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Diet and Cancer Prevention
Fact Sheet No. 9.313
Food and Nutrition Series| Health
by L. Bellows, R. Moore*
What is Cancer?
Cancer, also referred to as a
malignant tumor, is a general term
that refers to the rapid formation of
abnormal cells that grow beyond their
normal boundaries. Cancer can affect
any part of the body, and originates
from a single cell that transforms into
a tumor cell through interactions
between genetics and external agents.
What Increases the Risk for
Cancer?
The risk factors for cancer —
listed below — act cumulatively
to contribute to the occurrence of
cancer; they are not necessarily the
cause of cancer. Lifestyle risk factors
for cancer are usually preventable,
and avoiding certain factors may
lower one’s risk in developing cancer.
Key lifestyle risk factors to avoid
include:
1. Overweight or obesity
2. Unhealthy diet high in
processed foods
3. Lack of physical activity
4. Tobacco use
5. Alcohol use
6. Infections (hepatitis, HPV)
7. Environmental pollution (air,
water, and soil)
8. Occupational Carcinogens
(Asbestos)
9. Radiation (UV light, Radon
gas)
L. Bellows, Colorado State University Extension food and
nutrition specialist and assistant professor; and R. Moore,
graduate student. 11/2012
*
Obesity and Cancer: What
is the Relationship?
The American Cancer Society
(ACS) reports that 1 out of every 5
cancer deaths in the United States is
attributed to overweight and obesity.
Overweight or obesity is linked to
an increased risk for various cancers
such as breast, colon and rectum,
endometrium, esophagus, kidney,
and pancreas. It also raises the risk
for cancers of the gallbladder, liver,
cervix, ovary, prostate, as well as nonHodgkin lymphoma and multiple
myelomas.
The most important factor in
the relationship between diet and
prevention of cancer is healthy weight
maintenance throughout life. Weight
maintenance can be achieved by
balancing caloric intake from food
and beverages, with physical activity.
ACS recommends avoiding excess
weight gain by limiting high caloric
foods and beverages, decreasing food
portions, limiting high calorie snacks,
and engaging in regular physical
activity.
Key Dietary Guidelines for
Cancer Prevention
The following list contains key
dietary factors for healthy weight
maintenance — an important
recommendation for the prevention
of cancer. This guide also presents
recommendations to reduce ones
exposure to carcinogens present in
food.
Quick Facts
• Lifestyle choices such as poor
diet, lack of physical activity,
obesity, tobacco, and alcohol
use are all associated with an
increased risk for cancer.
• One-third of all cancer deaths
are preventable, and can be
attributed to lack of physical
activity and poor diet.
• Vitamin supplements have not
been shown to reduce the risk
for cancer.
• Consuming whole foods as
part of a healthy diet, and
controlling calorie intake,
will help maintain a healthy
weight and reduce the risk for
cancer.
© Colorado State University
Extension. 7/96. Revised 11/12.
www.ext.colostate.edu
1. Reduce intake of saturated
fat, processed meat, and red
meat
2. Limit intake of salt-cured
and charred foods
3. Increase consumption of
fruits, vegetables, and whole
grains
4. Consume alcoholic beverages
in moderation
These cancer recommendations
generally conform to the USDA
Dietary Guidelines for Americans,
and may help decrease risk for
cancer, particularly if there is an
increased risk due to other factors
such as genetics. These guidelines
may also lessen the risk for
other chronic diseases. For more
information on the USDA Dietary
Guidelines, see the website www.
choosemyplate.gov, and for coping
with cancer’s effect on the diet, see
fact sheet 9.332 Diet and Cancer
Treatment-Tips for Healthy Eating.
1. Reduce Intake of
Saturated Fat, Processed
Meat, and Red Meat
Increased consumption of
saturated fat, processed meat, and
red meat, have been shown to
raise the risk for cancer, possibly
through contact with carcinogenic
substances during cooking and
processing methods. Consumption
of these foods may also lead to
weight gain, which is also a risk
factor for cancer.
Saturated Fat — Research
suggests that too much dietary fat,
especially from unhealthy fats like
saturated and trans fat, may lead
to an increased risk for a variety of
cancers such as colon, rectum, and
prostate cancer. This is especially
true when fat, as a total percentage
of caloric intake, is increased. The
fat content in meat may contribute
to the production of secondary
compounds in the body that act as
carcinogens. Overall, Americans
should consume no more than
30-35% of their daily calories
from fat, depending on age and
gender, and should consume no
more than 7-10% of their daily
calories from saturated fatty acids.
Saturated fats are mostly found in
animal products. Major sources for
Americans include: cheese, pizza,
desserts, and red meat. These foods
should be replaced with foods rich
in unsaturated fats such as essential
omega-3 fatty acids found in
seafood and most plant based oils.
Tips to Reduce Saturated Fat:
• Use vegetable oils when
cooking (canola, corn, or
olive oil) instead of solid
fats (butter, or lard).
• Purchase fat-free or low-fat
milk instead of whole milk.
