Life Extension Magazine®

Small intestines at risk of bacterial overgrowth causing discomfort

Unique Test for Intestinal Complaints

Small intestinal bacterial overgrowth (SIBO) can cause gas, bloating, diarrhea, or constipation. Life Extension® now offers an innovative home breath test for easy diagnosis.

Scientifically reviewed by Dr. Gary Gonzalez, MD, in August 2023. Written by: Dr. Shanti Albani, ND, Physician.

William Faloon
Dr. Shanti Albani

For those troubled by intestinal problems such as gas, bloating, diarrhea, or constipation, it is often difficult to determine the exact cause and proper treatment.

But now, as explained by Dr. Shanti Albani, there is an innovative home breath test that will help determine if the cause relates to bacterial overgrowth in the small intestines. The results may provide helpful answers to you and your physician.

LE: Many people suffer from intestinal ailments but have not been able to identify the cause of their symptoms. Now Life Extension® is offering a test that holds promise for those who suffer from chronic intestinal complaints, correct?

SA: That’s true. We recently introduced a home test that looks for a common, but underappreciated problem called small intestinal bacterial overgrowth (SIBO).

SIBO is thought to be the underlying cause in at least 60% of irritable bowel syndrome (IBS) cases, and it is also suspected when people have chronic symptoms of gas, bloating, and intestinal discomfort, even without a diagnosis of IBS.

What excites me about this test is that once SIBO is identified, specific suggestions are available that can help support and improve microbial balance in the intestinal tract. Such an approach affords more relief than therapies designed only to manage intestinal discomfort without a lasting solution.

What you need to know

A common condition that most are unaware of is called small intestinal bacterial overgrowth (SIBO). Life Extension now offers an innovative at-home breathe test for this condition. Those who have chronic symptoms of gas, bloating and intestinal discomfort may benefit from this test.

LE: Can you tell us more about what SIBO (small intestinal bacterial overgrowth) is?


SA: For optimum health, we should have a diverse and sizable population of bacteria in our large intestine, and comparably fewer bacteria in our small intestine. In fact, the bacterial population in our gut increases as we move through the small intestine toward the colon, but it is in the colon where the microbial populations expand exponentially. In the case of SIBO, bacteria that may be considered normal in the colon can populate and overgrow in the small intestine. This overgrowth causes gas, bloating, cramping, and even systemic symptoms such as brain fog and acne. The underlying cause of SIBO is almost always a loss of normal intestinal motility.

LE: By “loss of intestinal motility,” do you mean constipation, or can people who have loose stools also have SIBO?

SA: Both people with constipation and those with diarrhea can have SIBO. There are two main types of movement within the intestine: peristalsis and the migrating motor complex (MMC). Peristalsis occurs during digestion and moves large food masses through the digestive tract. MMC occurs during the fasting state and sweeps residual undigested material and bacteria from the small intestine into the colon. So peristalsis is the primary mover of meals through the system and the MMC provides the small intestines with an important between-meal house-cleaning.

Underactive peristalsis is often associated with constipation and overactive is associated with diarrhea, but a faulty MMC is the main underlying cause of SIBO. When the MMC is not working properly, bacteria are not swept out of the small intestine and into the colon, thus they can grow and overpopulate in the small intestine. As the movements produced by peristalsis and the migrating motor complex are distinct, a compromised MMC and SIBO can occur in the presence of either diarrhea or constipation. If you ever hear your stomach growling between meals, that is your MMC doing its job of moving excess bacteria and debris into the colon!

LE: Sounds like the migrating motor complex is like the street sweeper of the intestines! What could cause it to stop working?

SA: That is a great question. One thing we do know is that if you ever had food poisoning, your chances of developing SIBO are much higher. Other conditions that damage the nerves in the intestines, or interfere with motility can also cause SIBO. For example, hypothyroid, previous abdominal surgeries, use of opioid medications, poor eating habits, diabetes or even constant eating, since the migratory motor complex only functions between meals.

LE: You mentioned gas and bloating as key symptoms of SIBO, what else should someone look for?

SA: While gas, bloating, diarrhea, and/or constipation are hallmarks of SIBO, there are other clues to consider:

  • Gut symptoms will sometimes temporarily improve with antibiotics as bacteria in the small intestine are eliminated.
  • Gut symptoms are sometimes worse with fiber because the bacteria in the small intestine use the fiber as a food source and multiply.
  • Individuals with SIBO may have nutritional deficiencies, as the many bacteria in the small intestine interfere with absorption and use much-needed nutrients for their own propagation.
  • The health of our gut impacts the health of the rest of our body. Those with SIBO frequently suffer from acne, rosacea, depression, fatigue, fibromyalgia, and/or joint pain.

