Nutrition for Inflammatory Bowel Disease (IBD) on a Plant-Based Diet

July 1, 2022

Are you wondering whether you can manage inflammatory bowel disease (IBD) on a plant-based diet? You’re not alone. Plant-based diets for IBD have been gaining traction and attention amongst some of the 80,000 Australians diagnosed with IBD (1).

This article will discuss what IBD is and how it is affected on a plant-based diet. IBD is regularly mistaken for irritable bowel syndrome (IBS) as they share some common symptoms, but these are very different conditions. For more information, we have a blog post discussing IBS in more detail.


What is IBD? (Crohn’s Disease and Ulcerative Colitis)  

Inflammatory bowel disease refers to ongoing (chronic) inflammation within all or part of the digestive tract (1). There are two conditions that fall under the IBD category. These are:


Crohn’s Disease

Crohn’s affects the lining within any part of the digestive tract (mouth to anus) however it is predominantly found in the ileum which is located at the end of the small intestine (3). Crohn’s causes swelling and inflammation in the affected area and increases the risk of colorectal cancer (1,2).

Symptoms of Crohn’s disease include:

  • Abdominal pain (2)
  • Diarrhoea (2)
  • Reduced appetite (2)
  • Weight loss (2)
  • Fatigue
  • Blood in stool (2)


Ulcerative Colitis (UC)

Ulcerative colitis affects the surface layers of the large intestine (bowel) and/or rectum. UC results in small ulcers forming on the lining of the intestine (3, 9). UC also increases risk of developing colon cancer (9).

Symptoms of ulcerative colitis include:

  • Abdominal pain and cramps (9)
  • Diarrhoea (9)
  • Fatigue (9)
  • Reduced appetite (9)
  • Rectal bleeding (9)
  • Blood and/or mucus in stool (9)

While IBD is a life-long disease, people are either in an active state/flare-up or in remission. When in an active state, this condition affects your energy levels, appetite, and bowel movements (1).

There are medications to help lower symptoms in these conditions. The most common types of medications are steroids, antibiotics, and medicines that suppress the immune system (1, 2). However, as there is no cure, it is important to also use dietary strategies to help minimise symptoms, especially when experiencing flare-ups.


bloating and nutrition for ibd on a plant-based diet


Who is at risk of developing IBD?

While the root cause of inflammatory bowel disease is unknown, we do know that anyone can develop IBD, with most people diagnosed between the ages of 15-30 (1, 2). However there are risk factors that are thought to increase the likelihood of acquiring these conditions. Some of these include:

Family history – Some studies have an shown increased likelihood for those to develop Crohn’s or UC if there is a close relative with the condition (2).

Environment – Crohn’s and UC have been shown to be more common for those living in western countries such as Australia, the United States and Western Europe compared to Asia and Africa (2). It is suggested that the modern, ‘Western’ lifestyle may play a role in this.

Smoking – Studies have shown that smoking can increase the likelihood of developing Crohn’s (2, 7).


How does plant-based eating affect IBD?

Studies have shown many benefits of plant-based eating on overall health. Plant-based eating promotes high intakes of grains, fruits, vegetables, legumes, nuts, and seeds. These are full of nutrients that generally help our body and gastrointestinal (GI) tract to function and thrive (3).

Research has supported that the best diet for those with IBD is one that nourishes your gut bacteria (3). Our gut microbiome is made up of trillions of organisms that play many roles in the body. Some of these include reducing inflammation while also contributing to digestion.

There are many foods that feed our gut bacteria, with the majority originating from plant-based sources. Foods such as leafy green vegetables, whole grains, and high-fibre meals all contribute positively to creating a healthy gut microbiome.


This should mean that following a plant-based diet is the most efficient in minimising symptoms, right?


It’s true these foods have a positive impact on the gut microbiome, but there are some challenges for IBD on a plant-based diet too.

Plant-based diets can be a double-edged sword for those with IBD as the foods listed are also culprits that can worsen symptoms during flare-ups or times of active inflammation. We will discuss this in more detail further on.

Additionally, as plant-based diets restrict foods originating from animal sources, there is a risk of developing deficiencies in various nutrients that further increases when implementing a plant-based diet for IBD.


leafy greens nutrition for IBD on a plant-based diet


Benefits and risks of a plant-based diet for IBD



Fibre – This feeds the gut bacteria and promotes a healthy gut microbiome. Soluble fibre is a type of fibre that assists with slowing digestion, softening stools and preventing constipation (7). Soluble fibre is found in foods such as oats, beans, carrots, citrus fruits, and psyllium.

Polyphenols – These are a type of natural plant compound that are beneficial as they reduce inflammation (3,4). Polyphenols can be found in foods such as berries, plums, beans, nuts, spinach, onion, green tea, and dark chocolate (4, 8).

Excludes animal products – Foods such as red meat and dairy have been found to cause negative impacts on gut health and are known to aggravate symptoms. For those with IBD, regardless of dietary choice, it is recommended to minimise dairy and meat consumption (3,6).



Fibre – Wait a minute, I thought fibre was a pro? For someone with this condition, fibre is both a pro and a con. As mentioned, fibre is extremely important for gut health. However, fibre can also worsen symptoms during a flare-up (11). This is due to fibre not being digested and at the wrong time (during a flare) this can cause diarrhoea, constipation, bloating, gas and/or cramping as it moves through the digestive tract.

