The evaluation of nightshade elimination diet (NED) on inflammatory and rheumatologic markers of rheumatoid arthritis patients: study protocol for a randomized controlled trial

Rheumatoid arthritis (RA) is a chronic disease with a global prevalence rate of 1%. Patients with RA often associate specific foods like tomatoes and eggplants with adverse symptoms. These plants contain solanine, which could potentially contribute to bone and joint damage. Despite patient reports, there is a lack of randomized controlled trials (RCTs) investigating the effects of nightshades on patients with RA. This study aims to assess the effect of nightshade elimination diet (NED) on inflammatory and rheumatologic marker levels in rheumatoid arthritis patients for the first time.

A single-blinded controlled trial will be conducted to evaluate the effect of an NED on 40 participants over 8 weeks (2 months). Participants will be equally divided into intervention and placebo groups. Both groups will receive general anti-inflammatory dietary recommendations, with the intervention group undergoing an NED during the study. Clinical symptoms will be assessed using questionnaires, and blood samples will be collected to measure relevant indicators.

This RCT signifies a groundbreaking exploration into NED effects on RA markers, potentially initiating crucial discussions in the field. Its outcomes could serve as a cornerstone for larger and more robust trials, offering pivotal insights to nutritionists and physicians for the nuanced management of patients with RA.

Iranian Registry of Clinical Trials IRCT20230220057465N1 (https://irct.behdasht.gov.ir/trial/68959). Registered on 8 April 2023.