A few years ago a patient came into my office complaining of migraines. He said, “You might think I’m crazy, doc, but I only get these headaches when I eat certain vegetables.” Which ones? It was hard to be sure. Salads gave him a headache only sometimes, and usually only in restaurants. Cole slaw gave him a headache no matter where he ate it. The list seemed completely random, and included Brussels sprouts, watercress, broccoli, and radishes. I grinned like an amateur holding a royal flush. The patient was naming only cruciferous vegetables.
Many common vegetables belong to the cabbage family in the plant genus Brassica. Edible plants in this family are called cruciferous vegetables, so named because their four-petaled flowers look like a crucifer, or cross. The importance of this family of crops for food cannot be overstated. Some cruciferous veggies include arugula (or rocket), bok choy, broccoli, Brussels sprouts, cabbage, cauliflower, chard, collard and mustard greens, daikon radish, horseradish, kale, kohlrabi, radish, rapini (broccoli rabi), rutabaga, turnip, wasabi, and watercress.
The Triangle of U theorizes that all the modern-day cruciferous vegetables evolved from three different ancestral plants that combined, in various configurations, to create many of the common vegetables known today. The wide variety of cruciferous veggies available today was also probably influenced by gardeners who, through the ages, selectively bred those plants that exhibited appealing characteristics. That is why some, like kale, are grown for their leaves, whereas others, like kohlrabi, are grown for their (swollen) stems, and others, like broccoli and cauliflower, for their buds.
Arugula’s unmistakably appealing and spicy flavor makes it a great addition to mixed salad greens in restaurants. A few years ago it seeded itself in my garden, and I loved it so much that, for a few glorious weeks, I headed straight for the garden after work every day to grab a few handfuls and stuff them into my mouth before entering the house.
Luckily, except for the patient whose unusual story I’ve shared, most of us get to enjoy cruciferous veggies without suffering any negative consequences. Their versatility makes them a great addition to stir-fries, salads, soups and stews. Not only do they taste great alone, but their strong flavors also stand up against lots of distinctive spices, herbs, and garnishes. The sweet, spicy crunch of a pure, translucent slice of radish or kohlrabi is like nothing else.
Last year I found this fantastic sauce for chicken or salmon. First you layer the meat or fish over a thick bed of chopped, rinsed bok choy and cabbage. Then mix 1/4 cup of balsamic vinegar with a tablespoon of honey; one teaspoon each of garlic and ginger chopped fine; one teaspoon of olive oil; one small tomato; and a few shakes each of salt and pepper. Spin together the ingredients in a blender, pour the sauce all over everything, and bake it at 350 until done. Cook approx. 30 min for salmon, 1 hr for chicken depending on the amount. Cover the pan loosely with tin foil about halfway through.
Or you could break apart a head of cauliflower and place it in a deep pan with ¼ cup water and 2 T olive oil. Add any combination of toasted sesame seed oil, lemon juice, soy sauce, cumin, coriander, anise or chili pepper, and cook on medium high heat for about 10 minutes. All of these additions have strong, distinctive flavors that taste great with cruciferous vegetables. Or you could grate lots of cheddar cheese over the cauliflower and cover the pot for the last 5 minutes of cooking. In some people’s opinions, just about everything tastes better with cheese melted on it.
I am not a fan of ‘nutritionism,’ the widely shared but unexamined assumption that it is the scientifically identified nutrients in a food that determine its value in the diet. Nevertheless, for those who are interested, cruciferous vegetables contain lots of soluble and insoluble fiber, vitamin C, vitamin B9 (folate), potassium, selenium, and numerous phytochemicals. Cruciferous vegetables are also rich sources of sulfur-containing, cancer-fighting compounds known as glucosinolates. I am going to guess that those sulfur-containing compounds were the cause of my patient’s headaches.
The scientific literature provides evidence linking the eating of a diet rich in cruciferous vegetables to decreased rates of a variety of cancers, including breast, pancreatic, lung, bladder, prostate, and colon cancer. Possible mechanisms of action include the presence in cruciferous vegetables of several enzymes that protect cell DNA from damage, protect against oxidation of microsomes (a cell organelle), and counteract the cancer-causing properties of products of incomplete combustion like nitrosamines and polycyclic aromatic hydrocarbons. Researchers at Oregon State University have found that sulforaphane – a compound found in high levels in broccoli, broccoli sprouts (sold next to the alfalfa sprouts), bok choy, and brussels sprouts – may play a major role in preventing prostate and colon cancer.
So increase your dietary intake of broccoli and other cruciferous vegetables. It can’t hurt, and it might help. And they taste so good. As Michael Pollan says, “There’s something terribly wrong when it’s cheaper to buy a double cheeseburger than a head of broccoli.”