Transcript dietary guidelines for cancer prevention

CANCER PREVENTION
Dr. Gily Ionescu
2004
INTRODUCTION
• Cancer is the second cause of death in the US.
– 1.4 million new cases, >560,000 deaths/year
(>1/minute)
– >$110 billions total costs
– 1 in every 2 men and 1 in every 3 women will
develop some form of cancer during their lifetime
– 10 million cases of cancer worldwide in 1999 (WHO)
• Cancer – name for a group of > 100 diseases
– Abnormal cell multiplication
CAN CANCER BE
PREVENTED?
CAUSES OF CANCER - TEST
2%
2% 1% 1%
3%
3%
3%
30%
5%
5%
?
5%
5%
5%
30%
Radiation & env. pollution
Radiation & food contaminants
Smoking & env. pollution
Smoking & diet
CAUSES OF CANCER
1%1%
2% 2%
3%
Tobacco
3%
Diet/Obesity
3%
30%
5%
Sedentary lifestyle
Occupational factors
Family history of cancer
Viruses
5%
Perinatal factors
Reproductive factors
5%
Alcohol
Social status
5%
Environmental pollution
Ionizing/ultraviolet radiation
Prescription drugs/medical procedures
5%
Salt/other food additives/contaminants
30%
Source: Harvard University, 1999
Tobacco – 30%
• An estimated 30 percent of all US
cancer deaths can be attributed to
tobacco use
• In 1993, EPA designated tobacco smoke
as a Group A carcinogen, for which
there is no known safe level of
exposure
• Passive smoking can cause cancer
Sedentary lifestyle - 5%
• Higher levels of physical activity
– can reduce the incidence of colorectal cancer
– may help reduce cancers of the breast and
prostate.
• Regular physical activity during childhood and
adolescence may prevent excessive weight
gain and delay onset of menstruation
– early age at menarche is a major risk factor for
breast cancer.
Occupational factors – 5%
• Examples:
– 4-Aminobiphenyl, Arsenic, Asbestos, Benzene,
Benzidine, Benzotrichloride, Bis (chloromethyl)
ehter, Cadmium and compounds, Chromium (VI)
compounds, Coal-tars, Erionite, Ethylene oxide,
Mineral oils (untreated and mildly treated), 2Naphthylamine, Nickel compounds (expect Ni
metal), Soots, Sulphur dichlordiethyl, Talc
containing asbestiform fibers, Dioxin, Vinyl
chloride, Wood dust
• Are known to cause cancer in lung, bladder,
and bone marrow
Family history of cancer - 5%
• Increased susceptibility to cancer due to
– genetic mutations running in families
– genetic polymorphisms that affect the absorption,
transport, metabolic activation, or detoxification of
environmental carcinogens
• These processes could play an interactive role in the
majority of cases of cancer
• Preventive measures
– genetic counseling, through which couples may
decide not to have children
– more frequent screening among those at high risk
Viruses & biologic agents - 5%
• Human papilloma viruses (HPV) types 16 & 18
– cancer of the uterine cervix
• Hepatitis B virus (HBV)
– liver carcinoma
• Preventive measures
–
–
–
–
Pap screening programs
anti-HBV vaccine
improved screening of blood and blood products
use of disposable syringes and needles
Perinatal growth factors - 5%
• Excess energy intake early in life
– probably responsible for the positive
association between height and the risk of
breast cancer and possibly other cancers.
• Larger birth weight
– associated positively with breast and
prostate cancer.
Reproductive factors - 3%
• Early age at menarche
• Late age at first birth
• Late age at menopause
– Increased risk of breast cancer
• Parity
– Decreased risk of endometrial and ovarian cancer
• Multiple sexual partners
– Increased risk of cervical cancer
Alcohol - 3%
• Alcohol interacts with tobacco smoking
in the causation of cancers of the upper
respiratory and gastrointestinal tracts.
• Alcohol is implicated in
– cirrhosis-mediated liver cancer
– may cause a proportion of cancer of the
breast and the large bowel
• Safest route = zero intake
Socioeconomic status - 3%
• Poverty is associated with a higher incidence
of of some types of cancer:
– Lung
– Stomach
– uterine cervix
• Poverty is associated with increased
exposure to tobacco smoke, alcoholism, poor
nutrition, and certain infectious agents.
Environmental pollution - 2%
• Investigations have
focused on
– air pollution
– water fluoridation
– chlorinated water
byproducts
– metabolites of
organochlorine pesticides
(e.g., DDT)
– residential proximity to
hazardous waste sites or
contaminated wells
• Few causal links are
firmly established.
