Tag: Breath Test

Common Breath Test Results Part 3: Atypical Breath Test Results

Posted on by Bradley Bush

Atypical breath test patterns provide unique insights into digestive health and treatment direction. Consequently, interpret results within the clinical context. In general, despite expert and research-based guidelines for diagnostic breath testing, the interpretation of results lacks a clear, universally accepted consensus. This leaves room for broad, sometimes varied clinical interpretation, making results more functional and insightful. As hydrogen and methane breath test markers signal different underlying conditions based on timing, peak patterns, and gas fluctuations, clinicians rely on experience and understanding of individual patient patterns.

Atypical Breath Testing Patterns

Breath tests are essential for diagnosing digestive issues such as small/large intestinal bacterial overgrowth (SIBO and LIBO). However, some results fall into atypical patterns, giving unique insights. Here’s an overview of six atypical breath test result patterns.

Flat Methane

In this case of atypical breath results, methane (CH₄) levels are elevated, but flat, throughout the small intestine (0–120 min) (Figure 1). Elevated methane gas levels throughout test results suggest increased bacterial activity throughout the intestines or elevated colonic activity combined with reduced gut motility.

Test results showing an atypical breath test pattern: elevated flat methane
Figure 1: This is a lactulose breath test example of an atypical breath test result for a flat-line, elevated methane SIBO positive results.

Baseline Elevated Hydrogen

Initially high hydrogen (H₂) that either dips or remains high across the small intestine reflects potential pre-existing fermentation (Figures 2a, 2b). 

Atypical breath test results showing elevated baseline hydrogen
Figure 2a: This is an example of an elevated baseline hydrogen breath test. Elevated baseline (34 ppm) gas activity quickly cleared out with a significant reduction in activity. Possible causes of elevated hydrogen baselines include, but are not limited to, not following preparation diet guidelines, reduced gut motility, oral microbial imbalance, or significant colon gas activity.

 

Atypical breath test pattern showing baseline elevated hydrogen
Figure 2b: This is an example of an elevated baseline hydrogen breath test. An elevated baseline (34 ppm), followed by continued elevation in hydrogen gas activity does not meet diagnostic criteria for SIBO. Possible causes of continually elevated hydrogen gas activity include, but are not limited to, reduced gut motility, sugar malabsorption syndrome, and/or yeast overgrowth.

Flat Negative

Low hydrogen and methane (<3ppm) suggest low fermentative activity or microbial population (Figure 3).

atypical pattern for breath test showing flat methane and hydrogen levels in a negative SIBO result
Figure 3: This lactulose breath test result shows little to no measurable gas activity (hydrogen and methane). Common causes for a “flat-line” result include: testing too soon after antimicrobials (antibiotics, anti-fungals, herbal antimicrobials) or the presence of dominant hydrogen sulfide (H2S) SIBO.

Delayed Gut Motility

A hydrogen spike after 120 min with a second increase (double peak) shows slowed motility (Figure 4). Normally, a classic looking “double peak” of gas activity shows an initial spike in gas activity just prior to and after the intestinal transition zone (commonly around 100-120 min). The pattern becomes atypical when the double peak occurs outside of that time frame.

results showing delayed gut motility which is an atypical breath test pattern
Figure 4: These results show delayed emptying of lactulose from the small to large intestines. Reduced gut motility and delayed emptying may be identified with a transition zone occurring in the 140-160 minutes specimens.

Multiple Peaks and Valleys

Fluctuating H₂/CH₄ peaks may result from uneven microbial distribution (Figure 5).  Causes include segmental delays in motility, uneven transit times with pockets of microbes at different points, and SIBO. Additionally, different bacterial species producing gas at varying rates can fluctuate gas levels. Finally, physiological gut responses with normal motility patterns or minor motility disorders may influence gas patterns in the intestines.

multiple peaks and valleys in hydrogen methane breath tests are atypical
Figure 5: Multiple peaks and valleys in gas activity may be due to a variety of conditions.

Atypical Colon

A notable hydrogen and/or methane spike in the colon indicates possible microbial imbalance in the large intestines (Figures 6a, 6b).

Atypical colon breath test result
Figure 6a: This is atypical breath test example shows a slightly elevated SIBO (combined H₂ & CH₄) result with significant colon gas activity at 140-180 minutes. Additionally, the total hydrogen activity (Total Bacterial Load) of these results strongly suggests irregular colon fermentation/ microbial activity.

