This sub-group is by no means minuscule. And, scientists are confident that they can reveal more. According to Timothy Smith, MD, author of Renewal, The Anti-Aging Revolution, carotenoids are the most extensively researched category of phytochemicals, which are naturally occurring chemicals found in plants, fruits, vegetables, herbs and trees. They are produced by bacteria, algae, fungi, and plants, but humans and animals get them through food. Carotenoids also prevent every conceivable type of cancer.
Carotenoids also function as chain-breaking antioxidants.
These carotenoids are alpha carotene, beta-carotene and cryptoxanthin. Of all the carotenoids, beta-carotene is probably the most familiar, thanks to a rash of publicity in the late 1990's proclaiming it first to be a miracle nutrient in the protection of various degenerative diseases, followed by the backlash of media proclaiming it to be of little or no biological value in such disease states. Keep in mind that the study participants already had a high risk of developing lung cancer. As we are beginning to understand, the carotenoids are a nutritional collective that work best in a fashion similar to the B complex. Their therapeutic worth may be only as good as the weakest link of the chain, and an overload of one could compromise the work of others.