• Trim fat and skin from
meat.
• Decrease consumption of
fried foods.
• Eat smaller portions.
• Pay attention to fat content
on food labels.
• Substitute low-fat products
in recipes.
• Consume meat that has
lower levels of saturated fat,
such as seafood.
Processed Meat and Red Meat —
High intakes of processed meat
(lunch meat or hotdogs) and
red meats (beef or pork) may be
associated with an increase in
stomach and colorectal cancers; and
consumption should be limited.
Evidence suggests that risk for colon
and rectal cancer may increase by
15-20% for every 3.5 oz. (100g)
of red meat or 1.8 oz. (50g) of
processed meat consumed per day.
Red meat contains compounds such
as iron that may cause the formation
of free radicals. Processed meats
contain nitrates, which are often
used in the curing process. Nitrates
cause cancer in laboratory animals
and are suspected of causing
cancer in humans. Consumption of
processed meat also increases ones
exposure to carcinogenic chemicals
from methods of preservation that
involve smoke or salt.
Tips to Reduce Consumption of
Processed Meat and Red Meat:
• Use meat as a side dish, in
small portions.
• Consume lean meats like
fish and skinless poultry.
• Consume alternative
protein sources such as
beans and legumes.
2. Limit Intake of SaltCured and Charred Foods
Carcinogens are present in
certain foods, and evidence suggests
that eating salt-cured, smoked,
pickled, and charcoal-broiled foods,
increases the risk for cancer. Rates
of stomach and esophageal cancer
cases are especially high in parts
of the world where food is often
prepared using these methods.
Salt-Cured Foods — Salt-cured and
pickled foods may increase one's
risk for stomach cancer, especially
when eaten in large quantities.
Nitrates used in the curing process
are known cancer causing agents
in laboratory animals, and are
suspected of causing cancer in
humans. There is no evidence,
however, that table salt or salt used
in cooking increases the risk for
cancer.
Smoked Foods — These foods
absorb large amounts of tars that
arise from incomplete combustion
of wood or charcoal fire, which
are known to contain numerous
carcinogens. "Liquid Smoke,"
which may be less hazardous, is a
commonly used substitute.
Charcoal and Gas-Broiled Foods —
A substance called benzopyrene is
formed when fat from meat drips
on to hot coals. The rising smoke
then deposits the carcinogenic
substance on the meat. However,
little evidence suggests that
Americans are at risk from excessive
consumption of charcoal-broiled
food.
High-temperature frying or broiling
— This process may convert some of
the meat proteins into products that
damage the genetic material of the
body's cells.
Tips to Limit the Charring of Food:
• Cover grill with aluminum
foil to protect the food
from smoke and fire.
• Cook meat until done, but
do not char it.
• Remove charred portions
before eating.
• Precook foods in the
microwave to decrease
grilling time.
3. Increase Consumption
of Fruits, Vegetables, and
Whole-Grains
Specific nutrients and food
constituents of fruits, vegetables
and whole grains may act as anticancer substances when consumed
in amounts found in a varied diet.
Consuming fruits, vegetables,
and whole grains may also help in
healthy weight maintenance — the
ultimate goal in cancer prevention
according to research.
Whole-Grains — Plants such as
wheat, oats, rice, and barley, contain
vitamins, minerals, and dietary
fiber, which may help prevent
cancers of the gastrointestinal tract
such as colon and rectal cancer.
Dietary fiber is the material from
plant cells that the body cannot
digest completely, and it is found
in vegetables, legumes, fruit and
whole-grain cereals, nuts and
seeds. Fiber provides bulk in
the diet, and it helps move food
through the intestines and out of
the body at regular intervals. It is
unclear whether total fiber intake
or components of dietary fiber
are beneficial in reducing cancer
risks. Fiber supplements are not
recommended.
Fruits and Vegetables — Plants
contain many beneficial compounds
such as vitamins, minerals,
antioxidants, phytochemicals,
and fiber, which may act to
reduce the risk for cancers such
as lung, mouth, pharynx, larynx,
esophagus, stomach, and colorectal.
Researchers are still examining the
effects of these complex interactions.
There are several groups of fruits
and vegetables that may offer
particularly protective effects such
as dark green and orange vegetables,
cruciferous vegetables (cabbage,
broccoli), flavonoids (soy, tea),
legumes, sulfides (garlic, onion),
and tomato products.
Antioxidants and Cancer —
Antioxidants are compounds
present in fruits and vegetables
which help protect tissues from
being damaged. Tissue damage
is linked to increased cancer risk;
therefore antioxidants may play a
role in cancer prevention. Types
of antioxidants include vitamin
C (ascorbic acid), vitamin E, and
the carotenoids — vitamin A,
and beta-carotene. Many studies
have demonstrated the role that
antioxidants play in reducing the
risk for cancer. Their protective
effect is only observed when one
consumes antioxidants from plant
foods such as fruits and vegetables,
and not from supplements.
