They are all synthetic chemicals. Their danger lies in their carcinogenic potential. The color of foods is part of their pleasure. But you don't need to create something unreal to enjoy the natural variation in fruits, vegetables, grains, and beans. Even though synthetic dyes are so common, I suggest trying hard to avoid them.
Natural dyes do exist.
Annatto is a reddish-orange one made from the seed of a tropical tree and widely used to color butter and cheese. Chlorella is a green dye derived from algae. Inc. All rights reserved. Reproduction in whole or in part without permission is prohibited. All material provided in the Ask Dr. Weil program is provided for educational purposes only.