Eat Your Colors
Current emphasis on consuming foods of varying colors stems from the understanding that beneficial secondary metabolites, phenolic compounds are responsible for the bright colors.
Phenolic and polyphenolic compounds include flavonoids, phenolic acids and lignins. These abundant chemical compounds are considered secondary metabolites because they are not directly involved in growth and development, but seem to be very beneficial in many other ways. In research and consumer news, much attention has been paid to the antioxidant benefits of particular compounds. Of course, this has spurred a large number of commercially produced supplements of isolated compounds. It should be noted that there is limited evidence of the benefit of these supplements and no recommended daily intake has been determined for phytonutrients.
There is one great lesson in the research regarding phytonutrients – it is best to get nutrition by eating the whole food (rather than rely on supplements). Consider that, until fairly recently, the general assumption was that consuming adequate amounts of vitamins and minerals identified in the DRI’s would be enough to ensure proper nutrition. Since estimates place the number of beneficial phytochemicals found in foods to be in the hundreds of thousands, how could we keep track of all those?
Of the flavonoids, anthocyanins are the most abundant. Anthocyanins are responsible for the deep blue pigments in berries, plums, red grapes, pomegranates, etc. The carotenes are found in foods of dark orange color such as: carrots, pumpkins, mangos, apricots, cantaloupe, and sweet potatoes. Lycopene is found in red foods like tomatoes and tomato products, but also in watermelon and pink grapefruit.
While dietitians may appreciate the science of beneficial secondary metabolites, nature has provided us with a color coded teaching tool for emphasizing good nutrition. Eating fruits and vegetables of varied color will ensure the consumption of beneficial nutrients.
N. Hounsome, B. Hounsome, D. Tomos, G. Edwards-Jones. Plant metabolites and nutritional quality of vegetables. Journal of Food Science; May 2008; Volume 73, Issue 4 (pages R48-R65)
Wang, L. and Stoner, G. Anthocyanins and their role in cancer prevention; Cancer Letters; Received 14 March 2008; received in revised form 14 March 2008; accepted 8 May 2008. published online 24 June 2008.