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Diet and Health
Introduction
• Infectious diseases
– Diseases that are caused by bacteria, viruses, parasites, and other
microbes
– Can be transmitted from one person to another through air, water, or
food; by contact; or through vector organisms such as mosquitoes and
fleas
• Degenerative diseases
– Chronic, irreversible diseases characterised by degeneration of body
organs
– Due in part to such personal lifestyle elements as poor food choices,
smoking, alcohol use, and lack of physical activity
– Also called lifestyle diseases, chronic diseases, or the diseases of
age
• Infectious diseases have been major killers of humankind since before
the dawn of history
– In any society not well defended against them, infectious diseases
can cut life shirt so that the average person dies at 20, 30, or 40
years of age
• With the advent of vaccines and antibiotics people in developed
countries had become complacent about infectious diseases until
recently
• Bioterrorism
– The intentional spreading of disease causing organisms or
agricultural pests as a political weapon to produce fear and intimidate
others
• Emergence and global spread of new diseases
• The rising death toll from once conquered diseases
• Scientists are working to develop new controls for these perils
• Government and health agencies are hastening to strengthen existing
mechanisms for emergency preparedness and to protect our food and water
supplies
• Individuals can take steps to protect themselves
– Although nutrition cannot directly prevent or cure infectious
diseases, it can strengthen or weaken your body's defenses against them
• "immune strengthening" foods, dietary supplements, and herbs
are hoaxes
• The best help you can provide your immune system is to nourish
it properly to ensure that it works to its capacity every day
• In developed nations, degenerative diseases far outrank infections as
the leading cause of death and illness
– The longer a person lives, the more likely that these diseases will
take their toll
• Degenerative diseases do not arise from a straightforward cause such
as infection
– But from a mixture of three factors
• Genetic predisposition
• Personal medical history
• Lifestyle choices
– As people age, their bodies accumulate the effects of these choices
• In the later years these impacts can make the difference
between a life of health or one of chronic disability
Nutrition and Immunity
• Deficient intakes of many vitamins and minerals are associated with
impaired disease resistance
– As are some excessive intakes
• Immune tissues are among the first to be impaired in the course of a
nutrient deficiency or toxicity
• Some deficiencies are more immediately harmful than others
– The speed of the impact is affected by
• Whether another nutrient can perform some of the metabolic
tasks of the missing nutrient
• How severe the deficiency is
• Whether an infection has already taken hold
• The person's age
• Rates of sickness and death increase dramatically when medical tests
of a malnourished person indicate weakened immunity
• Once a person becomes malnourished, malnutrition often worsens
disease, which, in turn, worsens malnutrition
• The cycle often begins when impaired immunity opens the way for
disease
– The disease impairs food assimilation, and nutrition status suffers
further
– Drugs become necessary, and many of them impair nutrition status
– Treatments, such as surgery, take a further toll
• Certain groups of people are more likely than other to be caught in
the downward spiral of malnutrition and weakened immunity
– Among them are people who
• Restrict food intake
• Are very young or very old
• Are poor
• Are hospitalised
• Are malnourished
• In protein energy malnutrition (PEM)
– Indispensable tissues and cells of the immune system dwindle in size
and number
• Making the whole body vulnerable to infection
• Malnutrition can result not only from a lack of available food but
also from diseases, such as AIDS and cancer, and their treatments
• These alter the appetite and metabolism
– Causing a wasting of the body's tissues similar to that seen in the
last stages of starvation
– The body uses its fat and protein reserves for survival
• AIDS
– Wasting or nutrient deficiencies can shorten survival
• Making medical therapy a critical need
– Nutrients cannot cure AIDS
• Adequate diet may improve responses to drugs, shorten hospital
stays, promote independence, and improve the quality of life
– Exercise that strengthens muscles may hold wasting to a minimum
– Food safety is paramount
• Common food bacteria and viruses can easily overwhelm a
compromised immune system
• A deficiency or toxicity of just a single nutrient can seriously
weaken even a healthy person's immune system
– For example, in vitamin A deficiency, the body's skin and membranous
linings become unhealthy and unable to ward off infectious organisms
Lifestyle Choices and Risks of Degenerative Disease
• Degenerative diseases of adulthood have suspected contributors known
as risk factors
– Factors known to be related to (or correlated with) diseases but not
