Dietary Changes That Will Lower Your Cancer Risk
Some
foods actually contribute to the development of cancer; other foods lessen the
risk. The following anti-cancer diet greatly lowers your risk of colorectal
cancer and nearly all other types of cancers. It can also prevent
cardiovascular disease. For people with a genetic tendency toward colorectal
cancer, it is not just an option, it’s a lifesaving necessity.
1.
Keep your diet low in total fat and very
low in saturated fats. There are at least two ways in which dietary fat
contributes to cancer. First, tumor cells need low density lipoproteins (LDL’s)
to grow. Therefore, a diet that helps to lower LDL levels could keep
potentially cancerous cells from growing. Eating fat also stimulates the
production of bile, which is needed to digest fat. If a lot of bile is allowed to
stagnate in the large intestine for a long period of time, it’s converted into
apcholic acid, a proven carcinogen. Here are tips for eating not only less fat,
but eating the right fats:
Eat less total fat. Limit your daily fat intake to no more than 20 percent
of your total food calories. This means that if you average 2,500 calories a
day, fat should provide no more than 500 of these calories. This means you
should eat around 55 grams of fat per day, maximum. (On a 2,000 calories per
day diet, you would eat about 45 grams of fat.)Eat the right fat. Eating
the wrong kinds of fat may be even more cancer-causing than eating too much
fat. Cancer researchers became aware of this fat fact when they noticed that
the incidence of most cancers is less in some cultures who actually have a
high-fat diet, such as Eskimos (who eat a lot of seafood rich in omega 3 fatty
acids) and the Mediterranean diet (which is plant-based, but high in
monounsaturated oils). Some fats don’t contribute to cancer and may in fact
have some anticancer properties:
o
Unsaturated fats, found in plant foods,
such as legumes
o
Vegetable oils that are high in
monounsaturated fats, such as olive (Greek women who tend to eat a diet rich in
olive oil have a very low incidence of breast cancer) and canola oil. A 1998
study showed that men who eat less animal fat and more vegetable fat in their
diets had less prostate cancer.
o
Seafood, such as salmon and tuna, that is
high in omega 3 fatty acids
o
Oils that contain more omega 3 than omega 6
fatty acids, such as flaxseed, pumpkin seed, canola, soybean (not
hydrogenated), walnut, safflower, sunflower, sesame, and virgin olive oils.
(Heating vegetable oils at high temperatures can change fatty acids and make
them carcinogenic. Peanut oil and extra virgin olive oil stand up best to
cooking, but try not to boil them. It helps to keep stirring stirfrys so the
oil doesn’t get burnt.)
Studies in experimental
animals showed that fish-oil-supplemented (high in omega 3 fatty acids) animals
had significantly fewer colorectal tumors. Omega 3 fatty acids (such as those
found in fish oils and flax seed oil) are not only the heart-healthiest fats,
but they may have anticancer properties. Eskimo women who have a high
concentration of omega 3 fatty acids in their diet have a lower incidence of
breast cancer. (It is thought that omega 3 fatty acids may block the effect of
estrogen on breast cells, thus lowering the risk of them becoming
cancerous.) Omega-3 dha
supplements from Dr. Sears can be added to the morning oatmeal for added
health benefits.
Don’t
eat bad fats. Avoid oils high in saturated fats,
such as palm, palm kernel, coconut, and cottonseed oils. Hydrogenated fats
(those that have been chemically changed from unsaturated to saturated fats),
are potentially carcinogenic. Adding hydrogen to a fat molecule may enable the
molecule to interfere with the normal metabolism of cells in the body, setting
the cell up for cancerous changes. So get used to reading labels. If any food
contains “hydrogenated” or “partially hydrogenated” fats, leave it on the
shelf. Most fast-food outlets use hydrogenated fats. (Ask! If they do, don’t
eat the food.) Nearly all packaged foods, such as potato chips, contain
hydrogenated fats, since these allow a longer shelf life.
