By Ellen Feldman, MD
Altru Health System, Grand Forks, ND
SYNOPSIS: This review of evidence for the use of dietary interventions to treat fibromyalgia shows symptom reduction associated with a variety of healthy diets. Weight loss may be key to understanding this connection, but more research is needed.
SOURCE: Pagliai G, Giangrandi I, Dinu M, et al. Nutritional interventions in the management of fibromyalgia syndrome. Nutrients 2020;12:2525.
We recognize fibromyalgia syndrome (FMS) as one of the most common chronic pain conditions presenting in medicine, affecting women more often and responsible for functional decline in up to 5% of the adult population worldwide.
Although FMS was not formally recognized as a disease until 1987, it is not a new condition. In fact, echoes of this syndrome can be found in the medical literature as far back as 1642, when French physician Guillaume de Baillou introduced the term “muscular rheumatism” to describe muscular pain not arising from injury and not causing deformity.1
During subsequent years, attempts were made to characterize, study, and treat this syndrome of chronic, diffuse pain combined with psychologic symptoms (such as depression) and somatic symptoms (such as fatigue and cognitive dulling). Once the disorder was formally accepted, diagnostic criteria soon followed. However, to this day, there remain many unanswered questions about the etiology and treatment of FMS.1,2
Pagliai et al noted both pharmacologic and nonpharmacologic interventions usually are necessary to alleviate symptoms of FMS, and that one of the emerging areas of nonpharmacologic treatment involves nutrition. Thus, the authors conducted a comprehensive review of the literature regarding FMS and nutritional interventions, including the role of dietary supplements, foods, and specific diet plans.
DIETARY SUPPLEMENTS
According to the FDA, a dietary supplement is a product taken by mouth that contains a “dietary ingredient” intended to supplement the diet.3 In a 2012 Spanish survey of 101 women with FMS, Arranz et al found 73% of respondents were using dietary supplements and 61% of this group started the supplement after receiving a FMS diagnosis.4 A 2020 survey of 504 Norwegian patients with FMS (90% women) revealed an even higher percentage (85.3%) using dietary supplements. The most used supplements were vitamin D, magnesium, and omega-3 fatty acids.5
Pagliai et al noted a 2017 meta-analysis covering 45 studies, mostly observational, revealed little evidence indicating a nutrient deficiency was involved in the etiology of FMS and/or the use of dietary supplements was helpful in treatment or symptom reduction.6 Pagliai et al conducted an additional review of 13 interventional studies:
- Vitamin D: Eight small studies focusing on vitamin D were reviewed, with 385 patients in all and a maximum duration of 20 weeks. The largest controlled study of 90 patients showed improved Fibromyalgia Impact Scores (FIQ) associated with 50,000 units of cholecalciferol vs. placebo after eight weeks. While other studies showed improvement in other aspects of FMS, outcome measures were heterogenous across the studies, making comparisons difficult.
- Vitamins C and E: No consistent published studies showed improvement in symptoms of FMS when controlling for vitamins C and E.
- Magnesium: Two small studies focusing on magnesium were reviewed, with 84 total participants. A 1995 study showed improvement in severity of pain with up to 300 mg of magnesium and malic acid over four weeks, while a more recent study revealed multiple symptom improvement in FMS with 300 mg of magnesium citrate and amitriptyline vs. amitriptyline alone.
- Iron: One controlled study assessing the association of iron intake with fibromyalgia symptoms included 80 participants and showed improvement in FIQ in the treatment group (compared to a placebo group) after six weeks.
- Probiotics: One pilot study of 40 patients with seven weeks ofa multispecies probiotic showed improved cognitive functioning in an intervention group without a significant change in other symptoms of FMS, including pain.
There have been proposals suggesting specific types of diet and additional food items may assist with symptom control in FMS. In general, the thinking behind these tactics is to correct any nutritional deficiencies or address low-grade systemic inflammation that may contribute to disease state.
Results of studies of dietary interventions concerned the following:
- Extra virgin olive oil: Extra virgin olive oil is loaded with phenolic compounds and is thought to be powerfully anti-inflammatory.7 Two studies with 53 total participants and three weeks of follow-up showed a significant improvement in FIQ and some cardiovascular risk factors.
- Ancient grain products: In this diet, Khorasan wheat, an ancient wheat known for a high content of nutrients and polyphenols, replaced modern grains.8 One study of 20 patients led to overall improvement in FIQ after eight weeks.
- Monosodium glutamate and aspartame-free diet: There is concern that monosodium glutamate and aspartame can be neurotoxic in excess.9 To that end, two studies with 118 patients were reviewed. Results were inconsistent, with only one study showing improvement in symptoms after eliminating monosodium glutamate and aspartame.
- Gluten-free diet: Gastrointestinal symptoms are common in FMS. Four studies, including a pilot study with seven patients and 159 participants altogether, were reviewed. These included two long-term studies (12 to 18 months), with both showing improvement in FMS pain measurements. However, a six-month trial of a gluten-free vs. low-calorie diet in 75 FMS patients led to similar improvements in FIQ and other outcome measurements in both groups.
