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Cancer, Diet &
Phytochemicals
Causes of Death in US, 2010
In 2010, a total of 2,468,435 deaths occurred in the United States. The
first two leading causes of death, heart disease (597,689 deaths) and
cancer (574,743), accounted for nearly 50% of all deaths..
Heart disease killed almost 300,000 women in 2010.
Key Concepts: Cancer
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Cancer has many causes
Diet is a factor that influences the
development of some types of cancer
Lifestyles and diets based on plant foods
that include lean meats, fish, and low-fat
dairy products regular physical activity, and
normal levels of body fat reduce cancer risk
Cancer is largely preventable, but there
are no guarantees that an individual will not
develop cancer
What Is Cancer?
Cancer, second leading cause of
death in the U.S., is really some 200
diseases that cause the uncontrolled
growth of abnormal cells (NIH director)
 Cells can begin to grow in any tissue,
but lungs, colon, prostate, and breasts
are the most common sites for cancer
development
 Some forms of cancer are highly
curable

Estimated Cancer Deaths in the US in 2013
38,280 deaths from
breast cancer
Development of Cancer
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Cancer develops by processes not yet fully
understood
Cancer development is not linear - cancer
can progress two steps forward and then
take a step or two back
Cancer begins when something goes wrong
that modifies cell division
Every minute, 10 million cells in the body
divide
Usually they divide the right way
Phases
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At initiation
something alters
DNA in certain cells
During promotion
phase, cancer cells
with altered DNA
divide, producing
large numbers of
abnormal cells
This phase takes
place over 10 to 30
years

Unless corrected by
some means,
abnormal cells
continue to divide,
leading to
progression phase
of cancer
development
Progression Phase
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Body loses control over abnormal cells,
numbers increase rapidly
Eventually cells become so numerous they
erode normal functions where they are
growing
Now abnormal cells can migrate
(metastasize) to other tissues and cause
DNA damage and abnormal cell
development in these tissues, too
What Causes Cancer?

80-90% of all cancers are related to
environmental factors, including
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–
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smoking
exposure to asbestos
chemical pollutants
radiation
And diet-- a major environmental factor-may account for 40% of cancer risk
Environmental Factors
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Rates of breast cancer are low in rural Asia
When rural Asians immigrate to U.S., rates
of breast cancer become same or higher
than U.S. rate by third generation
Rates of prostate cancer similarly increase
as people move from countries with low-tohigh rates
Dietary Factors
Westernization of dietary intake and
lifestyle increases the risk of many
types of cancer
 Rates of breast cancer in Japanese
and Eskimo women increase
substantially as Westernized diets and
lifestyles have become adopted

Genetic Factors
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Some people have genetic susceptibility to
certain cancers
They develop cancer if regularly exposed to
certain substances in the diet or environment
Genetic factors account for 42% of risk for
prostate cancer, 5 to 27% of risk for breast
cancer, and 36% of risk for pancreatic cancer
Cancer Preventable
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Cancer is a largely preventable disease
Increasing rates of new cases of lung
cancer took a turn for the better after 1992
and correspond to declines in rates of
tobacco use for men
Other changes in lifestyles and diets may
lead to further declines in cancer rates
… or to increases
Cancer-promoting
lifestyle
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DIET
Red meats and
saturated fat
Includes charred
and nitrate-cured
meats
Excessive alcohol
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Other Risk Factors
Smoking
Physical inactivity
Excess body fat
Eating to Beat the
Odds
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Two thirds of people in U.S. do not develop
cancer
Improve your odds by
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not smoking
Eating a low red-meat and saturated-fat diet
being physically active
drinking in moderation or not at all
consuming plenty of fruits and vegetables daily
maintaining a normal level of body fat
No guarantees, but you help prevent cancer
by a good diet and a healthy lifestyle
The Latest:
Red meat may raise young
women’s breast cancer risk

Compared with women who had one
serving of red meat a week, those who
ate 1.5 servings a day appeared to
have a 22% higher risk of breast
cancer. additional red meat seemed to
increase the risk of breast cancer
more. Harvard researchers drew from data on the health
of 89,000 women aged 24 to 43, who were followed over a 20year period. June 2014 British Medical Journal.
Fig. 22-1, p. 6
Grilled and Charred Meats
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Substances in beef, chicken, fish, and other
meats become cancer promoting if heated
to high temperatures
High temperatures can be reached by
broiling and grilling food
Cancer-promoting substances are in
charred portions of meat and fatty coating
that forms on meat when fat drips into heat
source and smokes
But the problem is not
just grilled meat…

One European study tracked 478,000
men and women…. those who ate the
most red meat (about 5 ounces a day
or more) were a third more likely to
develop colon cancer than those who
ate the least red meat (less than an
ounce a day on average).

Consumption of chicken did not matter, and
consumpton of fish reduced risk.
Nitrate-Preserved Meats
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Cancer of stomach and liver related to
regular consumption of hot dogs, lunch
meats, bacon, pickled eggs, and vegetables
preserved with nitrates
Most cases of cancer from nitrate use in
smoked, salted, and pickled foods now
occur in China, the former Soviet Union, and
Central and South America where such
foods are very frequently eaten
Recommendations for Protein
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Include plant sources of protein because
plants also provide unsaturated fats
Dried beans, soy products, nuts, and seeds
provide vitamins, minerals, fiber, and more
phytochemicals that help ward-off cancer
progression
Regular consumption of fish related to lower
rates of cancer
Poultry consumption doesn’t increase risk
Limit beef to no more than two 4-oz servings
a week
Harvard Summary, 2012
Alcohol-Attributable
Cancer Deaths
Total cancer deaths 574,743
 Alcohol consumption resulted in about
20,000 cancer deaths per year,