MORE LEAN –
LESS CANCER
Too much body fat is one of the leading risk factors for cancer, especially
colorectal cancer. Obesity is also a risk factor for breast cancer ;
increased fat tissue raises circulating estrogen levels, which increase the
risk of breast cancer. Vegetarian women who typically consume a low-fat,
high-fiber diet tend to have lower blood levels of estrogen, excrete more
estrogen in their stools, and therefore are less prone to breast cancer.
Obese men have a higher rate of prostate cancer . The two ways to stay lean
are to exercise and to maintain healthy eating habits.
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2.
Increase Your Fiber Intake. In
all the research between food and cancer, the evidence for a relationship
between a high fiber diet and lower chances of colorectal cancer is the most
conclusive. It follows common sense as well. Fiber moves potential carcinogens
through the intestines faster, decreasing the contact time between carcinogens
and the intestinal wall. The less exposure to carcinogens, the less chance of
colon cancer. Besides pushing them through faster, fiber binds carcinogens,
keeping them away from the intestinal wall. Fiber also absorbs bile acids,
keeping them from acting on bacteria to produce fecapentanes ,the
cancerous substances that are formed by decaying foods within the colon. There
are about twenty of these compounds that can mutate colon cells into cancerous
cells. Fiber also promotes the growth of healthy bacteria in the intestines,
which crowd out the undesirable bacteria that produce fecapentanes. A high
fiber diet seems particularly protective against cancer in persons who have a
hereditary risk of developing precancerous colorectal polyps. In a study of
persons who were at high risk for developing colorectal cancer, those who ate
at least thirteen grams of wheat bran fiber a day (All-Bran is a good source)
for eight weeks showed less growth of potential cancer cells in the colon.
Besides lowering the risk of colorectal cancer, a high fiber diet can lower the
risk of breast cancer by binding estrogen in the bowels, thereby lessening the
estrogen effect in the cells of breast tissue.Based on both these scientific
and common sense findings, we suggest you eat at least 25 grams of
fiber a day. Best anticancer fiber sources are: wheat bran, kidney
beans, garbanzo beans, navy beans, whole wheat, whole grains, legumes, whole
grain bread, and prunes. Get used to looking at the package label to find the
fiber content of foods. Simple modifications in your diet can increase the
amount of fiber you eat. Use whole grain breads instead of white bread (white
bread is junk bread). Eat beans regularly (try a salad composed of kidney
beans, garbanzo beans, broccoli, and other raw vegetables). Have a big bowl of
high fiber bran cereal for breakfast.
NUTRITIP:
An Apple a
Day May Keep the Cancer Doctor Away
Pectin, the
fiber in apple skin, is fermented in the intestines, producing short- chain
fatty acids that prevent the growth of harmful bacteria. They also nourish
the cells of the intestinal lining, making them more resistant to becoming
cancerous.
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3.
4.
Eat lots of raw fruits and vegetables. The
consensus of the hundreds of studies exploring the link between diet and cancer
is that eating more fruits and vegetables reduces the risk of all types of
cancers. Eating more fruits and vegetables decreases your appetite for fatty
foods, which themselves increase the risk of cancer. Plants also containphytochemicals .
Substances that may help your body fight cancer. The five major classes of
compounds that occur in fruits and vegetables as natural blocking agents
against carcinogens are: phenols, indols, flavones, cumines, and
isothiocyanates. These neutralizing agents prevent carcinogens from reaching
critical target sites within the cell. The vegetables most important to
reducing the risk of cancer are the cruciferous vegetables :
broccoli, cabbage, brussel sprouts, mustard greens, kale, and cauliflower.
These vegetables contain three cancer-protective biochemicals: sulforaphane,
which not only boosts immunity but blocks enzymes that draw carcinogens into
healthy cells; compounds that prevent the formation of carcinogenic
nitrosamines in the intestines; and indoles, which lessen the risk
of breast cancer.Researchers estimate that eating lots of cruciferous
vegetables could lower your risk of breast and colon cancer by 40 percent.
