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What heartburn and IBS have in common

Reviewed by Dr. Sarika Arora, MD

It’s one thing to have the occasional bout of heartburn or acid reflux. But if you’re finding yourself reaching for antacid medications on a regular basis, or being awakened in the night with a burning sensation in your chest, it may be time to look at your overall gut health for a larger GI tract problem, such as irritable bowel syndrome (IBS).

woman holding chest with heartburn

Even though the esophagus and the intestines are at opposite ends of the GI tract, many women who have IBS also have upper GI symptoms such as heartburn, reflux, “sour stomach” or nausea. And the reason is pretty simple: Much of the time, the distressing symptoms in the upper and lower GI tracts relate to problems in the middle — your stomach.

What causes acid reflux?

Acid reflux is often related to how the stomach processes food and empties itself. The stomach breaks food down using a combination of chemicals — acids and various enzymes — and motion, kind of like a washing machine agitates clothes through soapy water to get them clean. But just like how there are some types of stains that even the best machine can’t clear away, there are some kinds of foods that aren’t as easy to break down in your stomach.

Foods that are high in fat — think pizza — can be difficult to digest, which causes more “agitation” work for the stomach as well as slower emptying. Both may stimulate higher production of acid than is normal. That acid, sloshing into the esophagus, is one cause of heartburn. Heartburn often isn’t the only problem. Since food may not have been fully broken down by the stomach, the intestines receive a larger proportion of undigested food that can trigger uncomfortable symptoms like gas, cramps or diarrhea.

4 factors that contribute to acid reflux and IBS

There’s no one-size-fits-all cause for GI problems. Other factors that can contribute to both reflux and IBS are:

1. Low acid production. People sometimes produce less acid than is needed to process their food — disorders that are called hypochlorhydria (too little acid production) and achlorhydria (no acid production). This is often related to nutrient deficiencies or infection by the bacterium that causes ulcers, Helicobacter pylori.

Low acid production may be temporary, but it can also become a self-sustaining situation, particularly if symptoms such as reflux and diarrhea prompt the use of antacids and other medications in an effort to relieve chronic symptoms (we’ll talk about that more in a minute).

It’s a myth that drinking too much water with meals dilutes your stomach acid and causes hypochlorhydria. The stomach is able to sense when its pH becomes too low and produces more acid to compensate. If you’re drinking a lot of water with meals and you suffer from reflux, you may want to cut back even so — because you could be inadvertently encouraging greater acid production than is healthy!

2. Eating too fast, too much, or both. Many of us are in a hurry when we eat. If you’ve ever been working or traveling and said, “I need to get some food in my stomach before I…”, you know how this works. But digestion doesn’t start in the stomach, it starts in the mouth. Enzymes in saliva and the crushing and swishing motions of our teeth and tongue are what begins food breakdown. If we bypass this “pre-stomach” of ours by “wolfing” our food, we lose a major contributor to digestion. That means the stomach has to work harder. And often that means producing more acid.

The same is true when we overeat — which we’ve all done at some point! Putting too much food into the stomach all at once stretches the walls of the stomach and reduces its ability to churn the food around, which affects its ability to break food down effectively so it has to work harder. Not only that, but if we overeat on a regular basis, the opening between the esophagus and the stomach can become stretched and lose its elasticity. This allows more acid to move upward into the esophagus to cause heartburn. What’s more, acid that escapes the stomach isn’t doing its job on the food itself.

3. Enzyme deficiencies and allergies. Hard-to-digest fatty foods aren’t the only culprit, and many otherwise healthy foods can also cause problems. If you’re lactose intolerant, for example, you get GI upset from anything containing milk because you lack a key enzyme, lactase, to help break down milk sugars. Or maybe it’s beans and broccoli that give you trouble because you don’t produce enough galactosidase. It doesn’t have to involve an enzyme deficiency, though — a food allergy will cause similar troubles. Gluten is one common allergen. The body’s intolerance can even manifest as celiac disease, which is a serious autoimmune response triggered by eating gluten. There are also many foods that can cause gastrointestinal upset in a person with a mild or moderate allergy: eggs, fish or shellfish, nuts and legumes (beans and peanuts).

4. Too much fiber all at once. Yes, fiber is good for you. But too much of a good thing can have unintended results. If you eat a large meal high in both soluble and insoluble fiber, it could be more than your GI tract can handle, resulting in uncomfortable symptoms.

Do antacids help?

Certain types of antacids may help reduce symptoms in the short term. Unfortunately, like many medications, they don’t alter the root causes — and without that, their benefits may not last very long. Worse, if part of the issue you’re facing relates to acid production — hypochlorhydria — you may unwittingly increase or prolong your troubles by using medications that suppress acid in your stomach.

There are also some significant and concerning problems associated with long-term use of some common antacid medications in the proton pump inhibitor class (think Nexium or Prilosec). They range from deficiencies in important nutrients such as iron, magnesium and vitamin B-12, to bone fragility and osteoporosis, to susceptibility to infections in the GI tract, likely because they suppress the gut’s natural flora.

Using antacids may help for a few hours, but in the long run they generally make things worse. For this reason, we strongly recommend you avoid using such medications over-the-counter for more than occasional heartburn symptoms. Of course, if you are currently taking a prescription medication for heartburn, don’t stop without getting advice from your primary care provider first!

If not antacids, then what?

We always advocate seeking out the root causes of health issues so you can stop them at their source. One way is to identify whether certain foods are triggering GI symptoms by keeping a food/ symptom diary to see if symptoms happen when you eat specific foods. Or you can eliminate a specific food that you know causes trouble for a week or two, and see if your symptoms subside without using antacids. Supporting healthy GI flora with a probiotic and a balanced multivitamin can also help reduce GI symptoms, particularly if you’ve already been using antacids and find them becoming less and less effective.

If you experience symptoms primarily at night, when you’re lying down, it could be a sign that your esophagus has become over-stretched. Try using a wedge pillow that will support your upper body at an angle instead of lying flat, so that any acids that may slosh out of your stomach drain back down into it rather than staying in your esophagus. It can also be helpful to eat earlier — many of those with chronic acid reflux find that an early dinner (5 to 6 PM) results in fewer nighttime symptoms than a later one.


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Last Updated: July 5, 2021
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