Irritable bowel syndrome (IBS) is a relatively common condition that can have a significant impact on quality of life. If you’re reading this, you’re likely very familiar with the impact that IBS can have on someone’s life.

I’m a registered dietitian specialized in digestive health and I also live with IBS. In this post, my goal is to share more about the condition, as well as offer guidance on the nutrition strategies available for its management. This post is not meant as individual nutrition or medical advice, but I hope that it can offer helpful information, which could be further reviewed with your healthcare team for personalized support.

With that said, let’s start with the basics!

What is Irritable Bowel Syndrome?

Irritable bowel syndrome (IBS) is a chronic condition that affects your digestive tract. You may find that your symptoms vary over time and are affected by stress, specific foods, or eating patterns. IBS is thought to affect 3.8-9.2% of people, but this may be underestimated as it can sometimes go undiagnosed.

IBS Symptoms:

IBS symptoms can vary from person to person. Some common symptoms include lower abdominal pain, changes in bowel habits (diarrhea, constipation or both), bloating and gas. You can learn more about the specific diagnostic criteria below.

How is IBS Diagnosed?

IBS is diagnosed using symptom criteria and after excluding other gastrointestinal conditions, like celiac disease and inflammatory bowel disease (IBD). This may include blood work, stool tests, and/or a colonoscopy. It should be diagnosed by a doctor after testing and a review of symptoms using the Rome IV criteria.

Rome IV Criteria:

Recurrent abdominal pain on average 1 day per week in the last 3 months, associated with two or more of the following:

• Related to defecation
• Associated with a change in frequency of stool
• Associated with a change in form (consistency) of stool
• Symptoms must have started at least 6 months ago

Depending on the predominant symptom, IBS can be classified as IBS-C (constipation), IBS-D (diarrhea), IBS-M (mixed) or IBS-U (unclassified).

What is the Cause of IBS?

The cause of IBS is still unknown, but is likely multifactorial. Some proposed factors include altered gut motility, visceral hypersensitivity, low grade inflammation, immune system activation, and changes in the gut microbiome.

IBS Red Flags:

While IBS is a common condition, it can sometimes be misdiagnosed. Some red flags can indicate the presence of another condition and is worth reviewing with your doctor.

• Unexplained weight loss
• Family history of bowel diseases (cancer, inflammatory bowel disease)
• Blood in the stool
• Age of onset over 50 years
• Fever
• Recurrent vomiting
• Bowel movements waking you up at night
• Menstrual symptoms impacting quality of life (pain, heavy or prolonged bleeding) – You can learn more about the connection between IBS and endometriosis here.

Now that we covered the basics of IBS, let’s look at some nutrition strategies for symptom management.

Nutrition Strategies for IBS

1. Build a Routine

It’s often helpful to start with the basics! The gut works best with a routine. Aim to eat three meals at regular times each day, plus snacks as needed. Try eating slowly at a time when you feel relaxed. This is an important and underrated strategy for digestive health.

2. Stay Hydrated

Choose water as your main fluid. Staying hydrated will help with bloating and regularity. Sounds simple, but it can be a challenge!

3. Eat Enough Fiber

Most people need between 25-38g of fiber each day. There are two types of fibers:

• Soluble fiber is found in oats, oat bran, ground flax, psyllium, and some fruits and vegetables. It may help to relieve both diarrhea and constipation.
• Insoluble fiber is found in wheat bran, bran cereals, whole grain products, and the skins of fruits and vegetables. It can help with constipation, but may not be well tolerated by some people with IBS.

Make sure to increase fiber gradually and to stay well hydrated to help the fiber work its best and to avoid unpleasant side effects (mostly gas and bloating).

It can be tempting to reduce fiber with IBS, especially when you experience diarrhea and bloating. Avoiding fiber can often worsen symptoms over time and can lead to more and more food restrictions. If you find it difficult to tolerate fiber-rich foods, I recommend prioritizing foods with more soluble fiber. These can help with both constipation and diarrhea, and tend to be better tolerated with IBS. This is especially the case with low FODMAP sources of soluble fiber (more on the low FODMAP diet soon). If you struggle with fiber, I highly recommend working with a dietitian for more personalized support.

4. Be Mindful of High-Fat Meals and Snacks

Fats are important, but eating too much fat at once may cause cramping and diarrhea. Examples include deep fried foods, meals with cream and cheese, ice cream and high-fat meats. Instead, try eating a moderate amount fat spread out throughout the day.

5. Adjust Your Caffeine Intake

Caffeine stimulates the gut and may worsen diarrhea. It can be found in coffee, tea, some sodas, energy drinks, and chocolate. If caffeine triggers symptoms, try having less to find an amount that works for you. You may not need to cut it out completely!

