Anti-inflammatory medications are typically first line treatment options for many orthopedic conditions. Many of our patients are obese and having a BMI >30kgm2 is associated with a low-grade inflammation and pro-inflammatory mediators (Emily Calton, 2015; Philip Calder, 2011). By losing weight, there is not only less stress across joints, but we can also decrease the systemic inflammation that can be contributing to musculoskeletal pain. Our dietary intake is neglected in its role as an activator of our immune system. The general principles of an anti-inflammatory diet are to consume fruits and vegetables, fish, whole grains, and lean protein (Marcason, 2010). However, what makes this difficult to study is that there is a syngergistic relationship between different foods and nutrients which make studying their effects difficult (Philip Calder, 2011). They recommend avoiding red meat, dairy, saturated fats, trans fats, alcohol, and processed foods (Marcason, 2010). In this review, we will be evaluating the evidence of an anti-inflammatory diet in pain management.
Systemic inflammation can be traced back to saturated fats and carbohydrates (SK Totsch, 2018). In 2002 published in the American Journal of Clinical Nutrition, they looked at the role of dietary glycemic load and hs-CRP levels (Simin Liu, 2002). The dietary glycemic load is a measure used to estimate which foods can cause the most rapid increase of glucose and insulin (Simin Liu, 2002). They found that in middle-aged women who had higher quantities of carbohydrate intake were found to have the higher hs-CRP levels (Simin Liu, 2002). There is also evidence that shows that fatty acids can activate macrophages (SK Totsch, 2018). Adipose tissue as well, can trigger an inflammatory state by releasing leptin (Stacie Totsch, 2016). Leptin has been found to stimulate release of proinflammatory cytokines (Stacie Totsch, 2016).
In 2016, Stacie Totsch looked at the role of the Total Western Diet (TWD) on pain and inflammation in mice (Stacie Totsch, 2016). The TWD diet was found to have more calories from saturated and monounsaturated fat compared to the control group diet (Stacie Totsch, 2016). They found that when measuring inflammation, those mice on the (TWD) diet were found to have longer periods of significant pain and hyperalgesia compared to a group of mice eating a control diet (Stacie Totsch, 2016).
Elevated levels of saturated fats are also thought to be a risk factor for osteoarthritis. In 2015 published in the Annals of the Rheumatic Diseases, investigators looked at the role of a diet high in saturated fats on osteoarthritis following joint injury. What they found was that omega-6 polyunsaturated fatty acids and saturated fats were independent risk factors for osteoarthritis after joint injury (Chia-Lung Wu, 2014). Published in Arthritis Care & Research, patients with Rheumatoid Arthritis participated in a survey that asked them if one of 20 foods caused their symptoms to be unchanged, improve, or worsen (Sara Tedeschi, 2017). The participants of the survey also had their CRP drawn and had a disease activity score assigned by a physician (Sara Tedeschi, 2017). What they found was that blueberries and spinach were found to improve symptoms and drinking soda with sugar and eating dessert were found to worsen symptoms (Sara Tedeschi, 2017).
Most recently, published in the American Journal of Clinical Nutrition, a study randomized Rheumatoid Arthritis patients to an anti-inflammatory diet that was high in n-3 fatty acids, fiber, antioxidants, and probiotics (Anna Vadell, 2020). What they found was that during the intervention period with patients on the diet, they did not have statistically significant differences in disease activity and ESR compared to the control group (Anna Vadell, 2020). However, in the period immediately after the intervention the participants were found to have statistically significant improvements in their disease activity and ESR (Anna Vadell, 2020).
Further research has looked into the value of two n-3 polyunsaturated fatty acids: eicosapentaeonic acid (EPA) and docosahexaenoic acid (DHA) (Chaonan Fan, 2013). Both EPA and DHA are found in seafood and walnuts (Shawna Lemke, 2013; Marcason, 2010). EPA and DHA have been found to decrease adipose tissue inflammation (Chaonan Fan, 2013). Commercial doses of omega-3 polyunsaturated fatty acids only provide 500mg of omega-3 fatty acid in a 1000mg fish oil tablet (Tick, 2015). Typically, studies provide 6000-8000mg of fish oil (Tick, 2015).
Previous studies have shown that dietary fiber has an inverse relationship with CRP, IL-6, and TNF-alpha (Rebecca McLoughlin, 2017). A meta-analysis was done that looked at the role of short-chain fatty acids, which are byproducts of dietary fiber breakdown by gut bacteria, and their role on systemic inflammation (Rebecca McLoughlin, 2017). The meta-analysis found that prebiotic (soluble fibers that stimulate growth of commensal bacteria) supplementation of the gut can decrease CRP levels in overweight and type II diabetes patients (Rebecca McLoughlin, 2017).
There is limited evidence that Vitamin D deficiency can be associated with musculoskeletal pain. Patient’s with low vitamin D levels are found to have pain that starts in their low back and can develop into pain also found in the pelvis and upper legs (Jara, 2004). These symptoms have been found to resolve after 3-6 months of repletion (Jara, 2004).
The Mediterranean diet has also been studied as an anti-inflammatory diet. The principles behind the Mediterranean diet is consumption of lean proteins like fish and chicken, high levels of intake of fruits and vegetables, and olive oil (Ramon Estruch, 2013). The diet restricts intake of dairy, red and processed meats, and alcohol (Ramon Estruch, 2013). Studies have shown an inverse relationship between consuming a Mediterranean diet and IL-6 levels (Philip Calder, 2011).