A food additive is any substance not commonly regarded or used as food, which is added to, or used in or on, food at any stage to affect its keeping quality, texture, consistency, taste, colour, alkalinity or acidity, or to serve any other technological function in relation to food, and includes processing aids in so far as they are added to or used in or on food.1,2 Food additives in use today can be divided roughly into three main types: cosmetics, preservatives and processing aids, totalling presently about 3,794 different additives, of which over 3,640 are used purely as cosmetics, 63 as preservatives and 91 as processing aids.3 The growth in the use of food additives has increased enormously in the past 30 years, totalling now over 200,000 tonnes per year.45 Therefore it has been estimated that as today about 75% of the Western diet is made up of various processed foods, each person is now consuming an average 8-10 lbs of food additives per year, with some possibly eating considerably more.5"7 With the great increase in the use of food additives, there also has emerged considerable scientific data linking food additive intolerance with various physical and mental disorders, particularly with childhood hyperactivity.

http://orthomolecular.org/library/jom/1994/articles/1994-v09n04-p225.shtml