known to be causal
Environmental factors
Behavioral factors
Social factors
Genetic factors
• The exact contribution diet makes to each disease is hard to estimate
– Many experts believe that diet accounts for about a third of all
cases of coronary heart disease
– The links between diet and cancer incidence are harder to pin down
•Cancer's different forms associate with different dietary
actors
• Some choices, such as avoiding tobacco, are important to almost
everyone's health
• Other choices, such as those relating to diet, are more important for
people who are genetically predisposed to certain diseases
– Search your family's medical history for diseases common to your
forebears
Cardiovascular Diseases
• Atherosclerosis
– The most common form of cardiovascular disease
– Characterised by plaques along the inner walls of the arteries
• Arteriosclerosis
– All forms of hardening of the arteries
– Includes some rare diseases
• No one is free of atherosclerosis
– The question is how far advanced it is and what you can do to retard
or reverse it
– Usually begins with the accumulation of soft, fatty streaks along the
inner walls of arteries, especially at branch points
– These gradually enlarge and become hardened fibrous plaques
•Mounds of lipid material mixed with smooth muscle and calcium
that develop in the artery walls in atherosclerosis
• Plaques damage artery walls
– Making them inelastic
– Narrowing the passage through them
– Most people have well developed plaques by the time they reach age 30
• A diet high in saturated fat is a major contributor to the
development of plaques and the progression of atherosclerosis
– Atherosclerosis is a complex inflammatory response to tissue damage
• Protein markers of inflammation and other compounds in the
blood may one day help detect heart disease before a life
threatening event occurs
• Atherosclerosis
– Damage may begin from a number of factors interacting with the cells
that line the arteries
• High LDL cholesterol
• Hypertension
• Toxins from cigarette smoking
• Elevated blood levels of the amino acid homocysteine
• Or some viral and bacterial infections
– Such damage produces an inflammatory response
• The immune system sends white blood cells to the site to try to
repair the damage
• Particles of LDL cholesterol become trapped in the blood vessel
walls and become oxidised by free radicals produced during the
inflammatory response
• White blood cells macrophages flood the scene to remove the
oxidised LDL, but to no avail
– As the macrophages become engorged with oxidised LDL, the become
known as foam cells
• Which themselves become sources of oxidation that attract more
immune scavengers to the scene
• Muscles of the arterial wall proliferate in an attempt to heal
the oxidative damage, but they mix with the foam cells to form
hardened areas of plaque
– Mineralisation increases the hardening
• Normally, the arteries expand with each heartbeat to accommodate the
pulses of blood that flow through them
– Arteries hardened and narrowed by plaques cannot expand
– So blood pressure rises
– The increased pressure damages the artery walls further and strains
the heart
• Because plaques are more likely to form at damaged sites, the
development of atherosclerosis becomes a self accelerating
process
• As pressure builds up in an artery, the arterial wall may become
weakened and balloon out, forming an aneurysm
– An aneurysm can burst
• In a major artery, such as the aorta, the leads to massive
bleeding and death
• Abnormal blood clotting can threaten life
– Arterial damage, plaques in the arteries, and the inflammatory
response favor the formation of blood clots
• Platelets normally cause clots to form when they encounter
injuries in blood vessels
• In atherosclerosis, when platelets encounter hardened plaques,
they respond to them as to an injury clotting blood
• A clot may remain attached to a plaque in an artery and grow until it
shuts off the blood supply to the surrounding tissue
– That tissue may die slowly and be replaced by nonfunctional scar
tissue
– The stationary clot is called a thrombus
• When it has grown large enough to close off a blood vessel, it
is a thrombosis
• A clot can break loose becoming an embolus
– Which travels along the system until it reaches an artery too small
to allow for its passage
– There the clot becomes stuck and is referred to as an embolism
• The tissues fed by this artery will be robbed of oxygen and
nutrients and will die suddenly
• Such a clot can lodge in an artery of the heart, causing a
heart attack, or lodge in an artery of the brain, causing a
stroke
• Opposing the clot forming actions of platelets are active products of
omega3 fatty acids
– A diet lacking in seafoods that contain these essential fatty acids
may contribute to clot formation
• On many occasions, heart attacks and stroke occur with no apparent
blockage
– An artery may go into spasm
• Restricting or cutting off the supply of blood to a portion of
the heart muscle or brain
• Hypertension and atherosclerosis worsen CVD
– And each worsens the other
– Hypertension worsens atherosclerosis because a stiffened artery,
