1. Cancer
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"The scientific base is
very strong suggesting that fruits and vegetables are protective
elements for all gastrointestinal cancers and all smoking-related
cancers," says Tim Byers, professor of Preventive Medicine
at the University of Colorado Health Sciences Center in Denver.
That includes cancers of the lung, colon, stomach, mouth, larynx,
esophagus and bladder. And a recent study found that lycopene - a
carotenoid in tomatoes and tomato sauce - may protect against
prostate cancer.
It's not clear how fruits and vegetables may reduce cancer risk.
It could be their phytochemicals - things like carotenoids,
vitamins C and E, selenium, indoles, flavonoids, phenols and
limonene.
There is also evidence that high-fibre grains like wheat bran can
reduce cancer risk. "Fibre has a beneficial effect in preventing
colon cancer," says David Jenkins, a fibre expert at the
University of Toronto. And pasta, rice and other grains can
replace the animal foods - red meat, in particular - that may
increase the risks of some cancers.
"Men who eat red meat as a main dish five or
more times a week have four times the risk of colon cancer of men
who eat red meats less than once a month," says Edward
Giovannucci of Harvard Medical School. Heavy red-meat eaters were
also twice as likely to get prostate cancer in his study of 50,000
male health professionals.
That's just one study. Looking at others, says Lawrence Kushi of
the University of Minnesota, "the evidence
is quite consistent that red meat is associated with a higher risk
of colon - possibly prostate - cancer".
But even lean red meat seems to increase the risk of colon cancer.
"It could be the carcinogens created when meat is cooked or meat's
highly available iron, or something else in meat," speculates
Willett.
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A plant-based diet with lots of fruits and
vegetables can reduce the risk of heart disease. For the last 20
years, heart experts have emphasised cutting saturated fat and
cholesterol intake, but plants may protect the heart in other
ways. Among them:
* Soluble Fibre: "To reduce
your risk of heart disease, you may want to eat more beans, peas,
oats, and barley," says Jenkins, because their "sticky"
soluble fibre seems to help lower blood cholesterol.
* Folic Acid: "The evidence
that folic acid reduces the risk of heart disease is pretty
strong," says Willet. Folic acid, a B-vitamin, lowers blood
levels of a harmful amino acid called homocysteine. "And fruits
and vegetables are a major source of folic acid," he adds.
* Antioxidants: a growing body of evidence
suggests that LDL ("bad") cholesterol damages arteries only when
it has been oxidised (combined with oxygen). That's why
researchers believe that antioxidants like vitamin E may protect
the heart. And many of the phytochemicals in fruits and vegetables
are antioxidants. Read
more about antioxidants here.
* Squeezing Out Saturates: if you eat lots of
plant foods, there's simply less room for the saturated animal
fats that clog arteries.
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There's a lot of evidence showing that fruits
and vegetables are beneficial for reducing the risk of stroke,"
says Willet. For example, in a 20-year study of 832 middle-aged
men, the risk of stroke was 22 per cent lower for every three
servings of fruits and vegetables the men ate each day. Again, no
one's sure if it's the potassium, magnesium, fibre or other
components of fruits and vegetables that prevent arteries from
clogging in the brain. |
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4. Diverticulosis & Constipation
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High-fibre grains - especially wheat bran - can
help prevent constipation. That's not trivial in a country like
the US that spends millions a year on laxatives.
Diverticulosis is also common. About 30 to 40 per cent of people
over 50 have it, though most have no symptoms. Others experience
bleeding, constipation, diarrhea, flatulence, pain, or
diverticulitis (that's when the pouches - or diverticula - that
form in the walls of the colon get inflamed).
"In our studies, it's clear that fibre both
from bran and from fruits and vegetables is protective,"
says Willet. Men who ate the least fibre (13 grams or less a day)
were almost twice as likely to get diverticulosis as men who ate
the most fibre (at least 32 grams of fibre a day).
