Fibromyalgia and IBS

Fibromyalgia and IBS

Dakota Rhys-Jones - Research Dietitian, 28 August 2020

Fibromyalgia often comes up as a frequently asked question here at Monash FODMAP. We haven’t conducted any formal research in this area, so this blog is here to unpack the current state of evidence for fibromyalgia (FM) and the low FODMAP diet.

What is fibromyalgia?

Fibromyalgia is considered a ‘centralised pain state’ where individuals, more commonly woman than men, experience widespread pain in ‘tender points’ (1). According to the American College of Rheumatology, a diagnosis is made after individuals are assessed for their chronic musculoskeletal pain, fatigue and sleep problems (2). It can often be difficult to diagnose due to overlap of symptoms with other comorbidities, such as rheumatoid arthritis. The exact causes of FM are not completely understood, with a number of biological and psychosocial mechanisms thought to play a role. Interestingly, psychological triggers that affect the central nervous system are thought to play a part (1).   

How are IBS and fibromyalgia similar/different?

Central sensitivity syndrome is an umbrella term used to describe a broad spectrum of conditions with no specific aetiology (cause), including irritable bowel syndrome (IBS), FM and chronic fatigue syndrome (3). Common features of these conditions are pain including gastrointestinal pain, and symptoms such as diarrhoea and constipation, as well as headaches and fatigue (3). Increased perceptions of pain and low pain thresholds are also features of these conditions (3). It is suggested that IBS and chronic fatigue syndrome occur in 40% and 55% of individuals with FM, respectively (3).

Some differences seen in individuals with IBS and FM may be due to the types of pain experienced (4, 5). Somatic pain describes tissue or muscular pain that is commonly experienced by individuals with FM. Visceral or gut pain is more ‘internal,’ and is commonly experienced in a subset of individuals with IBS, where there is increased sensitisation from stretching of the abdominal wall (6).  One study that used rectal balloon distension found that individuals with FM don’t experience gut pain, while individuals with IBS or IBS+FM experienced both visceral gut and abdominal somatic pain (5).

Is there potential for the low FODMAP diet in fibromyalgia?                                                        

There are no current guidelines supporting the use of any dietary therapy to help manage fibromyalgia. A recent systematic review exploring dietary interventions for fibromyalgia found seven clinical trials with different diets used (7). These included the raw vegetarian diet, gluten free diet, low FODMAP diet, hypocaloric (low calorie) diet, and monosodium glutamate and aspartame-free diet (7). Unfortunately, all of the studies mentioned were of poor quality, so no conclusions could be drawn. Interestingly and similarly, a recent systematic review looking at dietary interventions to treat chronic fatigue syndrome, also found insufficient evidence for the use of diet to relieve symptoms (8).

The one trial mentioned that used the low FODMAP diet as a strategy for fibromyalgia involved providing dietary advice to those individuals who have both IBS and fibromyalgia (9). Over an 8-week period, these individuals reduced and reintroduced FODMAPs (9). Participants scored pain and gastrointestinal symptoms, as well as other measures such as quality of life. Both fibromyalgia related pain and IBS related gastrointestinal symptoms improved following the low FODMAP advice from researchers (9). However, there were major limitations to this trial, including a lack of control group, blinding and randomisation, which essentially means that the trial is of poor quality. Without a ‘control’ group, we have no comparator for these positive results, and cannot rule out the effect of placebo. That said, the results suggest a need for further studies in the area.


Although there are commonalities between the ‘centralised pain state’ conditions including FM, IBS and chronic fatigue, there is not enough robust evidence to support any diet, other than the low FODMAP diet, for only people with IBS. While the state of research is limited, there is a need for well-designed studies in the future, to explore dietary therapies as treatment options for FM. For those individuals living with both IBS and FM, following a low FODMAP diet may be warranted following advice from a health professional. 


1.            Clauw DJ. Fibromyalgia: A Clinical Review. JAMA. 2014;311(15):1547-55.

2.            Guymer E, Littlejohn G. Fibromyalgia. Australian Family Physician. 2013;42:690-4.

3.            Slim M, Calandre EP, Rico-Villademoros F. An insight into the gastrointestinal component of fibromyalgia: clinical manifestations and potential underlying mechanisms. Rheumatology International. 2015;35(3):433-44.

4.            Tremolaterra F, Gallotta S, Morra Y, Lubrano E, Ciacci C, Iovino P. The severity of irritable bowel syndrome or the presence of fibromyalgia influencing the perception of visceral and somatic stimuli. BMC Gastroenterol. 2014;14:182.

5.            Caldarella MP, Giamberardino MA, Sacco F, Affaitati G, Milano A, Lerza R, et al. Sensitivity disturbances in patients with irritable bowel syndrome and fibromyalgia. Am J Gastroenterol. 2006;101(12):2782-9.

6.            Zhou Q, Verne GN. New insights into visceral hypersensitivity--clinical implications in IBS. Nat Rev Gastroenterol Hepatol. 2011;8(6):349-55.

7.            Silva AR, Bernardo A, Costa J, Cardoso A, Santos P, de Mesquita MF, et al. Dietary interventions in fibromyalgia: a systematic review. Ann Med. 2019;51(sup1):2-14.

8.            Campagnolo N, Johnston S, Collatz A, Staines D, Marshall-Gradisnik S. Dietary and nutrition interventions for the therapeutic treatment of chronic fatigue syndrome/myalgic encephalomyelitis: a systematic review. J Hum Nutr Diet. 2017;30(3):247-59.

9.            Marum AP, Moreira C, Saraiva F, Tomas-Carus P, Sousa-Guerreiro C. A low fermentable oligo-di-mono saccharides and polyols (FODMAP) diet reduced pain and improved daily life in fibromyalgia patients. Scand J Pain. 2016;13:166-72.

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