Restriction of FODMAPs from the diet is associated with symptom improvement in 50% to 80% of IBS patients, which has been demonstrated in a range of studies. (1-6) However, some researchers are questioning the potential negative impact of longer term strict FODMAP restriction.
What is the low FODMAP Diet?
FODMAP stands for “Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols. These fermentable short-chain carbohydrates are found in many foods we eat and are poorly absorbed in the small intestine.
Numerous studies have shown a low FODMAP diet to reduce the symptoms of IBS in up to 80% of people and to improve their quality of life.
How does the low FODMAP Diet reduce IBS symptoms?
When bacteria in our gut break down carbohydrates they ferment them producing gas. When FODMAP containing foods arrive in the lower small intestine and colon, these poorly absorbed carbohydrates provide the food for bacterial fermentation, which then leads to gas, bloating, pain and general abdominal discomfort.
If someone has SIBO or Large Intestinal Dysbiosis then high FODMAP foods feed the bacterial over growths producing excess gas.
Potential problems with the low FODMAP Diet
There is no disputing that in the majority of IBS sufferers a low FODMAP diet will help them manage their symptoms but it wont treat or correct the underlying cause of the symptoms and if followed for a length of time may have negative effects.
The low FODMAP diet works because it stops feeding bacterial overgrowth in the gut reducing fermentation and gas production. But by starving the over growths we also stop feeding the good bacteria in our gut which fulfill many beneficial roles for our health..
Two studies have shown that a diet very low in FODMAPs carried out over only 3 and 4 weeks, respectively, is associated with a reduction in the abundance of Bifidobacteria. (7, 8)
This is interesting as other studies have shown reduced Bifidobacteria in IBS patients compared with healthy people (9, 10) and that a low abundance of Bifidobacteria is associated with a high pain score in IBS patients. (11, 12, 13) Because Bifidobacteria plays a big part in a healthy gut and low numbers are associated with IBS then the effect of a strict low-FODMAP diet might be counterproductive.
Strict reduction of FODMAP intake was also associated with a reduction in butyrate producing bacteria and increase in mucin degrading bacteria. Other studies show a correlation between IBS symptoms and low butyrate and increased mucin degrading bacteria again showing the potential counterproductive nature of a strict low FODMAP diet. (8)
There is some evidence that people with gastrointestinal disorders who undergo dietary change may be at increased risk for disordered eating behaviors. Some people can be anxious and concerned with the preparation of their food and experience anxiety around unfamiliar foods, leading them to avoid social situations around eating.
Treat the Underlying Cause
The low FODMAP diet works so well because you stop feeding bacterial over growth in the gut. For people who have tried a low-FODMAP diet and noticed significant improvements in their symptoms, it’s easy to think that this must be the answer, unfortunately, this is not the case. A low-FODMAP (or low-carbohydrate) diet will keep symptoms under control but a strict long term FODMAP diet will not correct the cause of the symptoms and may also have a negative effect as outlined above.
It is important you discover and treat the root cause of your symptoms so you don’t get stuck on a restrictive diet long term.
Proper functional gut testing such as a SIBO Breath Test and Comprehensive Stool Analysis will help us identify any bacterial over growths and imbalances in your gut and find the source of fermentation.
Once we have an understanding as to what’s happening inside your gut a natural treatment protocol can be prescribed to treat the underlying cause and restore proper digestive function. A low FODMAP diet can be part of this process but the end goal is that there is no need to be on a restrictive diet once the gut is in balance.
Key Points:
- The low FODMAP diet can be helpful for symptom management but is not a direct treatment for IBS or SIBO.
- Long term strict FODMAP restriction can have adverse effects such as a reduction in Bifido and butyrate producing bacteria, and creating anxiety and fear around food.
- Strict low FODMAP is a short term elimination diet which should be followed for only 4-6 weeks, followed by a reintroduction phase, then a diet personalisation phase.
- Discover and treat the root cause of your symptoms, with functional gut testing and natural treatment protocols, so you are not stuck on a restrictive diet.
The low FODMAP diet was never designed to be a long term or lifestyle diet, it should be used to manage your symptoms whilst you treat the underlying cause.
References
- Halmos EP, Power VA, Shepherd SJ, Gibson PR, Muir JG. A diet low in FODMAPs reduces symptoms of irritable bowel syndrome. Gastroenterology. 2014;146:67‐75 e5.3.
- Bohn L, Storsrud S, Liljebo T, et al. Diet low in FODMAPs reduces symptoms of irritable bowel syndrome as well as traditional dietary advice: a randomized controlled trial. Gastroenterology. 2015;149:1399‐1407 e2.4.
- Peters SL, Yao CK, Philpott H, Yelland GW, Muir JG, Gibson PR.Randomised clinical trial: the efficacy of gut‐directed hypnother-apy is similar to that of the low FODMAP diet for the treatment of irritable bowel syndrome. Aliment Pharmacol Ther.2016;44:447‐459.5.
- Staudacher HM, Lomer M, Farquharson FM, et al. A diet low inFODMAPs reduces symptoms in patients with irritable bowel syn-drome and a probiotic restores bifidobacterium species: a random-ized controlled trial. Gastroenterology. 2017;153:936‐947.6.
- McIntosh K, Reed DE, Schneider T, et al. FODMAPs alter symptoms and the metabolome of patients with IBS: a randomised controlled trial. Gut. 2017;66:1241‐1251.7.
- Hustoft TN, Hausken T, Ystad SO, et al. Effects of varying dietary content of fermentable short‐chain carbohydrates on symptoms,fecal microenvironment, and cytokine profiles in patients with irritable bowel syndrome. Neurogastroenterol Motil. 2017;29:e12969.
- Staudacher HM, Lomer MC, Anderson JL, et al. Fermentable carbohydrate restriction reduces luminal bifidobacteria and gastrointestinal symptoms in patients with irritable bowel syndrome. J Nutr. 2012;142(8):1510–1518.
- Halmos EP, Christophersen CT, Bird AR, Shepherd SJ, Gibson PR, Muir JG. Diets that differ in their FODMAP content alter the colonic luminal microenvironment. Gut. 2015;64(1):93–100.
- Kerckhoffs AP, Samsom M, van der Rest ME, et al. Lower Bifidobacteria counts in both duodenal mucosa-associated and fecal microbiota in irritable bowel syndrome patients. World J Gastroenterol. 2009;15(23):2887–2892.
- Parkes GC, Rayment NB, Hudpith BN, et al. Distinct microbial populations exist in the mucosa-associated microbiota of sub-groups of irritable bowel syndrome. Neurogastroenterol Motil. 2012;24(1):31–39.
- Jalanka-Tuovinen J, Salonen A, Nikkilä J, et al. Intestinal microbiota in healthy adults: temporal analysis reveals individual and common core and relation to intestinal symptoms. PLoS One. 2011;6(7):e23035.
- Rajilic-Sotjanovic M, Biagi E, Heilig HG, et al. Global and deep molecular analysis of microbiota signatures in faecal samples from patients with irritable bowel syndrome. Gastroenterology. 2011;141:1737–1801.
