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In addition, high blood cholesterol
is a major risk factor for heart disease, and there have been
a number of studies that have shown that soy protein helps lower
blood cholesterol levels. One study showed that replacing animal
protein with soy protein lowered total and LDL cholesterol levels
in people with high cholesterol. Another study found that adding
25 grams per day of soy fiber to the diet resulted in a significantly
greater decrease in LDL cholesterol than what occurred by just
eating a low fat diet. Other studies have shown that other components
of soy, like isoflavones and a-linolenic acid, also show promise
for reducing the risk of developing heart disease. The FDA recently
released a statement that said that diets low in saturated fat
and cholesterol that include 25 grams of soy protein a day may
reduce the risk of heart disease.
Cancer Prevention Connection
Isoflavones are also known as
phytoestrogens -- naturally occurring compounds in plants that
have weak estrogenic effects in humans. Soy contains two isoflavones
of particular importance -- genistein and daidzein. Epidemiological
(population) studies show that groups of people who regularly
consume soyfoods, like the Japanese, have lower incidences of
breast, colon, and prostate cancers. One study of dietary intakes
and breast cancer showed that in premenopausal women, consumption
of high amounts of animal protein (meat and dairy) increased
risk, while eating high amounts of soy was associated with a
decreased risk. Another study of 8,000 men of Japanese ancestry
in Hawaii showed that men who ate tofu daily were only one-third
as likely to get prostate cancer as men who ate tofu only once
a week or less. Tofu may not be so bad after all.
The reason isoflavones may prevent
cancers that are sensitive to too much estrogen (like breast
and prostate cancers) is that isoflavones act as antiestrogens
in the body. Estrogen receptors are found on cells in almost
every organ in the body (men have them too). Estrogen receptors
are present in the cardiovascular system and bone, as well. Research
has discovered that estrogen plays an important role in health
of all these tissues. Estrogen binds to these receptors. Some
pollutants and pesticides act as strong estrogens in the body.
Isoflavones, on the other hand, are weak estrogens. They bind
to these receptors preventing the foreign estrogens, or even
the body's own estrogen, from attaching and exerting a harmful
effect. Theoretically, consuming soy would put isoflavones in
the body that could then bind to the estrogen receptors, exerting
a protective effect.
Genistein has also been shown
to inhibit the growth of human prostate cancer cells and human
breast cancer cells. It has been shown to inhibit colon cancer
in rats. It can stop the proliferation of cancer cells. Genistein
also inhibits the growth of blood vessels, which could help prevent
a tumor from getting its own blood supply. Other soy compounds
have antioxidant effects, helping to prevent the formation of
tumor-promoting free radicals (oxygen atoms missing one or more
electrons that cause cell damage). One soy compound, phytosterol,
is not absorbed in the digestive tract and goes to the colon
intact, where it appears to help inhibit the creation of cancer
cells.
Still More Health Benefits
About 10 million Americans,
80% of them women, have osteoporosis. Premenopausal women are
protected from osteoporosis due to the naturally occurring estrogen
in their bodies. Because soy contains phytoestrogens (isoflavones),
it is possible that it will help prevent osteoporosis. And, in
studies with rats, genistein has been shown to prevent bone loss.
Americans normally associate
calcium consumption with osteoporosis prevention, and they think
of that calcium as coming from dairy products. Some soy foods,
like whole soybeans, are also good sources of calcium. Furthermore,
calcium consumption is not the whole story. Calcium can also
be lost and excreted from the body in urine. Excessive consumption
of sodium and/or protein increases calcium loss; this is particularly
true with dairy foods. Soy, on the other hand, provides protein
and calcium without as much calcium loss as dairy. In Japan,
where isoflavone consumption averages 200 mg a day (compared
to less than 5 mg a day in western countries), Japanese women
have lower rates of osteoporosis (and heart disease).
Soy consumption may also help
reduce some of the symptoms of menopause because phytoestrogens
may produce enough estrogenic activity in the body. For example,
Japanese women rarely report the symptoms of peri-menopause (like
hot flashes) that are common in the west.
