Great question! My family has a history of rheumatoid arthritis.
Inflammation is part of the body’s immune response; without it, we can't heal. But when it's out of control, it can damage the body. Plus, it's thought to play a role in obesity, heart disease, and cancer.
Foods high in sugar and saturated fat can spur inflammation. They cause overactivity in the immune system.
Dark leafy greens, salmon, tomatoes... These are all great. Here's a link from Harvard that may help. :)
http://www.health.harvard.edu/staying-healthy/foods-that-fight-inflammation