PAIN+ CPN

Doctor, is there a diet that is helpful for reducing chronic pain?

Several different diet types reduced chronic pain compared to a diet with no restrictions, but no single diet type was better than the others.

What is the evidence?

SUMMARY OF FINDINGS

Specific diets versus control (usual diet or a placebo substitute for one food item)

DietDescriptionNumber of Study Groups*Average Effect^
Omega-3cod liver oil, seal oil1did not reduce pain
Single-food changeadding one of the following: rosmarinic tea, dried blueberries, pomegranate, antioxidant berry juice, black soybean, chamomile tea, organic extra virgin olive oil, cherry juice, strawberry juice8

reduced pain by a moderate amount

(individual study results ranged from large reduction to no reduction)

Energy and/or macronutrient restrictioncalorie, carbohydrate, or fat restricted diets5did not reduce pain
Mediterranean diethigh in vegetables, fruits, legumes, nuts, beans, whole grains, fish, and unsaturated fats (olive oil); low in meat and dairy1

reduced pain by a small amount

Eliminationremoval of one or more of the following: refined high-glycemic index foods, hydrogenated oils, MSG, FODMAPS, gluten, dairy, high PUFA and MUFA4did not reduce pain
Vegetarian/veganvegan = vegetarian but also no milk products, eggs or other foods that come from animals6

reduced pain by a large amount

(individual study results ranged from large reduction to no reduction)

MSG = monosodium glutamate; FODMAPS = fermentable oligo-, di-, mono-saccharides and polyols; PUFA = polyunsaturated fatty acid;

MUFA = monoun´╗┐saturated fatty acid

*23 out of 43 studies in this review were combined together in a meta-analysis to produce these results

^quality of the evidence ranged from low (10 studies) to high (6 studies)

What kind of study was this?

This was a systematic review of 43 studies published up to December 2019.

Who? This review included studies involving people with chronic musculoskeletal pain not due to cancer. The studies included people with rheumatoid arthritis, fibromyalgia, osteoarthritis, neuropathic pain, and other musculoskeletal pain with pain lasting longer than 3 months.

What? The reviewers included studies that compared 6 different diet types given for at least 2 weeks with usual diet or substitute for a single food item.

Special Diet

vs

Control

Omega-3, Single-food change, Energy and/or macronutrient restriction, Mediterranean, Elimination, Vegetarian/Vegan



Usual (unrestricted) diet or usual diet plus a placebo substitute for a single food item



Why was this research done?

Low grade inflammation of the nervous system may cause pain signals to be released when they shouldn't be (because no damage is occuring). The foods we eat may play a role in producing or reducing inflammation. The reviewers wanted to know if following certain diets would help to reduce chronic pain. They found that several different diets (single-food change, Mediterranean diet, vegetarian/vegan) reduced pain, but no single diet type was better than the others and there were problems with many of the studies that made the results unreliable. It is suspected that factors that these diets share may be the reason for the positive effect (for example, eating high-quality nutritious food items and reducing weight). Diet studies are notoriously hard to do because of problems with knowing what else people eat, poor adherence to diets, and difficulty with maintaining changes over long periods of time. Some studies also showed weight loss making it hard to know if the weight loss itself reduces pain or the way in which one loses the weight.

This Evidence Summary is based on the following article:

Field R, Pourkazemi F, Turton J, et al. Dietary Interventions Are Beneficial for Patients with Chronic Pain: A Systematic Review with Meta-Analysis. Pain Med. 2021 Mar 18;22(3):694-714. doi: 10.1093/pm/pnaa378. PubMed

Published: Tuesday, July 20, 2021