Irritable Bowel Syndrome (IBS) is a complex diagnosis that’s highly varied among individuals. While there isn’t much research on IBS in vegans, or the use of a vegan diet to manage IBS symptoms, there are many important considerations to keep in mind.
This article reviews:
- What is IBS?
- What Triggers IBS Flare Ups?
- Lifestyle and Dietary Management of IBS
- Living with IBS
- Living with IBS as a Vegan
Please note: This is a broad topic overview and details about physiology and pathophysiology have been simplified for easy reading and understanding. Always speak to a doctor before changing your diet and/or medications.
What is IBS?
IBS, or Irritable Bowel Syndrome, is a chronic gastrointestinal disorder characterized by abdominal pain, discomfort, bloating, excessive gas and bowel changes.
The cause of IBS is not completely clear, however it’s known to be a multifactorial disease. This means it can be caused by multiple simultaneous factors including: 1
- Increased gut sensitivity to pain
- Abnormal gut mobility
- Imbalance of gut bacteria
- Gastrointestinal infections (ie. Infections in the digestive tract)
- Life stressors
- Emotional stress
- Food triggers
IBS is classified based on a person’s bowel movements. The three types of IBS include:
- IBS with constipation (IBS-C)
- IBS with diarrhea (IBS-D)
- IBS with alternating symptoms of constipation and diarrhea (IBS-A)
Symptoms of IBS
IBS symptoms vary between individuals and the type of IBS they experience. These symptoms range from mild to severe and fluctuate over time. As a result, it’s challenging to diagnose IBS as symptoms can overlap with other diseases or disorders 1. If you think you may have IBS, please contact your health care provider.
Common symptoms for IBS include:
- Lower abdominal pain
- Change in stool form or frequency
- Excessive gas
- Bloating or cramping
These symptoms are fairly general and could relate to many other disorders. Working with your primary care provider, or specialists, is necessary to receive a positive IBS diagnosis (or learn what else may be the cause of your symptoms). Always speak to a qualified healthcare provider if you experience any of the above symptoms or are concerned about your health.
It’s a challenge to diagnose IBS because symptoms are non-specific, vary from person to person, and there’s currently no medical test to accurately detect and diagnose IBS. It can take many years to receive an IBS diagnosis 2.
In addition, symptoms of IBS tend to overlap with other GI conditions such as celiac disease, colon and/or pancreatic cancer, lactose or fructose malabsorption, or inflammatory bowel disease 3.
Making a positive IBS diagnosis allows individuals to seek treatment and increase confidence on how to respond to IBS symptoms 3.
What Triggers IBS Flare Up?
Individuals with IBS have unique triggers. Identifying these triggers is extremely important for relief and prevention of symptoms. The two most common IBS trigger categories are diet and stress.
Diet can play a large role in developing IBS symptoms. Most individuals can experience symptoms soon after eating specific foods 4. Keep in mind everyone has their own food triggers which may include:
- High FODMAP foods
- High fiber foods
- Dairy Products
- High fat foods
- Spicy foods
- Processed foods
- Sugar free sweeteners
Lifestyle and Dietary Management of IBS
There’s currently no cure for IBS, but treatment options which focus on relieving symptoms and preventing IBS flare ups are available. Diet and lifestyle changes are the most effective tools to manage IBS.
Treatments should be individualized based on the type of IBS and symptoms one experiences. Working with a Registered Dietitian is a great way to identify treatments that are best suited to your symptoms and lifestyle.
Certain diet and lifestyle therapies may help relieve IBS symptoms, including:
- Low FODMAP Diet
- Alcohol Intake
- Caffeine Intake
- Spicy Food Consumption
- Fat Consumption
- Gluten-Containing Foods
- Modification of Fiber Intake
- Lactose Intolerance
- Physical Activity
- Stress Management
After lifestyle and diet changes have failed to resolve IBS symptoms, medications are the most common treatment approach. However, pharmacological treatments generally only target one symptom of the many experienced with IBS.
Please contact your healthcare practitioner for more information on pharmacological treatments available to you.
Low FODMAP Diet
FODMAPS (fermentable oligo-, di-, mono- saccharides and polyols) are a group of carbohydrates that are poorly digested and/ or absorbed in the intestines. They can cause digestive (or IBS) symptoms like gas, bloating, constipation and diarrhea in individuals who are sensitive to them.
The low FODMAP diet is a dietary therapy for IBS management, with current research suggesting it’s the gold standard in dietary interventions for people with IBS 5.
Before staring the low FODMAP diet, confirming a diagnosis is crucial. Since it’s challenging to follow (especially for vegans) and there are risks with its restrictive nature, it’s important to know that you have IBS first. Otherwise, the effort and risks are likely not worth it.
Keep in mind that many foods high in FODMAPs are healthy and nutrient dense. FODMAPs are not bad. The low FODMAP diet is meant to figure out which carbohydrates are major contributors to an individual’s IBS symptoms or flare ups. Every individual has unique triggers and tolerance levels that can be explored by following all three phases of a low FODMAP diet.
