The low FODMAP diet has been a revelation in helping people to reduce and control their symptoms of IBS, and it’s not surprising that many are hesitant to reintroduce them once they are feeling better. It is so important to understand that the low FODMAP diet is only designed for the short term, to help individuals understand which particular types affect them. Tolerance levels are determined through the structured reintroduction phase which is a vital part of the diet and should be completed by all of those who follow the diet. So why not restrict long term if symptoms are so much improved?
The risks of NOT reintroducing FODMAPs: Effect on gut microbiota
“Strict FODMAP restriction induces a potentially unfavorable gut microbiota, although the impact of this consequence upon health is unknown. This observation puts additional impetus on the reintroduction of FODMAPs according to tolerance during the maintenance phase of the diet.” (Peta Hill, Jane G. Muir, PhD, and Peter R. Gibson, MD. 2017. Controversies and Recent Developments of the low FODMAP diet) Please follow the link for the excellent open access paper this quote is taken from.
Foods high in FODMAPs are also prebiotics. Prebiotics are natural food components which are digested by your gastrointestinal microbiota therefore providing food for the good bacteria in your gut. This is a good thing and eating prebiotics is an important part of a healthy balanced diet and may help improve gastrointestinal health.
Prebiotics include fructo-oligosaccharides (FOS), such as inulin or fructans and galacto-oligosaccharides (GOS) including stachyose and raffinose. You may recognise these words from following the low FODMAP exclusion diet. During this phase of the diet you needed to avoid these prebiotic carbohydrates and this included not eating foods such as onions, garlic, leeks, asparagus, beans, pulses, cashews, pistachios, wheat foods and more!
However by not consuming foods containing these prebiotics you may affect the communities of bacteria living in your gut, which some research shows could impact on your overall health including gastrointestinal symptoms, your immune system and more. This is a very important issue and is why the two leading research institutes in the world looking at the low FODMAP diet have investigated the effects of the low FODMAP diet on your gastrointestinal microbiota.
The research team at King’s College London where I worked discovered that the low FODMAP diet reduced levels of bifidobacteria in people with IBS. Bifidobacteria is a gut microbe that has many benefits for health. You can read the original research article by the King’s College London FODMAPs Research Team from the link below (it is now an open access paper). The main conclusion from the study was:
“Restriction of fermentable short-chain carbohydrates (FODMAPs) is an effective management strategy for IBS, resulting in reductions in overall symptoms and bloating. However, this dietary therapy results in signiﬁcant reductions in luminal biﬁdobacteria after 4 weeks. Whether this effect persists over time or has any detrimental effects on long-term colonic health is yet to be determined.”
Interestingly previously studies have demonstrated that people with IBS already have reduced levels of Bifidobacteria compared to healthy controls. Reduced levels of Bifidobacteria are also related to an increase in pain scores reported by people with IBS. Theoretically if this further reduction in Bifidobacteria is maintained by long term restriction of FODMAPs then this has clear health implications.
The Monash University research team also investigated the association between a low FODMAP diet and the health of your gastrointestinal microbiota. Follow the link below to the article. The Monash authors concluded that:
Whether the low FODMAP diet causes a continued decrease in bifidobacteria in the long term or if this decrease has any negative effects on the health of the gut long term will continue to be studied. What these initial studies indicate however is that a continued low FODMAP diet is likely to have detrimental effects on your long term gut health. This may mean that although a short term low FODMAP diet helps reduce symptoms initially by continuing it may lead to increased symptoms or possible increased chances of worsening gastrointestinal health or in the future.
The bottom line….Reintroduce FODMAPs for increased chances of having better gastrointestinal health in the long term. There may be unintended consequences that affect your gut microbiota that have not fully been researched yet.
If this has sparked an interest in the gut microbiota you will not find many better explanations and summary of the research than in the video below, presented by Stephen Collins. It gives a really nice overview of IBS and the Gastrointestinal Microbiota. FODMAPs are not mentioned until the last few minutes of the presentation, and then only briefly, but this presentation is really all about the potential for altering the gut microbiota to influence IBS symptoms.
