Alexandra Falconer | 04 Aug 2020 | SIBO

SIBO Symptoms: What They Mean And What To Do Next

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Twenty years ago, almost nobody had heard of SIBO: most experts thought it was a rare disorder that only happened after surgery on the gut. Fast forward to today, and it’s widely acknowledged as one of the major causes of IBS. Read on to find out all you need to know about SIBO.

Contents

What Is SIBO?
Why Does SIBO Happen?
How Common is SIBO?
What Are The Symptoms Of SIBO?
What diseases are linked to SIBO?
How Does Small Intestinal Bacterial Overgrowth Affect Us Long Term?
How Do You Know For Certain If You Have SIBO?
What Happens If SIBO Is Left Untreated?
Can SIBO Go Away On Its Own?
How Do I Get Rid Of SIBO?
What Foods Should Be Avoided With SIBO?
SIBO: Is It Auto-immune?
Is IBS Really SIBO?
Conclusion

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What is SIBO?

SIBO stands for small intestinal bacterial overgrowth.

If you have SIBO, it means you have too many bacteria living in your small intestine, where numbers should be much lower than in your lower intestine, or colon.

Your small intestine should house less than 10,000 bacteria per millilitre of fluid. Your large intestine, or colon is home to a staggering 1,000,000,000 bacteria per millilitre of fluid. And, because your small intestine has a different role to play in your digestion to your large intestine, the types of bacteria that live there are a bit different too (Source: NCBI).

Your small intestine does a lot more work than its larger counterpart when it comes to digesting food and absorbing nutrients. It is also an important part of your immune system, containing an impressive network of lymphoid cells (cells of the immune system that help fight infections and regulate the immune system) (Source: NCBI).

The finding that there are ‘normal’ bacteria that live there, and that they do essential jobs, is relatively new: until the end of the last century most experts believed that the small intestine was free of bacteria in most people (Source: PUBMED), but we now know that a balanced microbiome in the small intestine is important for many reasons (Source: NCBI). For instance:

  • protecting against potentially pathogenic bacteria and yeasts
  • helping the body absorb nutrients
  • producing several nutrients (such as short chain fatty acids) and vitamins like folate and vitamin K
  • maintaining the normal muscular activity of the small bowel (pushing your food along)

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Why does SIBO happen?

SIBO can happen for a number of reasons. Here are just a few:

Insufficient stomach acid

Your stomach acid kills the bacteria that you swallow along with your food. If you don’t have enough, they can find their way into your small intestine and multiply (Source: PUBMED).

Low levels of bile

Bile is another substance your body uses to defend the small intestine against invading bacteria. Insufficient levels of bile can allow bacteria in the small intestine to get out of control (Source: NCBI).

Insufficient digestive enzymes

If your body isn’t producing enough digestive enzymes, your food can remain in your small intestine and instead of feeding you, feed your bacteria (Source: PUBMED), encouraging numbers to grow.

A compromised immune system

Many researchers have noted a link between SIBO and something known as post-infectious IBS (IBS symptoms that begin after a bout of food poisoning). There’s also evidence that people with SIBO and IBS have higher levels of inflammation in their guts (Source: NCBI), suggesting that an imbalanced immune reaction is at play.

Your immune system is designed to fight off any unwelcome bacteria that appear where they shouldn’t. If it’s not working as well as it should, bacteria can grow and multiply in the small intestine, resulting in SIBO.

sibo symptoms infographic

A faulty ileocaecal valve

Your ileocaecal valve is the ‘door’ that sits between your small and large intestines. It’s designed to enable food to flow down from the small intestine into the large intestine, and prevent it from going backwards. For a variety of reasons, that doesn’t always happen.

If it doesn’t shut when it’s supposed to, the hundreds of trillions of bacteria in your colon can start to migrate to your small intestine (Source: NCBI).

A faulty migrating motor complex

To push your food through your GI (gastro-intestinal) tract—the ‘tube’ that runs all the way from your mouth to your anus—your body performs a complex, tightly coordinated series of events. In between meals, your migrating motor complex (MMC) happens approximately every 90-120 minutes to sweep what you’ve just eaten through your GI tract.

Several studies have demonstrated that abnormalities in your MMC make it more likely that you’ll develop SIBO (Source: PUBMED).
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How common is SIBO?

While we can’t be sure about the number of people with SIBO in the general population, some studies suggest that between 6 to 15% of healthy people with no gut symptoms have SIBO, while up to 85% of people with IBS have SIBO (Source: NCBI).

