Diet for Irritable Bowel Syndrome (IBS)
by Sue Kira, Naturopath & Clinical Nutritionist
– What causes IBS?
– What are the symptoms of IBS?
– What symptoms are not caused by IBS?
– How is IBS diagnosed?
– Treatment of Irritable Bowel Syndrome
– A low FODMAPs diet for IBS support
– Foods high in FODMAPs to avoid
– Supportive foods low in FODMAPs
Irritable bowel syndrome (IBS) is a chronic digestive system disorder that mostly affects the large intestine, also known as the bowel or colon. It can cause abdominal pain, cramps, bloating and bouts of diarrhoea or constipation. IBS affects around 15% of the population globally and is more common in women than in men.
Those with IBS can be classified as having a predominantly diarrhea type (IBS-D) or a predominantly constipation type (IBS-C) or both (IBS-M). There is no definitive scientific investigation as no biomarker has been found, so IBS is diagnosed clinically by symptom picture and by the exclusion of other pathologies that can be tested.
What causes IBS?
While the exact cause of IBS is unknown, many experts think that several factors may be involved, including….
– Problems with digestion. Normally the muscles of the intestines work to squeeze food through the digestive system, but for those with IBS, this process may not work properly, so food either moves through the digestive system too slowly or too quickly. If it moves too slowly it can lead to constipation; if it moves too quickly it may cause diarrhoea. Either way it can cause symptoms such as upset tummy, pains, cramps and bloating etc.
– Overactivity of the nerves in the intestines. Normally we don’t have many nerve sensations in our digestive system, but some people can experience heightened awareness of sensations in their tummy and this makes them sensitive to pain. This oversensitivity can cause the cramping abdominal pain associated with IBS.
– Gastrointestinal infections. Some people develop IBS after a gastrointestinal infection such as parasites or bacterial overgrowth of unfriendly species. Even undergrowth of the friendly species of bacteria can cause issues.
– Genetic factors. It is common to see people with IBS if they have a family member with IBS.
– Early life factors. Some early childhood experiences such as C-section delivery or lack of breast feeding. This can lead to poor balance of good bacteria which may also be involved in the development of IBS.
– It is hypothesised that many who have IBS suffer from anxiety which triggers attacks. For some people any mental, physical or emotional stress can set them off. Interestingly, sometimes stress can affect digestion so much that it sets up the environment for some of the above-mentioned scenarios, like imbalanced gut bacteria etc.
However, the main issue is that stress triggers the nervous system to go into the flight or fight mode. Basically, this shuts down the digestive system from working properly because you are in the ‘running away from danger’ mode and anything already in your digestive system either gets pushed out quickly or is cramped in tight.
– Inflammation in the gut. The gut can get irritable and inflamed from things such as food allergies and sensitivities which can set off the typical symptoms of IBS. In many cases the types of foods that can set off IBS are gluten, dairy, or foods classified as FODMAPs, which are fermentable carbohydrates that cause many of the typical symptoms of IBS. More following.
– Hormonal changes e.g. some women have IBS just before or during their menstrual period.
It is essential to identify your triggers so that you can avoid or minimise the symptoms of IBS. Observe your body and feel how your body responds or reacts to your lifestyle and food habits. Most importantly, get help from a qualified health practitioner.
What are the symptoms of IBS?
The symptoms of IBS may vary from person to person. Symptoms tend to come and go over time, and often last for several days or weeks. There can be situations when symptoms are worse than others, such as during a stressful time, changes in food habits (holidays for example) or after an illness. Some women only get symptoms during their ‘period’, triggered by menstrual cramps that upset adjoining areas including the colon.
Common symptoms of IBS include:
- Abdominal bloating
- Abdominal pain and cramps
- Diarrhoea and/or constipation (sometimes these may alternate)
- Excessive flatulence (wind)
- Urgent need to go to the toilet
- Mucus in the stool
- Feeling of not completely emptying the bowels going to the toilet
- The symptoms of IBS are often relieved by a bowel movement (passing stool)
What symptoms are not caused by IBS?
If you notice bleeding from the back passage, blood in the stool, fever, weight loss or severe diarrhoea, it is important to see a doctor as these symptoms are not caused by IBS and may indicate a more serious condition needing medical attention.
If symptoms get progressively worse, or stools are pale, bulky, very offensive smelling and difficult to flush away, or if you are concerned about any symptoms at all, then see your doctor and don’t delay.