3.5% of all US cancer deaths.
 About 6,000 from breast cancer
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Heart disease killed almost 300,000 women in
2010.
Body Fat and Cancer
 Central
obesity increases the risk
of cancer at several sites
 Central fat alters metabolism of
hormones such as estrogen,
testosterone, and insulin to
promote growth of abnormal cells
FOCUS:
Phytochemicals

Diets containing
vegetables, fruits,
whole grains, all rich
in phytochemicals
strongly associated
with low rates of
chronic heart disease
and cancer
Phytochemicals
(aka phytonutrients)
Chemical substances found in plants
 Thousands of phytochemicals in plants,
and some foods contain hundreds
 Not essential, we do not develop a
deficiency disease if we consume too
little
 Many are antioxidants

How Do They Work?
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Phytochemicals:
-- Act as hormone-inhibitors to prevent initiation of cancer
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Antioxidants that prevent and repair damage due to oxidation
block enzymes that promote cancer and other diseases
modify absorption, production, or utilization of cholesterol
decrease formation of blood clots
Some plant pigments are powerful antioxidants
– zeaxanthin, anthocyanin and lycopene are strong antioxidants
– dark chocolate contains flavonoid antioxidants
– some phytochemical antioxidants reduce plaque formation by
preventing the oxidation of LDL
Antioxidants
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May participate in cancer prevention by protecting
cells from damage due to oxidation and by inhibiting
the multiplication of abnormal cells
Vitamin C, beta-carotene, vitamin E, and selenium
are well-known antioxidants in vegetables and fruits
Damage to DNA related to cancer initiation may be
caused by exposure to oxidizing substances that
disrupt molecules within DNA
Antioxidants are able to repair damaged DNA
Carotenoids
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Alpha, Beta, and Gamma carotenes
Lycopenes, lutein, etc., etc.
May protect against prostate cancer
 May protect against lung cancer
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Tomatoes, tomato sauce
Watermelon, red grapefruit, guava
Red peppers, chili peppers, green peppers
Apricots
Color Coding
Cruciferous Vegetables
Fig. 21-5, p. 5
Cruciferous Vegetables
3 cruciferous vegetable servings per
week may reduce the risk of lung,
bladder, and prostate cancer
 Broccoli
 Cabbage
 Collards, mustard, turnip greens,
 Bok choy, brussels sprouts, cauliflower
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Whole Grains and Cancer
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Whole grains have vitamins, minerals, fiber,
unsaturated fatty acids, and those
phytochemicals that work together in
cancer prevention
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Effect on cancer risk is related to the
combined action of these substances

Advice: include three or more 100% whole
grain products daily
Phytochemicals
Phytochemicals are heat and light stable,
not easily destroyed by cooking or storage
 Many are excreted soon after ingestion, so
intake of vegetables, legumes, nuts, fruits,
and other food sources should be frequent
 Cooking vegetables or eating with fat/oil
increases absorption of phytochemicals

Characteristics
Phytochemicals provide color and flavor
and protect plants from insects, microbes,
and oxidation due to exposure to sunlight
and oxygen
 Some are components of a plant’s
energy-making processes
 Some act as plant hormones
 Many are pigments, like anthocyanins
& function as antioxidants

Phytochemicals and
Health
Phytochemicals are associated with a reduced risk
of developing:
– heart disease
– certain types of cancer (lung, breast, cervical,
esophageal, stomach, and colon cancer)
– age-related macular degeneration, cataracts
– infectious diseases
– Type 2 diabetes
– Hypertension, stroke
– and other disorders
 Evidence supports role for phytochemicals
*Clinical studies to demonstrate cause-and-effect
relationships have yet to be completed
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Phytochemicals in Groups
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There is no solid evidence that individual
phytochemicals extracted from foods benefit
health
Absorption appears to depend on other
phytochemicals and nutrients
Most phytochemicals act together
synergistically
Optimal combinations are not yet known, so
let foods provide them
Broccoli: in just 1 cup
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Over 30 phytochemicals including
Indol-3-carbinol (first cancer-protective
phytochemical, discovered in 1970’s)
90% RDA for Vitamin A
200% RDA for Vitamin C
25% daily recommendation for fiber
Fair amounts of niacin, pantothenic acid,
folacin, iron, vitamin K, calcium, thiamin &
phosphorus
Fig. 21-2, p. 3
Dietary Risk Factors
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Foods contain vitamins and minerals, fiber and
phytochemicals that protect the body against
cancer
Substances in plant foods appear to work
synergistically to confer protection
Attempts to prevent cancer by dosing with
individual components of plants have not been
successful
Foods provide protection against cancer, but
extracted phytochemical supplements do not
Diets that prevent cancer are based on regular
intake of an array of foods
Extracts and Essences
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Dehydrated extracts of vegetables high in
phytochemicals are available
There is no evidence that these extracts benefit
health
“Broccoli Concentrate” contains one phytochemical
from the cruciferous family
Only so much will fit into a capsule, so it takes 100’s
of pills to get same amount as one serving of
broccoli!
Supplements of phytochemicals are unsafe and
ineffective
Diet and Cancer
Guidelines
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Dietary patterns and lifestyles to reduce risk
of cancer are compatible with dietary
recommendations to reduce the risk of heart
disease
Considered together, recommendations for
cancer prevention and heart disease
prevention can be transferred to dietary
intake by proper selection of foods
Benefits from diets
high in plant foods
Vegetables, fruits, whole grains, and other
plant foods reduce:
 Heart disease
Cancer
 Type 2 diabetes
Infections
 Eye disease
Premature aging
 and a number of other health problems

The End
Fig. 21-4, p. 5