Nutritional Profile Energy value (calories per serving): Low Protein: High Fat: Low Saturated fat: Low Cholesterol: None Carbohydrates: High Fiber: High Sodium: Low Major vitamin contribution: Vitamin A, folate, vitamin C Major mineral contribution: Potassium, iron
About the Nutrients in This Food Brussels sprouts are high in dietary fiber, especially insoluble cellulose and lignan in the leaf ribs. They are also a good source of vitamin A and vitamin C. One-half cup cooked fresh brussels sprouts has three grams of dietary fiber, 1,110 IU vitamin A (48 percent of the R DA for a woman, 37 percent of the R DA for a man), 47 mcg folate (16 percent of the R DA), and 48 mg vitamin C (64 percent of the R DA for a woman, 53 percent of the R DA for a man). Brussels sprouts also contain an antinutrient, a natural chemical that splits the thiamin (vitamin B1) molecule so that it is no longer nutritionally useful. This thiamin inhibitor is inactivated by cooking.
The Most Nutritious Way to Serve This Food Fresh, lightly steamed to preserve the vitamin C and inactivate the antinutrient.
Diets That May Restrict or Exclude This Food Antiflatulence diet Low-fiber diet
Buying This Food Look for: Firm, compact heads with bright, dark-green leaves, sold loose so that you can choose the sprouts one at a time. Brussels sprouts are available all year round. Avoid: Puff y, soft sprouts with yellow or wilted leaves. The yellow carotenes in the leaves show through only when the leaves age and their green chlorophyll pigments fade. Wilting leaves and puff y, soft heads are also signs of aging. Avoid sprouts with tiny holes in the leaves through which insects have burrowed.
Storing This Food Store the brussels sprouts in the refrigerator. While they are most nutritious if used soon after harvesting, sprouts will keep their vitamins (including their heat-sensitive vitamin C) for several weeks in the refrigerator. Store the sprouts in a plastic bag or covered bowl to protect them from moisture loss.
Preparing This Food First, drop the sprouts into salted ice water to flush out any small bugs hiding inside. Next, trim them. Remove yellow leaves and leaves with dark spots or tiny holes, but keep as many of the darker, vitamin A–rich outer leaves as possible. Then, cut an X into the stem end of the sprouts to allow heat and water in so that the sprouts cook faster.
What Happens When You Cook This Food Brussels sprouts contain mustard oils (isothiocyanates), natural chemicals that break down into a variety of smelly sulfur compounds (including hydrogen sulfide and ammonia) when the sprouts are heated, a reaction that is intensified in aluminum pots. The longer you cook the sprouts, the more smelly compounds there will be. Adding a slice of bread to the cook- ing water may lessen the odor; keeping a lid on the pot will stop the smelly molecules from floating off into the air. But keeping the pot covered will also increase the chemical reaction that turns cooked brussels sprouts drab. Chlorophyll, the pigment that makes green vegetables green, is sensi- tive to acids. When you heat brussels sprouts, the chlorophyll in their green leaves reacts chemically with acids in the sprouts or in the cooking water to form pheophytin, which is brown. The pheophytin turns cooked brussels sprouts olive or, since they also contain yel- low carotenes, bronze. To keep cooked brussels sprouts green, you have to reduce the interaction between chlorophyll and acids. One way to do this is to cook the sprouts in a lot of water, so the acids will be diluted, but this increases the loss of vitamin C.* Another alternative is to leave the lid off the pot so that the hydrogen atoms can float off into the air, but this allows the smelly sulfur compounds to escape, too. The best solution is to steam the sprouts quickly in very little water, so they retain their vitamin C and cook before there is time for reaction between chlorophyll and hydrogen atoms to occur.
How Other Kinds of Processing Affect This Food Freezing. Frozen brussels sprouts contain virtually the same amounts of vitamins as fresh boiled sprouts.