Making your main meal, such as lunch, a huge salad (with no more than a
tablespoon of vegetable oil as a dressing) would be one of the healthiest
habits you could get into. Best salad sources of anti-cancer nutrients are:
dark green leafy spinach (instead of iceberg lettuce, which is nutritionally
useless), broccoli, tomatoes, red peppers, kidney beans, and garbanzo beans. As
an added benefit sprinkle your salad with a bit of garlic , which has also been
shown to have health-promoting and possibly anti-cancer properties. In
addition, phytoestrogens from plant foods, especially cruciferous vegetables,
can lower the risk of estrogen-dependent cancers, such as breast cancer. The
phytoestrogens fill estrogen receptor sites on cells, keeping the
cancer-causing estrogen from promoting the growth of malignant cells.
NUTRITIP:
An
Anti-Cancer Salad
Antioxidants,
such as vitamin C and E and beta carotene, seem to have a synergistic effect
when taken together. So, eating lots of fruits and vegetables in a salad
together produces a greater anti-cancer effect than eating each one
individually.
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6.
Switch from red meat to seafood. Populations
who eat the most red meat and fat in their diet have the highest incidence of
colon cancer. My fifty years of eating steaks, cheeseburgers, and french fries
was not worth the price of getting cancer. Instead of red meat being the main
course, let it be an accent in a dish based on vegetables or grains, such as
stirfry or pasta.Beginning in 1976 a group of researchers at the Harvard School
of Public Health set out to study the role of dietary factors in colon cancer
and test some of the theories suggested by earlier studies. They followed
88,000 healthy women, ages 34 to 59 years of age, and discovered these
correlations:
o
The risk of colon cancer was 2.5 times
higher in women who ate beef, pork, or lamb as a main dish every day, as
compared with those eating it less than once a month.
o
The risk of developing colon cancer
correlated with the amount of animal fat in the diet.
o
Eating meat, especially processed meats,
was highly associated with increased risk of colon cancer. Eating fish and
chicken without skin was related to a decreased risk.
o
A low intake of fiber also increased the
risk of developing colon cancer.
No association was found
between the risk of colon cancer and vegetable fat or linoleic acid (the most
abundant polyunsaturated fat) in the diet.
The reason for the red
meat-colon cancer connection is still being studied. Current research suggests
a combination of factors. High fat diets increase the excretion of intestinal
bile acids, which act as tumor promoters. Some processed meats contain
nitrosamines , which can be carcinogenic to the colon. Also, compared with
vegetarians, meat-eating persons have different colonic flora. The effects of
the meat may cause intestinal bacteria to transform bile acids into potential
carcinogens.
In a fourteen-year study
of 16,000 Swedish men and women, the foods that were associated with the
highest risk of colon cancer were beef and lamb. As a lambchop lover, I took
this study personally. Whenever our local meat market got in a shipment of
lambchops, I stocked up. A month after my colon cancer was diagnosed, Martha
took the thirty pounds of lambchops that were in our freezer back to the market
and traded them in for salmon.
Not only can red meat
itself be carcinogenic, but how you prepare it can also elevate the cancer
risk. Grilling under high heat (such as searing or flame-cooking meat to well-
done) can release carcinogens into the meat called heterocyclicamines, which
can damage cellular DNA. Poaching , stewing, microwaving , or slow low-heat
cooking releases fewer carcinogens.
7.
Switch from an animal-based diet to a
plant-based diet. The most compelling research linking
diet to cancer are studies of groups of people who have primarily plant-based
diets, for example vegetarians and Seventh Day Adventists, and who have a much,
lower risk of cancer. One of the theories on the high incidence of cancer in
modern times is the belief that the switch from plant based to animal based
diets correlates with the increase in cancer. Plant food / less cancer
correlation is primarily due to three health-promoting factors: Plants have
less fat, more fiber, and more phytonutrients. Besides providing the
anti-cancer properties of fiber, legumes (such as seeds, rice, soy beans,
beans, and chick peas) contain anticancer properties called protease
inhibitors, which have been shown to reduce the growth of breast, colon, and
skin cancers in experimental animals.
