Foods to avoid if you have arthritis are the same foods that cause or aggravate the disease. Glucosamine and chondroitin are two essential amino acids necessary for joint health. Eating foods with these ingredients can help increase their levels in your body. The problem is that some foods are more harmful to your joints than others.
For instance, if you have arthritis in your knee, you should not consume a lot of seafood because they contain high levels of mercury. The best choice would be fish with smaller amounts of mercury.