Fruits and vegetables have therapeutic properties that science is only beginning to understand. We know a lot about vitamins and minerals, but there are many other substances in fruits and vegetables that have't been as well studied. Known collectively as anutrients, these substances include pigments, which give plants their color, and enzymes, substances produced in the plant that help humans digest it.
Probably the best-known pigments are carotenes, which are responsible for the vivid color of vegetables such as carrots, sweet potatoes, and squash. Though scientists have identified more than 400 carotenes, the one most people have heard about is beta-carotene that the body easily converts into vitamin A. Studies indicate that beta-carotene has potent anti-cancer properties and may actually reverse precancerous conditions such as oral leukoplakia
A second group of pigments with potential healing power is the flavonoids, found in fruits, vegetables, and beverages, such as tea. Flavonoids give vegetables and flowers their vibrant hues. Numerous studies have shown that people who regularly consume fruits and vegetables rich in flavonoids are less likely to die of heart disease than those whose intake is lower, regardless of their intake of other nutrients.
Raw fruits and vegetables are also rich in enzymes, substances produced in plant tissue that kick off the many chemical reactions necessary for human digestion. But when you destroy these enzymes, as in the case of highly refined and processed foods, the body has to manufacture its own and ends up working very hard to break down the foods. This isn't the way the human digestion was designed to work.