One final point on gut microbiota is over recent years several commercial gut microbiome testing facilities have become available. People are very keen it seems to have their gut microbiota tested and then have a treatment to ‘cure’ their symptoms based on these results. This sounds fantastic but in reality there is simply not enough scientific information to make an informed and evidenced based treatment decision. If you are thinking of doing this and have read nothing but positive reports on these testing procedures then to provide some balance to the debate have a read of this short article: Can I Test the Health of My Gut Microbiota?
Watch this excellent presentation on the role of the intestinal microbiome in irritable bowel syndrome
The benefits of reintroducing FODMAPs: Quality of life
“As a restrictive diet, the low-FODMAP diet carries risks of nutritional inadequacy and of fostering disordered eating, which has received little attention” (Peta Hill, Jane G. Muir, PhD, and Peter R. Gibson, MD. 2017. Controversies and Recent Developments of the low FODMAP diet) Please follow the link for the excellent open access paper this quote is taken from.
Finding out a person’s individual FODMAP tolerance is as much important for the mind as the body (or gut). Most people find that following the restriction phase of the low FODMAP diet is a challenge, not only because it may cut out some of their favourite foods, but also for many social factors such as cooking for the family, eating out, holidays, as well as the cost implications a ‘free from’ diet can result in. Continuing to follow a restrictive diet long term may start to affect your relationship with friends and family as it prevents you joining in at social food occasions. For example you may become more anxious and concerned about how food is prepared and experience anxiety around unfamiliar foods. Or end up always ‘self-catering’ at social events or even avoid social situations around food and eating altogether.
As with any lifestyle change, if it is enjoyable and in keeping with normal routine it is more likely to be followed. In a recent study which I led on, it was found that those people with IBS who reintroduced FODMAPs had the same food related quality of life as those who consumed a normal diet and ate whatever they wanted. Sticking to the low FODMAP restriction diet could impair your food related quality of life – meaning you end up enjoying food less due to the self imposed restrictions.
A balanced diet
A balanced diet is completely achievable on the low FODMAP diet, however if doing the diet on a long term basis the amount of restrictions can become laborious especially if cooking for others as well. In the long term this can lead to sticking more to patterns of eating which are easier (ie. Only jacket potatoes suitable in the staff canteen?) and may lead to a more restricted diet. If you are not replacing the high FODMAP foods with suitable substitutes your diet may become nutritional inadequate. A balanced diet is the best for overall health, and so having a wider choice of foods can help to achieve this more easily. Sticking to a restriction diet long term may hide something more problematic causing your symptoms. Only by reintroducing can you then identify which FODMAPs are significant triggers of your IBS symptoms which will allow you to broaden your diet. There is almost a public confusion that the low FODMAP diet ‘cures’ IBS. Being completely symptom free with IBS is unlikely. Therefore although it is important to avoid the FODMAP triggers of IBS, the key is to incorporate this into a nutritionally balanced diet for life.
Your relationship with food
Psychological distress due to food restriction could become an issue with the low FODMAP restriction diet if you do not reintroduce FODMAPs. There are lots of different factors which can impact on IBS symptoms including stress and anxiety, hormones, the gut-brain axis, microbiota dysbiosis and food, but by only focusing on how foods affect you this may lead to blaming all symptoms on what or when you have eaten. As we eat many times per day this can become mentally consuming! If you can reintroduce successfully, it can give confidence that IBS symptoms are managed as well as possible with diet and understanding that some symptoms may never fully disappear due to other factors beyond your control. There is evidence of increased risk for disordered eating (not an eating disorder) in those with IBS and other gastrointestinal disorders. Gastrointestinal symptoms may create food aversion and cause alterations to eating patterns. Other disordered eating traits can be seen in people who religiously adhere to a restrict dietary programme such as the restriction phase of the low FODMAP diet. On the extreme end of the scale an obsessive focus on only choosing, planning, purchasing and consuming low FODMAP foods with the exaggerated faith that these will ‘cure’ their IBS is likely to impact their physical and psychological well-being.
Your gastrointestinal health
A regular intake of FODMAPs provides your gut with prebiotics that stimulate the growth and/or activity of bacteria in the digestive system which has been shown to be beneficial for health.
The plan ultimately is to find a balance between having enough FODMAPs in the diet to maintain a manageable and enjoyable diet, having a good amount of natural prebiotics whilst managing IBS symptoms. For detailed guidance into reintroducing FODMAPs, you can purchase a paperback copy or Kindle version of the self-hep guide to the reintroduction phase on Amazon.