Chocolate provides a fine example of why it's sometimes difficult for clinicians to accurately diagnose an allergy. Large numbers of Americans will tell you, with varying degrees of regret, that they're allergic to chocolate. Yet, true allergies to cocoa itself, chocolate's main component, are clinically rare. The explanation lies in the variety of ingredients found in most chocolate products, including dark chocolate.
Allergies and Sensitivities
In some individuals, specific foods cause a number of adverse reactions. With a true food allergy, your body mistakes a protein in the offending food as a threat. Your immune system reacts by assaulting the perceived infection with responses including antibodies and histamines, which cause a range of unpleasant effects. Foods can also trigger unpleasant reactions that don't involve your immune system, which are referred to as sensitivities or intolerances. Intolerances are generally less severe than allergies, though they can still be remarkably painful or inconvenient.
Pure chocolate is derived from cocoa beans, the seeds of a small tropical tree. They are fermented, dried and then roasted to make chocolate. Chocolate's two primary components, cocoa and cocoa butter, are usually separated as part of the manufacturing process. Cocoa contains chocolate's active ingredients, including the stimulants caffeine and theobromine, and its flavor compounds. Cocoa butter is the fat that gives pure chocolate its richness and texture. Allergies to one or the other are rare, but known. You might also be intolerant of caffeine or theobromine, which would produce an adverse reaction.
Dark Chocolate Products
Commercial dark chocolate contains a variety of additives designed to improve its texture, flavor, shelf life, handling characteristics and profitability. Many of these are known to be either allergens or common intolerance triggers. The best brands add only sugar, soy lecithin and vanilla, but lower-quality dark chocolate might contain dairy products, soy or egg-derived lecithin, gelatin, and corn syrup or other sweeteners. Cross-contamination at the factory can also result in trace amounts of eggs, nuts, peanuts, gluten or other allergens. Lower-quality dark chocolate also includes a variety of emulsifiers, preservatives and antioxidants that might cause reactions in sensitive individuals.
It can be difficult for your doctor or allergist to differentiate between a true chocolate allergy and a sensitivity to chocolate ingredients. It usually requires numerous tests to get a feel for which ingredients might be to blame, and to verify them. A true chocolate allergy produces a reaction with pure non-alkalized cocoa, but an intolerance to various ingredients can take a long time to nail down accurately. If you're genuinely chocolate allergic, you might be able to eat low-quality commercial chocolate candy. If you react to the additives, you might be able to eat the better grades of pure chocolate.