 

Atypical colon total bacterial load breath test results
Figure 6b: These breath test results show the total hydrogen gas activity (Total Bacterial Load) for the results in Figure 6a. Note high colon activity at 140-180 min.

Conclusion

Each atypical breath test pattern reveals distinct physiological and microbial dynamics. By combining the results with the clinical presentation, healthcare providers can create highly targeted and personalized treatment plans for various GI concerns. In some cases, these trends can be difficult to interpret. Neurovanna offers healthcare providers using our breath tests free consults with our SIBO expert Dr. Bradley Bush. Become a Neurovanna healthcare provider for quality and exclusive test results as well as skilled clinical support.

This is part 3 of a three part series on common breath test trends. Read part 1 to learn about common trends for lactulose and glucose SIBO breath tests. Part 2 discusses common trends in fructose, sucrose, and lactose sugar malabsorption breath test results.

Common Breath Test Results Part 2: Sugar Malabsorption Testing for Lactose, Fructose, and Sucrose 

Posted on by Bradley Bush

Sugar malabsorption affects many individuals, causing symptoms like bloating, gas, diarrhea, and abdominal discomfort. When the body cannot properly absorb sugars such as lactose, fructose, or sucrose, they pass into the large intestine. Once in the large intestine, gut bacteria fermented the sugars producing hydrogen and/or methane gas. Measuring the levels of hydrogen and methane gas through breath tests provides important insights into how well the body is digesting these sugars.

How Sugar Malabsorption Breath Tests Work

During a sugar malabsorption breath test, the patient consumes a specific sugar (either lactose, fructose, or sucrose). If the sugar is not properly absorbed in the small intestine, it reaches the colon. In the colon, bacteria ferment it producing hydrogen (H₂) and methane (CH₄) gas. Then, hydrogen gas absorbs into the bloodstream which carries it to the lungs. When the patient exhales into the collection tube, the gas is collected and measured using gas chromatography.

By analyzing the rise in hydrogen gas levels during the breath test, clinicians determine whether malabsorption is occurring and to what extent. The greater the rise in hydrogen, the more significant the sugar malabsorption.

Diagnostic Criteria for Sugar Malabsorption

The following diagnostic thresholds are used to interpret malabsorption breath tests for lactose, fructose, and sucrose:

  1. Hydrogen: A rise > 20 ppm above baseline during the breath test is diagnostic of malabsorption.
  2. Combined Hydrogen and Methane: A rise > 15 ppm above baseline during the breath test is diagnostic of malabsorption 
  3. Methane: A rise > 12 ppm above baseline during the breath test is diagnostic of malabsorption.

Common Trends for Each Sugar Malabsorption Test

Lactose Malabsorption (see Figure 1)

  • Hydrogen Gas Trend: For individuals with lactose intolerance, a significant rise in hydrogen levels commonly occurs within 60 to 90 minutes after ingesting lactose.
  • Diagnostic Interpretation:
    • A rise of 20 ppm or more indicates severe lactose malabsorption where the the small intestine absorbs little to no lactose.
    • An increase of 15 ppm or more indicates moderate malabsorption suggesting partial lactase deficiency.
    • A rise of 12 ppm or more indicates mild malabsorption. In this case, some lactose is absorbed, but not enough to prevent symptoms like gas and bloating.
  • Symptoms: Common symptoms include bloating, diarrhea, and abdominal pain after consuming dairy products.
Sugar malabsorption breath test results showing a negative results for lactose malabsorption
Figure 1: Example of lactose malabsorption breath test report. This breath test did not meet diagnostic criteria for malabsorption.

Fructose Sugar Malabsorption (see Figure 2)

  • Hydrogen Gas Trend: In cases of fructose malabsorption, hydrogen levels typically rise 30 to 60 minutes after consuming fructose.
  • Diagnostic Interpretation:
    • A rise of 20 ppm or more indicates severe fructose malabsorption, often causing significant digestive distress.
    • An increase of 15 ppm or more indicates moderate malabsorption, with symptoms occurring after consuming high amounts of fructose.
    • A rise of 12 ppm or more indicates mild malabsorption, where smaller quantities of fructose may still cause discomfort.
  • Symptoms: Fructose malabsorption can lead to bloating, gas, diarrhea, and cramping after consuming fructose-rich foods like apples, honey, or high-fructose corn syrup.
Test result showing positive fructose sugar malabsoprtion based on a breath test
Figure 2: Example of fructose malabsorption breath test report. Baseline measurement showed very little gas activity and then a significant increase was seen at 120 minutes. This breath test met diagnostic criteria for both an increase in hydrogen and combined (hydrogen + methane) gases.