How is IBS diagnosed?
The diagnosis of IBS can be challenging because the symptoms are also seen in other digestive conditions. There is not a single test that can show if a person has IBS. A doctor will usually base the diagnosis on symptoms and the elimination of other potential causes. Investigations such as blood tests may be done to rule out other conditions.
To help the process of diagnosis, experts have developed criteria to help decide if a person has IBS. One example is the ‘Rome criteria’. This definition says that a person with IBS will have had abdominal pain and discomfort that lasts for at least 3 days a month over the last 3 months, plus 2 or more of the following:
1. When bowel movements relieve symptoms e.g. cramping, tummy pain
2. Altered frequency of bowel movements e.g. going to the toilet more frequently or less frequently
3. Altered consistency of stool e.g. softer, harder
Treatment of Irritable Bowel Syndrome
The main treatment for irritable bowel syndrome (IBS) is to make dietary changes and lifestyle modifications that include stress management, exercise and getting enough sleep.
It can also be helpful to keep a diary of events, symptoms, and foods eaten around each episode to help discover any potential triggers for the IBS symptoms or anything that makes the symptoms worse.
Probiotic rich foods such as coconut yoghurt and supplements that contain probiotics with ‘good’ bacteria that are normally found in your bowel may help with some symptoms of IBS, including diarrhoea, pain and bloating.
Medicines for IBS
Medicines are available for treating of different IBS symptoms and your doctor will recommend a treatment based on whether you have diarrhoea-predominant IBS (IBS-D) or constipation-predominant IBS (IBS-C).
Medicines for diarrhoea
Anti-diarrhoeal medicines can be effective when taken ‘as-needed’ on an intermittent basis, but it is still advisable to find the cause of your symptoms.
Anti-diarrhoeal medicines include: loperamide (brand names include Imodium, Stop-It Gastro-Stop); and atropine-diphenoxylate combination (e.g. Lofenoxal, Lomotil).
Side effects depend on the type of medicine you take.
Medicines and supplements for constipation
It is definitely better to find out what causes your symptoms, but your doctor may also prescribe laxatives such as:
- psyllium (e.g. Metamucil)
- macrogol 3350 (e.g. Movicol, OsmoLax)
- frangula plus sterculia (Normacol Plus)
- lactulose (e.g. Actilax, Dulose, Duphalac)
- sorbitol (e.g. Sorbilax, Sorbisol)
- paraffin liquid (e.g. Agarol, Parachoc)
- docusate (e.g. Coloxyl)
Many laxatives are not suitable for people with IBS. People with irritable bowel syndrome tend to find the side effects of lactulose and sorbitol (such as wind, bloating, cramping and diarrhoea) difficult to manage. Finding the cause is the most appropriate treatment.
Medicines for pain and bloating
Medicines that relieve abdominal cramping should only be used ‘as-needed’, rather than on a regular basis.
Prescription and over-the-counter products that help alleviate the pain associated with IBS include:
- peppermint oil – brand name Mintec
- Buscopan or Setacol – muscle relaxants
- Donnatab, Colofac or Colese – anti-spasmodic pain relief drugs
- Some antidepressant medicines including tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs) may be beneficial in reducing pain for people with IBS when taken in low doses. In these situations the antidepressant medicines are used for pain-relieving properties rather than their effect on mood.
Side effects will depend on the type of medicine you take.
FODMAPs is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides and polyols, which are a collection of types of carbohydrate that create fermentation in the gut and can be difficult to digest. Foods that are high in FODMAPs often cause problems for people with irritable bowel syndrome.
These particular sugars and fibres are naturally found in many fruits and vegetables and are often poorly digested, then fermented in the gut by bacteria to produce symptoms such as:
- Lower abdominal pain and discomfort
- Bloating, distension (looking pregnant) and wind/gas
- Altered bowel habits ranging from diarrhoea to constipation
For most people, FODMAPs are not a problem unless they eat too many of them. But some are sensitive to them and cannot eat any amount. Most who do have a FODMAP sensitivity are reactive to just one or two types of these fermentable foods.
This sensitivity is often due to having SIBO (small intestine bacterial overgrowth) and once this has been resolved you will often be able to tolerate these foods better.
A diet for IBS is a Low FODMAPs diet
While a diet for IBS is not considered a cure, the idea is to eliminate foods considered detrimental and include foods that support your body, so it has the best chance to do its natural job of healing. That’s why it is so important to exclude antagonistic foods and drinks listed in the foods high in FODMAPS section below .