already strained by each pulse of blood surging through it, is stressed
further by high internal pressure
• Injuries multiply, more plaques grow, and more weakened vessels
become likely to burst and bleed
– Since hardened arteries cannot expand, the heart's beat raises blood
pressure
– Hardened arteries also fail to let blood flow freely through the
kidneys, which control blood pressure
• The kidneys sense the reduced flow of blood and respond as if
the blood pressure were too low
Risk Factors for CVD
• Many of the major risk factors for heart disease are the same factors
that predict the occurrence of stroke
– All people reaching middle age exhibit at least one of these factors
• And many people have several factors
– Diet is not the only, and perhaps not the most important, factor in
the development of heart disease or stroke
• Age, Gender, and Family History
– The increasing risk associated with growing older reflects the steady
progression of atherosclerosis in most people as they age
• Men: age becomes a significant risk factor for heart disease at
age 45 or older
• Women: age becomes a significant risk factor after age 55
– Up to age 45 a woman's risk is lower than a males
– After menopause, the rate of heart disease increases 2x3x over
pre-menopause rates
– Men die earlier of heart attacks than women
– CVD kills more women than any other disease
• Family history
– Early heart disease in immediate family members is a major risk
factor
• The more family members affected and the earlier the age at
which they become ill, the greater the risk to the individual
• High LDL and Low HDL Cholesterol
– LDL cholesterol in the blood is strongly linked to a person's risk of
developing
atherosclerosis and heart disease
• The higher the LDL, the greater the risk
• High LDL and Low HDL Cholesterol
– LDL carry cholesterol to the cells
• Including the cells that line the arteries
– Where it can build up as part of the plaques of atherosclerosis
– In clinical trials, lowering LDL greatly reduces the incidence of
heart disease
• Stroke is less consistently associated with elevated LDL
cholesterol
– HDL carry cholesterol away from the cells to the liver for other uses
and disposal
• Elevated HDL indicated a reduced risk of atherosclerosis and
heart attack
• With growing evidence that it may prevent stroke as well
– High LDL and low HDL correlate directly with heart disease
– Low LDL and high HDL correlate inversely with risk
• How elevated LDL increases the risk of heart disease remains unclear
– One mechanism may be through reducing plaque stability
• As LDL is incorporated into plaques, the plaques weaken and
become unstable
• When this happens, they can rupture, causing heart attack
• In advanced atherosclerosis, a goal of treatment is to lower LDL
cholesterol to stabilise existing plaques while slowing the development
of new ones
• Hypertension
– Chronic hypertension worsens CVD
• The higher the blood pressure above normal, the greater the
risk of heart attack or stroke
• The relationship between hypertension and disease holds for
– Men and women
– Young and old
• Hypertension injures the artery walls and accelerates plaque
information
– Initiating or worsening the progression of atherosclerosis
• Diabetes
– A major independent risk factor for all forms of cardiovascular
disease
– In diabetes, atherosclerosis progresses rapidly
• Blocking blood vessels and diminishing circulation
– For many people with diabetes, the risk of a future heart attack is
roughly equal to that of a person with a confirmed diagnosis of heart
disease
• 2x-4x as high as that of a person without diabetes
– When heart disease occurs in conjunction with diabetes, the condition
is likely to be severe
– Diabetes, left uncontrolled, holds a grave threat of all forms of CVD
– Even insulin resistance without diabetes may elevate risk
• A symptomless type of insulin resistance may greatly increase
the likelihood of a heart attack
– Without abnormal blood glucose or lipid values
• Obesity and Physical Inactivity
– Obesity, especially central obesity, and physical inactivity amplify
a person's risk of CVD
• Elevates LDL cholesterol
• Lowers HDL cholesterol
• Worsens hypertension
• Worsens diabetes
• Weight loss and physical activity
– Lower LDL
– Raise HDL
– Improve insulin sensitivity
– Lower blood pressure
• Routine physical activity
– Strengthens muscles
• Including muscles of the heart and arteries
– Improves the heart's response to everyday demands
– Expands the volume of blood the heart can pump to the tissues with
each beat
• Reducing the heart's workload
– Stimulates the development of new arteries to nourish heart muscle
– Favors lean over fat tissue
– If pursued daily, even 30 minutes of light, balanced exercise,
performed at intervals throughout the day, can improve the odds against
heart disease
• An hour a day, as recommended by the DRI, benefits the heart
even more
• Think Fitness: Ways to Include Physical Activity in a Day
– Coach a sport
– Garden
– Hike, bike, or walk to nearby stores or to classes
– Mow, trim, and rake by hand
– Park a block from your destination and walk
– Etc.
