Diet and Health Guidelines to Lower Risk of Cancer

Diet and Health Guidelines to Lower
Risk of Cancer
Presented by
Janice Hermann, PhD, RD/LD
OCES Adult and Older Adult Nutrition Specialist
Oklahoma Cooperative Extension Service
 Cancer second leading cause of death in the
United States
 Cancer not a single disorder
 Many types
 Different characteristics
 Occur in different body locations
 Take different courses
 Require different treatments
Cancer Development
 Genes work together to regulate cell division
and ensure new cells are replicas of parent
 Process allows:
 Body to grow
 Replace dead cells
 Repair damaged cells
Cancer Development
 Cancer develops from mutations in genes
regulating cell division
 Mutations inhibit genes that ordinarily monitor
and correct errors
 Affected cells lose ability to stop cell division
 Result is an abnormal mass of cells
Cancer Development
 An abnormal mass of cells is called a tumor
 Benign
 Tumors that stop growing without intervention or can be
surgically removed
 Most often pose no threat to health
 Malignant
 Tumors that multiply out of control
 Threaten surrounding tissues and health
How Cancer Develops
 As a malignant tumor grows, blood vessels
form to supply the tumor with nutrients
 Eventually, the tumor invades more and more
healthy tissue and may metastasize
 Malignant cancers are described by:
 Location
 Size
 Extent of growth
 If spread to surrounding lymph nodes
 If spread to distant sites in the body
Cancer Development
Cancer Development
 Genetic Factors
 Immune Factors
 Environmental Factors
 Physical Activity
 Dietary Factors
 Cancer Initiators
 Cancer Promoters
 Protective Factors
Cancer Development
 Genetic factors
 All cancers have a genetic component in that a
mutation causes abnormal cell growth
 Some cancers have a genetically inherited
component as well
 Example: someone with a family history of color cancer
has a greater risk of developing colon cancer than
someone without a genetic predisposition; however, this
does not mean that they will develop colon cancer
Cancer Development
 Immune factors
 A healthy immune system recognizes foreign cells
and destroys them
 Theorized an ineffective immune system may not
recognize tumor cells as foreign, thus allowing
unchecked cell growth
 Aging affects immune function, and incidence of cancer
increases with age
 Diseases that weaken the immune system can increase
cancer risk
Cancer Development
 Environmental Factors
 Environmental factors known to cause cancer:
 Exposure to radiation and sunlight
 Water and air pollution
 Smoking
Cancer Development
 Physical Activity
 Lack of physical activity may play a role in the
development of some types of cancer
 People whose lifestyles include regular, vigorous physical
activity have the lowest risk of colon cancer
 Physical activity may also protect against breast cancer
by reducing body weight and by other mechanisms
unrelated to body weight
Cancer Development
 Dietary Factors
 Estimates are 1/3 of cancers attributed to nutrition
 Cancer Initiators
 Some dietary factors may initiate cancer development
 Cancer Promoters
 Other dietary factors may promote cancer development
once it has started
 Protective Factors
 Still other dietary factors may protect against cancer
Diet and Cancer Studies
 Epidemiological studies try to identify relationships
between the diet of population groups and
incidence of specific cancers
 Diet complexity makes identifying relationships
 Thousands of chemicals in a diet
 Diets contain initiators, promoters and protective factors
 Changing one factor in the diet may change others, making
identifying individual factors difficult
 Many cancers have a long latency period, thus diet at
initiation or promotion may not be the same as at
Dietary Factors: Cancer Initiators
 Pesticides
 Some pesticides may be carcinogenic at extremely
high doses, however, they are safe at the levels
permitted on fruits and vegetables
 The benefits of eating fruits and vegetables are far
greater than any potential risk
 Food additives
 Those approved for use in foods are not
Dietary Factors: Cancer Initiators
 Alcohol
 Alcohol associated with increased risk of mouth,
esophageal and breast cancer
 Mouth and esophageal cancer are especially increased if
alcohol is combined with smoking
Dietary Factors: Cancer Initiators
 Alcohol
 If alcohol intake causes liver cirrhosis, there is an
increased risk of liver cancer
 Malnutrition associated with alcoholism is also
likely to be important in the increased risk for
certain cancers
 Thus, potential benefits of moderate alcohol
intake for cardiovascular disease must be
weighed against potential risks
Dietary Factors: Cancer Initiators
 Food preparation methods
 Cooking meat, poultry, and fish at high
temperatures and smoking meat causes
