

Hunger may indicate peptic, typically duodenal, ulceration. Conversely functional dyspepsia, where there is no organic disease, is often suggested by early satiety and loss of appetite. In the end hunger is likely to be a psychological need in many of us whereas in the truly hungry it reflects the ineptitude of our politicians.


Patients seldom recognize that belching follows the swallowing of air. Typically patients believe that the belchate is from their stomachs, due possibly to fermentation or gassy foods. These beliefs are seldom true except when severe gastric outlet obstruction is present. Gassy carbonated drinks contain carbon dioxide. This gas is rapidly absorbed by the gut so although it may cause short term belching, does not cause bloating or increased flatus.

The fact is that excessive swallowing of air and belching is associated with oesophageal irritation related to acid reflux or aerophagia. The latter is associated with anxiety often seen in public speakers who quell the eructation with an elegant sip of bottled water or pause, flex their necks and swallow before continuing. President Bush was a good example of the latter.


Bloating is always perceived by patients as a gas buildup in the stomach or bowel. The former is a feeling associated with lack of normal dilatation of the stomach with eating. This is normally felt as early satiety and associated with anxiety.

Abdominal bloating due to gas is a false perception. Abdominal X rays reveal that bloated patients do not have increased gas in their bowels. They have downwards movement of the diaphragm and relaxation of the abdominal muscles. This then causes the abdomen to bloat. This primitive reflex is in response to intestinal cramps even if the patient is not aware of them.

Normally bloating is associated with the gradual build up of stress during the day and spasm of the bowel which triggers the reflex. In some patients “instant” bloating sans gas build up is the result of spasm set off by a glass of cold water or sudden stress.

Extra swallowed air with stress can trigger the reflex in the bowel but this is usually accompanied by a need to pass stool plus volumes of gas at the end of a stressful day.


The passing of flatus by boys in grade 7 is associated with merriment and envy. Young girls of all ages are acutely embarrassed whereas more senior ladies sometimes view it as a sign of maturity and independence. Men do it naturally. Dogs do it to protect their owners from embarrassment.

There are three main reasons why we pass flatus. Firstly we have followed consumer advice and eaten broccoli or cauliflower for their anti-oxidant value rather than a glass of red wine. Secondly we have stool in our rectums and need to pass it but ignore the warning. It is one of our bodies special skills that our rectums can differentiate gas from stool and tell us which is about to emerge. Thirdly our colons may be loaded with stool so excess gas is made by our colonic bacteria even if we pass stool once a day and do not view ourselves as constipated. It remains a human perception that two or more stools a day are a privilege and not a right. Those with multiple defaecations seldom if ever pass orphan flatus between sittings.


While discussing intestinal movement, borborygmi or heard bowel sounds are a result of excessive bowel activity and acute hearing. Anxiety and a silent meeting seem to bring this intestinal sabotage into the hearing range of all present. This may be a disaster because no one takes someone with a growling stomach seriously.


A final false perception is that simple diarrhea causes weight loss. Many a young girl has taken laxatives to secure the sylph like appearance that is so desired but dehydration and electrolyte depletion is the likely result from loss of colonic contents. Most food is absorbed in the first 50 cm of small bowel so calorie absorption is essentially unchanged.

As a final thought Mr. Brown’s book repeats the discovery that we live in a world of 11 dimensions. (Unfortunately he mentions 10 in a typo). The three dimensions of vertical, horizontal and depth are commonly understood. Time is less easy to understand. There are 7 other dimensions around as. These are still elusive but apparently co-exist alongside us. One day when we belch, fart or have growling guts we may be able to slip into another dimension where these functions are considered normal.