• Smoking
– Cigarette smoking is a powerful risk factor for heart disease and
other forms of CVD
• The more a person smokes, the higher the CVD risk
– Smoking damages the heart directly with toxins and burdens it by
raising the blood pressure
• Body tissues starved of oxygen by smoke demand more heartbeats to
deliver blood
– Increasing the heart's workload
• Deprives the heart muscle of the oxygen it needs to maintain a steady
beat
• Damages platelets
– Making blood clots likely
• Toxins in cigarette smoke directly damage the lining of blood vessels
– Making atherosclerosis likely
• When people quit smoking
– Risk of heart disease begins to drop within a few months
• A year later their risk has dropped by half
• After 15 years of staying smoke free, their risks equal those
of lifetime nonsmokers
• Atherogenic Diet
– Diet high in saturated fats, trans fats, and cholesterol
– Increases LDL cholesterol
• A well chosen diet often lowers the risk of CVD
– Does so to a greater degree than might be expected from its effects
on blood lipids alone
– Factors that might take credit
• Vitamins
• Minerals
• Antioxidant phytochemicals
• Omega3 fatty acids
• Metabolic Syndrome
– Primary features relate to CVD risk factors
• Central obesity
• Abnormal blood lipids
– Low HDL
– High triglycerides
• Elevated blood pressure
• Elevated fasting blood glucose or insulin resistance
– ˜47 million people in the U.S.
• Other Risk Factors
– Emerging risk factors
• Links among B vitamins, homocysteine, and atherosclerosis
Diet to Reduce CVD Risk
• Diet's effects are felt in two opposing ways
– A diet high in saturated fat and trans fatty acids contributes to
high blood LDL cholesterol
– Reducing those fats in the diet lowers blood LDL cholesterol and may
reduce the rate of CVD
• Wherever in the world diets ...
– Are high in saturated fats and low in fish, fruits, and vegetables
• blood cholesterol is high, and heart disease takes a great toll
on health and life
– Dietary fat consists mostly of unsaturated fats with abundant fish,
fruits, and vegetables
• Blood cholesterol and the rate of death from heart disease is
low
• Controlling Dietary Lipids
– Lowering intakes of saturated fat and trans fat lowers blood LDL
cholesterol and reduces heart disease risk
– For healthy people living in the U.S. and Canada
• Saturated fat, including trans fatty acids, should account for
no more than 10% of calories
• DRI recommendations: the diet should contain no more that 35%
of total calories from fat
• Other authorities recommend: no more than 30% of total calories
from fat
• Healthy people should limit cholesterol intake to 300 mg a day
– Although cholesterol plays a lesser role than saturated fat and trans
fatty acids, it still elevates blood cholesterol
• People with heart disease often consume diets rich in all three
• Strictly limiting all kinds of dietary fats is probably not necessary
to maintain the health of the heart
– As long as the diet is low in saturated fat and trans fat
– Energy intake is controlled
– The diet is ample in fish, fruit, vegetables, and milk products
• It matters what people choose to eat instead of saturated fats
– Simple carbohydrates seem to elevate blood triglycerides and reduce
HDL cholesterol
– Rather than adding sugars to replace saturated fats, choose
unsaturated fats or complex carbohydrates from whole grains or
vegetables
• Fish oils
– Rich in omega3 polyunsaturated fatty acids
– Lower triglycerides
– Prevent blood clots
– May reduce the sudden death associated with CVD
• The American Heart Association recommends at least 2 servings of fish
per week
• Plant sources of essential fatty acids also confer benefits on the
heart
– Flaxseed and flaxseed oil
– Canola oil
– Soybean oil
– Nuts
• Use of fish oil supplements carries its own risks
• Effects of fibre, Nutrients, and Phytochemicals
– The viscous (soluble) fibre of oats, barley, legumes, and pectin rich
fruits and vegetables helps to improve blood lipids
• These fibres bind cholesterol and bile in the intestine,
reducing their absorption
• An extra 5 10 grams of viscous fibre daily lowers LDL
cholesterol levels by about 5%
• Viscous fibre
– A high fibre diet may reduce a blood marker of inflammation thought
to indicate an elevated risk of having a heart attack
– Foods rich in viscous fibre provide
• Minerals to help control blood pressure
• Antioxidants to help protect against LDL oxidation
• And an array of vitamins and minerals
• Diets rich in legumes, fruits, vegetables, and whole grains
– Abundant in fibres, nutrients, and phytochemicals
– Correlate with low CVD rates
– Benefits are observed consistently only when whole foods supply the
needed compounds
• Alcohol
– Research on middle aged and older people who drink one or two drinks
a day with no binge drinking supports the idea that moderate
consumption of alcohol will reduce their CVD risk
• For this group, moderate alcohol consumption has been reported
to raise HDL cholesterol levels or reduce the risk of blood clots
– Thereby reducing the risk of heart attack
– The effect is small and cannot reverse the effects of other
risk factors
• Heavy alcohol use, more than three drinks a day:
– Elevates blood pressure
– Damages heart muscle
– Elevates the risk of stroke
– Etc.
