The Anti-Inflammatory Diet and Rheumatoid Arthritis

A recent study carried out in 2020 and published in The American Journal of Clinical Nutrition investigated whether an anti-inflammatory diet could reduce disease activity and improve the quality of life for patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovial inflammation (an acute or chronic inflammation of tendon tissue) and often followed by cartilage and bone erosion¹. Patients with RA suffer from reduced functional capacity, pain and stiffness that often lead to an impairment in their quality of life.

In this single blinded crossover study, i.e. a study in which the subject is exposed, at different times, to one or more different treatments, following a random sequence and without being aware of the type of treatment received, the 50 Swedish patients with RA enrolled were randomly assigned to either an anti-inflammatory intervention diet that included non-inflammatory foods or a diet similar to a typical Swedish diet for 10 weeks.

The intervention diet was provided by the study and was created based on the average dietary intake for men and women aged 45 to 64 years in Sweden (17% protein, 34% total fat, 13% SFA and 43% carbohydrates).

• Lunch and dinner contained fish (mainly salmon) 3-4 times a week and vegetarian dishes with legumes 1-2 times a week. Potatoes, whole grains, vegetables, yogurt for dips, spices, and other flavorings were included.

• Snacks consisted of fresh fruit.

• Breakfast contained low-fat dairy, whole grains, pomegranate and cranberries, nuts, and juice shots with probiotics.

The probiotic strain used contained Lactobacillus plantarum 299, known for its systemic anti-inflammatory and immune response regulator properties, and 5g/week were provided to the participants.

For those meals not provided by the study, participants were instructed to limit their meat intake to no more than 3 times per week, to eat no more than 5 servings of fruit, berries, and vegetables per day (including those provided), to use oil or margarine when cooking, and choose low-fat dairy products and whole grains.

The control diet followed by the other group, provided by the study, had a daily structure of:

• meat or chicken, a maximum of 5 times a week,

• refined cereals,

• protein bars or quark (cream cheese) as snacks

• a breakfast of white bread with butter and cream cheese and a mix of either quark or yoghurt with corn flakes and orange juice.

In addition, participants were also asked to consume ≤5 servings-per-day of fruits, berries, and vegetables; seafood ≤1 time/week; to use butter when cooking; to choose high-fat dairy products and avoid products with probiotics.

After a 4-month break from the dietary treatment, the participants switched diets, therefore those who followed the anti-inflammatory diet started following the control diet and vice versa.

The primary objective of this study was to evaluate disease activity, the secondary objective was to evaluate any improvements in painful and swollen joints, general health status and C-reactive protein (an index of inflammation detected through blood tests).

RESULTS

While following the anti-inflammatory diet, patients had a significant post-operative improvement in disease activity compared to patients following the control diet, whilst there were no statistically significant improvements in joint pain, swelling, etc. although some patients did report some improvement.

In conclusion, this study demonstrated the positive effects of an anti-inflammatory diet on disease activity. However, further studies are needed to determine whether this type of diet can lead to clinically relevant improvements².

SOURCES

1. Choy E. Understanding the dynamics: pathways involved in the pathogenesis of rheumatoid arthritis. Rheumatology. 2012;51(5):v3–11.
2. Anna K E Vadell, Linnea Bärebring, Erik Hulander, Inger Gjertsson, Helen M Lindqvist, Anna Winkvist, Anti-inflammatory Diet In Rheumatoid Arthritis (ADIRA)—a randomized, controlled crossover trial indicating effects on disease activity, The American Journal of Clinical Nutrition, Volume 111, Issue 6, June 2020, Pages 1203–1213.