The actual incidence of allergic sensitivity to chocolate is far less common than positive reactions to skin scratch tests would seem to indicate. In at least one double-blind study to determine the correlation positive skin tests for chocolate allergy and the manifestation of clinically observable symptoms, researchers could find only one patient out of a possible 500 who showed both a positive response to the skin test and an objective clinical reaction after eating chocolate. This allows for objective evaluation of clinical symptoms. According to S. Allan Bock, M.D., a researcher in food allergy at the National Jewish Center for Immunology and Respiratory Medicine, evaluation of hundreds of patients at that institution has shown no confirmed allergic reaction to chocolate during double-blind challenges. Caffeine and Theobromine Caffeine and theobromine belong to a group of substances known as methylxanthines.
Caffeine occurs naturally in coffee, tea, cola and, to some degree, cocoa beans.
The amount of caffeine ingested when people eat chocolate in normal quantities is very small. One ounce of milk chocolate, for example, contains 6 mg of caffeine, little more than the amount found in a cup of decaffeinated coffee. Moreover, there have been no reports in the scientific literature of any health problems among children or adults as a result of the caffeine consumed in chocolate. In fact, theobromine is virtually inert as a CNS stimulant. Despite the weakness of theobromine's effect on the brain, many people have mistakenly assumed that it is effective in warding off fatigue and sleep, especially when it is consumed in combination with caffeine, as in chocolate.