carcinogens to form on food surfaces which have
been related to colon, breast and stomach cancer
 High heat cooking methods such as grilling, broiling, and
 Healthier cooking methods include roasting,
broiling, poaching, steaming, stewing, braising
and microwaving
 Fruits and vegetables appear to provide a
protective effect
Dietary Factors: Cancer Initiators
 Food preparation methods
 Large amounts of salt-cured and salt-pickled foods
have been related to stomach, colon and bladder
 Sodium and potassium nitrates used in salting, pickling,
and curing processes
 Nitrates can be converted into nitrite, which can form
potential carcinogens nitrosamines
 Diets with high amounts of fruits and vegetables
contain vitamin C and phytochemicals can retard
conversion of nitrites to nitrosamines
Dietary Factors: Cancer Promoters
 High fat diets
 High dietary total fat and saturated fat may be
related to increased risk of breast, colon,
endometrial and prostate cancer
 Omega-3 fatty acids however, may be protective
 Thus same dietary fat advice applies to cancer
protection as to heart disease
 Reduce total fat and saturated fat
 Increase omega-3 fatty acids
Dietary Factors: Cancer Promoters
 High fat diets
 May increase cancer risk by increasing:
 Obesity
 Bile acid production
 Estrogen levels
 Because fat is calorie dense it is difficult to
distinguish between the effects of high dietary fat,
and total calories
Dietary Factors: Cancer Promoters
 High calorie intake
 In most epidemiologic studies, a positive
association has been seen with high calorie intake
and promotion of breast, colon and endometrial
 Increased risk may be due to:
 Excess calories themselves
 Weight gain due to excess calories
 High fat intake that often supplies excess calories
Dietary Factors: Cancer Promoters
 Obesity may increase risk of colon,
endometrial and breast cancer
 Increased risk may be due to:
 Extra weight
 Adipose tissue production of estrogen
 Extra calories
 High fat intake that often supplies excess calories and
contributes to weight gain
 Protective effect of physical activity related to
breast and colon cancer may be due in part to
helping to control obesity
Dietary Factors: Cancer Promoters
 Protein
 Excessive muscle meat sources of protein have
been related to increased risk of colon and
prostate cancer
 Not know if increased risk due to:
Protein level
Fat content
Fat type
Increased calories from fat
Other factor such as being low in fiber, antioxidants and
 Further research needed
Dietary Factors: Cancer Promoters
 Protein
 In general tumor development is:
 Suppressed by diets that contain protein below that
required for optimal growth
 Enhanced by protein levels two to three times the
amount required
Dietary Factors: Protective Factors
 Fruits, vegetables, whole grains and legumes
 Epidemiological studies show a link between diets
with plenty of fruits, vegetables, whole grains and
legumes and reduced incidence oral cavity,
esophagus, stomach, colon and lung cancer
 Compounds in these foods that may help lower
cancer risk:
Dietary fiber
Vitamin C
Vitamin E
Low fat
Dietary Factors: Protective Factors
 Fruits, vegetables whole grains and legumes:
 Fiber-rich diets may protect against colon cancer
 In the intestine bile can be converted into potential cancer
causing substances. Soluble fibers can bind bile acids and
increase their excretion
 Insoluble fibers absorb water making a larger, softer stool
which can dilute potential cancer causing substances
 A larger, softer stool moves through intestine faster so
colon exposed to cancer causing substance for less time
 Foods high in fiber are typically lower in fat, which may
also help protect against colon cancer by reducing bile
acid production
Dietary Factors: Protective Factors
 Fruits, vegetables, whole grains and legumes:
 Fruits, vegetables, whole grains and legumes also
contain antioxidant nutrients that may protect
against cancer
 Antioxidants stop free radical oxidation which may help
to prevent cell and tissue damage that can promote
 Possible these nutrients have many other effects in the
body which lower cancer risk
Dietary Factors: Protective Factors
 Fruits, vegetables, whole grains and legumes:
 Fruits, vegetables, whole grains and legumes also
contain phytochemicals that may protect against
 Some function antioxidants, protecting against harmful
cell damage from oxidation
 Others lower cancer risk in different ways such as
activating enzymes that destroy carcinogens
Dietary Factors: Protective Factors
 Fruits, vegetables, whole grains, and legumes
 Because it is not known which specific substances
in fruits, vegetables, whole grains and legumes
help to lower cancer and whether it is the
substances themselves or their presence in food,
the best recommendation is to eat a variety of
these foods.
