Don’t Just Eat Your Greens—Cook Up Pinks, Purples, Reds, and Yellows Too
In April, especially when the temperature is languishing in the 40s, I don’t expect to be captivated by my local supermarket produce aisle, but that’s exactly what happened the other day. The guy stocking the refrigerated bins had just finished channeling his inner artist, arranging a generous heap of red-, white-, and multicolor-stalked chard next to an array of cauliflower—varying from the traditional creamy white to orange, purple, and green—and an equally colorful assortment of carrots. The general effect was enough to stop me in my tracks, and I wasn’t the only customer who was mesmerized. Another shopper paused to look, and then asked in all seriousness, “Are they dyed, like Easter eggs?”
Well, no, they’re not, but they’re just as fun in their way and make it easy to both “eat the rainbow”—that is, consume a diverse assortment of vegetables to get all the vitamins, minerals, and other nutrients you need for good health—and cook the rainbow, thus expanding your culinary horizons. Chard and its mellow stems, for example, are delicious tucked into lasagna. Roasted cauliflower “steaks” make a terrific main dish that just happens to be meatless. When you start thinking of parsley as a vegetable, the way they do in the Middle East, tabbouleh gets a whole new lease on life.
When it comes to flavor, it’s difficult to generalize about color because there are so many other factors to take into account, including variety, climate, and freshness. Those variously hued cauliflowers, for example, all pretty much taste the same. At their best (i.e., when very fresh), they are mild, nutty, and delicious raw or cooked.
It’s worth noting that Broccoflower—the (trademark) brand name for several green cultivars—is not a cauliflower-broccoli cross as is widely reported but was developed from a green cauliflower first grown in the Macerata province of Italy. Broccoli Romanesco, with its exuberantly faceted chartreuse head—you gotta see it to believe it—is a cauliflower too (an Italian heirloom from the Mediterranean coast) and is sometimes called Romanesco cauliflower, a more accurate moniker.
These days, many people look at atypical vegetables and presume they must be genetically modified, but in truth, plant breeders have selectively bred vegetables for color, size, and other characteristics for centuries. Take the carrot, for instance. “There is nothing new about ‘colored’ carrots,” William Woys Weaver wrote in Heirloom Vegetable Gardening. “While the white carrot is native to Europe, the genetic origin of both yellow and violet carrots is believed to be Afghanistan. Both the yellow and violet carrots were mentioned by Arabic writers and moved westward through Iran into Syria, and then into Spain by the 1100s.” The orange-hued carrots we know today were developed in Holland in the late 1600s, Weaver added—making them more “modern” than some of the eye-catching iterations cropping up at grocery stores and farmers markets.
The colors, or pigments, in plants are known generally as phytochemicals (aka phytonutrients), and some, but not all, act as antioxidants. If you need a cheat sheet to that world—and who doesn’t?—we’ve got you covered. For our purposes here, it’s helpful to know that there are four main classes of natural plant pigment: chlorophylls, carotenoids, flavonoids such as anthocyanins and anthoxanthins, and betalains.
We all know how good greens are for us, so I’ll keep this short and sweet. Chlorophylls are what give green vegetables (and fruits such as limes, kiwifruit, and honeydew melon) their color. Broccoli, cabbage, and other brassicas contain glucosinolates, organosulfur phytochemicals that may help protect against some cancers. Other common nutrients in green veggies include vitamins A, C, K, and folate, a B vitamin that helps reduce the risk of birth defects. In other words, what is not to love?
Orange and Yellow Vegetables
These are usually colored by carotenoids, which may help keep your immune system strong and lower the risk of coronary heart disease, vision problems, and cancer. One widely studied carotenoid is beta-carotene, which is converted to vitamin A in the body. It’s found in sweet potatoes (which are not the same thing as yams), carrots, winter squash, and, yep, orange cauliflower—which has about 25 percent more beta-carotene than white cauliflower. It’s important to realize that color isn’t everything when assessing the nutritional content of produce: Mature red chiles, for instance, are among the richest sources of carotenoids, including beta-carotene, and vitamin C.
When it comes to the carotenoids lutein and zeaxanthin, which may decrease the risk for age-related macular degeneration, I was surprised to learn that corn is the vegetable with the highest amount of lutein, and orange peppers contain the highest amount of zeaxanthin. “Most of the dark green leafy vegetables, previously recommended for a higher intake of lutein and zeaxanthin, have 15-47% of lutein, but a very low content (0-3%) of zeaxanthin,” concluded a study published in the British Journal of Ophthalmology. “Our study shows that fruits and vegetables of various colours can be consumed to increase dietary intake of lutein and zeaxanthin.”
Red, Pink, Blue, and Purple Vegetables
Red, blue, and purple vegetables typically contain anthocyanins, which are found not just in vegetables such as eggplant, cabbage, beans, onions, and radishes but also in red wine, certain varieties of cereal grains, and, most commonly, berries, cherries, and other fruits. The antioxidant properties in anthocyanins help limit damage caused by free radicals and may aid in lowering the risk of cardiovascular disease.
Tomatoes are perhaps best known as a source of carotenoids—in particular, lycopene, which may lower risk for heart disease, stroke, cancer, macular degeneration, and memory problems—but purple tomatoes such as Oregon State University’s Indigo Rose cultivar are being bred for the antioxidant potential of the purple anthocyanin, which appears in some wild tomato species. Again, no genetic engineering techniques were used to develop these lines: Indigo Rose was released as an open-pollinated variety, so seeds saved from self-pollinated plants will grow true and not produce hybrids.
Beets, by the way, get their crimson (or yellow) color from betalain pigments, not anthocyanins. The same is true for bright, multicolor-stemmed “rainbow” chard, a close beet relation. Like anthocyanins, betalains may provide radical-scavenging properties for protection against certain oxidative stress-related disorders.
You may think of white as the absence of pigment but that’s not really true: White vegetables such as cauliflower, potatoes, parsnips, kohlrabi, turnips, and onions get their color from anthoxanthins—a flavonoid, like anthocyanins—which may help lower the risk of high blood pressure, high cholesterol, cancer, and heart disease. As I mentioned a few years back, unprocessed white vegetables are just as critical to a well-balanced, healthy diet as the deeply colored vegetables that garner most of the attention these days. So eat up! The rainbow awaits.