Sucrose Malabsorption (see Figure 3)

  • Hydrogen Gas Trend: For those with sucrose malabsorption, hydrogen levels typically  rise 30 to 60 minutes after ingesting sucrose.
  • Diagnostic Interpretation:
    • A rise of 20 ppm or more suggests severe sucrose malabsorption, indicating a deficiency in the enzyme sucrase.
    • An increase of 15 ppm or more indicates moderate malabsorption, with symptoms occurring after consuming moderate amounts of sucrose.
    • A rise of 12 ppm or more indicates mild malabsorption, where some sucrose is absorbed, but not enough to prevent symptoms like bloating and gas.
  • Symptoms: People with sucrose malabsorption often experience digestive discomfort after consuming sugary foods like candy, baked goods, and sweetened beverages.
Breath test report showing positive for sucrose sugar malabsoprtion
Figure 3: Example of sucrose malabsorption breath test report. Even with an elevated baseline, this patient met diagnostic criteria for both an increase in hydrogen and combined (hydrogen + methane) gases.

What Do These Trends Mean?

The trends in hydrogen gas production during sugar malabsorption breath tests provide valuable insight into how well the body is absorbing specific sugars. A sharp increase in hydrogen levels, especially within the first 90 minutes, indicates a significant amount of undigested sugar is reaching the colon, where it is fermented by bacteria. The higher the hydrogen gas levels, the more severe the sugar malabsorption.

Understanding these hydrogen gas trends helps clinicians tailor dietary recommendations and treatment plans for individuals struggling with lactose, fructose, or sucrose malabsorption. For patients experiencing significant rises in hydrogen gas levels, reducing or eliminating the offending sugar from the diet can help manage symptoms and improve digestive health.

Prevent False Positives: Rule Out SIBO Before Sugar Malabsorption Breath Testing

SIBO can interfere with the accuracy of sugar malabsorption test results. Therefore, the North American Consensus for Breath Testing recommends ruling out Small Intestinal Bacterial Overgrowth (SIBO) with a glucose or lactulose breath test before testing for sugar malabsorption (such as lactose, fructose, or sucrose). If SIBO is present, bacteria in the small intestine may ferment sugars prematurely causing false positives during sugar malabsorption testing. By addressing SIBO first, clinicians can ensure that any malabsorption detected is due to enzyme deficiencies or transport issues rather than bacterial overgrowth.

This is part 2 of a three part series on common breath test trends. Read part 1 to learn about common trends for lactulose and glucose SIBO breath tests.

The Case for Large Intestine Bacterial Overgrowth (LIBO)

Posted on by Bradley Bush

Breath testing is commonly used to diagnose Small Intestinal Bacterial Overgrowth (SIBO), but it could also be used to identify Large Intestine Bacterial Overgrowth (LIBO). The SIBO breath test measures amounts of the gasses hydrogen and methane produced by bacteria in the small intestine when they ferment carbohydrates. However, these breath tests also assess the hydrogen and methane gas activity in the large intestines. In most cases, this data is ignored, but this oversight may prevent proper diagnosis and treatment.

SIBO vs LIBO

In a healthy digestive system, the small intestine has relatively few bacteria compared to the large intestine. However, in SIBO, an overgrowth of bacteria in the small intestine ferments carbohydrates prematurely. This fermentation produces gasses, primarily hydrogen, methane, or hydrogen sulfide, which are absorbed into the bloodstream and then exhaled through the lungs. After a patient ingests a specific carbohydrate substrate, like lactulose or glucose, the breath test detects the levels of these gasses. Abnormally high levels indicate bacterial overgrowth in the small intestine.

The large intestine, or colon, is naturally populated with a vast number of bacteria responsible for fermenting undigested carbohydrates. This fermentation produces gasses like hydrogen, methane, and carbon dioxide as a normal part of digestion. Because this process is a normal function of the large intestine, the conventional medical community believes that assessing gas activity of the colon has no diagnostic value. In other words, elevated gas levels detected later in the breath test are expected, to some degree, and therefore do not specifically indicate pathology.