• Heart attacks among apparently healthy young people have been
associated with alcohol intoxication from heavy weekend drinking
• For young people, the risks from alcohol greatly outweigh any benefit
to the heart
• Other Dietary Factors
– Sterol and stanol esters
• Block absorption of cholesterol from the intestine
– Dropping blood cholesterol by about 7%10%
– The effect may be as powerful as some medication in lowering
blood LDL cholesterol
• Some foods naturally contain compounds related to sterol or
stanol esters
– The amount present in a typical portion is too small to affect
the health of arteries
– Sterol and stanol esters reduce the absorption of some potentially
beneficial phytochemicals
• Use may be best reserved for those who fail to lower their
elevated cholesterol by other means
• More Strategies against CVD
– Pharmaceutical doses of a specific form of niacin act like a drug in
lowering blood cholesterol and prolonging life
• Other drugs effective for this purpose probably have fewer side
effects
– The "statin" drugs lower blood LDL
– Work best in association with a cholesterol lowering diet and
exercise
• Ordinary niacin supplements are useless in lowering blood
cholesterol
• Low carbohydrate diets, with high intakes of meats and saturated
fats:
– Reduce blood triglycerides and reduce HDL
• This profile is not known to benefit the heart
– When the diets are low enough in calories to produce weight loss,
blood cholesterol diminishes along with body fatness
• This occurs with weight loss achieved on any kind of diet
• Standard cholesterol lowering diets that are low in saturated fats :
– Improve or maintain beneficial HDL
– Lower LDL cholesterol
– May produce beneficial weight loss if calories are kept low
• Diet and exercise from a powerful and safe combination for improving
health
• Needed weight loss often reduces blood pressure
• So does eating a diet
– Low in fat
– Restricted in cholesterol
– High in complex carbohydrates, whole grains, fruits, and vegetables
– normalises blood glucose
• More Strategies against CVD
– Don't smoke
– Relax
Nutrition and Hypertension
• People with healthy low blood pressure generally
– Enjoy a long life
– Suffer less often from heart disease
• Chronic high blood pressure (hypertension) remains one of the most
prevalent forms of CVD
– Affecting almost one third of the entire U.S. adult population
• For people age 65 or older, the lifetime risk of developing it
approaches 90%
– Contributes to half a million strokes and over a million heart
attacks each year
– Especially threatening when paired with atherosclerosis
• Blood pressure
– High blood pressure presents no symptoms you can feel
– Systolic pressure
• The first figure in a blood pressure reading
• Reflects arterial pressure caused by contraction of the heart's
left ventricle
– Diastolic pressure
• The second figure in a blood pressure reading
• Reflects the arterial pressure when the heart is between beats
• Ideal resting blood pressure is 120/80
– A reading of 130/85 can be considered borderline normal
• Especially in the absence of other risk factors
– Above this level the risks of heart attacks and strokes rise in
direct proportion to increasing blood pressure
How Does Blood Pressure Work in the Body ...