Chris Kresser, a naturopathic doctor based in the US, says that SIBO is largely under-diagnosed. “Many people don’t seek medical care for their SIBO symptoms, and many doctors aren’t aware of how common SIBO is”, he says on his website.

Dr. Hazel Veloso, a gastroenterologist at Johns Hopkins University in the US, said in the magazine for the American College of Physicians that doctors used to think of SIBO as something rare: “We were just labelling patients with IBS before, and they were not getting better because there was actually an underlying cause”, said Dr. Veloso.

The best way to test for SIBO is with a breath test measuring levels of hydrogen and methane gas. But while this is an accurate and very useful tool, the test still can give false negatives (meaning the test results come back as negative but you actually do have SIBO) (Source: PUBMED).

This is why it’s important to use the test with the guidance of an experienced practitioner who looks at your symptoms and health history—and any other test results—alongside your SIBO test results. A positive or negative SIBO test result is just one piece of your health puzzle. Good practitioners look for all the pieces to find the reasons for your symptoms.
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What are the symptoms of SIBO?

Many typical symptoms of SIBO are also the symptoms of IBS. Research has found that people with IBS are five times more likely to have SIBO than people without IBS (Source: PUBMED).

Common SIBO symptoms include:

  • bloating
  • abdominal pain
  • constipation
  • diarrhoea
  • belching
  • flatulence
  • nausea
  • fatigue
  • brain fog
  • fatty stools

Because you can have these symptoms without having SIBO, and the breath test isn’t 100 percent reliable, it’s difficult to know if you have SIBO for sure.

Again, that’s why you need the help of an experienced practitioner to guide you through the maze. While the breath test is an indispensable part of their tool kit, our Functional Medicine Practitioners and Registered Nutritional Therapists look at other clues too. Here are some examples:

Intolerance to probiotics and/or prebiotics

Some people with SIBO can take probiotics and prebiotics without any problems, but many find their symptoms worsen (Source: NCBI). This is likely to be because they’re feeding an already overpopulated small intestine: in a ‘normal’ situation, they would simply travel through the first part of our guts and take up residence in the large intestine, where the bacteria already there work their magic with them.

With SIBO, the misplaced bacteria in the small intestine get them first, welcoming the arrival of even more new friends in the case of probiotics, and chowing down on the free party food in the case of prebiotics. Either way, the pesky bacteria give off more gases and bingo: you feel worse.

Intolerance to FODMAPs

FODMAPs are special kinds of carbohydrates that bacteria love to eat. You can find out more about them, and what to do about FODMAP intolerance in our blog on the FODMAP diet and the NHS.

If FODMAP foods make your symptoms worse, it’s another red flag for SIBO (Source: NCBI). In fact, practitioners often use the low-FODMAP diet as part of a protocol to tackle SIBO.

Intolerance to starches and/or fibre

As far back as the 1940s, doctors had identified starches and some types of fibre as contributing to digestive disease. Dr Sidney Haas was a pediatrician who treated celiac disease and other gastrointestinal disorders with the diet he developed: the Specific Carbohydrate Diet (SCD), that eliminates grains, most root vegetables, sugar and most dairy products (Source: EUROPEPMC).

The diet then fell out of favour until more research towards the end of the last century revealed that the types of carbohydrates not allowed on the SCD did indeed feed bacteria in the small intestine, and that eliminating them relieved many people of their digestive symptoms (Source: NCBI).

Low iron on a blood test

Another nutrient on the menu for SIBO bacteria is iron. If they eat yours before you can absorb it, you end up with an iron deficiency, which in turn may result in anaemia, or just an iron deficiency without anaemia. In either case, otherwise unexplained iron deficiency may be a clue that SIBO is present (Source: NCBI).

High folate on a blood test

One of the many jobs of our beautiful bacteria is producing vitamins and nutrients to help our body work optimally. An example is folate, or vitamin B9. So if your folate levels are high on a blood test, it’s another sign you might have SIBO (Source: NCBI).
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What diseases are linked to SIBO?

SIBO is associated with many disorders, as a cause, an effect or as a coexisting condition: the below list is a small sample of papers from a huge amount of research looking into the links between SIBO and chronic disease.

If you have one or more of the following conditions, it could be a good idea to get a SIBO test:

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How does SIBO affect us long term?