6. Consider the Low FODMAP Diet

FODMAPs are short-chain carbohydrates (sugars) that are found in various types of foods. These are poorly absorbed and can increase IBS symptoms. FODMAPs include lactose (dairy), fructose (some fruits, honey), fructans (wheat, onions, garlic), GOS (beans, lentils) and polyols (some fruits, vegetables). A low FODMAP diet is a temporary elimination diet to help you learn more about your food triggers.

A low FODMAP diet is not necessary for every single person living with IBS. It’s also very restrictive and can be contraindicated for some. In my practice, depending on the client’s preference, we often start with the basics before jumping into the low FODMAP diet. Some may be able to manage their symptoms well with a regular eating routine, good hydration, and an adequate fiber intake.

If you’ve tried other strategies without success and would like to try a low FODMAP diet, I highly recommend doing it with the guidance of an experienced dietitian.

7. Supplements for IBS

Some supplements may be helpful in the management of IBS. This is not a one-size-fits-all situation. Each person can benefit from different supplements, based on their own symptoms and tolerance. Some supplements to consider with your health care team:

• Fiber supplements: I often recommend psyllium husk (such as Metamucil) or partially hydrolyzed guar gum (Fiber4 in Canada). These supplements are generally well tolerated and can help with regularity, whether you have IBS-C, IBS-D or IBS-M. These may not be well tolerated if you have stool back-up. If you experience an increase in symptoms when using them, you can review your options with your doctor or dietitian. It’s also important to drink enough water when supplementing with fiber or you risk experiencing constipation. It’s also advised not to take a fiber supplement within 2 hours of taking medication.
• Peppermint: Peppermint oil, such as IBGard, may help in reducing symptoms of abdominal pain related to IBS.
• Probiotics: Not all probiotics are created equal. Their benefits are strain-dependent and each person’s response can vary. It’s best to start with a supplement with evidence for your own symptoms. A dietitian can help you find a probiotic supplement that best meets your needs.
• Other: Ginger can help with motility and nausea. Iberogast can also be helpful with symptoms of indigestion. A ginger or peppermint tea could be soothing for digestion as well. If you have reflux, be careful with peppermint as it may increase symptoms.

8. Limit Food Restrictions

Restrictive diets without a specific plan and guidance from a dietitian are likely to cause more harm than good. When making diet changes for IBS on your own, I recommend starting with the basics and focusing on what you can add, more than what you can take away. Consider keeping a food and symptom journal to notice which foods tend to increase your symptoms. This could help you and your dietitian develop a personalized approach to manage your condition, while limiting food restrictions.

Note that IgG food sensitivity tests are not evidence-based and not recommended for the diagnosis of food allergies and intolerances. If you suspect a food allergy or intolerance, talk to your doctor and dietitian to review your options.

Non-Nutrition Strategies for the Management of IBS

Some lifestyle habits can have an impact on IBS symptoms. Habits such as managing stress, good sleep, being physically active, and limiting alcohol can have positive impacts on your symptoms. A few more strategies to consider:

• Pelvic floor physiotherapy: A pelvic floor physiotherapy assessment may be worthwhile if you have IBS. Pelvic floor dysfunction can increase symptoms of constipation, diarrhea, and more. An assessment can help determine if your pelvic floor muscles are impacting your symptoms, plus offer exercises to help.
• Therapy: A psychologist or counsellor can offer support with sleep and stress management, which can impact IBS symptoms. Stress management strategies, such as meditation, yoga, walking, spending time with loved ones, and other relaxing activities may be helpful.
• Gut-directed hypnotherapy: The brain-gut axis (connection) has a role in IBS symptoms. Gut-directed hypnotherapy targets the brain-gut connection and has been shown to reduce IBS symptoms at a similar rate as the low FODMAP diet. This can be done through the Nerva app or through a trained therapist. This is not sponsored!
• Medication: Sometimes lifestyle is not enough. Some medications can offer relief for IBS symptoms, such as diarrhea, constipation, pain, and more. If you would like to use medications as part of your IBS management, I recommend reviewing the options with your doctor.

Final Notes:

IBS management is complex and personal. I hope that this post offered some guidance on the basics of nutrition for IBS. If you’re considering making diet changes for IBS management, I highly recommend starting with the basics. Eat regularly during the day (and eat enough), drink enough water, eat adequate amounts of fiber, move your body as able, and reduce stress in any way you realistically can. If you need to make more adjustments, I recommend keeping a food and symptom journal and working with an experienced dietitian. This can help you find your triggers and approach food restrictions in the safest way possible. It can take time, but I hope that you will eventually find the right strategies for you.

If you live with IBS and are looking for dietitian support, I would be happy to help! I offer virtual nutrition counselling to those living in British Columbia and New Brunswick. I also offer in-person support at CAYA Health Centre in Vancouver. You can learn more about my approach, training, and availability here. I also offer 15-minute complimentary consults if you want to review your goals and make sure we’re a good fit.

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This information is intended for educational purposes only and is not meant to replace individualized nutrition or medical advice.