• The Role of Kidneys
– For the kidneys to filter waste materials out of the blood and into
the urine, blood pressure must be high enough to force the blood's
fluid out of the capillaries into the kidneys' filtering networks
– If the blood pressure is too low, the kidneys act to increase it
• They send hormones to constrict blood vessels and to retain
water and salt in the body
– Dehydration sets these actions in motion
– By obstructing blood vessels, atherosclerosis fools the kidneys,
which react as if there were a water deficiency
– The kidneys raise the blood pressure high enough to get the blood
they need
• In the process they make the pressure too high for the arteries
and heart to withstand
– Hypertension aggravates atherosclerosis by mechanically injuring the
artery linings
– Increasing the likelihood that plaques will form
• Plaques restrict blood flow to the kidneys
• Which may then raise blood pressure still further
• The Role of Risk Factors
– Primary among the risk factors that precipitate or aggravate
hypertension are atherosclerosis, obesity, and insulin resistance
• Excess fat means miles of extra capillaries through which blood
must be pumped
• Other risk factors that predict hypertension
– Age
• Most people who develop hypertension do so in their 50s and 60s
– Genetics
• A family history of hypertension and heart disease raises the
risk of developing hypertension 2x-5x
• African Americans are likely to develop more severe
hypertension earlier in life than people of European or Asian
descent
• Related to insulin resistance
– Probably through a common genetic link
– Measures to prevent diabetes may also protect against hypertension
• Environmental factors
– Africans living in Africa have a much lower rate of hypertension than
African Americans living in the U.S.
How Does Nutrition Affect Hypertension?
• Even mild hypertension can be dangerous
– Individuals who adhere to treatment are less likely to suffer illness
or early death
– Some people need medications to bring their blood pressure down
• Diet and exercise can bring improvements for many
• And prevent hypertension for many others
• Nutrition factors for lowering blood pressure
– Lowering salt intake
– If overweight, lose weight
– Using moderation with regard to alcohol
– Increasing intakes of fruit, vegetables, fish, and low fat dairy
products
– Reducing intakes of fat
– Calcium, potassium, magnesium, and other nutrients seem to play roles
• As does physical activity
• Blanket recommendation for prevention of hypertension
– Control weight
– Consume a nutritious diet
– Exercise regularly
– Control alcohol intake
– Hold sodium intake to prescribed levels
• DASH (Dietary Approaches to Stop Hypertension)
– Recommends significant increases in fruit and vegetable intakes
– Provides 30% of its calories from fat
– emphasises legumes over red meats
– Restricts sodium
– Meets other recommendations of the Dietary Guidelines for Americans
• The DASH diet and other similar diets consistently improve blood
pressure in both
– study subjects whose diets are provided by researchers
– and those freely choosing and preparing their own foods in accordance
with instructions
• Weight Control and Physical Activity
– For people who are overweight and hypertensive, a weight loss of as
little as 10 pounds can significantly lower blood pressure
– Those who are taking medication to control their blood pressure can
often cut down on their doses if they lose weight
• Moderate physical activity
– Helps in weight loss
– Helps reduce hypertension
– Changes the hormonal climate in which the body does its work
• By reducing stress, physical activity reduces the secretion of
stress hormones
• This lowers blood pressure
– The right kind of regular physical activity can lower blood pressure
in almost everyone
• Even those without hypertension
• The "right kind" pf activity can be walking, jogging, cycling
or other exercises that increase blood HDL and lower LDL
• The exercise need not be strenuous and may be broken up into
manageable segments throughout the day
– Redistributes body water
– Eases transit of blood through the peripheral arteries
• Salt, Sodium, and Blood Pressure
– A high dietary intake of salt and sodium is associated with
hypertension
– The benefit of reducing salt intake in the treatment of hypertension
is unquestionable
• For people with hypertension, a lower salt (or sodium) intake
often leads to a reduction in blood pressure, even to the degree
that they can stop taking blood pressure reducing medication
• Such salt sensitive people often: have a family history of
hypertension, are African American, have kidney problems or
diabetes, are older, have experienced sustained psychological
stress
• Reducing sodium and salt may also prevent hypertension in healthy
people
– People who consistently consume diets low in sodium have lower blood
pressure than people with higher intakes
– Recommendation: everyone should moderately restrict salt and sodium
intake to a level not exceeding the DRI committee's UL
• No more than 2,300 mg of sodium per day
• Alcohol
– In moderate doses, alcohol initially relaxes the peripheral arteries
and so reduces blood pressure
• High doses raise blood pressure
– Hypertension is common among people with alcoholism
• Is apparently caused directly by the alcohol
• Hypertension caused by alcohol leads to CVD
– The same as hypertension caused by any other factor
• Alcohol may cause strokes
– Even without hypertension
• The Dietary Guidelines for Americans urge moderation for those who
