It may be hard to imagine any crops thriving in the chill of winter. As snow blankets the soil in the Northeast and Midwest, delicate produce is all but absent from the landscape. Yet, even in the deepest frosts, there is a distinctive crop of greens that endures, with leaves unfurling like emerald petticoats beneath snowy white skirts. These hardy vegetables — the Brassicas — are both versatile and nutritious. Descendents of wild cabbage, the Brassica family encompasses a variety of cruciferous vegetables including kale, collards, arugula and bok choy. Their growth is nurtured by the cold, and the more frosts they enjoy, the sweeter their leaves.
These greens are gaining attention due to the cancer-fighting potential of their sulfur-containing phytonutrients. When cruciferous vegetables are chopped or chewed, they release compounds that researchers believe activate detoxifying enzymes in the liver. In turn, these enzymes may neutralize free radicals thereby reducing the risk of breast, ovarian, colon and other cancers. While all vegetables are advantageous in maintaining health, cruciferous vegetables appear to have an edge in preventing cancer. A recent study conducted in the Netherlands found that those who regularly ate vegetables had a 25% lower risk of colorectal cancers, but those who consumed the most cruciferous vegetables had a 49% drop in their risk. Studies on prostate and lung cancers have yielded similar results.
Among the Brassicas, kale is the family prodigy. Perhaps because of its unique and colorful appearance, kale has long been a member of the salad bar decoration. Curly kale has ruffled, deep green leaves; ornamental kale is green, white or purple; and dinosaur kale boasts shiny blue-green leaves. Yet kale’s merits extend far beyond its appearance. It is particularly rich in beta-carotene (which protects against diseases of the skin) and the carotenoid lutein (which prevents damage to the eyes), with seven times the beta-carotene and ten times the lutein that fellow Brassica family member broccoli contains. Kale’s vitamin content is also exceptional. Just one cup of raw kale contains 15% of the recommended daily value of calcium and Vitamin B6, 40% of the magnesium, 180% of the Vitamin A, 200% of the Vitamin C and a whopping 1020% of the Vitamin K. The boost in immune support and antioxidant protection provided by these vitamins could help ward off the colds and flus of the winter season, not to mention more serious diseases.
Not Just a Garnish
To get the full benefits of kale and its cruciferous cousins, eat at least three-to-five servings of these winter greens per week. It also helps to choose organically grown vegetables, which contain higher concentrations of phytonutrients. Lightly steaming the greens retains the nutrients best and may actually make them more available. Beyond that, let creativity be your guide. These earthy vegetables are an excellent complement to hot soups like Portuguese caldo verde or hearty beef and pork dishes. Though your greens like it out there in the cold, you certainly don’t have to.