The Effect of Diet on Chronic Pain

Chronic pain, typically defined as “pain that continues beyond the typical tissue healing time of 3 months”, affects 1 in 5 adults who are 18-65 years old and over 1 in 3 adults who are older than 65 internationally (1). People who suffer from chronic pain are more likely to experience disability, reduced function, poorer quality of life, mental health issues, and higher healthcare costs (1). Though this condition is complex and highly variable across individuals, one known factor that can affect chronic pain is an individual’s nutrition and diet (1, 2).

Several conditions that are closely linked to chronic pain, such as obesity, high blood pressure, and joint disease, are affected by nutrition and diet. A key mediating factor in the experience of persisting pain is maladaptive immune system changes, often via inflammation and oxidative stress (1). In the words of Dr. Fred Tabung, a cancer and nutrition researcher, “a lot of chronic pain is the result of chronic inflammation”, which is known to be impacted by diet, stress, and exercise (2, 3). Extended inflammation can damage cells, cause “constant pain in muscles, tissues, and joints”, and trigger chronic disease (2, 3). Ideally, a healthy body experiences a balance between reactive oxygen species (ROS) — unstable compounds produced by metabolic reactions that can cause cell damage — and natural antioxidant defense mechanisms. However, if equilibrium is disturbed, the body can experience oxidative stress and associated damage, such as excessive inflammation (4). As a result, one major area of research investigates the impact of diet on chronic pain, with some specific interest in antioxidants (5).

Studies on broad dietary interventions have found that vegetarian, vegan, and Mediterranean diets led to significantly reduced pain in patients with chronic pain symptoms, fibromyalgia, and arthritis (1, 3). There is general consensus on the benefits of eating more vegetables, which are high in micronutrients, and less dairy, refined carbohydrates, and red meat, which are pro-inflammatory (3).

In terms of specific nutrients in one’s diet that may improve chronic pain, studies have concluded that omega-3 fatty acid, which is found in seafood and some vegetable oils, can significantly reduce symptoms in patients with chronic joint pain (1). There is also some evidence that deficiencies in zinc, selenium, iron, folic acid, and vitamins A, B6, C, and E may alter immune system function — these micronutrients can be found in legumes, fruits, and vegetables, as well as multivitamins (2). In a meta-analysis of 46 studies, Brain et al. found that the “supplement type that most consistently had statistically significant results” was amino, specifically collagen, carnitine, and theramine, as studied in knee osteoarthritis, joint pain, and back pain (1). According to Harvard Health, the “strongest scientific evidence suggests foods rich in a group of antioxidants known as polyphenols can have an anti-inflammatory effect” — these foods are common in the Mediterranean diet and include fruits, leafy green vegetables, nuts, legumes, and whole grains (2). It is important to note that high-dose supplements of antioxidants may be linked to health risks. As a result, many experts recommend that increasing antioxidant intake should primarily occur via diet (5).

There is a clear link between some forms of chronic pain, immune system response, and diet. Inflammation plays a role in many painful, chronic joint conditions. Discussing appropriate nutrition with a health professional may help improve symptoms in addition to ongoing rehabilitation.

References

1. K. Brain, T. L. Burrows, M. E. Rollo, L. K. Chai, E. D. Clarke, C. Hayes, F. J. Hodson, C. E. Collins. (2018). A systematic review and meta‐analysis of nutrition interventions for chronic noncancer pain. Pain Management, vol. 32, no. 2, pp. 198-225. doi:10.1111/jhn.12601
2. Harvard Health. “Can diet heal chronic pain?”. Harvard Health Publishing. Updated February 15, 2021. https://www.health.harvard.edu/pain/can-diet-heal-chronic-pain
3. Cleveland Clinic. “How an Anti-Inflammatory Diet Can Relieve Pain as You Age”. Cleveland Clinic, Health Essentials, Chronic Pain. September 27, 2019. https://health.clevelandclinic.org/anti-inflammatory-diet-can-relieve-pain-age/
4. P. Arulselvan, M. T. Fard, W. S. Tan, S. Gothai, S. Fakurazi, M. E. Norhaizan, and S. S. Kumar. (2016). Role of Antioxidants and Natural Products in Inflammation. Oxidative Medicine and Cellular Longevity, vol. 2016, pp. 5276130. doi:10.1155/2016/5276130
5. National Center for Complementary and Integrative Health. “Antioxidants: In Depth”. NCCIH, Health Information. Updated November, 2013. https://www.nccih.nih.gov/health/antioxidants-in-depth