 Best to get these nutrients from foods not
Dietary Factors: Protective Factors
 Calcium
 Calcium may have a role in lowering colon cancer;
however, more research is needed
 In the meantime, adequate calcium is known to be
important for growth and bone development
Cancer Development
 Evidence suggests millions of cases of cancer
could be prevented by changes in:
 Diet
 Weight control
 Physical activity
 Smoking
Consequences of Cancer
 Nonspecific effects of cancer include:
 Anorexia and reduced food intake
 Metabolic alterations
 Tissue wasting and weight loss
 Anorexia, tissue wasting, weight loss and
fatigue typify cancer cachexia
 Occurs in as many as 80% of people with cancer
Consequences of Cancer
 Anorexia and Reduced Food Intake
 Major contributors to wasting
 With cancer body may not be able to respond to
reduced nutrient intake and nutrient stores are
rapidly depleted
 Without adequate energy and nutrients, the body is
poorly equipped to:
 Maintain immune defenses
 Support organ function
 Absorb nutrients
 Repair damaged tissues
Consequences of Cancer
 Anorexia and Reduced Food Intake
 Factors contributing to anorexia and reduced food
 Chronic nausea and early satiety
 People with cancer frequently experience nausea and a premature
feeling of fullness after eating small amounts of food
 Fatigue
 People with cancer often tire easily and lack the energy to prepare
and eat meals
 If cachexia develops, these tasks become even more difficult to
Consequences of Cancer
 Anorexia and Reduced Food Intake
 Factors contributing to anorexia and reduced food
 Pain
 People in pain may have little interest in eating, particularly if
eating makes pain worse
 Mental stress
 A cancer diagnosis can cause distress, anxiety, and depression, all
of which may reduce appetite
 Facing and undergoing cancer treatments causes additional
psychological stress
Consequences of Cancer
 Anorexia and Reduced Food Intake
 Factors contributing to anorexia and reduced food
intake (cont.):
 Effects of cancer therapies
 Therapies for cancer (including medications, chemotherapy
radiation therapy, surgery, and bone marrow transplants) can
affect food intake by causing nausea, vomiting, altered taste
perceptions, food aversions, inflammation of the mouth and
esophagus, dry mouth, mouth sores, difficulty swallowing,
intestinal cramping, diarrhea, and constipation
Consequences of Cancer
 Anorexia and Reduced Food Intake
 Factors contributing to anorexia and reduced food
intake (cont.):
 Obstructions
 A tumor may partially or completely obstruct a portion of the GI
tract, causing complications such as nausea and vomiting, early
satiety, delayed gastric emptying, and bacterial overgrowth
 Some patients with obstructions are unable to tolerate oral diets
Consequences of Cancer
 Metabolic Alterations
 Metabolic changes can also exacerbate wasting
 Increased protein turnover, but reduced muscle protein
 Increased gluconeogenesis, further straining supply of
body proteins
 Increased triglyceride breakdown, but decreased fat
 Many develop insulin resistance
 Metabolic alterations help explain why people
with cancer fail to regain lean body mass or
maintain healthy body weights even when
receiving adequate energy and nutrients
Consequences of Cancer
 Tissue Wasting
 Weight loss often evident at time cancer diagnosed
 Factors contributing to wasting
 Anorexia and reduced food intake
 Metabolic alterations
 Cytokines released by both tumor and immune cells
induces a hypermetabolic, catabolic state
 Diversion of nutrients to support tumor growth result in
lower energy and nutrients available to healthy tissues
 Severe tissue wasting, often seen in the later stages
of cancer, may be ultimate cause of death
Cancer Treatments
 Primary medical treatments for cancer are:
 Surgery
 Chemotherapy
 Radiation Therapy
 Aim is to remove cancer cells, prevent further
tumor growth, and alleviate symptoms
