9 Amazing, Weird Facts About Your Gut

Your digestive tract plays a key role in your health
magnifying glass looking microbes in intestines

By Bret Lashner, MD

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As long as everything is working well, you probably don’t give much thought to your digestive system and its main component, your digestive tract, or gut. But it can get your attention fast when something goes amiss.

From beginning to end, your gut plays a key role in your health and it’s the source of many unexpected and fascinating tidbits of human biology.

For instance, you’ve likely heard that your small intestine is surprisingly long. But did you know that if you unraveled and spread it out, it would cover a tennis court (that’s 2,800 square feet)? Such a tremendous area is needed to efficiently absorb nutrients from your diet!

And that’s just one of the more well-known examples. Let’s look at nine other fascinating facts about your gut.

1. The acid in your stomach is strong enough to burn your skin

So, why doesn’t it burn your stomach? Because a thick layer of mucus protects your stomach lining and keeps the acid on the inside, where it’s churned with your food.

When gastric acid sometimes leaks up into your esophagus, which lacks this mucus layer, you know that burning feeling as heartburn. Proton pump inhibitors are drugs you can take to temporarily reduce acid production and allow your esophagus to heal.

2. Certain bacteria and drugs can cause ulcers

We used to think that stress caused sores in your stomach that don’t heal. We now know that prolonged use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen (Motrin®, Advil®) or naproxen (Aleve®), can interfere with stomach mucus.

Ulcers result when stomach acid reaches the lining, and when they bleed, they can cause pain and even be life-threatening.

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A bacterium called Helicobacter pylori, or H. pylori, also can cause ulcers. An Australian doctor proved this by drinking the bacteria himself, and he and his colleague won a Nobel prize for the discovery. 

3. Stomach cancer was No. 1 in the 1940s, now it’s No. 8

We’re seeing a lower incidence of gastric cancer these days, partly because our diet contains fewer foods that cause cancer (as refrigeration became widespread, we ate fewer smoked and cured meats).

We now also know that H. pylori can cause stomach cancer, but H. pylori is relatively easy to diagnose and treat.

4. You have detergents in your intestines

Bile acids are the detergents in bile, the digestive liquid made by the liver. Without these detergents, you couldn’t digest or absorb fats. And just like dish detergent, they make fat mix well with water, and only then can digestive enzymes break down the fat for absorption into your bloodstream.

5. Cholesterol and fats are completely different

Your liver uses cholesterol to make bile acids, and bile is the only way your body can get rid of excess cholesterol.

Your body also uses cholesterol to make sex hormones, like estrogen and testosterone. If you have liver disease, you’ll have trouble absorbing fats, as well as hormonal issues.

But fats are chemically different from cholesterol; the body burns fats for energy. That’s why food labels list fat and cholesterol separately.

6. Most people with ‘gluten intolerance’ don’t have celiac disease

Celiac disease occurs when gluten (a protein in wheat, barley and rye) causes your immune system to damage your small intestine. Symptoms include abdominal pain and bloating, chronic diarrhea and fatigue.

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Two types of genetic changes that occur in about 2% of the population cause true celiac disease, and your doctor can order tests that identify it.

Many people who claim they’re gluten-intolerant don’t have this diagnosis, but they still may feel better on a low-gluten or gluten-free diet. The reason you may feel better or lose unwanted weight is that this restrictive diet is low in carbohydrates. In fact, eating a low-carb diet is the best and safest way to lose unwanted weight.

7. It’s unlikely that probiotic supplements will help your gut

Your digestive tract contains many beneficial bacteria, but taking a probiotic supplement (live or dried bacteria) is unlikely to give them a boost.

The reason is that these beneficial bacteria are mostly in your large intestine, or bowel. Probiotic supplements will rarely survive the acid and churning of the stomach or the detergents and enzymes of the small intestine. 

8. Prebiotics are better

If you want to boost the bacteria in your bowel, eat a high-fiber diet or take fiber supplements. Fiber is a prebiotic that the bacteria can convert to healthy chemicals for nourishment (that can also help prevent colon cancer).

9. Fecal transplants are ancient medicine made modern

Fecal microbiota transplantation is a method of restoring beneficial bacteria in your colon. The only approved use for fecal transplantation is for someone infected with Clostridiodes difficile (or C. diff) that’s unresponsive to antibiotics. The procedure involves a colonoscopy and transplants feces from a healthy person into a sick person.

In the U.S., doctors completed the first fecal transplants for C. diff infections in 1958. But the practice dates back to 4th century China, where they used a fecal suspension called “yellow soup” to treat digestive problems.

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