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What is the relationship between SIBO and alcohol?

A recent study concluded that moderate alcohol consumption is a strong risk factor for small intestinal bacterial overgrowth, SIBO. Since then, I have been approached by several SIBO sufferers wondering if they should abstain from alcohol. This post addresses their concern and evaluates the study. But, before jumping into the heart of the matter, I want to go over SIBO and alcohol in regard to gastrointestinal health in general.

What is SIBO?

Small Intestinal Bacterial Overgrowth (SIBO) is a common condition linked to a variety of functional gastrointestinal disorders (FGIDs) and other conditions including:

  • irritable bowel syndrome (IBS)
  • Laryngopharyngeal Reflux Disease (LPR)
  • gastroesophageal reflux (GERD)
  • celiac disease
  • Crohn’s disease
  • diverticulitis
  • fibromyalgia
  • asthma
  • rosacea
  • interstitial cystitis
  • autoimmune disorders
  • cystic fibrosis

If you rounded up everyone with these conditions, you would end up with well over 100 million people.

SIBO is defined as the presence of an abnormally high number of bacteria in the small intestine. Most SIBO bacteria originate from the large intestine. It’s normal to have lots of bacteria in the large intestine. It’s also helpful for digestion. But if you end up with more than 100,000 bacteria per milliliter in your small intestine, you are SIBO positive.

It’s a bad thing because these harmless and helpful large intestine bacteria become harmful in the small intestine. They can disrupt digestion by producing toxins, enzymes and intestinal gases. They can also cause intense physical discomfort and damage the small intestine.

The symptoms of SIBO include:

  • abdominal pain or cramps
  • diarrhea
  • constipation
  • gas
  • bloating
  • acid reflux
  • flatulence
  • nausea
  • dehydration
  • fatigue

More severe symptoms related to SIBO can include:

  • weight loss
  • failure to thrive
  • steatorrhea (the body’s failure to digest fats)
  • anemia
  • bleeding or bruising
  • night blindness
  • bone pain and fractures
  • leaky gut syndrome
  • autoimmune reactions

Alcohol and Gastrointestinal Health

Alcohol abuse is well studied, and I think we all can agree that it’s pretty bad for your health.

People who regularly consume large amounts of alcohol experience a variety of health issues often. This is particularly true with regard to the digestive system.[1] Excessive alcohol consumption is linked to:

  • liver and pancreas disease
  • fat malabsorption
  • gastritis
  • gallstones,
  • steatorrhea (poor fat digestion)
  • villi and microvilli damage
  • malnutrition
  • diarrhea
  • leaky gut
  • immune deficiency
  • changes in gut microbiota

Many of these gastrointestinal (GI) problems could contribute to SIBO. In fact, one study[2] linked SIBO to alcoholic cirrhosis while another[3] measured excessive bacterial growth in both the small intestine and stomach of alcoholics. GI problems and a much higher cancer rate take their toll, and alcoholics die about 10 – 12 years earlier.

But what about moderate alcohol consumption?

Moderate alcohol consumption is defined as no more than 9 drinks per week for women and 12-14 for men. If heavy alcohol use is bad for your health, moderate alcohol might not be as bad, but abstaining should be best, don’t you think? But, it turns out that is not the case. People who consume alcohol in moderation actually live longer than those who abstain.[4]

Why? Because of reduced risk of heart disease.

A Canadian team of researchers found a significant reduction in risk of heart-related disease and death in women having 1 drink per day or in men having 1 to 2 drinks per day. This is based on 84 different studies involving about 1 million people. Reduced risk of heart disease may center on alcohol’s ability to reduce arterial plaque and blood clots.

Less is known about the effect of moderate alcohol consumption on digestive health.

But a systematic review of published studies[5] found that moderate alcohol consumption is associated with only small increases in gastrointestinal health risks. This includes liver disease, oropharyngeal and esophageal cancer and pancreatitis. On the other hand, moderate alcohol use reduces risk of gastritis and gallstones. The overall conclusion was that moderate alcohol intake is not a high risk factor for gastrointestinal diseases.

Evaluation of The Alcohol and SIBO “Gabbard” Study

Now, what about this study? A quick summary of the paper is this. It was a retrospective (observational) study of 196 people who had previously taken lactulose hydrogen/methane breath tests for SIBO. The researchers compared the results of their breath tests to other information on their medical charts for things like:

  • smoking
  • alcohol consumption
  • PPI use
  • Gastroesophageal reflux disease (GERD)
  • Irritable bowel syndrome (IBS)
  • gallbladder removal, etc.

Among the 93 people who tested positive for SIBO, here are the results: Of the patients who were moderate drinkers, 58 % had a positive breath test, compared to 38.9% of abstainers. This difference led the authors to conclude that moderate alcohol consumption was “a strong risk factor”for SIBO.

On a positive note, their statistical methods as well as the way they conducted the breath test and interpreted the results were well thought out and sound. On the other hand:

  • the study population was relatively small (statistical power of 80%)
  • the study design was observational, which cannot prove a cause and effect relationship
  • the subjects were all sick with a variety of maladies making it more difficult to assign alcohol as the cause vs. other illness
  • alcohol use was determined simply by reading information on the patient’s medical chart as opposed to a validated self-report form. This matters because different doctors or nurses may complete these charts differently.

SIBO and Carbohydrate Malabsorption

But the biggest reason I remain skeptical has to do with carbohydrates. Carbohydrates, not alcohol are the primary source of energy for SIBO.

