Food & Disease: How Diet May Affect Rheumatic & Musculoskeletal Diseases

EULAR 2021—Ask any rheumatologist what is among the most common questions patients ask and the answer will certainly include a variation of “Which foods should I be eating, and which foods should I avoid?” Questions surrounding pro-inflammatory and anti-inflammatory diets abound, and it can be challenging to reply to these inquiries with evidence-based responses.

During EULAR 2021, Elena Nikiphorou, MBBS/BSc, MD (Res), FRCP, PGCME, FHEA, consultant rheumatologist and an honorary senior lecturer at King’s College London, U.K., addressed this topic in a lecture on diet in rheumatic and musculoskeletal diseases.

Dr. Nikiphorou began her presentation by noting that diet undoubtedly plays a role in inflammation. Using the mosaic autoimmunity model, she described the interplay between the environmental, genetic, immunological and hormonal pathways that ultimately lead to the development of autoimmunity in patients.1 Individual dietary components sometimes play clear roles in contributing to inflammatory pathways, such as how salt intake leads to upregulation of pro-inflammatory macrophages, an increase in Th17 cell activity and interleukin (IL) 17 levels, and a decrease in regulatory T cell function.

Aside from pro- and anti-inflammatory features of various foods, a healthy diet can help reduce body mass index (BMI) and prevent the onset of comorbidities, such as cardiovascular disease and osteoporosis, which can complicate matters for patients with rheumatic disease.

Diets

A typical Western diet often includes high levels of refined carbohydrates, salt, sugar and omega-6 fatty acids, and low levels of fiber and long-chain omega-3 fatty acids, Dr. Nikiphorou said. Good sources of omega-3 fatty acids include olive oil, soybean oil, flaxseed oil, sardines, mackerel and salmon. Unfortunately,many of these healthy foods are lacking in the diets of most Americans.

The intake of sugary beverages may, on its own, be a risk factor for the development of certain forms of autoimmune disease. In a prospective study of nearly 80,000 women enrolled in the Nurses’ Health Study, regular consumption of sugar-sweetened soda was associated with an increased risk of seropositive rheumatoid arthritis (RA), independent of other dietary and lifestyle factors.²

Good and consistent evidence exists that the Mediterranean diet is effective in reducing the risk of cardiovascular disease and overall mortality, Dr. Nikiphorou explained.^3,4 This diet mostly entails consumption of fruits and vegetables, beans, nuts, whole grains, fish, olive oil, and small amounts of dairy and red wine. Several components of this diet—including oily fish, cocoa and the resveratrol found in red wine—appear to be associated with reduced inflammation. This association may indicate why patients with RA may benefit by adopting a Mediterranean diet.

In a 2018 review on this subject, Petersson et al. noted the Mediterranean diet may reduce pain and swollen and tender joints in patients with RA. Moreover, the authors noted that n-3 polyunsaturated fat supplementation (i.e., fish oil supplements) may reduce inflammation and possibly slow the progression to pharmacotherapy in patients with RA.⁵

Comorbidities

In addition to managing rheumatic diseases, rheumatologists must be attuned to preventing common comorbidities in patients. Among these conditions is osteoporosis, and Dr. Nikiphorou said patients on particular diets, such as vegan diets, may be at risk of inadequate calcium and vitamin D intake. Other dietary considerations important to bone health include the intake of vitamin C, vitamin K, magnesium and potassium.

Focusing on vitamin D, evidence exists that deficiency of this vitamin may correlate with disease activity for patients with autoimmune disease. Fernandes et al. found, in patients with spondyloarthritis, vitamin D correlates with disease activity, structural damage and extra-articular manifestations, including gut inflammation and anterior uveitis.⁶

Evidence exists that vitamin D deficiency can also significantly affect disease activity in systemic lupus erythematosus (SLE). Gao et al. measured serum levels of 25-hydroxyvitamin D3 in 121 patients with SLE and in 150 healthy controls. They found severe deficiency (defined as a level less than 10 ng/mL) correlated with increased SLE Disease Activity Index scores (odds ratio [OR] 6.420; P=0.006).⁷

In a separate study, Petri et al. found that among 1,000 patients with SLE monitored over 128 weeks, a 20 ng/mL increase in 25-hydroxyvitamin D level was associated with a 21% decrease in the odds of having a high disease activity score and a 15% decrease in the odds of having clinically important proteinuria.⁸