Large Intestinal Bacterial Overgrowth (LIBO) is a condition where there is an abnormal increase in the number and/or types of bacteria in the large intestine (colon). While the colon normally contains a vast and diverse population of bacteria that play essential roles in digestion, immunity, and overall health, an imbalance or overgrowth of certain bacterial species can lead to digestive issues and other health problems.

Key Aspects of Large Intestinal Bacterial Overgrowth (LIBO)

Causes of LIBO

  • Dietary Factors: A diet high in refined carbohydrates or sugars and low in fiber can promote bacterial overgrowth in the large intestine.
  • Dysbiosis: An imbalance in the gut microbiota, often caused by factors like antibiotics, poor diet, chronic stress, or other medications, can lead to LIBO.
  • Slow Transit Time: Conditions that slow down the movement of food through the colon, such as constipation, can lead to bacterial overgrowth as bacteria have more time to ferment undigested food.
  • Immune System Dysfunction: A weakened immune system, which fails to keep bacterial populations in check, can contribute to LIBO.

Symptoms of LIBO

  • Abdominal Bloating and Gas: Excess fermentation of undigested carbohydrates by bacteria can produce large amounts of gas, leading to bloating and discomfort.
  • Diarrhea or Constipation: LIBO can cause changes in bowel habits, leading to either diarrhea (due to rapid fermentation and irritation) or constipation (due to slower transit and hard stools).
  • Abdominal Pain: The buildup of gas and changes in motility can cause cramping and discomfort in the abdomen.
  • Fatigue and Malaise: Chronic LIBO can lead to malabsorption of nutrients, resulting in fatigue, nutrient deficiencies, and general feelings of unwellness.

Hydrogen Gas Production in the Large Intestine

The large intestine is home to a vast and diverse community of bacteria, many of which play a key role in digesting food components that were not fully broken down in the small intestine. These bacteria ferment undigested carbohydrates, fibers, and other nutrients, producing gasses as byproducts. Hydrogen gas (H₂) is one of the primary gasses produced during this fermentation process.

When carbohydrates, especially complex carbohydrates and fibers, reach the large intestine, they become substrates for bacterial fermentation. The bacteria break down these carbohydrates to obtain energy, and in the process, hydrogen gas is released along with other gasses like carbon dioxide (CO₂) and methane (CH₄).

Fate of Hydrogen Gas in the Large Intestine

  • Hydrogen-Consuming Microbes: In a healthy gut, hydrogen gas produced by one group of bacteria is often consumed by other microbes. For example:
      • Methanogenic Archaea: These microbes convert hydrogen gas into methane, which is another gas commonly found in the colon.
      • Sulfate-Reducing Bacteria: These bacteria use hydrogen to reduce sulfate to hydrogen sulfide (H₂S).
      • Acetogens: These microbes can convert hydrogen gas into acetate, which is a short-chain fatty acid beneficial for gut health.
  • Exhalation and Flatulence: Some of the hydrogen gas is absorbed into the bloodstream and then exhaled through the lungs, which is why hydrogen breath tests are used to diagnose certain gastrointestinal conditions. The remaining hydrogen gas, along with other gasses produced in the colon, can be expelled as flatulence.

Conditions Influencing Hydrogen Production in the Large Intestine

  • Dietary Composition: Diets high in fermentable fibers, sugars, and complex carbohydrates can increase hydrogen gas production in the large intestine because they provide more material for bacterial fermentation.
  • Gut Microbiome Balance: The balance of different types of bacteria in the large intestine influences hydrogen production. A healthy balance means that hydrogen production and consumption are balanced, minimizing excess gas.
  • Digestive Disorders: Conditions like irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), or malabsorption syndromes can lead to increased hydrogen production, contributing to symptoms like bloating, discomfort, and gas.

Summary

Hydrogen gas is indeed produced in the large intestine as a result of bacterial fermentation of undigested carbohydrates and fibers. The gas is either consumed by other gut microbes, absorbed into the bloodstream and exhaled, or expelled as flatulence. The production of hydrogen gas in the colon is a normal part of digestion, but excessive production may contribute to digestive discomfort, bloating, excessive flatus, irritable bowel symptoms and may suggest the presence of LIBO. Total hydrogen activity assessed during breath tests, e.g. the Neurovanna Total SIBO Bacterial Load, offer another functional diagnostic tool for assessing the presence and extent of LIBO. 

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Learn more about the author, Dr. Bradley Bush.