In the study, the carbohydrate content of alcoholic drinks was not reported. Had that data been available I would view the results differently.

A growing body of evidence supports the idea that too many fermentable carbs promote SIBO. Published studies on diets that limit dietary carbs, i.e., Specific carb, low FODMAP, low carb and elemental diets all result in symptomatic improvement of SIBO related conditions.[6][7],[8],[9]

A recent news headline citing the study in question read “Just One Drink per Day May Be Cause of GI Woes Like Bloating, Gas, Abdominal Pain, Diarrhea.” Yet, where is the evidence that abstaining from alcohol improves these symptoms one iota?

Ten years ago, I made a connection between carbohydrate malabsorption and SIBO being the primary cause of acid reflux. I was able to treat my own acid reflux simply by limiting carbohydrates, especially hard to digest carbs. There is a lot of scientific evidence for my theory presented in the Fast Tract Digestion Heartburn book and for the connection between IBS and SIBO in the Fast Tract Digesiton IBS book.

Fast Tract Digestion Heartburn              Fast Tract Digestion IBS

But my point is this: once I reduced dietary carbohydrates, nothing else seemed to matter for instance, moderate alcohol consumption (minus the carbs), stress, other trigger foods, and additives. I believe it’s because carbohydrates are the preferred food of bacteria that cause SIBO hence the key dietary factor that controls it.

These two studies support my contention that GERD can be improved with a carbohydrate restricted diet.[10],[11]

One of the studies noted that “Use of substances such as tobacco products and alcohol did not change after they initiated the diet. Therefore, these substances are unlikely to factor into their symptom relief.” Also, a systematic review of studies published from 1975 through 2004 on lifestyle modifications for GERD concluded that there was no evidence that cessation of alcohol improved symptoms.

And the amount of carbohydrate in many alcoholic drinks is not insignificant. I consider distilled spirits, dry wine, or light beer safer alcoholic drinks for SIBO because they have very few hard-to-digest carbohydrates.

But many people drink regular beer, sweet or dessert wine, liqueur or mixed drinks which contain lots of sucrose, fructose or resistant starch in the case of beer. These carbohydrates are hard-to-digest for many due to their molecular structures in food chemistry and / or individual digestive deficiencies. They can promote bacterial overgrowth and dramatic symptoms in susceptible individuals. Here is a good article listing the sugar content of alcoholic beverages.


For me, science speaks at the end of the day, and I am always open to new research. But I believe that carb counts must be considered in studies on SIBO.

My own experience, my review of the scientific literature on alcohol, and the success of carbohydrate restriction (but not abstaining from alcohol) for treating SIBO-related conditions lead me to believe that controlling dietary carbs is the key to prevent and control SBIO, not abstaining from alcohol.

Of course, you should abstain if you are concerned, but I stick by my recommendation. The three keys to controlling SIBO are:

  • Identify and address potential underlying causes – of which I don’t consider moderate alcohol consumption as one
  • Limit fermentable carbohydrates in foods and drinks that fuel SIBO
  • Implement pro-digestion behaviors

I welcome your views and / or experience with moderate alcohol for acid reflux, IBS and SIBO.

Feel Better, Live Long , Enjoy Life.


[1] Alcohol and the Gastrointestinal Tract. Singer MV, Brenner DA (Eds) S Karger Pub. 1st Edition, May 2, 2006.

[2] Casafont Morencos F, de las Heras Castaño G, Martín Ramos L, López Arias MJ, Ledesma F, Pons Romero F. Small bowel bacterial overgrowth in patients with alcoholic cirrhosis. Dig Dis Sci. 1996 Mar;41(3):552-6.

[3] Hauge T, Persson J, Danielsson D.Mucosal bacterial growth in the upper gastrointestinal tract in alcoholics (heavy drinkers). Digestion. 1997;58(6):591-5.

[4] Holahan CJ, Schutte KK, Brennan PL, Holahan CK, Moos BS, Moos RH. Late-life alcohol consumption and 20-year mortality. Alcohol Clin Exp Res. 2010 Nov;34(11):1961-71.

[5] Alcohol and the Gastrointestinal Tract. Singer MV, Brenner DA (Eds) S Karger Pub. 1st Edition, Page 15. May 2, 2006.

[6] Shepherd SJ, Gibson PR. Fructose malabsorption and symptoms of irritable bowel syndrome: guidelines for effective dietary management. J Am Diet Assoc. 2006 Oct;106(10):1631-9.

[7] Austin GL, Dalton CB, Hu Y, Morris CB, Hankins J, Weinland SR, Westman EC, Yancy WS Jr, Drossman DA. A very low-carbohydrate diet improves symptoms and quality of life in diarrhea-predominant irritable bowel syndrome. Clin Gastroenterol Hepatol. 2009 Jun;7(6):706-708.

[8] Pimentel M1, Constantino T, Kong Y, Bajwa M, Rezaei A, Park S A 14-day elemental diet is highly effective in normalizing the lactulose breath test. Dig Dis Sci. 2004 Jan;49(1):73-7.

[9] Barrett JS, Gibson PR. Fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) and nonallergic food intolerance: FODMAPs or food chemicals? Therap Adv Gastroenterol. 2012 Jul;5(4):261-8.

[10] Yancy WS Jr, Provenzale D, Westman EC. Improvement of gastroesophageal reflux disease after initiation of a low-carbohydrate diet: five brief cased reports. Altern Ther health med. 2001. Nov-Dec; 7(6):120,116-119.

[11] 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.[/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]