Weight

On the subject of obesity, Dr. Nikiphorou referred to some of her own research. Using data from two consecutive, similarly designed, multicenter RA inception cohorts in the U.K., Dr. Nikiphorou and colleagues collected data on the BMI for more than 2,300 patients with newly diagnosed RA. The researchers found that being obese at baseline was associated with a 43% reduction in the odds of achieving a low EULAR Disease Activity Score in 28 Joints (DAS-28) on at least one occasion by year 2 compared with those in the normal/overweight category (OR 0.57; 95% confidence interval 0.61, 0.90). Also, scores on the Health Assessment Questionnaire (HAQ) and the 36-item Short Form Health Survey (SF-36) were significantly worse in year 2 of follow-up for patients who were obese at baseline.⁹

Although weight loss through diet and exercise is clearly an important topic for rheumatologists to discuss with their patients, it was also noted that weight loss through bariatric surgery may hold promise to help reduce disease activity. In a 12-month prospective cohort study, 32 patients with RA underwent bariatric surgery and 33 patients received only pharmacotherapy for RA. Using outcome measures that included ACR20, ACR50, ACR70, DAS28-ESR, DAS28-CRP and Clinical Disease Activity Index (CDAI), weight loss after bariatric surgery was associated with statistically significant, lower disease activity than that found in obese patients who did not undergo surgery.¹⁰

Bottom Line

Diet is at the forefront for many patients, and more research is needed to better understand how to tailor dietary advice to individual patients and for specific diseases.

One thing is clear: Diet should be taken into account when counseling patients. Even if the plate is full of topics to discuss during an office visit, this important subject should not be neglected.

Jason Liebowitz, MD, completed his fellowship in rheumatology at Johns Hopkins University, Baltimore, where he also earned his medical degree. He is currently in practice with Skylands Medical Group, N.J.

References

1. Shoenfeld Y, Zandman-Goddard G, Stojanovich L, et al. The mosaic of autoimmunity: Hormonal and environmental factors involved in autoimmune diseases—2008. Isr Med Assoc J. 2008 Jan;10(1):8–12.
2. Hu Y, Costenbader KH, Gao X, et al. Sugar-sweetened soda consumption and risk of developing rheumatoid arthritis in women. Am J Clin Nutr. 2014 Sep;100(3):959–967.
3. Fung TT, Rexrode KM, Mantzoros CS, et al. Mediterranean diet and incidence of and mortality from coronary heart disease and stroke in women. Circulation. 2009 Mar 3;119(8):1093–1100. Erratum in: Circulation. 2009 Mar 31;119(12):e379.
4. Lopez-Garcia E, Rodriguez-Artalejo F, Li TY, et al. The Mediterranean-style dietary pattern and mortality among men and women with cardiovascular disease. Am J Clin Nutr. 2014 Jan;99(1):172–180.
5. Petersson S, Philippou E, Rodomar C, et al. The Mediterranean diet, fish oil supplements and Rheumatoid arthritis outcomes: Evidence from clinical trials. Autoimmun Rev. 2018 Nov;17(11):1105–1114.
6. Fernandes S, Etcheto A, van der Heijde D, et al. Vitamin D status in spondyloarthritis: Results of the ASAS-COMOSPA international study. Clin Exp Rheumatol. 2018 Mar-Apr;36(2):210–214.
7. Gao CC, Liu SY, Wu ZZ, et al. Severe vitamin D deficiency increases the risk for moderate to severe disease activity in Chinese patients with SLE. Lupus. 2016 Oct;25(11):1224–1229.
8. Petri M, Bello KJ, Fang H, Magder LS. Vitamin D in systemic lupus erythematosus: Modest association with disease activity and the urine protein-to-creatinine ratio. Arthritis Rheum. 2013 Jul;65(7):1865–1871.
9. Nikiphorou E, Norton S, Young A, et al. The association of obesity with disease activity, functional ability and quality of life in early rheumatoid arthritis: Data from the Early Rheumatoid Arthritis Study/Early Rheumatoid Arthritis Network U.K. prospective cohorts. Rheumatology (Oxford). 2018 Jul 1;57(7):1194–1202.
10. Xu F, Yu C, Li DG, Yan Q, Zhang SX, Yang XD, Zhang Z. The outcomes of bariatric surgery on rheumatoid arthritis disease activity: A prospective cohort study. Sci Rep. 2020 Feb 21;10(1):3167.