To all the reasons you might choose one vegetable variety over another--appearance, flavor, yield, pest resistance, or regional adaptation--now you can add enhanced nutrition. The vegetables you'll read about here aren't just good for you. They've been bred to be better for you.
As nutrition research makes clearer each year, good foods are the best way to supply nutrients to our bodies. So naturally, a vegetable's nutrient content is becoming an important measure of its value. Research is also showing that fruits and vegetables provide us with important disease-fighting chemicals. So it makes sense that plant breeders would focus on making vegetables even more healthful.
Needless to say, home gardeners are best positioned to take advantage of these breeding advances. None of these varieties are any more difficult to grow than older ones, and most are readily available.
Researchers have gradually increased carotene levels over the years, says Phil Simon, a USDA plant geneticist at the University of Wisconsin, Madison. As recently as 1980, a typical hybrid carrot had 80 to 100 parts per million (ppm) of carotene. New high-carotene varieties have twice as much, and breeders are testing varieties that have up to 500 ppm.
Although dark, leafy greens, sweet potatoes, and winter squash are all good sources of carotene, carrots are the champs. If these carotene-rich carrots were widely available, the positive impact would be immense, because Americans rely upon carrots for most of their dietary vitamin A. "With some standard varieties, you'd have to eat 1 to 2 pounds of carrots a day to meet your dietary needs," Simon points out. "By comparison, you only need to consume as little as half a carrot of a high-carotene variety to meet your dietary need."
By the way, don't worry about eating too many carrots. While too much vitamin A in pill form can be harmful, you can't consume too much carotene. Your body just takes as much as it needs to make vitamin Aand discards the rest. (Notable exceptions are babies and those individuals with an extra sensitivity to carotenoids: Too many carrots can make their skin turn orange.)
An unusually colored, nutrient-enhanced carrot will reach supermarkets in 1997. At Texas A&M University, researchers have developed a purple-skinned, orange-cored carrot named 'BetaSweet', with carotene levels of 180 to 220 ppm. It will be test-marketed as precut slices or "BetaBites". If you see them in the stores, give them a try and decide if you want to grow them; seeds will become available to home gardeners in 1998 or 1999.
In the meantime, here are three high-carotene carrots you can grow now. The number of days until harvest after sowing seed is listed in parentheses.
'Ingot' (63 days). This 6- to 8-inch-long, blunt-ended, Nantes-type hybrid carrot has a sweet flavor. Its carotene levels are between 120 and 170 ppm.
'Beta Champ' (74 days). This Imperator-type hybrid has 10-inch-long tapered roots. It is great for juicing. Testing shows it consistently contains 150 to 270 ppm carotene.
'Healthmaster' (110 days). These large, 3-inch-diameter, 10-inch-long, hybrid Danvers-type carrots take a long season to mature but are sweet-tasting. Carotene levels are between 60 and 95 ppm, about 35 percent higher than levels in older, open-pollinated Danvers varieties.
What about carrot flavor? Unfortunately, says Simon, when his team started selecting for high carotene levels, it didn't simultaneously select for flavor. High-carotene carrots tend to also be high in turpenoids, which can make some carrots strong-tasting and bitter. "I'd have to say that the flavor of most of these high-carotene carrots is just average. But the genetics of the two characteristics are independent, and there's no reason superior flavor can't be bred in." John Navazio, vegetable breeder at Chriseeds in Mount Vernon, Washington, agrees. "I'm working on some material with over 250 ppm that will have great flavor and great eating quality."
Tomatoes are also getting a boost in vitamin A, as well as in vitamin C.
Significant impetus for this work on tomatoes comes from the processing industry, which sees marketing potential in using nutrient-spiked tomatoes to increase the health value of soups and vegetable juices. John Stommel, a researcher at the USDA Experiment Station in Beltsville, Maryland, anticipates several processing varieties will be released this year. More home garden varieties, including beefsteak and cherry types, should follow in a few years, but there are a few gardeners can grow right now.
The lowercase "t" after the number of days to harvest means the number is days from transplants.
