If you are considering altering your diet, we recommend that you do so under the guidance of a qualified dietitian. You can request that your specialist or GP refer you to a dietitian, or locate your nearest practising dietitian at

What you eat and drink can have a profound impact on how you feel. Many people feel that food affects their Crohn’s or colitis symptoms and change how they eat to try and manage their symptoms. Short term specific diet or nutrition treatments can be used to treat active disease and can also help you to identify symptom triggers when your disease is in remission. In the long term however, a varied diet that includes many different foods from all of the food groups is very important. A varied diet supports optimal gut, mental and overall health and ensures you get the nutrition that your body needs to heal after a flare and respond to inflammation.


Is it true that milk will make the symptoms of IBD worse?

Animal milks (from cows, sheep, goats etc) contain a natural sugar called lactose.  A small number of people cannot digest the lactose in milk and cream because their gut does not produce enough of the enzyme lactase, which breaks down the lactose sugar. Lactase enzyme is released in the upper part of the small bowel. Lactose that is not broken down by the lactase enzyme can lead to diarrhoea, cramping, abdominal pain, gas and bloating.  Temporary lactose intolerance can occur during active small bowel Crohn’s disease, although it often goes away after the inflammation is treated.  Most people who are lactose intolerant can still tolerate small amounts of liquid dairy products (e.g. milk in their tea) and usually tolerate hard cheese and butter because they contain very little lactose.  Lactose-free dairy products are now widely available and it is also possible to purchase lactase enzyme capsules or drops to help with digestion.

Currently there is no high quality human research that shows that eating minimally processed dairy products promotes IBD inflammation. Regularly eating fermented dairy products such as yoghurt and kefir has been shown to have a positive impact on gut health and gut symptoms in people with Crohn’s and colitis. Dairy products are also high in protein and an important source of dietary calcium for most New Zealanders. If you do not to eat dairy products, choose alternatives that are calcium fortified. This is particularly important for children whose bones are still growing.

Does resting the intestine help the inflammation?

There is no evidence that resting the bowel by having periods of starvation is helpful. In fact, it may be more harmful as this can lead to malnutrition which slows down recovery and healing.  A person with active IBD requires increased nutrients and energy because of inflammation and the poor digestion and absorption of nutrients.  Specialised liquid formulas or tube feeds may be needed if there is a blockage in the bowel, very severe disease, or before or after surgery.  It is best to seek guidance about nutritional requirements from your healthcare team.

Is it helpful to take more or less fibre than usual in the diet?

A low fibre diet which limits the amount of ‘bulk’ in the diet is often used when there is active disease in the large bowel or terminal ileum (last part of the small intestine), to help control symptoms of diarrhoea, bloating and abdominal cramping.  As discussed below, most people with IBD can eat a normal or near-normal diet without making diarrhoea or pain worse.  The usefulness of the strict, traditional, “low residue” diet is now seriously questioned as there is no evidence that it helps people with IBD.  It is recognised that an excess of fruit can make diarrhoea worse, just as it can cause diarrhoea in healthy people.  For this reason, it is best to eat a normal healthy diet unless particular foods cause you to experience unpleasant symptoms.

For people with Crohn’s disease with small bowel strictures (narrowing), it is advisable to reduce foods containing coarse fibre and those which may cause blockages and abdominal cramping. Discuss this with your dietitian so that you do not restrict your diet too much.

For those with ulcerative colitis, a high fibre diet, possibly including fibre supplements, can be useful to improve gastrointestinal symptoms and decrease disease activity.  Fibre supplements that have shown a positive effect include psyllium (e.g. Konsyl-D, Metamucil), oat bran and germinated barley.  Increasing fibre in the diet should always be done gradually to give your gut time to adjust and it is important to have plenty of fluid as well.

Is alcohol harmful?

There is no evidence that alcohol taken in moderation makes IBD worse. Some healthy people notice bowel looseness after drinking alcohol, and people with IBD may notice the same thing.  If you are on medication for your IBD and associated health issues you should consult your doctor or pharmacist to ensure that alcohol intake doesn’t interfere with the metabolism of your medication or cause additional side effects. 

