Zinc-rich foods could cause join pain

Zinc-rich foods, including seafood, cocoa and chicken, could be causing the painful condition osteoarthritis.
Cartilage can be destroyed by molecular changes involved in processing zinc, a naturally occurring metallic element, a new Korean study has found.
When the cartilage breaks down in osteoarthritis, the bones rub together, causing pain, swelling, and stiffness. 
Osteoarthritis affects the joints and is the most common type of arthritis in the UK, with around 1 million people seeing their GP about it every year. The NHS in England and Wales performs over 140,000 hip and knee replacement operations every year as a result, but almost any joint can be affected by the disease.
However, there has been a lack of effective therapies for the disease because before now the underlying molecular causes have been unclear. But a new study revealed that osteoarthritis-related tissue damage is caused by a molecular pathway that is involved in regulating and responding to zinc levels inside of cartilage cells. 

Source  - Daily Mail