But Tofu?
You don't have to eat tofu to
get the benefits of soy. You can have any of the following.
Soymilk -- The liquid expressed
from cooked, pureed soybeans. It can be used in the same way
as cow's milk. Different brands have different flavors, so you
should try a few if you don't like the first brand. But remember
that soymilk does not taste like cow's milk. You'll find soymilk
in aseptic quart and 2-quart sized packaging that does not need
refrigerating until after opening.
Tempeh -- This product is made
from fermented, compressed soybeans. It has a nutty flavor and
chewy texture and absorbs other flavors well. Before use in recipes,
it is normally steamed 10 minutes to make it more digestible
and to keep it moist when baked. Tempeh can also be fried. It
is sold in refrigerator sections in plastic-wrapped, rectangular
slabs.
Miso -- A paste made from fermented
soybeans (and sometimes with grains like brown rice). It is used
in Japanese soups and to flavor sauces and dressings. It is very
salty and a little is all that is needed. Miso comes in several
varieties. Light miso, which is a light tan color, is rather
mellow and sweet. The darker misos -- red, amber, and brown types
-- have been aged longer and have stronger flavors.
Beans -- Can be eaten fresh,
dry-roasted, or cooked. The fresh immature beans can be served
freshly steamed (called edamame in Japanese restaurants) and
have a mild flavor. They are green and shaped rather like lima
beans.
The beans can also be dry-roasted
like peanuts and make a tasty protein-rich snack food. They are
usually called soy nuts.
Canned beans come in beige pr
black varieties and can be added directly to soups. Dried beans
need an overnight soaking and three hours of cooking time to
make them edible.
Powder -- Soy protein powder
is the protein from the bean that is left over after the oil
has been extracted. Powders are sold as shake mixes (with the
soy carbohydrates and flavors like chocolate added) or as soy
isolates (with no carbohydrates and no flavors added). Both kinds
of powders can be added to drinks. Soy isolates can be added
to baked goods to boost protein levels.
If you don't know what to do
with these soy products, pick up a soy cookbook at your local
library or bookstore and give some of the recipes a try.
Don't Say No to Tofu
Tofu may look like inedible
white bricks, but it can be used in all kinds of recipes. It
also comes in two distinct styles.
Japanese-style silken tofu is
sold in aseptic packages that don't require refrigeration until
opening. After opening, the tofu is good for about 4 days in
the refrigerator. Silken tofu comes in three varieties -- soft,
firm, and extra-firm. It is best used in sauces, puddings, and
shakes.
Chinese or "regular"
style tofu is sold in containers packed with water in the refrigerator
section of the store. This type of tofu comes in three varieties,
soft, firm and extra-firm, but these varieties are not the same
as the silken tofu varieties of the same name. The soft tofu
can be used in dips, dressings, and sauces much like the soft
silken tofu. But the firm and extra-firm Chinese tofu is much
more solid than the silken varieties. The firm and extra-firm
Chinese tofu can be baked, grilled, or fried. These firm types
of tofu are often pressed to remove their water before using.
They can also be frozen. Freezing makes regular tofu chewy which
makes it a good substitute for meat in chili and Sloppy Joes.
Drink Your Tofu
When all else fails, you can
create a drink with tofu in it where you won't even know the
tofu is there.
Banana-Peanut Butter Soy Shake
-- 1 generous serving or 2 smaller servings
1 cup low-fat vanilla flavored
soymilk
1 ripe banana
1 tablespoon peanut butter
1/4 of a 12.5 ounce box of firm Lite Japanese-style silken tofu
1/2 scoop soy protein powder (isolates, not shake powder)
Add all ingredients to a blender.
Blend until smooth, scraping down sides as needed.
This recipe makes a thick shake.
Add more soymilk to make a thinner drink. Feel free to try other
flavor combinations. Leave out the peanut butter and add strawberries,
for example. Or replace the peanut butter and banana with a half
cup of frozen blueberries. |
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