8.
Eat more soy products. Soy
is a more healthful source of protein than meat. The primary anti- cancer value
of soy seems to come from phytonutrients (for example, isoflavones) which
inhibit the growth of new blood vessels necessary for tumor survival. Soy also
protects against colon cancer by blocking the carcinogenic effects of bile
acids (a process called angiogenesis). Isoflavones also help regulate the
production of sex hormones, which could affect the risk of prostate and breast
cancer. Studies have shown that women who eat more soy foods have less risk of
breast cancer. Don’t rely on highly-processed soy foods, such as soy burgers,
soy sauce, and soy beverages to contain a lot of cancer-fighting
isoflavones.American women, especially those whose diets are low in soy
products, are four times more likely to die of breast cancer than Japanese
women whose diets are plentiful in soy. The reason this reduced risk is
contributed mainly to the soy and not to the genes is that even in their own
country those Japanese who eat the most soy foods get the least cancer. Soy
seems to protect against the most common types of cancer, including lung,
rectal, colon, stomach, prostate, and breast. Experimental animals who are fed
high soy diets and then given a chemical that causes cancer, develop fewer
tumors than the animals who are not fed soy. And you don’t need to eat much to
reap the benefits. One serving of soy (equal to a 1/2 cup of cooked soybeans,
tofu, tempeh, or one cup of soy milk) a day can lessen the risk of cancer.
GENISTEIN
CONTENT IN SOY
The
isoflavone in soy that has the most potent anticancer properties isgenistein. The
highest content of genistein is found in these soy foods, rated from highest
to lowest:
Soy Food
|
Genistein Content
(milligrams/100 grams)
|
Soy flakes
|
156
|
Soy nuts
|
94
|
Soy flour
|
94
|
Soybeans, roasted
|
87
|
Soy protein isolate
|
56
|
Tempeh
|
40
|
Miso
|
26-38
|
Tofu, firm
|
5-30
|
Soy burgers
|
20 (varies)
|
Soy milk
|
4-10
|
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9.
Be sure to consume soy products from a
manufacturer that uses a water extraction process and not alcohol extraction,
which can remove much of the genistein from the soy. Check the label or call
the manufacturer.
10.
Change your oils. Oils
that are rich in omega-3 fatty acids (i.e., fish and flax oils) have
anti-cancer properties. Studies in experimental animals have shown that
fish-oil-supplemented animals develop significantly fewer colorectal tumors.
Omega 3 fatty acids, such as those found in oily fish and flax seeds, help
produce cancer-fighting phytochemicals. Flax oil also contains the anticancer
phytonutrient lignans. Best protection against cancer is a diet
that contains more omega 3 than omega 6 fatty acids, just the reverse of the
typical American diet. Coldwater fish, such as salmon and tuna, are high in
omega-3 fatty acids. Most vegetable oils (except flax oil) contain little omega
3 fatty acids and a lot of omega 6 fatty acids. I take one tablespoon of
flax seed oil a day, which mixes beautifully in a yogurt shake or as a salad
dressing.Monounsaturated oils, such as olive oil, also play a role in cancer
prevention. Populations with an olive oil -rich diet, such as Mediterranean
cuisine, have a lower incidence of cancer. Greek women, who tend to have an
olive-oil rich diet, have a much lower risk of breast cancer. One study found
that the incidence of breast cancer correlated with the amount of hydrogenated
oils in the womens’ diets. As much as possible, avoid saturated and hydrogenated
oils. (For more information, see All About Oils.
11.