The low FODMAP diet’s three steps include: 6
- Restriction: Swapping high FODMAP with low FODMAP foods for 2-6 weeks. This phase can be a challenge for most vegans and it’s critical to work with a dietitian to ensure nutritional adequacy.
- Reintroduction: Slowly reintroducing one high FODMAP food at time for 8-12 weeks. This is a critical step in the process. One of the biggest mistakes people make is staying in the elimination phase and not working to reintroduce higher FODMAP foods back into their diet to assess tolerance levels.
- Personalization: Long-term follow up where the diet is customized to be as liberal as possible. Information gathered during the reintroduction phase is used to determine which high FODMAP foods someone could tolerate (and add back into their diet) or which ones should be limited or avoided.
The low FODMAP diet is not a one-size fits all approach, nor a diet to be kept for life. It’s highly restrictive and adherence to it long-term can lead to nutritional inadequacies 7.
Long-term, low FODMAP diets should slowly reintroduce high FODMAP foods and investigate one’s individual tolerance of specific FODMAP foods through food tastings 8. It’s a complex dietary intervention that should be implemented with education and assessment from a dietitian.
Many people have self-reported that alcohol intake increases their IBS symptoms. However, it’s unclear whether alcohol intake increases symptoms in those with IBS.
Studies have shown that binge drinking was associated with IBS symptoms of diarrhea, stomach pain and indigestion. In addition, alcohol intake and IBS symptoms were strongest upon individuals with specifically IBS-D 9.
Caffeine is a known stimulant that increases gut motility and leads to a laxative effect in people. Therefore, caffeine intake can be detrimental for those with IBS, especially IBS-D.
Studies have showed that individuals with IBS associate their symptoms with caffeine intake. Nevertheless, the role of caffeine in IBS is still unclear.
If caffeine increases your IBS symptoms, it’s generally recommended to reduce daily intake to 400mg, which is the safe limit for most adults 10. Some people may benefit from further reducing caffeine consumption.
Spicy Food Consumption
Spicy foods commonly trigger IBS flare ups. Some individuals with IBS benefit from reducing consumption of spicy foods 10.
In one study, 40% of individuals with IBS reported that spicy foods triggered their IBS symptoms such as abdominal pain and burning 11. It’s also been found that spicy foods can cause diarrhea in people with IBS. People with IBS-D may need to be extra cautious with spicy foods or may choose to avoid them completely.
Capsaicin, an active component in chili peppers, has been associated with triggering abdominal pain for people with IBS 10.
Avoiding high fat foods, or high fat meals, is a common dietary approach for individuals with IBS. This is because higher fat meals may increase symptoms in individuals with IBS 7.
In a study, one-third of people with IBS reported fat intake as a trigger for their IBS symptoms 11.
However, no clinical studies have found that reducing fat intake results in IBS symptom improvement 10. As with everything related to IBS, diet modifications need to be individualized as there’s never a one-size-fits-all approach.
Gluten free diets have grown in popularity over the past decade. The use of a gluten free diet, outside of the diagnosis of Celiac Disease, has shown promising data for those with IBS.
Many studies have demonstrated clinically significant improvements in IBS symptom severity within 6 weeks 7. Despite studies demonstrating the benefits of a gluten free diet, controversy remains.
It’s believed that other components in wheat may cause IBS symptom flare ups, not gluten. Specifically, it’s thought that the FODMAP content of gluten-containing foods can be a concern for people with IBS 7.
Modification of Fiber Intake
Dietary fiber are carbohydrates found naturally in plant-based foods. Increasing dietary fiber has been recommended for those with IBS because it’s believed that certain symptoms are a result of low fiber intake 12.
There are two subtypes of dietary fiber, soluble and insoluble fiber. Health benefits of increased fiber are specific for each type of fiber. Therefore, dietary fiber recommendations vary based on the type of IBS and the individual.
In general, increased intake of soluble fibers are found to improve overall IBS symptoms while increased intake of insoluble fibers may worsen IBS symptoms such as bloating or pain 12.
Alternatively, some people may consume too much fiber, including vegans who eat a lot of whole plant foods. While fiber is a beneficial nutrient, some vegans with IBS may find it helpful or necessary to reduce fiber intake. This may sound completely backwards to many people as the message is usually to eat more fiber. However, individuals with IBS who consume excess fiber may find relief with lower intake.
As always, work with a dietitian to make modifications to your diet.
Many individuals with IBS attribute their symptoms to consuming dairy products. This is because dairy products consist of a high FODMAP carbohydrate known as lactose.
Lactose is a disaccharide that’s broken down in the intestines by an enzyme called lactase. Many people do not make enough lactase and therefore cannot properly break down lactose.
Many people with IBS can improve symptoms from following a dairy free, or lactose reduced diet 10.
There are tests to determine lactose intolerance and these options can be explored when working toward an IBS diagnosis. If lactose intolerance triggers your symptoms, this would be very helpful to know before further modifying your diet (trialing a low FODMAP diet for example).