- Low fermentable oligo-di-monosaccharides and polyphenols diet: Restricting these short-chain, poorly absorbed carbohydrates (such as lactose and fructans) has shown efficacy in the treatment of irritable bowel syndrome, which frequently is comorbid with FMS.10 One study with 38 women over four weeks showed improvement in FMS pain scores and weight loss when participants reduced the intake of those substances.
- Low-calorie diet: Pagliai et al cited suggestions in the literature suggesting obesity worsens severity of FMS symptoms. Three studies of low-calorie diets, including one pilot study, with a total of 248 patients for up to six months showed improvement in pain symptoms, sleep, depression, and lower measures of inflammation.
- Vegetarian diet: The idea that an antioxidant-rich diet may help alleviate pain in FMS (because of reduced inflammation) sparked these studies. Six studies with a total of 225 patients for up to 12 weeks showed temporary improvement in FMS pain scores when participants switched to vegetarian diets. However, the scores reversed when participants changed back to omnivorous diets.
- Mediterranean diet: Two studies with a total of 57 patients for up to 16 weeks showed improvements in mood but no changes in measures of inflammation when participants consumed a Mediterranean diet.
COMMENTARY
FMS is a chronic and often debilitating condition. The hallmark symptom of diffuse pain combined with fatigue and other comorbidities, including depression, gastrointestinal symptoms, and sleep disturbances, often are underrecognized. Patients report encountering skepticism among medical providers regarding the condition, but even after a diagnosis, treatment often is inadequate.11 Without effective treatment, many patients with FMS look toward complementary interventions. A 2020 survey of 670 individuals diagnosed with FMS showed while more than 90% reported using conventional pharmacologic agents (including opioids) to address symptoms of FMS, 66% of this group used complementary therapies. In this survey, the top such intervention was vitamins.12
Pagliai et al have added to our knowledge of the effectiveness of dietary interventions for FMS in general. Perhaps the most striking finding from this review is the need for more robust and controlled studies to better understand and apply these tactics. As it is, while there may be some suggestion from these investigations indicating specific diets can be helpful in symptom reduction in FMS, the small sample sizes, difficulty blinding (given the nature of the intervention), and short follow-up periods limit the clinical utility of this information. In addition, future studies that incorporate methodology to evaluate compliance with dietary interventions and address other confounding factors will serve to strengthen the legitimacy of the results. For now, it is interesting to speculate on a common mechanism that could explain the association of this diverse collection of diets with symptom improvement in FMS. Pagliai et al noted that all the diets are antioxidant- and/or fiber-rich, and most lead to weight loss (although weight was not always documented in the studies.) The association of weight loss with reduced inflammation may be an explanation for the association of these diets with symptom improvement in FMS.
At first glance, this information may seem to carry limited value and clinical application for the primary care provider working with FMS patients. However, introducing the idea that a dietary plan could be useful in controlling or reducing symptoms of FMS may be an initial step toward a broader discussion about lifestyle interventions that may lead to better health outcomes for these patients.
REFERENCES
- Wolfe F. The history of the idea of widespread pain and its relation to fibromyalgia. Scand J Pain 2020;20:647-650.
- Galvez-Sánchez CM, Reyes del Paso GA. Diagnostic criteria for fibromyalgia: Critical review and future perspectives. J Clin Med 2020;9:1219.
- United States Food and Drug Administration. Questions and answers on dietary supplements. Updated July 22, 2019.
- Arranz L-I, Canela M-Á, Rafecas M. Dietary aspects in fibromyalgia patients: Results of a survey on food awareness, allergies, and nutritional supplementation. Rheumatol Int 2012;32:2615-2621.
- Kvæl LAH, Løchting I, Molin M. Use of dietary supplements and perceived knowledge among adults living with fibromyalgia in Norway: A cross-sectional study. Nutrients 2022;14:5.
- Joustra ML, Minovic I, Janssens KAM, et al. Vitamin and mineral status in chronic fatigue syndrome and fibromyalgia syndrome: A systematic review and meta-analysis. PLoS One 2017;12: e0176631.
- Gaforio JJ, Visioli F, Alarcón-de-la-Lastra C, et al. Virgin olive oil and health: Summary of the III International Conference on Virgin Olive Oil and Health Consensus Report, JAEN (Spain) 2018. Nutrients 2019;11:2039.
- Whittaker A, Dinu M, Cesari F, et al. A Khorasan wheat-based replacement diet improves risk profile of patients with type 2 diabetes mellitus (T2DM): A randomized crossover trial. Eur J Nutr 2017;56:1191-1200.
- Pressinger R. Monosodium glutamate (MSG) & aspartame during pregnancy: Two common food additives show potential for damaging the brain at normal human exposure levels. CHEM-TOX. Published 1997.
- FODMAPs and irritable bowel syndrome.
- Chen A, Swaminathan A. Factors in the building of effective patient-provider relationships in the context of fibromyalgia. Pain Med 2020;21:138-149.
- Pfalzgraf AR, Lobo CP, Giannetti V, Jones KD. Use of complementary and alternative medicine in fibromyalgia: Results of an online survey. Pain Manag Nurs 2020;21:516-522.
This review of evidence for the use of dietary interventions to treat fibromyalgia shows symptom reduction associated with a variety of healthy diets. Weight loss may be key to understanding this connection, but more research is needed.
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