I was thinking about where to begin this blog, and I keep coming back to a subject that has been fascinating me for months: the benefits of eating a variety of colorful fruits and vegetables. I realize this is not exactly the weighty sort of topic that gets your blood pounding. But ever since I saw a presentation on this theme at work, I have been making different choices at the grocery store, and I think the information is worth sharing.
Different colors of fruits and vegetables contain unique nutrients and chemicals that aid in body function and health. Specifically, colorful veggies contain a variety of phytonutrients (or phytochemicals).
According to the USDA website, phytonutrients are “organic components of plants…thought to promote human health… Unlike traditional nutrients (protein, fat, vitamins, minerals), phytonutrients are not ‘essential’ for life, so some people prefer the term ‘phytochemical.’”
Although these chemicals are not “essential” for day to day life, there is a plethora of research indicating that these agents play a significant role in the prevention of disease. Phytonutrients are believed to serve as antioxidants, improve the immune response, and/or detoxify carcinogens (harmful cancer-causing toxins), among other things. Some studies have even linked them to killing cancer cells or repairing DNA damaged by smoking.
For example, a study published in 2007 by the American Society for Nutrition (from UMass-Dartmouth) suggests that the phytonutrients in cranberries (ployphenols and flavenols) inhibit the growth of breast, colon, prostate, lung, and other tumors.
The Brazilian Journal of Microbiology published a study showing that extracts from clove, jambolin, thyme, and pomegranate plants were able to combat antiobiotic-resistant bacteria in a laboratory.
Now back to the point – COLORS.
These chemicals are frequently associated with specific pigments in the foods you eat.
Flavanoids (polyphenols), which are known for their strong antioxidant, anti-allergenic, and anti-inflammatory mechanisms, are typically linked to red, blue, and purple pigments, such as those found in strawberries, cranberries, grapes, and black-eyed peas.
Carotenoids (tetraterpenoids), which have been shown to improve the immune system and engage in antioxidant activity, are usually found in plants with orange pigments, such as carrots, pumpkins, oranges, tomatoes, guavas, and sweet potatoes. Beta carotene is a well-known carotenoid that aids our ability to see at night.
And these are only a few examples in the long list of phytonutrients.
These color associations are not necessarily exclusive. For example, dark leafy greens also contain carotenoids, and “greens” are obviously not orange. But the colors are a helpful way to gauge whether or not you are getting a wide variety of phytonutrients in your diet.
Nowadays, when I make a salad, I make sure to use lettuce with a nice dark green or purple hue, and I add splashes of color, such as red peppers, white mushrooms, purple beets, or blueberries. Or when I make a casserole, I try to vary the vegetable colors, with yellow squash, green beans, or orange carrots. (Better yet, did you know that carrots also come in white, yellow, and purple, as well? Check your local farmers market!)
And this colorful practice has the added benefit of making my food more pleasing to the eye.
If nothing else, remember that the color of a fruit or vegetable is usually a primary indicator of the chemicals within. Eating a wider variety of colors helps you pack more health benefits into a single meal!
For more information, see the following links:
- USDA page on phytonutrients: http://www.ars.usda.gov/aboutus/docs.htm?docid=4142
- “Cranberry and Its Phytochemicals…” http://jn.nutrition.org/content/137/1/186S.short
- “Antibacterial Activity of Plant Extracts…” http://www.scielo.br/scielo.php?pid=S1517-83822000000400003&script=sci_arttext
- For an extensive listing of phytochemicals contained in various foods and color pigments, you may also want to consult the ever reliable Wikipedia: http://en.wikipedia.org/wiki/List_of_phytochemicals_in_food