According to the American Cancer Society,
smoking causes one-third of the 500,000 annual U.S. cancer deaths.
Another third is attributable to poor diet and sedentary living.
The final third’s causes remain controversial. The implications of
this breakdown are clear: Don’t smoke, and embrace the diet and
active lifestyle that help prevent what just this year became the
nation’s leading killer. (For decades, heart disease was number one
— now it’s number two.)
Unfortunately, eating and exercising to reduce cancer risk are
easier said than done. In most households, Mom no longer spends her
day preparing meals the American Cancer Society would applaud. Most
adults have jobs and time-consuming commutes. They come home
exhausted, so meal preparation gets short shrift and convenience is
king. As a result, according to the U.S. Department of Agriculture,
restaurants — often fast-food places — now supply one-third of
Americans’ calories, almost double the proportion of 30 years ago.
Meanwhile, according to the Centers for Disease Control and
Prevention, fewer than half of Americans are as physically active
as health experts recommend. But with some planning and
determination, it’s not all that difficult to embrace a
cancer-preventive diet and lifestyle.
Eat More Fruits and Vegetables
Many people imagine cancer as an alien that invades our bodies
inexplicably and consumes us from the inside out. But cancer is no
alien. The biochemical processes that produce it are at work in our
bodies from the moment we’re conceived. They’re part of what helps
us grow; but in cancer, growth spins out of control — or more
precisely, burns out of control. Slow burning is how we metabolize
food. Metabolism is fueled by oxygen. But some of the body’s oxygen
molecules turn into nasty electrically charged ions called free
radicals that become so highly chemically reactive that they damage
our DNA. To repair and prevent free radical damage, the body
marshals compounds known as antioxidants, among them vitamins A, C
and E, and the mineral selenium. A mountain of research shows that
ingesting anything that promotes free radical creation — for
example, cigarette smoke — boosts cancer risk. But ingesting
antioxidant nutrients reduces risk.
Antioxidant nutrients are found overwhelmingly in fruits and
vegetables. As fruit and vegetable consumption increases, cancer
risk decreases. The classic study was published in 1992 by an
epidemiologist at the University of California, Berkeley, who
analyzed every prior study published that correlated diet and
cancer risk, some 200 studies in all. Compared with people who ate
few fruits and vegetables, those who ate the most had only half the
cancer risk. Since then, many more studies have corroborated this
finding.
As a result, the National Cancer Institute recommends eating at
least five — and preferably nine — servings of fruits and
vegetables a day. (See “What’s a Serving?” on Page 22.) Currently,
most Americans eat only about three daily servings of fruit and
vegetables, so we’ve got a way to go, but the goal is within reach.
Once you get the hang of it, it’s not difficult to get at least
five. Have one or two pieces of fruit or fruit juice with breakfast
— for example, raisins on cereal and a glass of orange juice. Have
a vegetable and salad at lunch. Snack on fruit or vegetables
(carrot sticks, bell pepper slices, etc.). Have a vegetable and
salad with dinner. And have some fruit for evening snacks — instead
of ice cream, try fruit sorbet.
Now for two fine points: First, french fries and other
deep-fried vegetables (for example, vegetable tempura) don’t count
toward your five to nine servings. Deep frying means loads of fat,
which negates vegetables’ cancer-preventive benefits (see
below).
Second, all plant foods help prevent cancer, but two categories
are particularly beneficial: highly colorful fruits and vegetables
(blueberries, beets) and cruciferous veggies (broccoli,
cauliflower, Brussels sprouts). The pigments that give plant foods
their color are potent antioxidants. The crucifers also are high in
antioxidants.
Should You Buy Organic Produce?
One of the rationales behind consuming organic food goes
something like this: Pesticides are carcinogenic; therefore, it
makes sense that eating food grown using pesticides — and
containing pesticide residues — might increase cancer risk. (Other
valid reasons include the better flavor of organic foods, the
health of the soil and support of alternatives to corporate
agribusiness and the chemical industry.) According to a 2003
article in Alternative Medicine Alert, Americans now buy 40 times
more organic produce than they did in 1986, almost $8 billion a
year. Considerable evidence, including a study published in
Occupational and Environmental Medicine in 2003, shows that farmers
occupationally exposed to large doses of pesticides have an
increased risk of some cancers, notably non-Hodgkin’s lymphoma.
