The Effect of a Ketogenic Diet versus Mediterranean Diet on Clinical and Biochemical Markers of Inflammation in Patients with Obesity and Psoriatic Arthritis: A Randomized Crossover Trial.

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• A short-term ketogenic diet is reported to reduce inflammation and disease activity in patients with obesity and psoriatic arthritis, performing better than a Mediterranean diet in clinical and biochemical outcomes.
• A Ketogenic diet may be considered as an adjunct in the comprehensive management of psoriatic arthritis, especially in obese patients.

Introduction: A randomised cross-over trial was conducted to evaluate the effectiveness of the Mediterranean Diet (MD) with an isocaloric Ketogenic Diet (KD), in patients with obesity and psoriasis along with psoriatic arthritis.

Methods: Twenty-six participants, with a mean age of 52, were randomly assigned to either the MD or KD group for eight weeks. After a six-week washout interval, the two groups were switched to the other type of diet for eight weeks. Sixteen out of the 23 participants (69%) completed the trial.

The primary outcomes were to investigate changes in clinical scores of disease severity - Psoriasis Area and Severity Index (PASI) and Disease Activity Index for Psoriatic Arthritis (DAPSA) - after an 8-week KD intervention compared to an 8-week MD intervention.

Results

• After KD patients displayed a reduction in triglycerides (TGs) compared with baseline (p=0.022). No changes in TGs were observed after MD.
• KD patients displayed a significant reduction in PSAI (p=0.04) compared to baseline, showing a 2-fold higher reduction compared to the MD (-61.58% vs -31.24%, p=0.038)
• Similarly, KD resulted in a significant reduction in DAPSA (p=0.004) compared to baseline, showing a 3-fold higher reduction compared to the MD (-98.62% vs. -32.64%, p=0.034).
• KD patients displayed a significant reduction in IL-6 (p=0.047) compared to baseline, showing a 2-fold higher reduction compared to MD (-55.6% vs. -20.56%, p=0.041).
• Additionally, KD patients showed a reduction in IL-17 (p=0.042) and IL-23 (p=0.037), whereas no significant differences were observed in the inflammatory markers in MD.

Conclusion: This cross-over trial concluded that patients on a Ketogenic diet experienced greater reductions in clinical scores of disease activity and inflammatory markers in obese patients with psoriasis and psoriatic arthritis than those on a Mediterranean diet.

• This cross-over clinical trial demonstrates that a short-term ketogenic diet (KD) may help reduce disease activity and reduce inflammatory markers in patients with obesity and psoriatic arthritis, more effectively than a Mediterranean diet (MD).
• KD is reported to have improvements in PASI and DAPSA scores, as well as reductions in IL-6, IL-17, and IL-23.
• Clinicians may consider offering a ketogenic diet as adjunctive to pharmacological treatment for managing inflammation and disease severity in psoriatic conditions in obese patients.

• The sample size of this study was small, therefore large and more diverse patient population groups are needed for future studies.
• The findings of this study identify an association between dietary interventions and auto-immune disorders and thus emphasise a need for more interventional trials to compare different dietary patterns.
• Further investigations are needed to explore the molecular and immunological mechanism by which ketogenic diets modulate specific cytokines and pathways involved in psoriatic disease.