Is Your GERD Due to Gut Bacteria?

At first glance, it does not seem to make any sense that there would be a connection between heartburn and gut bacteria. How could something downstream (the intestines) have anything to do with anything upstream (heartburn)? However, there is an intriguing theory that connects the two. Let's take a look.

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Small Intestine Bacterial Overgrowth

In his book "Fast Tract Digestion," Norman Robillard, Ph.D., makes a case that small intestine bacterial overgrowth (SIBO) may be the real cause of gastroesophageal reflux disease (GERD).

SIBO is a health condition in which there are too many bacteria in the upper part of the small intestine, a place where these microorganisms really shouldn't be. GERD is a disease in which stomach acid burns the lining of the esophagus (acid reflux), causing the symptoms of heartburn.

How might these two be connected? Dr. Robillard's theory is that the gas produced by the bacteria residing in the small intestine puts enough pressure on the small intestine and stomach that it can push the acid from the stomach into the esophagus.

In addition to identifying a new way to look at the cause of GERD, Dr. Robillard also offers a new look at treatment. He does not endorse the use of acid-reducing medications, particularly the use of proton pump inhibitors (PPIs), which is currently the standard treatment for GERD.

His theory is that the reduced stomach acid resulting from PPIs contributes to the bacterial overgrowth in the small intestine in the first place, as stomach acid serves a preventative role in terms of keeping bacteria from populating the small intestine.

What Dr. Robillard recommends is that GERD patients follow a diet that is low in what he calls "difficult to digest" carbohydrates. It is his belief that a diet high in these carbohydrates contributes to both the overgrowth of these bacteria and the increased gas output that is directly causing reflux.

Interestingly, his list of carbohydrates to avoid is very similar to those of the low-FODMAP diet for IBS. A crucial difference is those foods that are high in resistant starch, such as unripe bananas and corn, which are encouraged on the low-FODMAP diet but discouraged by Dr. Robillard in terms of treating GERD.

The Science Behind the Theory

Although the theory is compelling, there is not yet a lot of research to support it.

One small study involved having GERD patients swallow a solution of either fructooligosaccharides (FOS) or placebo after meals for one week each. FOS are non-digestible and, therefore, available to be fermented by intestinal bacteria. Interestingly, FOS is a type of FODMAP, found in foods like onions, garlic, and asparagus.

The researchers found that the FOS increased the times of relaxation of the esophageal sphincter muscles, as well as increased the amount of acid reflux and GERD symptoms. In this study, there was no mention of SIBO, but the researchers did conclude that it was fermentation within the colon that caused the increase in GERD symptoms.

Another very small study found that a low-carbohydrate diet significantly improved GERD symptoms in a group of eight obese GERD patients.

The Bottom Line

For now, it seems that all we can conclude is that this is an interesting theory. Hopefully, further research will be conducted to find out if a low-carbohydrate diet does indeed resolve SIBO and ease the symptoms of GERD.

Unfortunately, funding for dietary treatments for medical problems tends to be scarce. More research on whether the low-FODMAP diet improves heartburn symptoms would be welcome, as it is being used by people in hopes of relief.

Persistent GERD is a condition best managed by your healthcare provider. However, if this theory resonates with you, talk to your healthcare provider about it.

If you decide that you want to try the low-carbohydrate diet recommended by Dr. Robillard and then assess its effects on your symptoms, you should consult with a qualified dietary professional to ensure that all of your nutritional needs are being met.

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2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Piche T, des Varannes SB, Sacher-Huvelin S, Holst JJ, Cuber JC, Galmiche JP. Colonic fermentation influences lower esophageal sphincter function in gastroesophageal reflux disease. Gastroenterology. 2003 Apr;124(4):894-902. doi:10.1053/gast.2003.50159

  2. Austin GL, Thiny MT, Westman EC, Yancy WS Jr, Shaheen NJ. A very low-carbohydrate diet improves gastroesophageal reflux and its symptoms. Dig Dis Sci. 2006 Aug;51(8):1307-12. doi:10.1007/s10620-005-9027-7

Additional Reading

By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.