At the moment, we just don’t know for sure whether SIBO affects us in the long term. We can only speculate based on what we know about how SIBO affects the small intestine: for example, we know SIBO can cause both nutrient deficiencies and leaky gut. Let’s unpack both of those.

Nutrient deficiencies

SIBO can damage your small intestine and interfere with how you digest your food, preventing your body from getting the nutrients it needs to function at its best. This is because the bacteria and the substances they produce can harm the cells lining your small intestine (Source: NCBI), stopping them from doing their job of absorbing nutrients.

SIBO can lead to nutrient deficiencies in another way, too: SIBO bacteria can ‘eat’ your nutrients, before your body can even try to absorb them. The most common nutrients affected by SIBO include:

Leaky gut

SIBO is linked to leaky gut: a condition where your intestinal barrier starts to let large protein molecules out into your bloodstream (Source: PUBMED). Leaky gut has been linked to a whole host of chronic illnesses, autoimmune diseases, food allergies and sensitivities (Source: PUBMED).

Although there’s definitely a connection between SIBO and leaky gut, we don’t know that one causes the other. It could be that both conditions share the same underlying imbalance (Source: NCBI).
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How do you know for certain if you have SIBO?

Unfortunately there is no perfect test for SIBO. The small intestine is a hard place to get to, so if doctors want to see or take a sample from it, endoscopy (a tube down the throat) only reaches into the top portion of your GI tract, and a colonoscopy (a tube up your bottom) only reaches into the large intestine. The whole part in the middle, which is about 17 feet long, is only accessible with surgery or a wireless capsule.

Stool testing is a fantastic way to get a window into the goings-on of your gut, but it mostly gives a picture of the large intestine. Luckily, there is an easy to use, non-invasive test that scientists, doctors and practitioners all over the world routinely use: the hydrogen and methane breath test.

The SIBO test

The SIBO test measures the hydrogen and methane gas produced by bacteria in the small intestine.

If you decide to take a SIBO test, you’ll get a sugar solution to drink. Soon after you drink it, the solution hits your small intestine, where the bacteria there eat those sugars and produce gases. Small amounts of gas are normal, but larger amounts mean there’s too many bacteria there, and you have SIBO.

You expel 80% of this gas through your intestines, but the other 20% is absorbed into your blood. By measuring the levels of gases in your breath, a lab can estimate the degree of bacterial overgrowth.

So, technicians at the lab aren’t measuring the actual bacteria, but looking at the levels of the gases to estimate the numbers of bacteria. Because the gases they’re measuring (hydrogen and methane) are gases produced by bacteria, not by humans, we know that levels of those gases present in your breath reflect levels of bacteria in your small intestine.

Some SIBO breath tests only measure hydrogen, but it’s better to measure hydrogen and methane to get a more accurate picture of potential overgrowth. Here at Healthpath, we perform a hydrogen and methane SIBO test.

Healthpath’s at-home SIBO breath test is easy to use, and comes with simple instructions to guide you through. You can read more about it on our blog: SIBO test: all you need to know.

There are some things you need to be aware of well in advance of taking the actual test:

  • Four weeks before the test: finish taking any antibiotics, but you should never stop a course of antibiotics in order to take a test. Talk to your GP first.
  • One week before the test: stop taking any laxatives. Again, ask your doctor first.
  • One day before the test: eat only the foods you’re ‘allowed’ to as set out by the instructions. If you skip this part, you’ll skew your test results.
  • Twelve hours before the test: fast and drink only water. Most people find it easy to do a SIBO breath test first thing in the morning, so they can do the fast automatically overnight.
  • On the day of the test: avoid smoking and physical activity before and during the three-hour test period.

When you’ve finished the test, you’ll need to send back the bags (with your breath in them!) to our lab. You should get the results within seven working days.
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What happens if SIBO is left untreated?

Because SIBO has only been recently widely recognised as a potential cause or complication of chronic conditions, we can’t say for sure if any disease is a direct consequence of leaving SIBO untreated. However, on top of the conditions listed under ‘Symptoms Of SIBO’ above, the following conditions have strong links to SIBO:

SIBO has also been associated with various types of cancer, mostly in the digestive tract (Source: NCBI). It’s really important to say here that this doesn’t mean if you have SIBO, you’ll get cancer. It could be that there are underlying reasons why people get SIBO—for instance, a problem with immunity—and it’s those things that make it more likely that someone will develop cancer, not the SIBO itself.

It could also be that the SIBO developed after the cancer for the people in these studies. Like so many questions on health and disease, we just don’t have the answers yet.
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Can SIBO go away on its own?

