Q**I wish to disagree with the assertion in one of your columns that diet has nothing to do with arthritis. I was developing severe symptoms of arthritis when I came across an article by Dr. Norman F. Childers stating that sensitivity to foods of the nightshade family (tomatoes, potatoes, peppers, eggplant and paprika) can cause arthritis. Having eliminated these foods from my diet, I am free of pain. I do not understand why the medical profession persists in perpetuating the myth that arthritis and diet are unrelated.
A***Members of the medical profession must base their recommendations on the best available evidence rather than on speculative articles or anecdotes reported by individual patients.
It is difficult to study the relationship between diet and arthritis, but a number of physicians have examined the effect of various dietary components on rheumatoid arthritis. Rheumatoid arthritis was chosen for these studies because it is believed to be caused by an immunologic (possibly allergic) abnormality.
The most extensive study, carried out at the University of Florida and published this year, found that food sensitivity can contribute to the symptoms of some patients with rheumatoid arthritis. However, the investigator concluded that no more than 5 percent of people with rheumatoid arthritis have a food sensitivity, whereas 30 percent of their subjects alleged that their symptoms were related to specific foods.
In those instances where food sensitivity has been demonstrated by objective measures, milk and other dairy products have most often proved to worsen symptoms of rheumatoid arthritis, but some individuals had increased pain after eating shrimp, corn flour or other foods.
I have been unable to find any studies showing that eliminating foods of the nightshade family reduced arthritis symptoms. Nor is there any evidence that dietary measures are beneficial for forms of arthritis other than rheumatoid arthritis or gout, which may be improved by avoiding organ meats such as liver, etc.
Q**I am worried about my mother, who has begun to eat a lot of cornstarch. What can that mean?
A**A compulsive hunger for unusual substances, such as starch, ice or clay is called pica. Pica can be a manifestation of a deficiency of body iron that may also cause anemia. It is not clear why iron deficiency provokes pica.
Eating clay is also a cultural habit in parts of the South. It can interfere with the absorption of iron from the intestine and cause an iron deficiency. In contrast, eating starch does not impede iron absorption or produce iron deficiency or anemia.
Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine and associate dean for academic affairs at the school.