Other research shows that compared with children who eat
commercially grown food, those who eat organic have lower levels of
pesticides in their bodies. But to date, there are no compelling
studies showing that eating organic food reduces cancer risk. All
the studies demonstrating that fruits and vegetables significantly
reduce cancer risk used conventionally grown produce. So eat
organic if you want to (I do) and certainly reduce your exposure to
pesticides of all kinds, but don’t expect organic food to be the
magic bullet that immunizes you against cancer. Currently, the best
evidence shows that any plant foods, even those grown using
pesticides, help reduce cancer risk.
Use Antioxidant Herbs
Notice that two of the top antioxidant foods mentioned on Page
21 are also considered herbs — garlic and onion. Several other
herbs also are rich in antioxidants, notably tea and turmeric.
Among herbs, garlic has the best evidence of cancer-preventive
action. Research at the MD Anderson Cancer Center in Houston shows
that garlic reduces the risk of bladder cancer. National Cancer
Institute researchers, in a study published in the Journal of the
National Cancer Institute in 2002, have found that garlic and its
close botanical relative, onion, help prevent prostate cancer.
Chinese researchers have correlated garlic and onion consumption
with reduced risk of esophageal and stomach cancers. And a study of
42,000 Iowa women published in the Journal of Epidemiology in 1994
showed that compared with people who ate the least garlic, those
who ate the most had a 32 percent lower risk of colon cancer.
Tea (primarily green tea) has been shown to reduce the risk of
several cancers: bladder, breast, colon, esophageal and pancreatic.
Research on the cancer-preventive activity of turmeric is in its
infancy, but there is no doubt that this herb is a potent
antioxidant. One study, published in Cancer Research in 1999, shows
the herb reduces the risk of colon cancer.
Eat Less Meat
Meat is problematic for several reasons. First, it tends to
displace plant foods from the diet. Meat has low levels of
antioxidants, so diets heavy on meat tend to be low in
cancer-preventive antioxidants. Red meat also is high in animal
(saturated) fat. This type of fat (as opposed to fish oils,
vegetable oils and the fats found in plant foods) has been found to
increase risk of several cancers: colon, prostate, uterine and
breast. Cooking meats (especially grilling) introduces potent
carcinogens (heterocyclic amines) into them. Finally, a gram of fat
contains twice as many calories as a gram of protein or
carbohydrate. Because meat is high in fat, it’s also high in
calories, which promotes weight gain — and obesity is a risk factor
for several cancers (see “Watch Your Weight” on Page 24).
Meat is fundamental to most Americans’ diets, and eating less
can be difficult — serving less can elicit howls of protest from
the family. An excellent way to cut back on meat — without anyone
noticing — is to use soy-based substitutes. In casseroles, pasta
sauces, soups and sloppy Joes, it’s hard to tell the difference
between ground beef and soy substitute. Other suggestions: Instead
of red meat, serve dishes made with fish, or skinless chicken or
turkey breasts. Serve pizza topped with vegetables instead of meat
(and go easy on the cheese). Or serve tomato-based vegetable sauces
over pasta.
Eat Less Fast Food and Junk Food
Fast food (burgers, pizza, french fries) and junk food (ice
cream, doughnuts, etc.) are high in fat, which contributes to
weight gain, a key risk factor for cancer. They’re also low in
plant material, so they tend to displace foods containing
cancer-preventive antioxidants. Sure, there’s a little lettuce on
a Big Mac. But it’s overwhelmed by the beef, cheese and high-fat
special sauce. If you haven’t seen Morgan Spurlock’s documentary
Supersize Me, rent the video or DVD. The protagonist eats nothing
but fast food for a month, gains 20 pounds and develops a host of
health problems. Before the month is up, his doctor is so appalled
by Spurlock’s physical deterioration that he begs him to stop. (I
played the DVD for my kids. It made a big impression on them.)