The only truthful answer at this stage is: we don’t know if SIBO will go away on its own. At Healthpath, we believe that there’s a reason you got SIBO in the first place. If you want to tackle your SIBO symptoms and beat them long term, you need to fix the underlying imbalances.

If you have symptoms of SIBO, like diarrhoea, constipation or bloating, you probably don’t want to wait to see if they go away on their own. If you think you have SIBO, the best plan of action is to take a SIBO test and talk to an experienced practitioner who can guide you through the results and what to do next. Here at Healthpath, every SIBO test comes with advice from a Registered Nutritional Therapist or Functional Medicine Practitioner, so there’s no need to pay separately for guidance on what to do after a positive result.

Because SIBO is a sort of dysbiosis (an imbalance of the bacteria and other microbes in your gut) it’s possible that changes in your lifestyle or environment could re-balance your microbiome and squash your symptoms (see below for more on that line of thought). For instance, it’s quite common for pregnant women with IBS to go into ‘remission’, and stay symptom-free after the baby is born. The opposite can also happen: women can develop IBS symptoms in pregnancy that persist after the birth (Source: NCBI).

This is likely to be because pregnancy induces changes in a woman’s microbiome: it usually results in a drop in diversity of the species that reside in the gut (Source: NATURE). So, it makes sense that if one of the species that disappears is one that contributes to her gut symptoms, pregnancy may resolve those issues permanently.

Many people find lifestyle changes help their SIBO symptoms. Anything that calms you down and reduces stress chemicals in your body has a direct impact on the gut (Source: NCBI). So much research now backs this up that nobody can credibly argue with it: stress is one of the top enemies of good gut health (Source: NCBI).

The bottom line? Although there’s no studies on whether or not SIBO can go away on its own, we know that your gut is incredibly responsive to your environment. While diet is arguably the most important factor, we know other factors like stress, hormonal fluctuations (like pregnancy or the menopause) or exercise levels have a massive impact on your gut health.

So while you can ‘get rid’ of SIBO with various antimicrobials and antibiotics, that’s only one element of a much bigger plan you need to employ if you want to beat SIBO long term.

Which brings us to…
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How do I get rid of SIBO?

As SIBO is an overgrowth of bacteria in the small intestine, you might assume that if you get rid of the bacteria, it will get better.

That’s partly true. But SIBO is a complex condition, and everyone responds differently to treatment. While some people find relief soon after they begin a SIBO protocol, and manage to stay symptom free for good, others may need to try a few different avenues before they feel better.

Eradicating, or at least lowering the numbers of bacteria in your small intestine has a good chance of working to reduce your SIBO symptoms (Source: BSG). Plenty of studies prove this, but each approach has varying results, and even the same approach yields different results in different studies, so there’s no guarantee the approach you go for will work right away.

Looking at all the research carried out over the last two decades or so, it’s clear that completing one or more courses of antibiotics (only prescribed by doctors) or antimicrobials is the most important part of tackling SIBO (Source: NCBI).

Conventional doctors use antibiotics to treat SIBO, while a Functional Medicine Practitioner/Registered Nutritional Therapist will usually use a combination of antimicrobial herbs, along with other nutrients, digestive aids and methods to support gut healing and health.

SIBO and the NHS

Because SIBO was only accepted by the medical establishment as a legitimate condition not so long ago, right now, the NHS doesn’t have a standard way to approach it.

If you go to your GP with symptoms of SIBO, they won’t necessarily refer you to a gastroenterologist, who can give you the breath test. On the other hand, they might. It depends on your district, your GP, and the information you tell them.

If you do see a gastroenterologist, and you get a SIBO test, a positive result will usually mean you’ll get a course of antibiotics. Your doctor will decide which antibiotic is appropriate, and for how long you should take them.

SIBO and Healthpath

At Healthpath, we believe that there’s a reason why you got SIBO: at least one underlying issue that ‘allowed’ too many bacteria to set up shop in your small intestine.

So while it’s important to address SIBO with an antimicrobial protocol, it’s also crucial to address the root cause, because if you don’t, it’s likely to come back: one study showed 44 percent of patients who had cleared SIBO (proved by a ‘normal’ breath test result) saw it return within nine months (Source: NCBI). However the authors noted that the underlying causes of SIBO were not investigated or addressed in any of the participants.

