In addition to the beneficial effects on oxidative stress, cardiovascular health, nervous system diseases, aging, and cancer prevention, cocoa has been revealed as a food with immunoregulatory properties; a remarkable effect on the immune system. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3671179/
Dark chocolate contains a higher amount of phytochemicals than milk or white chocolate do and is linked to reducing inflammation in the body; it may reduce the severity of symptoms associated with arthritis. The key is consuming foods with a high cocoa content, ideally 70 % or higher.
Chocolate is an energy-dense food and could easily contribute to weight gain if you over-consume it so carefully enjoy the health benefits of chocolate in moderation.
https://www.livestrong.com/article/490087-the-effects-of-chocolate-on-arthritis/?fbclid=IwAR3u8_7oECM_cRfT_QdAEkWQ699fde44YUO-dlUbLGRhIMixpwOyeCl96u0
An interesting discussion by a group of Rheumatology doctors and patients has been raised on this matter too.
https://www.facebook.com/groups/19448554147/search/?query=Chocolate%20and%20Arthritis%20Livestrong&epa=SEARCH_BOX