After six weeks on a Low FODMAPs/IBS diet, if you feel that your symptoms have improved but not cleared then talk to your health care practitioner who may suggest to go onto a SIBO diet (Small Intestine Bacterial Overgrowth). It’s similar to this diet but with more restrictions on certain foods.
Once your symptoms have gone, it’s worth considering to plan with your health practitioner how to reintroduce foods.
The other consideration when addressing IBS with diet is histamine. If your symptoms have not improved sufficiently with a low FODMAP or a SIBO diet, then talk to your practitioner about the possibility that you may have a histamine intolerance. Further info at the Low Histamine diet.
A low FODMAP Diet for IBS support
As mentioned, a low FODMAPs diet may benefit to determine if this is the cause of your IBS. It is not a typical low-carb diet. A low FODMAPs diet only limits carbs that are fermentable.
The most common culprits with FODMAPs are the onion family, garlic, legumes and brassica vegetables like broccoli, cabbage and Brussels sprouts. So if you get ‘windy’ after eating these foods then there’s a good chance you have FODMAPs sensitivity.
The types of carbs that are considered FODMAPs are:
1. Fructose: fruits, honey, high-fructose corn syrup, agave
2. Lactose: dairy
3. Fructans: wheat, onions, garlic
4. Galactans: legumes, such as beans, lentils, and soybeans
5. Polyols: sugar alcohols and fruits that have pits or seeds, such as apples, avocados, cherries, figs, peaches, or plums
Avoiding FODMAPs doesn’t help everyone with irritable bowel syndrome. But reports claim that symptoms eased soon after starting a low-FODMAP diet for approximately three out of four people with IBS.
If your symptoms persist then you may have another condition contributing to your symptoms. It is best to seek the help of your health care practitioner for further advice.
Important: Before you commence a new diet, see your medical or health care professional for qualified guidance about what foods and supplements are best for your body. While on the diet do not stop any medications or supplements previously prescribed unless advised otherwise by your medical or health care professional.
Note: During the early stages of a new diet, you may experience symptoms such as fatigue, headaches or body aches, which may occur because your body is detoxifying. However, if you are unsure about a symptom at any time, check immediately with your medical or health care professional.
Foods high in FODMAPs to avoid include:
- Anything made with wheat, barley or rye (contains gluten)
- Artificial sweeteners such as those found in chewing gum & mints
- Dried fruits
- Garlic and onions – these are by far the worst offenders
- High-fructose corn syrup
- Ice cream
Supportive foods low in FODMAPs include:
- Almond, coconut, rice and soy milks
- Bell peppers
- Kale (small amounts)
Client name and identifying information changed
Jeremy came to see me for a consultation with what he felt was a very embarrassing problem. He was getting terrible wind pains and bloating in his belly, so much so that the girls at work were asking him when he was going to have his baby.
For women who have IBS and bloating this can create embarrassing moments, especially if they are of child-bearing age, but not actually pregnant.
When I looked at Jeremy’s diet, it was quite clear that he enjoyed lots of onions and garlic with every meal except breakfast. For breakfast, he loved oats with honey and grated apple.
I told him that just about everything he ate came under the classification of FODMAP foods and that his bloating was probably coming from the fermentation of these foods in his digestive system. He mentioned that he had been eating this way all his life, but only had the symptoms for the past 12 months since a trip to Bali where he was a bit sick with a tummy bug that was treated with antibiotics.
I said that it was quite likely that he had a small intestine bacterial overgrowth (SIBO) of the wrong type of bacteria and was low in good bacteria, and these would be setting off the cascade of events that lead to his symptoms.
Because he couldn’t afford the test for SIBO or to look at his gut flora levels, we started with a low FODMAP diet and after a week on the diet his symptoms improved by about 80%. But because there was still some bloating, I changed him over to the slightly more restrictive diet for SIBO and put him onto some herbs for SIBO and the last 20% of his symptoms disappeared within another two weeks.
But the program to clear SIBO needs to go longer than just the three weeks it took for Jeremy’s symptoms to go when he thought he was cured and proceeded to eat his favourite foods again. Needless to say, his symptoms returned but not as bad – but enough to remind Jeremy to stick to the plan.
After the 12-week SIBO program he was completely symptom free
Jeremy found that the only thing he had to stay off completely was onions, although he could even eat a small amount if well cooked. He was happy with that.