December 12, 2013
By Robert H. Shmerling M.D.
Beth Israel Deaconess Medical Center
The stomach is a source of many myths. I've written about the supposed connection between personality type and ulcers (there is actually none). And about how crunches will make your stomach smaller or help you lose your pot belly (neither is true).
But how about these?
- Thin people get full sooner because their stomachs are smaller.
- Eating less will shrink your stomach.
- Heartburn commonly leads to ulcers.
- If a person with heartburn doesn't take something for it, they'll digest their own stomach.
As with most myths, there are elements of truth to these. For example, the most commonly prescribed and effective medications for heartburn also treat ulcers. So, it's possible that a person who stops taking a heartburn medicine will develop ulcers. But even then, heartburn is not the cause.
Even so, each of these statements is false. Stomach size does not vary by weight and eating less won't shrink your stomach. Heartburn (a symptom of gastroesophageal reflux disease or GERD) and ulcer disease are separate conditions. And one does not commonly lead to the other.
Even the location of the stomach is a bit of a myth: It's not located just above the navel as many believe. The bulk of your stomach is actually tucked up under the left lower ribs and breastbone (which serve to protect it).
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Churn, Baby, Churn
The stomach is more than just a receptacle for food you've chewed and swallowed. The stomach takes in the food, mixes and churns it, breaking it into tiny particles within a gel-like lump called "chyme." The chyme is then released gradually into the small intestine. It's there that most digestion occurs.
How Not To Digest Yourself
If you're a stomach, you're bathing in acid. That could be a problem unless you have a way to neutralize the acid with food, and turn off acid production when the stomach is empty.
In fact, the stomach has several systems in place to avoid acid-related trouble. For example:
- The arrival of food in the stomach stretches it a bit. This stimulates acid production.
- Between meals food passes out of the stomach and arrives in the small intestine. This triggers the stomach cells to reduce acid production.
- Cells lining the stomach produce fluid containing bicarbonate (similar to baking soda) that neutralizes acid.
- The lining of your stomach is replaced every few days.
Years ago we thought that stomach ulcers resulted from excessive acid production caused by stress or having a "Type A personality." We now know that relatively few ulcers are due to excess acid. Most are due to an infection with bacteria (Helicobacter pylori) or because anti-inflammatory medicines (such as ibuprofen) are interfering with the stomach's defense systems. And heartburn is due to acid backing up into the lower esophagus. People can have heartburn and ulcers but, again, one doesn't necessarily lead to the other.
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Don't Try This at Home
All this talk about stomachs naturally brings up the subject of competitive eating. The key to eating 46 ears of corn in 12 minutes or 59 hot dogs (with buns!) in 10 minutes is suppressing the gag reflex and the stomach's reflex to regurgitate (vomit) when it is overfilled. This can be learned over time. Competitors also train in techniques such as dunking foods in water or breaking food into pieces before putting it in the mouth. These strategies allow for faster chewing and swallowing.
Some competitive eaters train by stretching out their stomachs. For example, they drink large quantities of water in a short period of time. But this can be risky. "Water intoxication" can develop, in which the electrolytes in the body are diluted to dangerously low levels.
No one would suggest that competitive eating is a healthy way to get the nutrition you need. But it does point out the remarkable adaptability and capacity of the human stomach.
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The Bottom Line
If you think about what you put your stomach through over a lifetime, it's amazing how well it does its job. It's central to our digestive tracts. And that makes it prone to misunderstanding.
Don't fall for medical myths about your stomach. For most of us, our stomach size doesn't change over time, ulcers aren't due to stress and heartburn, and, fortunately, most of us don't digest our own stomachs. Treat your stomach well. Your reward may last a lifetime.
Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.