Phytochemicals and Cancer —
Phytochemicals (or phytonutrients)
are chemicals made by plants that
have antioxidant-like properties.
Types of phytochemicals include
dark green and orange vegetables,
cruciferous vegetables, flavonoids,
and sulfides. There is an association
with a high consumption of plant
foods and a decrease in risk for
cancer, but the relationship is
unknown.
4. Consume Alcoholic
Beverages in Moderation
Heavy consumption of alcoholic
beverages (more than two drinks
per day for men, and more than one
drink per day for women) increases
the risk of mouth, pharynx, larynx,
esophagus, liver, pancreas, bladder,
colorectal, and breast cancers. It is
unclear whether it is the alcohol
or other ingredients in these
beverages that are responsible for
the association with an increased
risk for cancer.
Alcohol Abuse and the Cancer
Connection: The link between
cancer and alcohol is complex
because frequent alcohol
consumption may result in many
health problems.
• The carcinogenic effect may
result from the direct contact
of alcohol on the mouth,
pharynx and esophagus.
• Heavy drinking can result
in liver cirrhosis, which may
lead to liver cancer.
• Alcoholics commonly have
nutritional deficiencies
because alcohol contains
only empty calories, and food
intake often is compromised.
This may result in a low fruit,
vegetable, and whole grain
intake.
• If heavy drinkers also smoke
cigarettes, the risk for cancer
is compounded.
• Alcohol is high in calories
and low in nutrients. Calories
from alcohol can contribute
to weight gain, which is a risk
factor for cancer.
Tips to Moderate Alcohol
Consumption:
• Instead of alcohol, try nonalcoholic wine, beer, mineral
or tonic water, cider, grape
juice, or fruit juice.
• Always provide non-alcoholic
beverages and nutrient-dense
foods at social gatherings.
• Drink alcohol in moderation
— no more than two drinks
per day for men, and no
more than 1 drink per day for
women.
Additional Resources
• American Institute for
Cancer Research: www.aicr.
org
• American Cancer Society:
www.cancer.org
• National Cancer Institute:
www.cancer.gov — or call the
Cancer Information Service
at: 1-800-4-CANCER
References
Duyff, ADA. American Dietetic
Association: Complete Food and
Nutrition Guide. Hoboken: John
Wiley & Sons, Inc., 2006.
Kushi LH, Doyle C, McCullough M,
Rock CL, et al. American Cancer
Society Guidelines on Nutrition
and Physical Activity for Cancer
Prevention: Reducing the Risk
of Cancer with Healthy Food
Choices and Physical Activity.
CA Cancer J CLin 2012;62:30-67.
Mahan, L. K., Escott-Stump, S.,
Raymond, J. L., & Krause, M.
V. (2012). Krause's food & the
nutrition care process. St. Louis,
Mo: Elsevier/Saunders.
McCullough ML, Patel AV, Kushi
LH. Cancer Epidemiology,
Biomarkers, and Prevention:
Following Cancer Prevention
Guidelines Reduces Risk of
Cancer, Cardiovascular Disease,
and All-Cause Mortality. Cancer
Epidemiol Biomarkers Prev
2011;20:1089-1097.
U.S. Department of Agriculture
and U.S. Department of Health
and Human Services. Dietary
Guidelines for Americans, 2010.
7th Edition, Washington, DC:
U.S. Government Printing Office,
December 2010.
World Health Organization.
Guidelines for Cancer
Prevention. 2012. http://www.
who.int/cancer/prevention/en/
Image Sources
http://fnic.nal.usda.gov/
professional-and-careerresources/nutrition-education/
sources-nutrition-educationmaterials
Whole-grains. Realage.com
http://office.microsoft.com/
en-us/images/results.
aspx?qu=farmers%20
market&ex=2#ai:MP900438718|
Summary
• Diets high in fiber and low
in fat, with plenty of fruits,
vegetables, whole-grain breads,
and cereals, may reduce the
risk of cancer, particularly in
individuals at increased risk.
• In addition to the
recommendations by the World
Health Organization (WHO)
and the Academy of Nutrition
and Dietetics (AND), the
American Cancer Society (ACS)
also strongly recommends
maintaining a healthy weight.
• A healthy weight can be
maintained by regular physical
activity and a healthful diet.
• A healthy diet should include
the following dietary
recommendations: 1) Reduce intake of saturated
fat, processed meat, and red
meat, 2) Limit intake of salt-cured
and charred foods, 3) Increase consumption of
fruits, vegetables, and whole
grains, 4) Consume alcoholic
beverages in moderation.
These are all important
preventive actions that may
safeguard ones health and
reduce the risk for cancer.
• These dietary guidelines are
intended for people who
are healthy. If you have a
condition that requires a special
diet, consult a physician or
registered dietician before
beginning any modified diet
plan.
Colorado State University, U.S. Department of
Agriculture and Colorado counties cooperating.
CSU Extension programs are available to all without
discrimination. No endorsement of products mentioned
is intended nor is criticism implied of products not
mentioned.