[Nutrition and fasting].

Background: Patients with rheumatic diseases often enquire about the options for nutritional therapy. Nutritional factors have been empirically described that are associated with the occurrence of inflammatory rheumatic diseases or flare-ups or improved disease states. A growing number of epidemiological and clinical studies deal with the evaluation of nutrition and dietary restriction in rheumatology.

Objective: Narrative presentation of the evidence of nutritional interventions and fasting and its clinical implications.

Results and discussion: Only limited data from smaller clinical studies are available for evidence assessment. A benefit in terms of symptoms and quality of life in rheumatoid arthritis was shown for the Mediterranean and plant-based diet as well as the anti-inflammatory diet. The effect sizes are small to moderate and the effectiveness in the context of complex lifestyle programs is probably sustainable. The evidence for elimination diets is weak. Initial clinical studies indicate a moderate benefit of plant-based nutrition for osteoarthritis in the context of the metabolic syndrome. There is moderate evidence for the benefit of dietary weight normalization in psoriasis. There is clear experimental evidence of a significant anti-inflammatory effect of prolonged fasting. Several clinical studies demonstrated a symptomatic benefit of prolonged modified fasting (therapeutic fasting) in rheumatoid arthritis (RA). If fasting is followed by a vegan and vegetarian diet, lasting effects of up to 1 year have been documented. Cardiometabolic but not antirheumatic effects have been proven for intermittent fasting. Nutrition and fasting can be classified as a possible useful addition to conventional treatment but are currently only rarely taken into account in practice.