What’s your favorite vegetable? While a few of you are cringing at the question because you don’t like any vegetables, most of you do have a few you really enjoy eating. How about broccoli, cauliflower, Brussel sprouts, cabbage, and collard greens? Do you like any of these? They are from the Brassica genus of plants and are known as cruciferous vegetables. Other vegetables in this group include kale, kohlrabi, mustard, rutabaga, turnips, bok choy, Chinese cabbage, arugula, radishes, wasabi, and watercress. Cruciferous vegetables are rarely as popular as their non-cruciferous counterparts. This is quite unfortunate. Read on and you’ll see what I mean.
One reason cruciferous veggies tend to be less popular is that they have pungent aromas and spicy or bitter flavors. These characteristics are due to sulfur-containing substances known as glucosinolates. While cruciferous vegetables are being prepared, chewed, and digested, glucosinolates are broken down into biologically active compounds including indoles and isothiocyanates. These compounds are being studied because they may inhibit the development of cancer.
Indoles and isothiocyanates have been shown to inhibit bladder, breast, colon, liver, lung, and stomach cancers in rats and mice. Some studies in humans have shown lower risks of prostate, lung, colon, and breast cancers among people who eat greater amounts of cruciferous vegetables. Other studies haven’t shown any particular benefit among humans who eat greater amounts of these veggies. These inconsistent findings mean more research is needed.
Does the need for more research indicate you should put off increasing your consumption of these vegetables? Certainly not! They are good sources of fiber and are rich in carotenoids (beta-carotene, lutein, and zeaxanthin), vitamins (C, E, K, and folate), potassium, and selenium. Moreover, it is well documented that diets rich in vegetables in general protect against several diseases, including heart disease and many cancers. Whether cruciferous vegetables offer protection against cancer that is superior to that provided by other vegetables or not, you might as well consume them because they offer at least the same protection.
As with any food, you don’t want to overdo it. Studies in animals have indicated that very high intakes of cruciferous vegetables can cause hypothyroidism. Evidence of this in humans is very limited and, as I noted, is linked with very high intakes of the veggies (e.g., an 88 year old woman who consumed over 2 lbs. of raw bok choy daily for several months). There is no indication of risk with intakes of typical amounts. Research also indicates that hypothyroidism may only be a risk when a person is also iodine deficient.
To preserve the activity of the protective compounds, it is best to consume cruciferous vegetables when raw or lightly cooked (e.g., stir fried, briefly steamed). No recommended intake has been developed, but the findings of some epidemiological studies suggest that adults should consume at least 5 servings each week. Not sure you can manage to consume this many servings? Check out some great recipe ideas on OF THE HEARTH’s Pinterest page. For more information on cruciferous vegetables, you can visit my sources: National Cancer Institute and Linus Pauling Institute.
Which of the cruciferous vegetables do you like? How do you usually prepare them?