The protocol your Healthpath Functional Medicine Practitioner or Registered Nutritional Therapist gives you depends on whether you have hydrogen or methane overgrowth. You can also have suspected hydrogen sulphide SIBO: this gas isn’t measured on the test but there are pointers that suggest it’s likely.

Tackling SIBO for good means not just getting rid of the bacteria, but improving the ‘terrain’ of the digestive system as a whole. We treat every person as an individual. Some of the tools we might use include:

A diet low in certain kinds of carbohydrates

There are several diets like this, such as the low-FODMAP diet, the Specific Carbohydrate Diet and the Bi-Phasic Diet. We create a SIBO diet guide for everybody who gets a positive result.

Antimicrobials

The antimicrobials you’ll take depend on whether you have hydrogen, methane or hydrogen sulphide-predominant SIBO, but common choices include oil of oregano, berberine, neem and garlic.

Prebiotics and probiotics (maybe)

The jury is still out on whether probiotics and/or prebiotics help or hinder SIBO. Everyone appears to have a different response.

Studies suggest that the species Lactobacillus casei, Bifidobacterium breve and Bifidobacterium bifidum (amongst others) are effective against SIBO (Source: PUBMED).
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What foods should be avoided with SIBO?

Bacteria primarily eat carbohydrates (Source: NCBI), and they favour some more than others. Certain types of bacteria also prefer certain kinds of carbohydrates (Source: NCBI).

The diet with by far the most weight of evidence behind it for tackling SIBO is the low-FODMAP diet, which restricts the carbohydrates most bacteria love to munch. You can read all about it on our blog NHS FODMAP diet: the complete guide.
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SIBO: is it auto-immune?

SIBO expert Allison Siebecker says that SIBO and autoimmunity are related in several ways. “SIBO is common in many autoimmune diseases, such as IBD, scleroderma, celiac disease, and Hashimoto’s hypothyroidism, although the exact nature of these associations isn’t fully known,” Siebecker says on her website.

Leaky gut, which is often found alongside SIBO, is one of the three underlying causes of autoimmunity, as demonstrated by many studies (Source: NCBI), along with an environmental trigger (for instance stress or exposure to toxins) and your genes. “SIBO, with its high likelihood of generating leaky gut, will need to be corrected for both prevention and treatment of autoimmunity,” she says.

So while SIBO doesn’t appear to be an autoimmune disease in itself, there are strong associations between SIBO, leaky gut and autoimmune disease. We just can’t say for sure—yet—which leads to which.
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Is IBS really SIBO?

It’s estimated that up to 22% of people in the general population have SIBO, and it’s now believed to be the leading cause of IBS, with up to 85% of people with IBS symptoms testing positive for SIBO (Source: NCBI).

If you think you have SIBO, the only way to find out is to take a test. Although the test is the most reliable method we have today of determining whether or not you have SIBO (Source: NCBI), and it’s used all over the world by doctors, research scientists and health professionals, it’s not 100% perfect. That’s why it’s important to work with a Functional Medicine Practitioner or Registered Nutritional Therapist who will look at your symptoms alongside your test result to create a personal plan to tackle your SIBO.

IBS is a term given to symptoms. That means that nobody has yet identified the cause, or causes of it. So far, research is telling us that there are many reasons for the unexplained diarrhoea, constipation, bloating and pain IBS sufferers experience. While SIBO looks to be a major one of those, it’s not the only one.

As always, let your doctor know if you have the symptoms of IBS or SIBO, or if those symptoms change.
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Key takeaways

  • SIBO is an overgrowth of bacteria in your small intestine, which should be home to relatively few bacteria: one millionth of the amount in your large intestine.
  • If your gut isn’t moving properly—or for a variety of other reasons—bacteria can build up in your small intestine.
  • To find out if you have SIBO, you can take a simple breath test at home.
  • If it’s positive, a course of antimicrobials (or antibiotics if you go through your doctor) comes next.
  • SIBO often comes back if the underlying cause isn’t addressed. Working with a professional maximises your chances of beating SIBO for good.

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Author

Alexandra Falconer MA (Dist) DipCNM mBANT is a Registered Nutritional Therapist specialising in IBS and related conditions. A graduate of Brighton’s College of Naturopathic Medicine, she is committed to fighting the root causes of chronic illness and bringing functional medicine to everyone who needs it.

Before her natural health career, Alex was a journalist and copywriter. She continues to write for magazines and media agencies, and now combines her two great passions—writing and health—by creating content that empowers people to claim their right to a healthy body and mind.
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