Health benefits and concerns
Asthma
Vitamin C, present in fruits and
vegetables, is a powerful antioxidant and
anti-inflammatory. This anti-inflammatory activity may influence the development of asthma
symptoms. A large preliminary study has shown that young children with asthma experience
significantly less wheezing if they eat a diet high in fruits rich in vitamin C.
Atherosclerosis
Diets high in insoluble fiber (found
in some vegetables) are associated with protection against heart disease in both men and
women.
Bruising
Many Americans eat insufficient amounts of foods containing vitamin
C; the disease caused by vitamin C deficiency, scurvy, causes easy bruising. While very few
people actually have scurvy, even minor deficiencies of vitamin C can increase the incidence
of bruising. People who experience easy bruising may want to try eating more fruits and
vegetables—common dietary sources of vitamin C.
Cancer
Foods high in vitamin K such as
vegetables typically are associated with low cancer risk. Despite the fact that the
anti-vitamin K drug warfarin might reduce the risk of
cancer under certain circumstances, no evidence suggests that avoidance of vitamin K (from
food or from supplements) would in any way help protect against cancer.
Calcium D-glucarate is available as a
supplement, and is also found in fruits and vegetables in a slightly altered
form—D-glucaric acid. Preliminary evidence suggests that calcium D-glucarate indirectly
helps the body lower its burden of estrogen—an effect that might reduce the risk of
breast cancer. Although animal research supports such a possibility, no human trials have been
published to evaluate whether calcium D-glucarate has a therapeutic or preventive effect.
Cruciferous vegetables—broccoli, Brussels
sprouts, cauliflower, and cabbage—contain a substance called indole-3-carbinol (I3C). In preliminary research, I3C has
been reported to affect the metabolism of estrogen in a way that might protect against breast and other female cancers, an idea supported by
animal and test tube research.
Diindolylmethane (DIM) is another substance found in cruciferous vegetables. Test tube and
animal studies suggest that it may help protect against breast cancer. However, no clinical
trials with cancer patients given DIM have yet been published.
Capillary fragility
Eating plenty of flavonoid- and
vitamin C-rich fruits and vegetables helps to support the structure of capillaries.
Cataracts
Some, but not all, studies have reported that eating more foods rich
in beta-carotene or
vitamin A was associated with a lower risk of cataracts. Synthetic beta-carotene
supplementation has not been found to reduce the risk of cataract formation. It remains
unclear whether natural beta-carotene from food or supplements would protect the eye or
whether beta-carotene in food is merely a marker for other protective factors in fruits and
vegetables high in beta-carotene.
High homocysteine
A controlled trial showed that eating a diet high in fruits and
vegetables containing folic acid, beta-carotene, and
vitamin C effectively lowered homocysteine levels. Healthy people were assigned to either a
diet containing a pound of fruits and vegetables per day, or to a diet containing 3 1/2 ounces
(99g) of fruits and vegetables per day. After four weeks, those eating the higher amount of
fruits and vegetables had an 11 percent lower homocysteine level compared to those eating the
lower amount of fruits and vegetables.
Hypothyroidism
Some foods, such as rapeseed (used to make canola oil) and Brassica
family vegetables (cabbage, Brussels sprouts, broccoli, and
cauliflower), contain natural substances that can interfere with thyroid hormone
synthesis, resulting in goiter. Cooking has been reported to inactivate this effect in
Brussels sprouts.
Multiple sclerosis (MS)
In one survey, researchers gathered information from nearly 400
people (half with MS) over three years. They found that consumption of vegetable protein, fruit juice, and foods rich in vitamin C, thiamine, riboflavin, calcium, and potassium correlated with a decreased MS risk.
Stroke
Diets high in fruit and/or vegetables are associated with a reduced risk of
stroke, according to most studies. In a large preliminary study, cruciferous and green leafy
vegetables, conferred the highest degree of protection. Because it is not clear which
components of fruits and vegetables are most responsible for the protective effect against
stroke, people wishing to reduce their risk of stroke should rely primarily on eating more
fruits and vegetables themselves rather than taking supplements.
Health benefits and
concerns for vegetables
Many health benefits and concerns associated with this food are applicable to other
vegetables. Read about health benefits and concerns
for vegetables for a full description.
Copyright © 2002 Healthnotes, Inc. All rights
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Foodnotes.
The information presented in Foodnotes is for informational
purposes only and was created by a team of U.S. registered dietitians and food experts.
Consult your doctor, practitioner, and/or pharmacist for any health problem and before using
any supplements, making dietary changes, or before making any changes in prescribed
medications. Information expires December 2003.