Masking foods for food challenge: practical aspects of masking foods for a double-blind, placebo-controlled food challenge.

In diagnosing a food allergy or food intolerance, a double-blind, placebo-controlled food challenge (DBPCFC) with the suspected food or food substance is the only method available for objective confirmation of an assumed relationship between a suspected agent and a complaint. When the use of capsules as a vehicle for DBPCFC with the suspected agent is not feasible, recipes have to be developed for masking the suspected food with another food. We describe demands and other aspects of the development of recipes for DBPCFC purposes. The taste, smell, color, and texture of the suspected agent have to be hidden in such a way that the patient cannot tell which of the two foods (the active food or the placebo food) contains the suspected agent. Once developed, the recipes have to be judged carefully to ensure that the foods do not contain ingredients other than the suspected agent that can possibly provoke complaints in the patient. Besides ordinary equipment such as cutlery, glasses, and dishes, the minimal equipment needed for preparing the recipes is an accurate balance. The more laborious a recipe is to make, the more equipment is needed. The development of recipes and the preparation of masked foods are time-consuming, which makes DBPCFC with masked foods difficult to perform in daily clinical practice. Performing a DBPCFC with masked foods in daily clinical practice can be a great challenge to the imagination and creativity of a dietitian.