drink alcohol
– Moderation means no more than one drink a day for women
– No more that two drinks a day for men
• Calcium, Potassium, Magnesium, and Vitamin C
– Increasing calcium often reduces blood pressure in both healthy
people and those with hypertension
– Adequate potassium and magnesium also appear to help prevent and
treat hypertension in certain populations
– Diets low in potassium are often associated with hypertension
– High potassium diets appear to both prevent and correct hypertension
– Magnesium deficiency causes the walls of arteries and capillaries to
constrict and so may raise blood pressure
– Consuming a diet adequate in vitamin C seems to help normalise blood
pressure
• While vitamin C deficiency may tend to raise it
– Other dietary factors may also affect blood pressure
• The roles of cadmium, selenium, lead, caffeine, protein, and
fat are being studied
• Vitamin supplements have not shown promise for lowering blood
pressure in the long term
• To get all of the nutrients needed to keep blood pressure low
– Consume a low fat diet with abundant fruits, vegetables, and low fat
dairy products that provide the needed nutrients while holding sodium
intake in bounds
– DASH diet
• Reduces blood pressure
• May lower blood cholesterol
• Should diet and exercise fail to reduce blood pressure, drugs such as
diuretics and other anti hypertensive agents may be prescribed
– Some work by increasing fluid loss in the urine
• So they may cause potassium loss
• People taking these drugs should make it a point to consume
potassium rich foods daily
Nutrition and Cancer
• Cancer ranks second only to heart disease as a leading cause of death
and disability in the U.S.
– Recent advances in early detection and treatment have transformed
many potentially deadly cancers into curable diseases or treatable
chronic illnesses
• Inherited tendencies exert on a modest effect on most people's risk
of cancer development
– Very few rare cancers are known to be caused by genetic inheritance
alone
• Will appear in members of an affected family regardless of
lifestyle choices
– A few more cancers are linked with viral infections
• Most often lifestyle and environmental factors come into play in the
development of cancer
– If everyone in the U.S. quit smoking and stayed quit, future total
cancers would probably drop by a third
– Another 15% may be preventable by preventing overweight and obesity
• Lack of physical activity almost certainly plays a role in the
development of colon and breast cancer
– And probably contributes to others
• 20%-50% of total cancers are influenced by diet
– Dietary fat, alcohol, excess calories, and low intakes of fruits and
vegetables have been the targets of much research with regard to the
occurrence of cancer
• Foods or their components cause cancer
• Foods or their components may promote cancer
• Foods or their components may protect against cancer
• For a person who has had cancer, diet can make a crucial difference
in recovery
Consumer Corner: Alternative Therapies and Herbal Medicine
Alternative Therapies and Herbal Medicine
• Complementary medicine
– Often combines some human elements of alternative therapies that fill
emotional needs along with the best of proven scientific medicine
• Alternative therapies have often been used for centuries
– But have not been scientifically evaluated for safety or
effectiveness
• Testimonials for mysterious "cures" abound
– The listener may think that unless the speaker is lying, the
therapies really do cure diseases
• Remember that an ill person's belief in a treatment, even a
placebo, often leads to physical healing
• Not all alternative therapies are shams
– Nevertheless, the common belief that many of today's alternative
therapies will become tomorrow's mainstream medicine is unfounded
• To tease apart potentially useful and safe alternative therapies from
the worthless or harmful, the National Institutes of health established
is National Center for Complementary and Alternative Medicine (NCCAM)
• NCCAM
– Has found acupuncture useful for quelling nausea from surgery, cancer
chemotherapy, and pregnancy, and for relieving pain during dental
procedures
• Other potential uses include treating chronic headaches and
migraines
• Dozens of herbal medicines contain natural drugs
– For example
• The resin called myrrh contains an analgesic compound
• Willow bark contains aspirin
• Valerian contains a tranquillising oil
• Senno leaves produce a powerful laxative
• The WHO recommends an herbal Chinese drug to developing nations
of the tropics as an effective tool for combating malaria
• Herbal medicines have several serious drawbacks
– When analysed a majority of herbal pills and supplements do not
contain the species or active ingredients stated on the labels
– Contamination can also be a problem
– Interactions of herbs with medications are also common
• Many people undergoing cancer treatment ask about the macrobiotic
diet
– Restrictive low fat diet of grains, soy beans, and certain vegetables
– Promoted for curing diseases
• Has not been proved scientifically to be beneficial
• Research weighs against its use
– This bulky, low calorie diet fails to provide the energy needed
to battle cancer
• To self diagnose illness, and then choose herbs for treatment, is to
invite problems
– Most herbalists selling the pills base herbal therapy on hearsay and
folklore
– By delaying effective medical help, this choice may allow serious
conditions to worsen
– Perilous mistakes with herbs are likely
How Does Cancer Develop?
