22. May, 2018

Does stress really cause stomach ulcers?

Back in late 2005, a couple of Aussies received the Nobel Prize in Physiology or Medicine. Their names are Barry James Marshall, a doctor and microbiologist, and John Robin Warren, a pathologist. Their discovery was that "The bacterium Helicobacter pylori (H. pylori) and its role in gastritis and peptic ulcer disease". 

Gastritis is inflammation of the stomach, and we now know that ulceration of the stomach or duodenum is the result of an infection of the stomach by H. pylori in 80-90% of cases, which can be permanently cured with a simple course of antibiotics. 

Why did it take so long to discover the real culprit?

Ulcers could temporarily be healed by inhibiting acid production, so we had a short term fix that worked. I guess we had bigger fish to fry, particulary the >200 different cancers that plague our species, I would imagine.

What type of bacteria is H. pylori, and what does it do?

It is a spiral-shaped Gram-negative type that is found in around half of all human stomachs. Interestingly it is not found in any other animal. It colonises the antrum, which is the lower part of the stomach, where it causes inflammation of the gastric mucosa (see image). Most people don't have any symptoms, but around 10 to 15% of those infected will go on to develop an ulcer. 

Are there other causes of ulcers? 

Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and aspirin, can also cause ulcers, because they too weaken the lining. 

Persistent myths about ulcers include: 

  1. There's no cure
  2. Eat only white foods (potatoes, milk, rice)
  3. They only happen in your stomach
  1. Spicy foods are a cause
  1. Stress and anxiety are a cause
  1. Stomach acid is a cause 

Number 5 is particularly interesting, because the ulcer almost certainly causes people stress and anxiety due of the amount of pain they're in, but it's not the cause of the ulcer. It is another example of how our observations can lead us to the wrong conclusions. 

That's the beauty of scientific research.

We find correlations, which is simply connections between things, through observational studies. This hopefully leads us to the next step in our process, which is to discover causation (exactly how this connection occurs). 

Are myths at all useful? 

Our predecessors made numerous such observations, and we are still working our way through some of those, research funding allowing of course. Call them old wives tales or urban legends, although most of the cause and 'natural healing' claims have little to no scientific basis, there is often helpful information in there worth investigating,  particularly the signs (what we can see) and symptoms (what the patient experiences). 

References 

Canadian Society of Intestinal Research 2005, Nobel Prize for H. pylori Discovery, <https://www.badgut.org/information-centre/a-z-digestive-topics/nobel-prize-for-h-pylori-discovery/>

CDC 2006, Helicobacter pylori and Peptic Ulcer Disease, <https://www.cdc.gov/ulcer/history.htm