Evidence is mounting that the healthiest diets are loaded
with plant foods (vegetables, fruits and beans) and short on animal
foods (meat, fish, poultry and dairy products), especially those with
a high fat content.
"A diet rich in fruits and vegetables plays a role
in reducing the risk of all the major causes of illness and death,"
says Walter Willet, Head of the Nutrition Department at the Harvard
School of Public Health.
To many people, vegetarian is a loaded word. It typically
refers to people who never eat meat, fish or poultry for ethical,
religious or health reasons. Vegans also avoid all dairy products
and eggs. But scientists are more interested in how often - not whether
- people eat animal foods. And much of their research points to the
same conclusion: people should eat fewer animal foods and more plant
foods, especially fruits and vegetables. Why? Here are 10 reasons
- some related to health, some not.
1. Cancer
"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.
2.Heart disease
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.
* Squeezing Out Saturates: if you eat lots of plant
foods, there's simply less room for the saturated animal fats that
clog arteries.
3. Stroke
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.
4. Diverticulosis & Constipation
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).
5. Other diseases
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.
6. Safer food
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.
7.The environment
"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.
8. Cost
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.
9.Animal welfare
It's unpleasant to think about, but before we slaughter
them, the animals we eat are often raised and transported under inhumane
conditions.
10. Taste
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.
Copyright 1996 CSPI.
Reprinted/Adapted from
Nutrition Action Healthletter