The NZ Health Promotion Agency advises that to reduce risks to your long-term health you should drink no more than:

  • two standard drinks a day for women and no more than 10 standard drinks a week
  • three standard drinks a day for men and no more than 15 standard drinks a week

AND have at least two alcohol-free days every week.

Do particular foods aggravate diarrhoea?

Watery frequent bowel motions are due to failure of the intestine to absorb fluid and nutrients properly.  Even healthy people without IBD can experience diarrhoea after some foods e.g. very spicy or fatty foods, excess fruit or beer.  While such foods may aggravate diarrhoea in people with IBD, it is doubtful if any of them do harm by triggering inflammation.  It seems sensible for you to try smaller portions of foods that you know cause diarrhoea and to eat them less often, but apart from this you should eat normally.  

For some people with Crohn’s disease, the capacity of the small intestine to absorb fat may be impaired.  For these people, even a normal amount of fat in the diet may cause diarrhoea.  It is important to continue having some fat in the diet to allow for absorption of certain vitamins, so if you are struggling with these symptoms, discuss this with your doctor or dietitian as there is a medication that can help to improve fat-related diarrhoea.

Do particular foods cause pain?

Abdominal pain can have many causes, for example it can be due to trapped wind, gynaecological causes (for women), bowel inflammation, constipation, a tummy bug/gastroenteritis, irritable bowel syndrome or intestinal strictures.  Whether or not food contributes to pain may depend on what is causing the pain.  If you experience gastrointestinal symptoms that cause pain even when your IBD is in remission, you may benefit from dietitian assessment and advice to determine whether diet is contributing to this.  Many people with IBD have some irritable bowel symptoms on top of IBD, which may respond to dietary changes.

Abdominal cramps may also occur when there is a narrowing of the intestine so that the intestinal muscle has to contract forcibly to push the contents through the narrowed area. In this situation, lumps of indigestible food such as meat gristle, vegetables with coarse fibre, orange pith, dried fruits, mushrooms or pieces of nuts may aggravate the pain because a lump of food lodges at the site of narrowing and the intestinal muscle contracts very strongly to push it through. When one or more narrowed areas of intestine are present, as may happen in Crohn’s disease, pain may be relieved by eating smaller meals more often rather than large meal, not eating these indigestible items of food and chewing all food to a puree in the mouth before swallowing.

Do particular foods aggravate wind?

Wind largely arises from bacterial fermentation of food as it moves through the digestive system. Failure to absorb components in food such as fat or milk sugar (lactose), as already described, may lead to flatulence. This can be helped by a low-fat or low-lactose diet respectively. Many other foods can also ferment in the gut. People do react differently to foods, so it is difficult to provide advice to follow that will be suitable for all people with IBD who experience flatulence.  If excess wind is a significant problem for you, request to see a dietitian who can assist you to establish a balanced diet which does not cause excess wind.


Diet and nutrition treatments...

There has been a lot of research in recent years into how diet and nutrition may either improve inflammation or IBD symptoms.  It is important to remember that benefits vary for each person and what works for some may not always work for others.  


Foods that can reduce inflammation

There is a lot of interest in the Mediterranean-style diet to help reduce inflammation and support remission in IBD.  Here is a video you can watch of Professor Lyn Fergusson's presentation to our Wellington Support group on foods that can reduce inflammation.
'You are what you eat'


The low FODMAP diet is a 3-step dietary treatment (eliminate, reintroduce foods, personalise diet) recommended for people with irritable bowel syndrome (IBS).  It can be helpful for those with IBD who have ongoing symptoms when their disease is in remission.  The elimination phase of this dietary treatment eliminates foods that contain large amounts of fermentable carbohydrates that can cause  symptoms. The reintroduction phase involves a systematic process of reintroducing foods to find which foods, and how much of those foods, cause symptoms. The personalisation phase involves putting together the information learnt from the first two phases to find the best balance for the individual.  It is best guided by a dietitian as research shows that this dietary treatment has a higher success rate when people work through the three phases with a dietitian rather than self-guided.

If you do decide to trial the diet without dietitian support, remember not to stay on the elimination diet longer than six weeks, as long-term FODMAP restriction can lead to the loss of some healthy bacteria in your bowel.