Eat foods containing calcium. Studies
have shown that populations with a high intake of calcium (e.g., people in
Sweden) have a lower incidence of colorectal cancer. Calcium controls the
multiplication of epithelial cells lining the colon. When these cells
proliferate at a fast rate, the risk of cancer increases. Calcium also binds
cancer-producing bile acids and keeps them from irritating the colon wall. One
study showed that an average intake of 1,200 mg. of calcium a day was
associated with a 75 percent reduction in colorectal cancer. In another study
of persons with an increased risk of colorectal cancer, a daily supplement of
2,000 mg. of calcium carbonate significantly decreased the risk by suppressing
the uncontrolled growth of the cells that line the colon. To lower your risk of
colorectal cancer, consider taking between 500 and 1,000 milligrams of calcium
carbonate or calcium citrate daily, depending on how much calcium you get from
food each day. Best sources of calcium are dairy products, such as yogurt, and
bony fish.
12.
Eat a diet high in antioxidants. While
there are many unsubstantiated claims about the benefits of antioxidants, there
is reliable scientific evidence that beta carotene, vitamin C and vitamin E
definitely lower the risk of colorectal cancer. Fruits and vegetables are the
main sources of these naturally occurring antioxidants. Antioxidants protect
against cancer in several ways:
o
They protect the membrane of intestinal
cells.
o
They prevent free-radical reactions that
can cause bowel contents to be carcinogenic
o
They prevent faulty metabolism in the cell,
which can predispose a cell to becoming carcinogenic.
Beta
carotene. Beta carotene fights against cancer by both
boosting the immune system and releasing a specific chemical called tumor
necrosis factor. Beta carotene can block the growth of potentially cancerous
cells. The recommended cancer prevention dose of beta carotene is 15 to 25 mg.
per day (around 30,000 IU). This is about ten times the amount in the average
American diet, but it’s actually easy to get enough beta carotene in your diet
without taking supplements. Best sources of beta carotene are sweet potatoes,
carrots, cantaloupe, pumpkins, butternut and other types of winter squash,
spinach, broccoli, mango, and papaya. Eating pink grapefruit (which contains
beta carotene) instead of white grapefruit gives you a beta carotene boost. You
could get enough protective beta carotene each day by eating: half a sweet
potato, half a cup of pumpkin, two medium-size carrots, 1.5 cups of cooked
spinach, or two medium-size mangos. Best sources of beta carotene are these:
o
carrots – 1 carrot contains 4.4 milligrams
o
sweet potatoes – 1 medium contains 12
milligrams
o
butternut and other types of winter
hard-shell squash – 1/2 cup contains 2.4 milligrams
Tomatoes contain
lycopene, which enhances the absorption and utilization of beta carotene, so
eating tomatoes with beta carotene-rich foods provides an added boost. Carrots
and tomatoes are a good combination.
Vitamin
C. A
big dose of vitamin C fights the big “C.” Studies have shown that persons with
the highest intake of vitamin C have the lowest incidence of intestinal
cancers. Vitamin C blocks the formation of nitrosamines in the gut. These are
potent carcinogens made from nitrates and nitrites found in food, especially
processed meats. Vitamin C also boosts the immune system by increasing the
production of lymphocytes. Best sources of vitamin C are fresh fruits and
vegetables. Taking 1,000 to 2,000 milligrams of vitamin C daily may have
anticancer benefits.
Vitamin
E. The
anti-cancer properties in vitamin E are similar to vitamin C. In a ten-year
study that followed 21,000 men, those with high levels of vitamin E in their
diet showed a 30 percent lower risk of all types of cancer. Women with low
blood levels of vitamin E and selenium had ten times the risk of breast cancer
in one study. In another study at the University of Toronto, researchers gave
colon cancer patients vitamin C and E supplements after surgery and found two
years later that the supplements reduced the recurrence of precancerous colon
polyps by 20 percent. Studies suggest a dose of 200 to 400 IU a day, which is
nearly impossible to get from foods. You may get less than ten percent of this
amount from even the best diet.
NUTRITIP:
Natural vs.
Synthetic E
Whether or
not natural vitamin E from foods or the factory-made vitamin is biologically
better is still a subject of debate, yet the natural vitamin E may be more
biologically active. Natural vitamin E is recognized on the package label by
the “d” prefix or “d-alpha tocophenol;” the synthetic compound will have a
“dl” prefix.
