Arthritis and avoidance diets

Avoidance diets are based on the idea that certain foods are the aggressors when it comes to arthritis. By subtracting the offending foods from your diet, proponents claim, people with arthritis will experience significant improvements in their symptoms.

• Probably the best known avoidance diet, it's based on the idea that the "nightshade" family of foods — tomatoes, potatoes, eggplant and peppers — contain chemicals that promote inflammation, increase pain and interfere with the repair of damaged joints.
• The "nightshade theory" was proposed by horticulturist Norman Childers, who knew that tomatoes and other nightshades were once considered poisonous — and noticed that they seemed to worsen his arthritis. He carried out an uncontrolled study in which more than 5,000 arthritis patients were asked to avoid nightshade foods for seven years; nearly three-quarters of the patients said their pain and disability gradually improved.
• The nightshade-free diet has never been studied in a scientifically rigorous way, though some rheumatologists have reported that a few of their patients improved after nightshades were removed from their diets. It can't hurt to try the diet (provided you don't make radical dietary changes that could interfere with nutrition), but a drastic improvement isn't something that should be just expected.

• Named for Collin Dong, the physician who devised it for his own arthritis, this diet is patterned after one that many Chinese have followed for centuries. It imposes much broader food restrictions than the anti-nightshade diet.
• Arthritis patients are urged to eat vegetables but to eliminate red meat, fruit, dairy, herbs, alcohol, additives and preservatives.
• In a 1983 study, some arthritis patients were placed on the Dong diet while others consumed a diet allowing for a variety of foods. No significant differences were noted, with about half the people in each group reporting that they felt better.
• No scientific evidence supports the Dong diet, which could actually harm people with arthritis: The diet excludes joint-healthy fruit; and it bans dairy products, the main dietary source of the calcium and vitamin D needed to maintain bones and assist in cartilage formation.
• Consult your doctor before starting any diet.