Risk of nutrient deficiencies – A major concern for anyone diagnosed with IBD can be malnutrition (lack of essential nutrition) due to poor absorption (4). This may mean higher requirements for certain nutrients (5). When following a plant-based diet and experiencing flare-ups, certain nutrient-dense foods may be avoided in the diet such as vegetables or whole grains (11). This can lead to further risks of becoming malnourished.

Volume eating – A lot of plant-based foods are naturally lower in calories/energy in comparison to animal-based products. This means that meals may be bigger to compensate to ensure fullness. Examples of this can be a salad or stir fry full of vegetables that are lower in energy/calories. Consuming large amounts of food in one sitting can put strain on the digestive system which can contribute to uncomfortable symptoms such as bloating or diarrhoea.


salad with strawberries and avocado for IBD nutrition on plant-based diet


Whole foods vs. plant-based alternatives to discretionary foods

Current advice for those with inflammatory bowel disease is to eat a well-balanced diet while limiting processed foods and avoiding foods identified to worsen symptoms (7).

Whole foods are identified as unprocessed and free of any additives. They are also typically nutrient-dense and have positive outcomes for health. Many whole foods are shown to have anti-inflammatory properties to help create a healthy gut microbiome to help minimise symptoms and reduce inflammation (8).

Whole foods include:

  • Fruits
  • Vegetables
  • Legumes
  • Whole grains
  • Nuts and seeds

A lot of processed foods may also be referred to as discretionary foods. Discretionary foods refer to foods that don’t fit into the five food groups – fruit, vegetables, dairy or alternatives, meat or alternatives, and grains.

Many discretionary foods often lack essential nutrients and contain added sugars and salt. They also contain food additives such as thickeners and emulsifiers. Some research has found that these compounds may increase inflammation and the risk of flare-ups for people with IBD (8).

Discretionary foods are often found to be high in fat which has been found to worsen symptoms.

Plant-based discretionary foods include:

  • Sugar-sweetened beverages – soft drinks and bottled iced tea
  • Mock meats
  • Plant-based baked goods and pastries
  • Plant-based fast-food – veggie burgers and fries
  • Chips, savoury biscuits, pretzels

While we don’t advocate for cutting these foods out completely (as this would likely be unsustainable), it may be wise to base the majority of your diet around whole foods when managing IBD.


plant-based discretionary foods and IBD


How to get started with eating more plant-based for IBD

It’s important to start small when implementing any new dietary changes with IBD. While you may want to jump in headfirst, the gut can be quite sensitive. A slow and steady change to your diet may be the best approach. Here are some tips to help get you started with IBD on a plant-based diet.


Slowly increasing fibre intake

As discussed, fibre can be beneficial for a healthy digestive tract. However, if you are experiencing an active flare-up or are new to a high-fibre diet, the drastic change can worsen symptoms. When there is no active inflammation, try slowly introducing more soluble (‘soft’) fibre sources (e.g. oats, beans, carrots, citrus fruits, and psyllium) to help create a healthy gut microbiome (10).


Choosing lower fibre options when necessary

Contrary to the last point, when experiencing a flare-up, a high-fibre diet may not be beneficial. This means sometimes it is necessary to choose lower-fibre options. Additionally, it may mean cutting the skin off fruit and vegetables as they are high in insoluble fibre (otherwise known as ‘rough’ fibre). As a reminder, this is not advised long-term and only when experiencing symptoms or recommended by a health professional (10).


Cooking vegetables

When experiencing a flare-up, raw vegetables may further aggravate symptoms. Cooking vegetables can help improve digestion and lower the insoluble fibre content.


Eating enough protein

As the risk of malnutrition is higher in those diagnosed with Crohn’s or UC, ensuring you get enough protein is important. This can include tofu and other soy products (11). We have an article dedicated to getting enough protein on a plant-based diet.


calcium-fortified tofu on a vegan diet - bowl with broccoli, rice, herbs


Recognising trigger foods

Understanding foods that trigger symptoms is important and can help you eliminate foods that worsen flare-ups. This may be done with a food diary or a temporary elimination diet (5). It is highly recommended to work with a health professional such as a dietitian to ensure this is personalised and avoid any deficiencies.


What other dietary strategies can help IBD?

While there is no cure for IBD, there are other dietary strategies that may help minimise symptoms. Some of these include:

  • Frequent mealtimes – eating in smaller volumes, more often, creates less stress on the GI tract which can help minimise feelings of abdominal pain. This may look like smaller main meals and regular snacks eaten every 3-4 hours.
  • Avoiding foods that cause flare-ups – each person may have different foods that trigger symptoms, however some common foods that have been identified to worsen symptoms include fried foods and spicy foods.
  • Limiting alcohol – minimising alcohol consumption has shown to have positive effects on minimising symptoms (8).
  • Increasing omega-3-rich foods – omega-3-rich foods such as chia seeds, olive oil, and nuts can help with reducing inflammation in the body.
  • Chew your food – take smaller bites and chew your food well before swallowing
  • Limit sugar alcohols (mannitol, sorbitol, erythritol, xylitol, isomalt)
  • Drink enough water – most people need around 2L per day, aim for straw-coloured urine



Managing IBD on a plant-based diet can be an overwhelming topic to explore, and there are a lot of individual considerations.

Some people may be experiencing a flare-up of their disease, while others may be symptom-free.

Regardless, it is important to work with a health professional when navigating the endless supply of information.

If you think you need support, book in with one of our PNW dietitians to understand trigger foods and create a personalised plan to help minimise symptoms. You can book a free discovery call here.





Article written by: Leanna Fyffe, Student Dietitian

Reviewed by: Megan Boswell, PNW Clinic Dietitian

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