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13.
Don’t forget your flax. Flaxseeds
contain two cancer-preventive compounds: omega 3 fatty acids and lignans, which
may reduce the risk of breast cancer and colon cancer. Ground flaxseeds,
because they contain both the fiber and the oil, have more potent anticancer
properties than flax oil alone. Cancer researchers suggest 25 grams of ground
flaxseeds a day. You can grind your own in a coffee grinder or purchase
pre-ground flaxseed meal, which mixes well in smoothies or sprinkled like bran
flakes over yogurt and cereal.
14.
Drink less alcohol. Alcohol
consumption slightly increases the risk of colorectal cancer, and the alcoholic
beverage with the strongest link to colon cancer is beer. Beer is
thought to contain nitrosamines, a carcinogen or pre-carcinogen that is
activated in the intestines. Tannins are a carcinogenic compound that is found
in red wine and some coffee and tea. While red wine is touted to have
health-promoting properties, due to the natural phytonutrients that are found
in the grape skin, you’re better off simply eating the grapes.
15.
Eat other anti-cancer nutrients. Increasing
several other daily nutrients can also lower your risk of cancer.Vitamin D . Vitamin
D, which you get from exposure to sunshine (around 10 to 15 minutes a day) and
from vitamin D-fortified milk and other foods, has anticancer properties. It
suppresses angiogenesis, the formation of new blood vessels that nourish the
growth of tumors. The rates of breast, prostate, and colon cancer are lower in
climates that have the most sunshine. Low levels of vitamin D have been found
in some people with colon cancer. Women whose diets are high in vitamin D have
a lower risk of breast cancer.Selenium. This overlooked mineral is
a potent antioxidant or scavenger of carcinogenic free radicals. Studies have
shown a lower incidence of colon cancer in people taking selenium supplements
in the range of 100 to 200 mcg a day. Studies have shown that persons who have
lower levels of selenium in their blood are more likely to have colon polyps,
and those with higher levels of selenium have much less of a chance of getting
cancer. Selenium is most effective when taken along with foods or supplements
that are high in vitamin E. Consider taking 100 mcg of selenium a day as a
supplement. Best sources of selenium in food are fish (especially red snapper)
lobster, shrimp, whole grains, and vegetables, depending on the selenium
content of the soil they’re grown in. Other sources include: brown rice,
cottage cheese, lambchops, chicken (white meat), sunflower seeds, and garlic.Acidophilus.These
intestinal-friendly bacteria have been shown to have anti-cancer properties.
They promote the growth of healthy bacteria in the colon and reduce the
conversion of bile acids into carcinogens. Studies have shown that consuming
dietary supplements of lactobacillus acidophilus greatly diminishes the level
of colon enzymes that produce carcinogenic decomposition products from food. In
studies on experimental animals, 75 percent of the animals tested showed slower
tumor growth when fed yogurt containing live bacterial cultures.
Populations such as the
Finns who have a diet relatively high in fat but who also eat a lot of fiber
and a lot of yogurt, have a relatively low incidence of colon cancer. In an
experiment in which carcinogens were given to rats, the animals that were fed
large amounts of lactobacillus acidophilus developed less colon cancer compared
with those who were not given doses of these health-promoting bacteria. Take 1
to 2 teaspoons of live lactobacillus daily, the one that is in the refrigerated
section of the nutrition store. This can be added to a smoothie or a shake. Or,
eat yogurt with the L.A.C. (live active cultures) seal.
Garlic.Whether
or not garlic has health-promoting and anticancer properties is still
controversial, but it’s possible that garlic may have some anticancer benefits.
The Kyolic brand of garlic supplements seems to be the most thoroughly tested
and the one that is often used in research studies.
Green
tea.Green
tea has been shown to inhibit the growth of cancer cells, possibly because of a
phytochemical it contains called “catechins.”
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