Does poor diet increase inflammation in rheumatoid arthritis?

This study investigated if diet quality was associated with disease activity in patients with rheumatoid arthritis. They found that patients with poor diet had higher levels of inflammation. Some background Rheumatoid arthritis (RA) is a chronic (long-term) condition. It is an auto-immune disease. In RA, the immune system attacks healthy tissue in the joints causing inflammation. This also causes pain and can make it difficult to move about. Medication is used to manage RA symptoms and reduce disease activity. Disease activity is assessed using a number of methods. Measuring inflammatory proteins in the blood is one method. Using x-rays to determine if joints are damaged is another. Many factors can influence inflammation and disease activity. Diet is one important factor. Some studies suggest that a healthy diet may improve RA disease activity. Nutrients such as fatty acids and antioxidants may help reduce symptoms. It is unclear if diet quality is associated with disease activity or inflammation.

Methods & findings

This study included 66 patients with RA. Patients were asked to list their food intake during the last 12 months. The quality of the diet was determined based on this information. Patients were classified as having poor, fair or high diet quality. Diets rich in fruit and vegetables, whole grains and fish were high quality. Disease activity was measured using the Disease Activity Score-28 (DAS28). Erythrocyte sedimentation rate (ESR) was also used as another indicator of disease activity. Inflammation was assessed by measuring C-reactive protein (CRP) levels.  There was no association between diet quality and DAS28 score. However, patients with higher diet quality had lower levels of inflammation (lower CRP and ESR). Poor quality diet was associated with higher CRP and ESR levels. 

The bottom line

The authors concluded that patients with RA and having a poor diet have higher levels of inflammation.

The fine print

This study included a relatively small number of patients. Larger studies are needed to confirm the results of this study. 

Reference:

Nutrients 2018, 10(10), 1535; https://doi.org/10.3390/nu10101535: Poor Dietary Quality Is Associated with Increased Inflammation in Swedish Patients with Rheumatoid Arthritis by Linnea Bärebring , Anna Winkvist , Inger Gjertsson and Helen M. Lindqvist