'Caro-Rich' (80t days). This determinate variety produces 10- to 12-ounce, globe-shaped, orange fruits that contain 10 times the vitamin A of other tomatoes.
There are other orange tomatoes, but in this case, skin color doesn't necessarily indicate higher carotene. "Orange tomatoes other than 'Caro-Rich' gain their color from a 'tangerine' gene, not the much rarer high-carotene 'beta' gene," says Stommel.
'Double Rich' (65t to 75t days). These 3- to 4-inch bright red fruits contain twice the vitamin C of other tomatoes-as much as in an orange. Indeterminate plants grow 2- to 4-feet tall and need the support of a trellis. Maturity is midseason for a tomato.
Winter squash, especially the Cucurbita maxima types (such as the buttercups, some pumpkins, and hubbards), are good sources of vitamin A. But 'Jade-A', a 5- to 10-pound, dark green, heart-shaped squash, holds the record for highest total carotene in tests done at Cornell University in Ithaca, New York, a few years ago. 'Jade-A' is also very high in lutein, an antioxidant and antitumor carotene. John Schneeberger, co-owner of Garden City Seeds in Hamilton, Montana, is enthusiastic about 'Jade-A': "It's early, very productive, and has an extraordinarily good flavor. If there's a downside, it's that the plants are very large."
'Jade-A' (92 days). This hybrid buttercup-type squash produces four or five 8-pound squash per plant.
Hot off the breeder's bench and available to home gardeners are a few other carotene-enriched vegetables.
'Orange Bouquet' cauliflower (58t days). This hybrid produces pastel orange heads with a yellow interior. Color is best when heads are not covered. "It has the color of orange sherbet," says Rob Johnston of Johnny's Selected Seeds in Albion, Maine.
'Orange Queen' Chinese cabbage (80 days). This upright-growing hybrid produces Napa-type heads with higher-than-normal carotene levels. When the head is cut and exposed to light, the internal color changes from lemon yellow to pale orange.
Perhaps the most fascinating high-carotene vegetable on the horizon is the orange-fleshed cucumber developed by John Navazio and Phil Simon. The USDA has already made it available to seed companies, and it should be in catalogs within a few years. This cucumber has a vitamin A level equivalent to that of muskmelon (ordinary cucumbers have almost none).
Peppers, cabbage, tomatoes, and dark leafy greens are all excellent sources of vitamin C. The champs, however, are ripe peppers. They have three times the vitamin C of any citrus. Among these peppers, yellow wax or banana peppers-hot or sweet-have the most vitamin C.
'Sweet Banana' (72t days). This widely adapted variety is the most popular of the banana peppers. It produces 6-inch tapered yellow peppers that turn red at maturity.
'Hungarian Hot Wax' (70t to 80t days). These medium-hot, 8-inch peppers can be used at their canary yellow stage, or when red and fully mature.
Though potatoes are only a so-so source of vitamin C, they can be a major source for those whose consists of burgers, fries, and sodas. It's been said that if it weren't for the vitamin C in potatoes, a lot of Americans would have scurvy!
'Ranger Russet' is a new processing potato that was developed by USDA potato breeder Joe Pavek at the Aberdeen Research Station in Idaho. Intended for commercial growers, it has about twice the vitamin C of an average potato. A close runner-up nutritionally, and much more practical for home gardeners to grow, is 'Butte', which is one of the parents of 'Ranger Russet'.
'Butte' potato (90 to 100 days). This late-maturing, high-yielding russet baking potato has medium to large tubers and dry, white flesh. Compared with ordinary russets, it is 50 percent higher in vitamin C and 20 percent higher in proteins.
Hyping vegetables with vitamins can be problematic. Vitamin content is influenced by variations in growing conditions, time to maturity, post-harvest handling, and food preparation. The vitamin levels claimed for vegetables usually assume optimum conditions. Don't forget, too, the best way to be sure you're getting enough vitamins: eat more kinds of more vegetables more often.
Deborah Wechsler lives in Pittsboro, North Carolina.
Photography by National Gardening Association.
Article published on June 23, 2008.