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Ask Dr. K: Age-related changes affect GI tract

Thu., Aug. 28, 2014

DEAR DOCTOR K: As I’ve entered my 70s, I’ve noticed that my eating and bowel habits have changed. Is this normal?

DEAR READER: Well, I could tell you what it says in the medical textbooks, or I could speak from personal experience. The answer would be the same: It sure is normal.

Aging most definitely affects our eating and bowel habits. The human digestive system – our gastrointestinal tract, or “gut” – is a series of hollow organs linked to form a long, twisting tube. It begins at the mouth and winds down through the esophagus, stomach, small intestine and colon. These organs break down food into components that the body can absorb and use for energy. What’s left is expelled by an efficient disposal system. (I’ve put an illustration of the GI tract on my website,

Here are some age-related changes you may have noticed:

The mouth. As we age, the number and sensitivity of our taste buds decline. Our chewing muscles also weaken and we begin to lose teeth.

The esophagus. Food does not simply drop down the esophagus; it is pushed down by coordinated contractions of the muscles in the esophagus wall.

Muscles at the bottom of the esophagus, where it enters the stomach, normally squeeze down hard after food passes through. This keeps stomach acid from squirting back up into the esophagus. When those muscles become weaker with age, it can contribute to acid reflux.

The stomach and small intestine. As we age, the stomach produces less acid. This doesn’t usually interfere with digestion. And it may make acid reflux and “heartburn” less of a problem.

But lower levels of stomach acid can lead to vitamin B12 deficiency. That’s because stomach acid helps the small intestine absorb vitamin B12 in food.

The colon. Just as happens in the esophagus, muscles in the wall of the colon squeeze the waste downward. In general, people have more trouble having regular bowel movements after they reach age 65. Weakness and poor coordination of the muscles of the colon are a major reason for this.


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