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Plant-rich diets may prevent other illnesses:
* Macular Degeneration: a carotenoid called
lutein - which is found mostly in leafy greens - may help prevent
the deterioration of the retina that causes blindness in older
people. "In our study, people who ate spinach or collard greens
two to four times a week had half the estimated risk of macular
degeneration compared with those who ate them less than once a
month," says Johanna Seddon of Harvard Medical School.
* Neural Tube Defects: folic acid supplements can reduce
the risk of spina bifida and other neural tube birth defects.
Folic acid from foods (mostly fruits and vegetables) may also cut
the risk.
* Diabetes: "We found a
lower risk of adult-onset diabetes in people who ate more whole
grains," says Willet.
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Some of the deadliest food-borne illnesses
enter the body via animal foods. "Ground
beef is the most likely source of E. Coli 0157:H7. Poultry carry
Salmonella and Campylobacter, and the consumption of raw shellfish
has caused infection with Vibrio vulnificus," says David
Swerdlow of the Centers for Disease Control in Atlanta.
Any raw food - including fruits or vegetables - can carry harmful
bacteria. "For example, recent outbreaks of
Salmonella have been associated with cantaloupe, tomatoes and
alfalfa sprouts," says Swerdlow. But meat, seafood and
poultry are the most likely culprits in food-borne illness. |
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"Our eating habits have a
tremendous effect on the planet," says Jenkins.
"Eating animals wouldn't harm the
environment if it were done on a much smaller scale,"
explains Alan Durning, Director of North-west Environment Watch in
Seattle.
"Modern meat production involves intensive
use - and often misuse - of grain, water, energy and grazing
areas," says Durning. He cites the following examples:
* Water pollution: the manure and sewage from
stockyards, chicken factories, and other feeding facilities can
pollute water supplies.
* Air pollution: thirty million tons of methane -
a gas that contributes to global warning - comes from manure in
sewage ponds or heaps.
* Soil erosion: nearly 40 per cent of the world's
- and more than 70 per cent of US - grain production is fed to
livestock. For each pound of meat, poultry, eggs and milk we
produce, farm fields lose about five pounds of topsoil.
* Water depletion: an estimated half of the grain
and hay that's fed to beef cattle is grown on irrigated land. It
takes about 390 gallons of water to produce a pound of beef.
* Energy Use: it takes almost
ten times more energy to produce and transport livestock than
vegetables.
* Overgrazing: about 10 per cent of the arid West
of the US has been turned into a desert by livestock. But some of
that land couldn't be used for much else.
"That's why my argument isn't for vegetarianism, but for people to
reduce the consumption of animal products," maintains
Durning.
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Sure, you can spend $7.99 a pound on mesclun or
other gourmet foods. But from squash to sweet potatoes, most
plants are a downright bargain. And the lower price of plants
shows up when you eat out. On Chinese, Indian, and most other
restaurant menus, the vegetarian selections are usually cheaper
than the meat, seafood and poultry. |
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It's unpleasant to think about, but before we
slaughter them, the animals we eat are often raised and
transported under inhumane conditions. |
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10. Taste
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The number-one reason for eating a plant-rich
diet is that it tastes good. The five vegetables that Americans
eat most are French fries, tomatoes (mostly as sauce or ketchup),
onions, iceberg lettuce, and other potatoes.
But if most Americans shrink the meat, seafood and poultry on
their dinner plates, they - or many of their favourite restaurants
- wouldn't know what to replace them with. You have to go to
ethnic restaurants to get interesting plant-based dishes. It's no
coincidence that ethnic restaurants know how to make vegetable
dishes taste good. "Fortunately, there's a wealth of experience
around the world because almost all traditional diets are
plant-based," says Willet.
Yet many Italian, Mexican and other ethnic restaurants have become
so Americanised that their vegetables have been largely replaced
by meat and cheese. And that's a shame. In Asian and Mediterranean
cuisines, cooking fruits and vegetables is an art form. The
Italians don't put tremendous amounts of meat and cheese on pizza,
for example. I had a thin-crust pizza at a traditional restaurant
recently with no cheese - just fresh basil, tomatoes and garlic.
It was totally wonderful.
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Copyright 1996 CSPI.
Reprinted/Adapted from
Nutrition Action Healthletter |