Get Regular Exercise
To prevent cancer, the American Cancer Society recommends 45
minutes of moderate exercise at least five days a week. Activities
that qualify include walking, dancing, bike riding, yoga, roller or
ice skating, baseball, volleyball, tennis, golf, soccer, gardening,
lawn mowing — you get the idea. A University of Toronto analysis
shows that regular exercise reduces the risk of breast, colon,
prostate, testicular and uterine cancers, and possibly lung cancer.
The Toronto researchers found that regular exercisers have an
approximately 46 percent lower cancer risk compared to people who
live sedentary lives.
Why exercise reduces risk of cancer isn’t entirely clear.
However, this much is known: Exercise speeds the movement of food
through the colon, limiting the body’s exposure to any carcinogens
food contains. Exercise also reduces the amount of estrogen in
women’s bloodstreams, reducing the risk of breast cancer.
Watch Your Weight
Carrying extra pounds goes hand-in-hand with physical
inactivity, along with a high-fat diet heavy on meats, fast foods
and junk foods and lacking in plant foods. So it should come as no
surprise that being overweight is also associated with increased
cancer risk, particularly for cancers of the colon, esophagus,
kidney, gallbladder, pancreas and uterine endometrium. The
cancer-preventive lifestyle — a plant-based diet and regular
exercise, with a minimum of high-calorie, high-fat meats, fast
foods and junk foods — is also the lifestyle recommended for
long-term weight control, so as you reduce the pounds, you also
reduce your cancer risk. Good news all around.
Do Vitamin and Mineral Supplements Help?
Consume Alcohol in Moderation
Moderate alcohol consumption — two drinks a day for men, one for
women — is not a risk factor for cancer. But drinking any more than
that has been associated with cancers of the mouth, throat, larynx,
esophagus, breast and liver, and possibly colon. Excessive alcohol
has a direct cancer-promoting effect throughout the digestive
tract. It increases the risk of breast cancer because it increases
blood levels of estrogen.
Vitamins A, C and E, the mineral selenium and many other
nutrients are potent antioxidants, so it stands to reason that
taking them as supplements would reduce cancer risk. But it’s not
that simple. Over the past 20 years, a number of studies have shown
that supplementation with antioxidants reduces risk of some
cancers. The most persuasive report was a Cornell study that
followed 1,312 adults who took a placebo or selenium (200
micrograms a day) for up to 10 years. The selenium group showed a
significant decrease in cancer deaths, particularly with cancers of
the lung, colon and prostate.
Overall, though, the evidence in favor of a cancer-preventive
effect for supplements is nowhere near as consistent nor as
compelling as the evidence for fruits and vegetables. In fact, one
noted study, published in the New England Journal of Medicine in
1994, showed that beta-carotene supplements, which convert to
vitamin A in the body, increased the risk of lung cancer in
smokers. The current thinking is that taking a few isolated
antioxidants in supplements is simply not as effective for cancer
prevention as eating the much broader natural mix of antioxidants
found in plant foods. Take a multivitamin if you want to (I do),
but instead of splurging on exotic supplements, you’re more likely
to prevent cancer if you splurge on blueberries, blackberries,
strawberries and cherries — which taste better, too.
For some quick, simple, antioxidant-rich recipes, visit our
website at www.HerbsForHealth.com.
Beyond Cancer Prevention: Bonus Benefits
The cancer-preventive diet and lifestyle not only help prevent
cancer, they also help prevent heart disease, stroke, diabetes and
Alzheimer’s disease. Like cancer, all of these conditions are the
result of free radical damage that an active life and a diet high
in antioxidants help prevent. So take a nice long walk down to your
favorite produce store. Load up on delicious fruits and vegetables
— and antioxidant herbs. Then walk home and enjoy them. With every
step, and with every bite, you’re likely to live longer — and
healthier.
San Francisco-based health writer Michael Castleman is the
author of 10 consumer health guides. Visit his website at
www.mcastleman.com.
The reference list for this article is extensive. If you would
like a copy, please send a self-addressed, stamped envelope to
“Cancer,” Herbs for Health, 1503 SW 42nd St., Topeka, KS 66609; or
e-mail us at editor@HerbsForHealth.com.
