Tomatoes are low in purines and should not worsen gout, says WebMD. They are considered safe to eat along with other fruits and green vegetables. Foods and drinks that people with gout should avoid are those with high purine levels, such as meats, beer and certain seafood.
Purines are substances that human bodies need, according to The World's Healthiest Foods. Once degraded after cell death, uric acid is formed from purines. Uric acid is an anti-oxidant that protects blood vessels from damage, but high levels in the blood can cause it to build up as uric acid crystals in joints, tendons, kidney and other organs. This is gout or gouty arthritis.