Ionizing and UV radiation - 2%
• UV is responsible for over
90% of skin cancers
– prolonged sun exposure
– hx of severe sunburns
• Ionizing radiation
– unquestionably carcinogenic,
but risk is generally
overestimated.
• only 1% of Japanese atomic
bomb survivors died from
radiation-related cancers.
• Other types of radiation
– risk is small for usual
exposure
Prescription drugs & medical
procedures - 1%
• Radiotherapy
• Cancer chemotherapeutic
and immunosuppressive
drugs
– Cancer of bone marrow
• Menopausal estrogens
– Cancer of the endometrium,
possibly breast
• Anabolic steroids
– Liver cancer
• Phenacetin analgesics
– Kidney & pelvis cancers
Salt & other food additives and
contaminants - 1%
• Reduction of salt intake could reduce
stomach cancer risk.
DIET & CANCER
DIET & CANCER
DIET & CANCER
DIET & CANCER
DIET – 30%
• The link between diet and cancer has
been investigated for many years.
– Hundreds of studies published to date
• In 1997, the American Institute for
Cancer Research (AICR) has published
the results of its meta-analysis “Food,
Nutrition and the Prevention of Cancer:
A Global Perspective”
DIET & CANCER - AICR
• AICR’s expert panel
reviewed the
literature on diet
and cancer
– Over 4.500 studies
– Published 14 dietary
recommendations
designed to reduce
the risk of cancer
Eat a plant-based diet
1. Choose
predominantly plantbased diets rich in a
variety of vegetables
and fruits, pulses
(legumes) and
minimally processed
starchy staple foods.
Maintain a healthy weight
2. Avoid being
underweight or
overweight and limit
weight gain during
adulthood to less
than 5 kg (11
pounds).
Exercise
3. If occupational activity is low or
moderate, take an hour's brisk walk
or similar exercise daily, and also
exercise vigorously for a total of at
least one hour in a week.
Vegetables and fruits
4. Eat 400 - 800 grams
(15 - 30 ounces) or
five or more
portions (servings) a
day of a variety of
vegetables and
fruits, all year
round.
Other plant foods
5. Eat 600 - 800
grams (20 - 30
ounces) or more
than seven portions
(servings) a day of
a variety of cereals
(grains), pulses
(legumes), roots,
tubers and
plantains. Prefer
minimally
processed foods.
Limit consumption
of refined sugar.
Alcohol
6. Alcohol
consumption is
not
recommended.
Meat
7. If eaten at all, limit
intake of red meat to
less than 80 grams (3
ounces) daily. It is
preferable to choose
fish, poultry or meat
from non-domesticated
animals in place of red
meat.
Total fats and oils
8. Limit consumption of
fatty foods, particularly
those of animal origin.
Choose modest
amounts of
appropriate vegetable
oils.
Salt and salting
9. Limit consumption of
salted foods and use of
cooking and table salt.
Use herbs and spices
to season foods.
Food Storage
10. Do not eat food
which, as a result of
prolonged storage at
ambient
temperatures, is liable
to contamination with
mycotoxins.
Preservation
11. Use refrigeration
and other appropriate
methods to preserve
perishable food as
purchased and at
home.
Additives and residues
12. When levels of additives,
contaminants and other
residues are properly
regulated, their presence in
food and drink is not known to
be harmful. However,
unregulated or improper use
can be a health hazard, and
this applies particularly in
economically developing
countries.
Preparation
13. Do not eat charred
food. For meat and fish
eaters, avoid burning of
meat juices. Consume
the following only
occasionally: meat and
fish grilled (broiled) in
direct flame; cured and
smoked meats.
Dietary supplements
14. For those who follow
the recommendations
presented here, dietary
supplements are
probably unnecessary,
and possibly unhelpful,
for reducing cancer risk.
Good News!
• Healthy diet + physical activity + weight
control = risk of cancer lowered by 30% 40%.
• Healthy diet + smoking cessation = risk of
cancer lowered by 60% - 70%.
• 375.000 cancer cases could be prevented
each year in the US by diet alone!
• One study showed a 15% decrease in overall
cancer risk with each additional serving of
fruits and vegetables.
Cancer – a preventable disease!
• 60% - 70% of cancers are related to
lifestyle factors:
• smoking, diet, lack of exercise, overweight,
alcohol, etc.