Medical Uses and/or Benefits Protection against cancer. Naturally occurring chemicals (indoles, isothiocyanates, gluco- sinolates, dithiolethiones, and phenols) in brussels sprouts, broccoli, cabbage, cauliflower and other cruciferous vegetables appear to reduce the risk of some cancers, perhaps by pre- venting the formation of carcinogens in your body or by blocking cancer-causing substances from reaching or reacting with sensitive body tissues or by inhibiting the transformation of healthy cells to malignant ones. All cruciferous vegetables contain sulforaphane, a member of a family of chemicals known as isothiocyanates. In experiments with laboratory rats, sulforaphane appears to increase the body’s production of phase-2 enzymes, naturally occurring substances that inac- tivate and help eliminate carcinogens. At Johns Hopkins University in Baltimore, Maryland, 69 percent of the rats injected with a chemical known to cause mammary cancer developed tumors vs. only 26 percent of the rats given the carcinogenic chemical plus sulforaphane. In 1997, the Johns Hopkins researchers discovered that broccoli seeds and three- day-old broccoli sprouts contain a compound converted to sulforaphane when the seed and sprout cells are crushed. Five grams of three-day-old broccoli sprouts contain as much sulforaphane as 150 grams of mature broccoli. The sulforaphane levels in other cruciferous vegetables have not yet been calculated. Lower risk of some birth defects. Up to two or every 1,000 babies born in the United States each year may have cleft palate or a neural tube (spinal cord) defect due to their mothers’ not having gotten adequate amounts of folate during pregnancy. NOTE : The current R DA for folate is 180 mcg for a woman and 200 mcg for a man, but the FDA now recommends * Brussels sprouts will lose as much as 25 percent of their vitamin C if you cook them in water that is cold when you start. As it boils, water releases oxygen that would otherwise destroy vitamin C. You can cut the vitamin loss dramatically simply by letting the water boil for 60 seconds before adding the sprouts. 400 mcg for a woman who is or may become pregnant. Taking a folate supplement before becoming pregnant and continuing through the first two months of pregnancy reduces the risk of cleft palate; taking folate through the entire pregnancy reduces the risk of neural tube defects. Possible lower risk of heart attack. In the spring of 1998, an analysis of data from the records for more than 80,000 women enrolled in the long-running Nurses’ Health Study at Harvard School of Public Health/Brigham and Women’s Hospital, in Boston, demonstrated that a diet providing more than 400 mcg folate and 3 mg vitamin B6 daily, either from food or supple- ments, might reduce a woman’s risk of heart attack by almost 50 percent. Although men were not included in the study, the results were assumed to apply to them as well. However, data from a meta-analysis published in the Journal of the American Medical Association in December 2006 called this theory into question. Researchers at Tulane Univer- sity examined the results of 12 controlled studies in which 16,958 patients with preexisting cardiovascular disease were given either folic acid supplements or placebos (“look-alike” pills with no folic acid) for at least six months. The scientists, who found no reduction in the risk of further heart disease or overall death rates among those taking folic acid, concluded that further studies will be required to verif y whether taking folic acid supplements reduces the risk of cardiovascular disease. Vision protection. In 2004, the Johns Hopkins researchers updated their findings on sulfora- phane to suggest that it may also protect cells in the eyes from damage due to ultraviolet light, thus reducing the risk of macular degeneration, the most common cause of age-related vision loss.
Adverse Effects Associated with This Food Enlarged thyroid gland (goiter). Cruciferous vegetables, including brussels sprouts, contain goitrin, thiocyanate, and isothiocyanate. These chemicals, known collectively as goitrogens, inhibit the formation of thyroid hormones and cause the thyroid to enlarge in an attempt to produce more. Goitrogens are not hazardous for healthy people who eat moderate amounts of cruciferous vegetables, but they may pose problems for people who have a thyroid condi- tion or are taking thyroid medication. Intestinal gas. Bacteria that live naturally in the gut degrade the indigestible carbohydrates (food fiber) in brussels sprouts and produce gas that some people find distressing.
Food/Drug Interactions Anticoagulants Brussels sprouts are rich in vitamin K, the blood-clotting vitamin produced naturally by bacteria in the intestines. Consuming large quantities of this food may reduce the effectiveness of anticoagulants (blood thinners) such as warfarin (Coumadin). One cup of drained, boiled brussels sprouts contains 219 mcg vitamin K, nearly three times the R DA for a healthy adult.
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