There is more information about the low FODMAP diet at this website:

Monash University - FODMAPS

Exclusive Enteral Nutrition (EEN)

EEN is a 6 – 8 week treatment for active Crohn’s disease. It is used instead of, or alongside medication, to achieve disease remission. It is commonly used to treat children who are newly diagnosed with Crohn’s disease or who have mild to moderately active Crohn’s inflammation. It can also be used to treat adults with active Crohn’s disease. EEN treatment means that all of your nutrition comes exclusively from a specialised nutrition formula (e.g. Fortisip, Ensure Plus, PediaSure). These formulas are available on prescription and may be fully funded by the government. EEN works in multiple ways to reduce gut inflammation and promote healing of the gut lining.  After EEN treatment, there is a gradual transition to eating again.  This treatment should only be used in consultation with a dietitian and/or gastroenterologist. 

Crohn's disease exclusion diet

The Crohn’s disease exclusion diet is another treatment for active Crohn’s disease. It is a 12 week  treatment that combines enteral nutrition (EN) with a specific range of foods. One research study suggests that it treats Crohn’s disease inflammation and induces disease remission as effectively as EEN. This dietary treatment has three phases of treatment and should be used in consultation with dietitian and/or gastroenterologist.

Should I be taking nutritional supplements?

Specialised nutrition formulas (drinks)

If you have been unwell and have not been eating much or you have lost weight, your doctor or dietitian might prescribe supplement drinks (e.g. Ensure, Fortisip, Sustagen). These are high in protein, energy (calories) and vitamins/minerals, easy to drink and help you meet your nutrition needs when your intake of food is low. Some options are fully Pharmac-funded and others have a cost.


If you have active Crohn’s disease, probiotics are not recommended as there is some risk associated with this.  There is no strong evidence that probiotics are useful in helping to achieve or maintain remission in Crohn’s disease.

If you have mild - moderate ulcerative colitis, there is evidence that a particular combination of probiotic bacteria, alongside usual medication, can help to achieve remission during a flare.  This preparation, previously known as VSL#3, is also known as the ‘De Simone’ formulation or Vivomixx.  It is expensive to buy and the recommended dose may depend on your weight.  If you wish to trial this when your colitis flares, it is suggested that you discuss it with your dietitian, GP or gastroenterologist.  A lower dose of this probiotic and another probiotic strain, Escherichia (E.) coli Nissle 1917 have been shown to be helpful in maintaining remission in colitis.

Vivomixx probiotics have also proven effective at treating and preventing pouchitis for those who have an ileal-pouch.

Probiotics are not recommended in severe, acute ulcerative colitis as there are risks associated with this.

Vitamins and minerals

People with IBD do not always absorb all nutrients from food properly due to inflammation, diarrhoea or intestinal surgery.  For this reason, there is a slightly higher chance of developing specific nutrient deficiencies than the general population so it’s a good idea to have yearly blood tests with your GP or gastroenterologist to check for key nutrients (e.g. vitamin B12, folate, iron, vitamin D).  While taking vitamin/mineral supplements ‘just in case’ can sound like a good idea, high doses of some nutrients may interfere with the absorption of others so you should discuss this with your healthcare team.    

Omega-3 supplements

Omega-3 fatty acids are a type of fat with anti-inflammatory properties.  Good sources of omega-3 fats are fish/shellfish e.g. salmon, tuna, trout, kahawai, warehou, sardines, mussels, oysters, squid; walnuts; chia seeds; linseed/flaxseeds; canola/rapeseed oil (especially cold-pressed).  Research into whether omega-3 supplements (e.g. fish oil) help to achieve or maintain remission in IBD has produced mixed results. Currently, it is not recommended that you take an omega-3 fatty acid supplement. However, diets high in omega-3 have been shown to be beneficial, so including high omega-3 foods in your diet regularly is worthwhile.  


Curcumin is the biologically active part of the spice turmeric, an ingredient commonly used in traditional Indian and South-East Asian foods.  Research studies in people with active ulcerative colitis have shown that high dose curcumin supplements, given alongside regular medications, treat inflammation and helps people achieve disease remission.  Unfortunately the studies have all used different concentrations and curcumin formulations.  At the moment, we cannot recommend a specific supplement or supplement dose that will effectively treat active ulcerative colitis.


Nutritional Therapy for IBD have a wealth of information on their website which may be of use,

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