Broccoli, kale, cauliflower, and Brussels sprouts may look vastly different from each other, but they all evolved from the same plant species: Brassica oleracea. In each place that B. oleracea was introduced, farmers bred for a different edible part of the plant. In China, stems and flowers became gailan, Chinese broccoli. In the Mediterranean, vitamin-packed kale and collard leaves were favored for their ability to thrive in rocky soils. Other Brassicas have similar stories; B. rapa was bred by humans for crops as diverse as turnips, broccoli rabe, napa cabbage, and oilseeds.
Flavor with Purpose
Spicy mustard and horseradish are the product of a 90-million-year evolutionary battle between brassicas and their primary pest, cabbage butterflies. The plants evolved to contain glucosinolates, chemical compounds that taste spicy and bitter. Glucosinolates are toxic to most butterflies, but over time cabbage butterflies evolved to tolerate them. In return, brassicas developed more complex cocktails of glucosinolates using different amino acids to ward off the caterpillars. These complex cocktails are responsible for the spicy tastes of mustard, wasabi, and horseradish that many humans love!
All Hail Kale
Kale has a reputation for being the ultimate health food, thanks to the high levels of vitamins C and E, plus many antioxidants found in its leafy foliage. However, other brassicas such as collards and broccoli have just as much to offer. Broccoli and cabbage are both excellent sources of vitamins C and A (beta carotene) and fiber, while radishes are rich in potassium. Most of these plants’ glucosinolates also act as antioxidants.
Be sure to mark your calendars for February 17, which is #NationalCabbageDay—when we give thanks to the wild cabbage (Brassica oleracea) and humans’ insistence on breeding this noble species into all manner of popular shapes. Without it we wouldn’t have roasted broccoli or Brussels sprouts, kale salads, or cauliflower as a substitute for anything and everything. Thank you, cabbage, thank you science—for without cabbage, we might eat far fewer greens!
Check out these fun facts about brassicas!
- Cauliflower comes in four different colors: white, purple, orange, and green.
- In ancient China, some people believed cabbage was a cure for hair loss.
- The part of broccoli we eat is where the plant has flowered. In fact, the word broccoli comes from broccolo, meaning “the flowering crest of cabbage.”