Everything You Need to Know about Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common disorder that affects millions of Americans. Learn about symptoms, causes, diagnosis, treatment and more.

What is IBS?

Irritable Bowel Syndrome (IBS) is a chronic gastrointestinal disorder that affects an estimated 10-15% of the American population. That is approximately 50 million Americans. IBS is defined as recurrent abdominal pain, on average, at least 1 day/week in the last 3 months associated with altered bowel movements.

IBS Symptoms

Irritable Bowel Syndrome symptoms may include any combination of abdominal pain, excessive gas production, bloating, diarrhea, and constipation. Based on the bowel movement symptoms, there are three major subtypes of IBS: the one with predominant constipation (IBS-C), diarrhea (IBS-D), or both (IBS-M). IBS has also been strongly associated with mental health, with about 80% of IBS patients also suffering from anxiety or depression. This is due to the gut-brain axis, a direct connection between our brain and gut via the vagus nerve and neurotransmitters.

What causes IBS?

There is currently no known cause of the disease. However, genetics plays a minor role, so the disease is likely caused by nutritional and lifestyle factors. There is strong evidence that the gut microbiome dysbiosis plays a significant role in IBS. Evidence includes the overuse of antibiotics, colonoscopy (intestinal prep), and postinfectious IBS, which has been confirmed in animal models. Infections that have been associated with follow-on onset of IBS include Giardiasis, Campylobacter, and specific toxin-producing strains of Escherichia coli. However, many other types of non-specific gastroenteritis have been associated with the downstream development of IBS symptoms.

The most likely cause of IBS is functional gut microbiome dysbiosis (dysfunction), which affects both the intestinal lining and production of neurotransmitters that influence mental health. This dysbiosis can be established with antibiotics.

Is there a test for IBS?

IBS is diagnosed using established symptom criteria in the absence of “red flags” such as unexplained weight loss, blood in stool, or recent change in bowel habits. There is no examination or molecular test for IBS. Some physicians will perform a colonoscopy, which excludes other diagnoses, such as Inflammatory Bowel Disease (IBD), but does not diagnose IBS. Disease diagnosis has to be obtained at a healthcare provider.

How is IBS diagnosed?

The gold standard diagnostic test, called the Rome criteria, is all symptoms-based. There are no blood or stool tests. The Rome criteria include two questionnaires: one to determine if a patient has IBS and which subtype, and the other one to determine the disease severity. Some physicians will perform a colonoscopy, which excludes other diagnoses, such as Inflammatory Bowel Disease (IBD), but does not diagnose IBS. An official diagnosis can only be made by a healthcare provider.

IBS and Gut Health

With a complex condition like IBS, knowledge is power. Since there are many causes of IBS, there is no one treatment that works for everyone. Changes in how we assess our gut health can mean more than just cleaning up your diet – it can mean the freedom to go back to living. It means feeling good about your body, traveling, socializing, and eating. It means regaining control of your life. The Viome Gut Intelligence Test can help provide people suffering from Irritable Bowel Syndrome with the nuanced information they need to finely adjust their diet, help alleviate episodes of gastrointestinal discomfort, and build up a healthy gut microbiome. 

How do you treat IBS?

IBS is a chronic disorder, and there is no cure for IBS. Different approaches have been attempted as IBS therapy, all with limited success, especially long-term. Some antibiotics, such as rifaximin, have shown a modest improvement in certain participants. Certain diets can relieve some symptoms of some patients. The most well-known diet that is recommended by some physicians is a low FODMAP diet. However, even when it works, most patients find it challenging to maintain. Some providers have attempted to use fecal microbiota transplants (FMTs) to treat IBS, however, there is currently no scientific evidence for the effectiveness of FMT. Cognitive Behavioral Therapy (CBT) has been shown to be at least as effective as currently available gut-targeted therapies. CBT has shown efficacy on a percentage of the IBS patient population, so this avenue should be further developed and tested.

Can probiotics help with IBS?

While probiotics have shown efficacy towards IBS, as with the other therapies, they work in some patients, with uncertain long-term benefits. Again, the main reason for this is that the probiotics are chosen mostly based on a scientist’s opinion and anecdotes, or a manufacturer’s favorite product. While probiotics can restore the proper balance in the gut microbiome and relieve IBS symptoms in some patients, a data-driven approach has to be taken. That means that each IBS sufferer has to be given a very specific combination of strains, then fed a very specific diet that will ensure effective colonization of the strains and proper functional contribution to the gut microbiome health.

Best foods to eat for IBS?

The limited success of the low FODMAP (fermentable oligo-, di-, mono-saccharides, and polyols) diets has been obtained in several clinical trials, especially when it comes to reducing the symptoms of abdominal pain and diarrhea. However, the quality of life relative to a standard diet has been shown to be equivalent. In addition, most people have a difficult time maintaining a low FODMAP diet, and there are concerns about malnutrition during the low FODMAP diet that has been documented. Increased fiber intake has relieved symptoms of IBS, especially constipation, in some trials. However, there are no guidelines that recommend specific fibers to patients based on their microbiome. No specific foods have been identified as universally good for IBS sufferers. The reason for this is that the gut microbiome of IBS patients is very diverse compositionally. Each person needs to consume a very different diet in order for their gut microbiome to produce healthy biochemicals and stop producing disease-associated ones. Personalized diets, based on comprehensive and functional gut microbiome tests, will revolutionize the treatment of IBS, as they will truly restore the healthy functional gut microbiome for each person.

Are there foods to avoid if you have IBS? How about coffee and alcohol?

Besides FODMAPs, there are several other foods that have been reported to have negative effects on IBS symptoms in some patients. These include high-fat foods, gluten-containing foods (which may be an overlap with FODMAPs), spicy foods, dairy, coffee, and alcohol. Because the symptoms and likely causes of IBS are so diverse, and gut microbiomes of IBS patients can vary widely, it is necessary to personalize each person’s diet in order to reduce the symptoms of IBS.

Can you cure IBS?

If the symptoms can be permanently eliminated, IBS will be effectively cured. While there are reports of curing IBS with fecal microbiota transplants (FMT), the long-lasting effects of such therapies have not been reported. Given that the symptoms change over time and that some patients experience prolonged disease remission, it is very likely that curative therapy is possible.

Is IBS genetic?

The contribution of genetics to IBS varies widely from study to study (from 0-57% influence), which makes it difficult to quantify. However, the majority of people who have genetic predisposition do not develop IBS, and the majority of people who have IBS do not have a genetic predisposition. Most importantly, once a person has IBS, it does not matter what their genetic predisposition is, they can heavily influence their symptoms with diet and lifestyle changes.

By Momo Vuyisich, Ph.D., Biochemistry

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