If you’re already vegan and not consuming dairy products, this may not be applicable!
There’s been an increased interest in recommending probiotics for those with IBS. This is because certain probiotic strains can be potentially beneficial. Nevertheless, there’s not enough clinical evidence to recommend probiotics as a treatment for IBS.
The type of probiotic to use, dosage, and treatment duration is still unclear 10. If you’re interested in taking probiotics, seek advice from your healthcare practitioner or dietitian for more information.
Physical activity is recommended for people with IBS because it can improve digestive symptoms.
In one study, increased physical activity decreased the severity of digestive symptoms and improved quality of life among people with IBS 13. In addition, this study demonstrated how digestive symptoms may worsen among those who are physically inactive.
Physical activity may help protect against IBS symptoms, but more research is needed to figure out the type, frequency, and intensity of physical activity that provides the most benefit.
There’s a bidirectional relationship between stress and digestive symptoms in people with IBS. This means that increased stress can trigger IBS symptoms, then IBS symptoms can further increase stress levels, creating a vicious cycle 14.
Research has shown that stressful events can increase the severity of IBS symptoms too. Life stressors during childhood or later in life may be involved in the onset of IBS symptoms among vulnerable individuals 15.
IBS is a stress sensitive disorder; therefore, it’s necessary to prioritize stress management and self-care.
There’s a strong correlation between IBS severity and psychological disorders such as anxiety and depression 15. This is significant because seeking treatment for psychological disorders may provide additional IBS symptom relief.
Living with IBS
IBS is a chronic condition, meaning that it’s present throughout one’s lifetime.
IBS is not life-threatening or associated with decreased life expectancy, however it still has a significant impact on one’s quality of life and healthcare costs.
It’s been found that individuals with IBS are at a greater risk of depression and lower quality of life 16. This is because the occurrence of IBS symptoms is unpredictable and can negatively affect one’s daily activities, sleep, ability to travel and social relations 14.
Research has showed that individuals with IBS experience physical (ex. IBS symptoms), psychological (ex. depression or anxiety) and social consequences (ex. not being able to attend social activities). Therefore, IBS can have detrimental effects on one’s physical and mental health.
Again, this stress from living with IBS is damaging because it can worsen symptoms and create a vicious cycle 14.
If you or a loved one have been diagnosed with IBS, it’s important to seek family and friends for emotional support. Educate loved ones about IBS and how they could help during flare ups.
Overall, IBS is manageable but difficult to handle if not properly managed. Working with your doctor or dietitian will help identify treatments best suited for your symptoms and their underlying causes.
Living With IBS As a Vegan
Living with IBS as a vegan may a challenge. High-FODMAP foods are a common trigger for IBS and many vegan or vegetarian options are high in FODMAPs. Dietary management of IBS can be very restricting for vegans and may prevent one from meeting their daily nutritional requirements.
Avoiding high FODMAP foods may be difficult when eating out or travelling. Individuals will have to spend a considerate amount of time food shopping, cooking, and preparing meals.
If you haven’t already, read my article about a low-FODMAP diet as a vegan.
Knowing about the FODMAP composition of foods and how processing techniques can affect FODMAP content is beneficial for vegans following a low FODMAP diet.
It’s possible to maintain a vegan diet and manage IBS, but it may take more planning (and more cooking) to ensure an enjoyable, varied diet that meets nutritional needs.
If a low FODMAP diet isn’t possible to maintain, there are many options to explore with your healthcare team. Working with a dietitian can be very beneficial for finding dietary and lifestyle management techniques that work best for you and your IBS.
Summary: IBS and A Vegan Diet
IBS (Irritable Bowel Syndrome) is a chronic gastrointestinal disorder that can substantially affect one’s quality of life if not managed properly.
IBS symptom severity and frequency vary from person to person. For many individuals, diet and stress play a substantial role in triggering IBS symptoms.
There’s currently no cure for IBS. However, dietary and lifestyle changes have shown potential in helping individuals manage their IBS symptoms and flare ups. Management of IBS is the most successful when it’s individualized and directed by a dietitian with expertise with IBS and low-FODMAP diets.
Navigating IBS as a vegan poses some additional challenges but can be done. It can be very helpful to work with a dietitian to ensure an enjoyable lifestyle that includes tasty foods.
- Relationship Between Patterns of Alcohol Consumption and Gastrointestinal Symptoms Among Patients With Irritable Bowel Syndrome.
Please note that this is a curated list of references for the topics above and not intended to be comprehensive.
Disclaimer: always speak with a doctor before changing your diet. Please read our full website disclaimer.
Author Profile: Nicole Stevens
Nicole is a vegan Registered Dietitian (RD) and founder of Lettuce Veg Out. She provides vegans with balanced meals and easy-to-understand nutrition science.
Having attained a Masters degree and passing a national registration exam, Nicole is a trusted source of nutrition information. She uses this knowledge to educate others about vegan diets and how to thrive as a vegan.