When buying tomatoes, choose those that smell like tomatoes; unripe ones
have no scent.
Although they are used as vegetables, tomatoes
are actually fruits, and are members of the nightshade
family of plants. They come from Central and South America. Spanish explorers took them back
to Europe and they eventually found their way back to North America.
Varieties
There are hundreds of varieties of tomatoes, including large
“beefsteak” types that are especially good for salads and for slicing on
sandwiches; Italian plum tomatoes, called Roma tomatoes, which are ideal for cooked dishes
like tomato sauce; and small, sweet cherry tomatoes. While red tomatoes are most common, these
vegetables can also be yellow, green, pink, or orange.
Tomatoes are available fresh, and in a variety of canned products, such as stewed tomatoes,
whole tomatoes, tomato sauce, tomato purée, and diced tomatoes. Tomatoes can also be
dried and are sometimes packed in oil this way. Tomatoes are often juiced and can be
concentrated to produce tomato paste.
Buying and storing tips
Tomatoes should be firm and juicy, with bright, unblemished skin. Buy
them garden-ripe when possible, choosing those that give a little when squeezed and have a
deep color. A good way to tell whether a tomato is ripe is to smell it. It should smell like a
tomato; unripe ones have no aroma. Store tomatoes at room temperature and, once they are ripe,
use them within a few days. Placing them in a brown paper bag for several days will hasten
ripening.
Availability
Tomatoes are available year-round, but their flavor is far superior
in mid- to late-summer. In winter and spring, cherry tomatoes tend to have the best flavor of
all the varieties. Canned tomatoes are always available and, for cooked dishes, they are the
best choice in the winter.
Preparation, uses, and tips
Tomatoes should be rinsed thoroughly before preparation. If they are
being used to make tomato sauce for spaghetti or other dishes, they should be peeled and
seeded. To peel a tomato, drop it into boiling water for one to two minutes. Then remove and
dunk briefly in a bowl of ice water. Cut out a small cone around the stem end and slip off the
skin. To seed a tomato, cut it in half horizontally and squeeze the seeds out.
Raw fresh tomatoes are most often sliced onto sandwiches or eaten in salads. They can also
be cooked with herbs, onions, and garlic to
make homemade spaghetti sauce. Raw tomatoes can be diced and added to soups or stews. Halved
tomatoes can also be broiled. Place them on a baking sheet, drizzle with olive oil, and broil until the tops are lightly
browned, about five minutes. Tomatoes make an attractive dish when stuffed with crabmeat or with sautéed vegetables, such as spinach and
mushrooms, and baked.
Unripe, green tomatoes are often dipped in cornmeal and fried.
Canned tomatoes can be added to soups, stews, or bean dishes, or used to make spaghetti
sauce. Combined with vegetable broth, they make a good base for many kinds of soups. Canned
tomatoes can be puréed with soft tofu and then
thinned with milk,
soy milk, or broth, flavored with herbs, and heated to make a fast cream of tomato soup.
Canned tomato sauce can also be used in curry dishes and to make chili.
Never add canned tomatoes to uncooked beans or grains, since they toughen the skins of these foods,
making it difficult to cook them to a tender stage.
Unless they are packed in oil, dried tomatoes (sometimes called sun-dried tomatoes) must
first be slightly rehydrated by allowing them to soak in hot water. Dried tomatoes can be
chopped and tossed with pasta or vegetable dishes. They
can also be puréed with olive oil, toasted pine
nuts, and basil to make tomato pesto.
Nutritional Highlights
Tomato, 1 medium whole (raw, ripe)
Calories: 26
Protein: 1.04g
Carbohydrate: 5.7g
Total Fat: 0.406g
Fiber: 1.35g
*Excellent source of: Vitamin C (23.5mg)
*Good source of: Vitamin A (766 IU)
*Foods that are an “excellent source” of a particular
nutrient provide 20% or more of the Recommended Daily Value, based upon United States
Department of Agriculture (USDA) guidelines. Foods that are a “good source” of a
particular nutrient provide between 10 and 20% of the USDA Recommended Daily Value.
Nutritional information and daily nutritional guidelines may vary in different countries.
Please consult the appropriate organization in your country for specific nutritional values
and the recommended daily guidelines.
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.
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
Tomatoes contain lycopene—an
antioxidant similar in structure to beta-carotene.
Most of the lycopene in our diet comes from tomatoes, though traces of lycopene exist in other
foods. Lycopene inhibits the proliferation of cancer cells in test tube research.
A review of published research found that higher intake of tomatoes or higher blood levels
of lycopene correlated with protection from cancer in 57 of 72 studies. Findings in 35 of
these studies were statistically significant. Evidence of a protective effect for tomato
consumption was strongest for cancers of the
prostate, lung, and stomach, but some evidence of
a protective effect also appeared for cancers of the pancreas, colon, rectum, esophagus (throat), mouth, breast, and cervix. Many doctors recommend that people who
are not allergic to tomatoes increase their intake to reduce their risk of cancer.
Tomatoes are also a source of beta-carotene. The strong association between increased
intake of beta-carotene from food and a reduced risk of lung cancer does not necessarily mean
that supplementation with natural beta-carotene supplements would reduce the risk of lung
cancer. Dietary beta-carotene may be a marker for diets high in certain fruits and vegetables
that contain other anticancer substances that may be responsible for the protective effects.
Until more is known, some doctors advise smokers to avoid all forms of beta-carotene
supplementation—even natural beta-carotene.
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.
Macular degeneration
People who eat plenty of fruits and vegetables high in beta-carotene appear to be at lower risk for macular
degeneration than people who do not eat these foods. However, another study found no
association between age-related macular degeneration and intake of antioxidants, either from
the diet, from supplements, or from both combined. More research is needed to reconcile these
differences. In the meantime, beta-carotene-rich vegetables continue to be part of a healthful
diet.
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.
Night blindness
Low intake of fruits and vegetables containing beta-carotene, which
the body can convert into vitamin A, may contribute to a
vitamin A deficiency.
Osteoarthritis (OA)
Solanine is a substance found in nightshade plants, including
tomatoes, white potatoes, all peppers (except black pepper), and eggplant. In theory, if it is not destroyed in the intestine,
solanine could be toxic. A horticulturist, Dr. Norman Childers, hypothesized that some people
with OA may not be able to destroy solanine in the gut, leading to solanine absorption
resulting in OA. Eliminating solanine from the diet has been reported to bring relief to some
arthritis sufferers in preliminary research. Researchers have never put this diet to a strict
clinical test; however, the treatment continues to be used by some doctors in people who have
OA. Proponents claim exclusion of solanine requires up to six months before potential effects
can be seen. Totally eliminating tomatoes and peppers requires complex dietary changes for
most people. In addition, even proponents of the diet acknowledge that many arthritis
sufferers are not helped by using this approach. Therefore, long-term trial avoidance of
solanine-containing foods may only be appropriate for people with severe cases of OA who have
not responded to other natural treatments.
Pap
smear
Most dietary studies have found that women receiving high amounts of
nutrients from fruits and vegetables have less risk of cervical dysplasia. Protective effects
may be especially strong from diets high in dark yellow and orange vegetables (carrots, winter
squash, etc.) and tomatoes.
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
reserved. www.healthnotes.com
Learn more about Healthnotes, the company.
Learn more about the authors of
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.
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