 Medical treatments can effect nutritional
Cancer Treatments
 Surgery
 Performed to remove tumors
 Can affect nutritional status
 Acute metabolic stress caused by surgery raises protein
and energy needs and can exacerbate wasting
 Surgery may also contribute to pain, fatigue, anorexia
and reduced food intake
 Blood loss further contribute to nutrient losses
Cancer Treatments
 Chemotherapy
 Used to inhibit tumor growth
 Interfere or prevent cell division
 Affect rapidly growing cancer cells
 Unfortunately, most of these drugs can effect
normal cells (especially rapidly dividing cells, such
as those in the GI tract, skin and bone marrow)
and can effect nutritional status due to:
 Anorexia
 Nausea
 Malabsorption
 Diarrhea
Cancer Treatments
 Radiation Therapy
 Bombarding cancer cells with radiation induces
formation of reactive oxygen species, such as
superoxide and hydroxyl radicals, which can
damage cellular DNA and cause cell death
 Radiation can effect normal cells and can effect
nutritional status
 Radiation to head and neck may damage salivary glands
and taste buds, causing dry mouth and altered taste
 Radiation to lower abdomen can cause radiation
enteritis, inflammation of the small intestine, causing
nausea, vomiting, diarrhea, and malabsorption
Cancer Treatments
 Bone Marrow Transplants
 Replace bone marrow destroyed by chemotherapy
or radiation
 Primary treatment for leukemia
 Can substantially effect nutritional status
 After bone marrow is destroyed, immune function is
suppressed, increasing the risk of foodborne illness
 Effects of transplant include anorexia, dry mouth,
inflamed mucous membranes, altered taste, and
 Patients often unable to consume adequate food and
may require nutritional support
Cancer Treatments
 Medications to combat anorexia and wasting
 Medications sometimes prescribed to
stimulate the appetite and promote weight
Cancer Treatments
 Alternative therapies
 60 to 80% of cancer patients combine
complementary and alternative medicine (CAM)
approaches with standard treatment
 Many people do not discuss their use of
complementary and alternative medicine
approaches with their physicians
Cancer Treatments
 Alternative therapies
 Dietary supplements and herbal remedies among
most frequently used CAM
 Many supplements can be used without risk;
however, others may have adverse effects or
interfere with conventional treatments
 St. John’s wort can reduce effectiveness of some
anticancer drugs
 Antioxidant supplementation may interfere with
chemotherapy and radiation treatment
Nutritional Therapy
 Objectives of medical nutrition therapy are to:
 Minimize tissue wasting and weight loss
 Protein and energy needs are considerable to prevent
tissue wasting and weight loss.
 Correct nutritional deficiencies
 Help people maintain their strength and immune
 Provide a diet that can be tolerated and enjoyed
despite the complications of illness
Nutrition Therapy
 Nutrition therapy depends on the type and
severity of cancer, side effects of treatment
and patient’s nutritional status
 In addition, factors may interfere with eating
Nutrition Therapy
 Enteral (tube) and parenteral (intravenous) nutrition
 Tube feedings and intravenous nutrition not routinely
recommended for adequately nourished or mildly
malnourished people with cancer who are able to eat
 However, these approaches help to maintain nutrition
status when anorexia persists or when a patient is severely
malnourished and is about to undergo aggressive cancer
 Each case is decided individually
Nutrition Therapy
 Nutrition support for bone marrow transplants
 People undergoing a bone marrow transplant routinely
receive total parenteral nutrition (TPN) before and after
the transplant because the GI tract is severely
compromised by the preparatory procedure
 When GI function return, the patient begins to receive
foods orally along with TPN, whenever possible
 As oral intake improves, TPN is gradually tapered off