Protection against cancer. Naturally occurring chemicals (indoles,
isothiocyanates, glucosinolates, dithiolethiones, and phenols) in
Brussels sprouts, broccoli, cabbage, cauliflower and other cruciferous
vegetables appear to reduce the risk of some cancers, perhaps by
preventing 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
inactivate 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. The current RDA for
folate is 180 mcg for a woman and 200 mcg for a man, but the FDA now
recommends 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.
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 Woman's Hospital in Boston demonstrated that a diet
providing more than 400 mcg folate and 3 mg vitamin B6 a day from
either food or supplements, more than twice the current RDA for each,
may reduce a woman's risk of heart attack by almost 50
percent. Although men were not included in the analysis, the results
are assumed to apply to them as well. NOTE: Fruit, green leafy
vegetables, beans, whole grains, meat, fish, poultry, and shellfish
are good sources of vitamin B6.
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 condition 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.