Reactions to chemical components of the diet may be more common than true food allergies,[citation needed] although there is no evidence to support this. They are caused by various organic chemicals occurring naturally in a wide variety of foods, animal and vegetable, more often than to food additives, preservatives, colourings and flavourings, such as sulfites or dyes.[1] Both natural and artificial ingredients may cause adverse reactions in sensitive people if consumed in sufficient amounts, the degree of sensitivity varying between individuals.