This is a condition with an extensive impact on health. I am excited to get the word out because identifying SIBO can make a huge difference in quality of life for many people.

LE: How is it possible for these bacteria to cause so many symptoms?

SA: When we eat carbohydrates and fiber, we should break down the carbs into sugar and absorb them for energy production. The fiber should pass into the colon where it feeds colonic bacteria and helps form the stool. When too many bacteria make their home in the small intestine, they steal our food, fermenting the carbohydrates and fiber we eat into large amounts of hydrogen and methane gas.

LE: So, that is what causes the gas, bloating, diarrhea, and constipation?

SA: Yes, hydrogen gas tends to activate peristalsis and cause diarrhea, while methane gas slows it down and is more associated with constipation. In addition, the bacteria themselves can be irritating to the intestines resulting in inflammation, altered immune response, leaky gut, and some of the body-wide symptoms we discussed earlier.

LE: I can see the importance of testing for SIBO! How does the test work?

Collecting a SIBO breath sample
Collecting a SIBO breath sample

SA: The SIBO test is a breath test. We mentioned that the bacteria in the small intestine can produce large amounts of hydrogen and methane gas. This gas is actually absorbed from the intestines into the bloodstream and then exhaled through the lungs. The SIBO test comes as a kit that is completed at home. The subject drinks a solution containing either the sugar lactulose or glucose and then collects breath samples in tubes as the solution moves through the intestine. It takes about 90-120 minutes for the sugar solution to move from the mouth to the colon. If significant amounts of hydrogen or methane gas are detected in the breath during that time, it strongly suggests that excessive bacteria in the small intestine are producing gas from the sugar and the person likely has SIBO.

LE: You mentioned that you can use either a lactulose or glucose solution for the test. Which one is better?

SA: First off, I want to avoid any confusion by pointing out that lactulose is distinct from lactose, the sugar found in milk and dairy. That being said, between the lactulose and the glucose, the lactulose solution has a distinct advantage. It turns out that humans cannot digest or absorb lactulose, only bacteria can use it. Since it is not absorbed, lactulose travels the full length of the small intestine revealing SIBO throughout its entirety, including the lower end of the small intestine where it most commonly occurs.

Although glucose is highly fermentable, it is absorbed in the upper portion of the small intestines, so, if SIBO exists in the lower portion of the small intestines, it may be missed. We suggest starting with the lactulose SIBO test. If the test is negative and SIBO is still suspected, you can follow-up with a glucose SIBO test.

LE: Is this test something I can get through my doctor?


SA: Although the existence and clinical significance of SIBO has been well-established in the medical literature, unfortunately, it can take some time before this knowledge percolates into the way doctors practice medicine. So, although some forward-thinking doctors and gastroenterologists may offer SIBO testing, most doctors are still undereducated on the importance of SIBO and how to test for it. Naturopathic doctors are more likely to offer the testing, as well as holistic medical doctors.

LE: If someone suspects they have SIBO, is it safe to take probiotics like lactobacillus and bifidobacterium, or could these bacteria populate the small intestines and make things worse?

SA: Enough evidence has accumulated to say that multiple strains of bifidobacterium and lactobacillus may decrease symptoms and improve breath tests in individuals with SIBO. It is thought that probiotics can inhibit the growth of less beneficial bacteria, favorably modulate the immune system and help with intestinal motility. Taking all of this into consideration, a high-quality multistrain probiotic can be a valuable part of SIBO treatment and management.

LE: If someone does test positive for SIBO, what is the next step?

SA: Addressing SIBO is multifaceted and includes dietary changes, antibiotics or antimicrobial herbs, and agents to support intestinal motility. It is best to find a doctor who specializes in SIBO, but customers can also call in and speak with Life Extension’s specially trained Wellness Specialists who can assist them with finding a physician, provide helpful information and provide customized suggestions that they can discuss with their own doctor.

If you have any questions on the scientific content of this article, please call a Life Extension® Wellness Specialist at 1-866-864-3027.

Dr. Shanti Albani obtained her medical degree in Naturopathic Medicine in 2003 from the National University of Natural Medicine in Portland, Oregon. She practiced medicine for many years in central Mexico specializing in gastrointestinal disorders and hormone balance. During this time, she also owned a nutrition store and taught courses in bioidentical hormone replacement therapy for physicians. She has worked at Life Extension since 2010 and is currently the Manager of Clinical Information.