The Low-FODMAP Diet
The low FODMAP diet was developed as a form of symptom management for people with Irritable Bowel Syndrome (IBS) and food intolerances. It involves eliminating certain groups of "sugars" (or short-chain carbohydrates to use the scientific term) that are commonly poorly digested in the small intestine and are therefore likely to cause digestive related symptoms including abdominal pain, nausea, bloating, increased wind, changes in bowel habits (constipation or diahhorea). Fatigue is also often a symptom due to the extra energy and effort the body uses in an attempt to digest these foods. It is important to note that this period of heavy restriction should only last a few weeks (6-8 max). In this time period, you over-restrict your intake of the moderate and high FODMAP foods (ones that are likely to cause symptoms) to see if these foods have any affect over your symptoms. If you notice a change, then this doesn’t mean that you rely on this diet for the rest of your life. Infact, intake of FODMAPs is vitally important in long-term bowel health. But what it does mean is that some of the foods (but not all) are likely to be causing your IBS related symptoms.
The name 'FODMAP' is an accronym for the scientific names of the "sugars" that are commonly a cause of IBS/digestive related symptoms. Each letter stands for a different category of foods. (don't get freaked out by the overly complex sounding names - it stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols. The table below shows each type of "sugar" and also lists the foods that contain an amount likely to cause symptoms. All of the information in the table was sourced from the book ‘Food intolerance management plan’ by Dr Sue Shepherd and Dr Peter Gibson.
This table is a guide - the Monash University low FODMAP app is continually updated and handy to use. If you are starting teh diet or are already on the diet (whether it be elimination phase, re-introductory phase or past that) it is definitely worth the buy!
The most crucial phase is the re-introductory phase, where you introduce one type of FODMAP containing food at a time (each week) and see if any symptoms are brought on and how severe they are. For example, generally the first week your tolerance for Sorbitol (a Polyol, the P section of the FODMAP acronym) would be tested by having either 4 dried apricots or 4 tinned appricot halves. You would have this 2-3 times in the week and record any symptoms you feel. Just because you have it once and get symptoms, still means it is important to try eating it again on the chance that those symptoms were coincidental and because of something else (eg. Stress, stomach bug etc). After this week you should be able to gage how strong a cause Sorbitol is of your symptoms. If you don’t get any symptoms, then you can safely say that 1 serving of sorbitol is fine for you to eat without discomfort. If you get mild, moderate or severe symptoms then you could try decreasing the amount you eat, i.e. having 2 dried apricots, and seeing what affect this has. You might be affected by Sorbitol, but still be able to tolerate it to a certain degree without getting symptoms. This is what the re-introductory phase of the diet is all about - ensuring you figure out specifically which foods, and how much of them, brings on your symptoms so that you aren’t avoiding / cutting out anything unnecessarily.
The low FODMAP diet is based heavily on 'thresholds' & about finding the threshold (or the amount) of certain FODMAPs that you can tolerate before getting symptoms. Unlike a food allergy, a person needs a certain amount of a FODMAP food to bring on symptoms, i.e. usually over 0.5g/serving of Fructans are a problem. So things that contain wheat, i.e. vegemite, in small amounts won’t reach this threshold even though they contain a FODMAP food, because in that serving amount they are low FODMAP – there just isn’t enough wheat in there to reach the threshold to trigger symptoms!
However, this threshold level is different for everyone. And that is why it is so important to do the re-introductory phase properly – best done with a dietician supervising as well to ensure you do it as best possible as your diet is something so important. And I cannot stress this enough - this initial phase where you eliminate all fo the high FODMAP foods is just temporary! It is over restricting the diet. It is decreasing more than necessary in order to emphasise if these foods bring on any symptoms. the re-introductory phase is the most crucial and rewarding part.
There is plenty of information available on the low FODMAP diet. The book that I found most helpful was ‘Food intolerance management plan’ by Dr Sue Shepherd and Dr Peter Gibson. Dr Sue Shepherd originally developed the diet for treatment of IBS in 1999, so I found this book to be a reliable source of information. However if you are looking at commencing the diet I strongly recomment doing so with the assistance of a dietician. I have reccently had a consult with a dietician from Shepherd Works (Sue Shepherd is the Dietician who originally developed the diet), they also offer phone or skype consults for anyone who is unable to come to their location (interstate and internationally).
All information in this post is intended strictly for informational purposes and should be seen as guidelines only. This shouldn't be used to replace advice or treatment by a qualified health professional. I wrote this post with the pure intention of sharing the knowledge that I have learnt through my research and personal experience. All information contained within this post is in no way intended to give dietary advice. I do not claim to be a nutritionist or dietician, I am only a person who has self-researched and managed my symptoms through the following of this diet. All of my symptoms were discussed with my GP or a qualified health care practitioner prior to commencement of this diet. If you have any persisting symptoms or are interested in trialing the diet, I strongly recommend speaking to a qualified health professional.
A note on Irritable Bowel Syndrome:
Irritable Bowel Syndrome (IBS) is where the nerves that supply the gut become 'hypersensitive' (also known as visceral hypersensitivity). In people with out IBS, these nerves are mostly only activated in extreme situations or huge changes in the gut. However, with IBS, you don't need a huge change in the gut for them to be activated. Often only a small one is needed as these nerves, because they are 'hypersensitive', respond to changes more easily. When activated, these nerves bring on symptoms such as bloating, abdominal pain, wind, constipation or diarrhoea. There are a variety of things that can cause these to be activated; certain types of foods, hormones & stress, bacteria, movement, dehydration and many more. Sometimes even every day to day normal gut changes can cause symptoms. The food influence is where the low FODMAP diet comes in. It is a way of figuring out which foods 'trigger' these nerves to become activated and give you IBS releated symptoms. Something important to note is that, unlike food allergies, eating these foods doesn't cause any damage to the gut. Whilst symptoms can be extremely severe, eating them causes no harm to the digestive tract. IBS is often linked with hypermobility or POTS (Postural Orthostatic Tachycardia Syndrome) due to the autonimic nervous system hypersensitivity / dysregulation.
If you have any questions please feel free to contact me in the contract section of my blog :)
Shepherd, S., & Gibson, P. (2011). Food Intolerance Management Plan. Melbourne, Australia: Penguin Group.