• Cancer is really a disease of the genes
– Cancer begins with one healthy cell whose genetic material sustains
damage from a carcinogen such as a free radical compound, radiation or
other influences
• Carcinogen
– A cancer causing substance
• Damage to a cell's DNA occurs every day
– But most of the damage is quickly repaired
– Sometimes DNA collects bits of damage here and there over time
• Usually, if the damage cannot be repaired and the cell becomes
unable to faithfully replicate its genome, the cell self
destructs
• Occasionally, a damaged cell loses its ability to self destruct and
also loses the ability to stop reproducing
– The result is a tumour
• Life threatening cancer results when the tumour tissue
overtakes the healthy organ in which it developed and
disseminates its cells through the bloodstream to other parts of
the body
• Cancer develops through the following steps
1) Exposure to a carcinogen
2) Entry of the carcinogen into a cell
3) Initiation of a cancer as the carcinogen damages or changes the
cell's genetic material (Carcinogenesis)
4) Acceleration by other carcinogens, called promoters, so that the
cell begins to
multiply out of control tumour formation
5) Often, spreading of cancer cells via blood and lymph (metastasis)
6) Disruption of normal body functions
• Researchers think that the first four steps are key to cancer
prevention
– Many people think they should stop eating foods containing
carcinogens
• Doing so would be impossible because most carcinogens occur
naturally among thousands of other chemicals and nutrients the
body needs
• The body is equipped to deal with the minute amounts of
carcinogens occurring naturally in foods
• For those who suspect food additives of being carcinogenic
– Additives are held to strict standards
– No additive scientifically shown to cause cancer is approved for use
in the U.S.
• Contaminants that enter foods by accident or toxins that arise
naturally may be powerful carcinogens
– Or they may be converted to carcinogens during the body's attempt to
metabolise them
• Most such constituents are monitored in the U.S. food supply
and are generally present, if at all, in amounts well below those
that may pose significant cancer risks to consumers
Which Dietary Factors Most Influence A Person's Risk of Developing
Cancer?
• Low rates of many, but not all, kinds of cancers correlate with
intakes of fibre rich fruit, vegetables, and whole grains
– Particularly whole wheat
• Under study for possible effects regarding cancer are
– Excess calories
– Diets high in certain fats
– Daily use of alcohol
– Vitamins and minerals in foods
– Diets in which meat plays a dominant role
• Energy Balance
– Restricting energy intake inhibits cancer formation
• In animal experiments, this caloric effect proves to be one of
the most effective dietary interventions for cancer prevention
• At the moment, no experimental evidence exists showing this
effect in human subjects
• Some population observations seem to imply that the effect seen
may hold true for humans as well
– However, once started, cancer continues advancing even in a
person who is starving
• When calorie intake rises, cancer rates rise
– Excess calories from carbohydrate, fat, and protein all raise cancer
rates
– Obesity itself is a risk factor for certain types of cancer
• The risk of cancer rises with BMI
• In one study, cancer deaths among people with a BMI of 40 or
above were more than 50% higher than among people with a BMI in
the normal range
• Physical activity to balance energy intake may lower the risk of
developing some cancers
– 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
• Fat and Fatty Acids
– Laboratory studies using animals support the idea that high dietary
fat intake correlates with the development of cancer
• Feeding fat to experimental animals is not enough to get
tumours started
• An experimenter must also expose the animal to a known
carcinogen
• After that exposure, animals fed the high fat diet develop
cancers faster than animals fed low fat diets
• In studies of human beings evidence is mixed as to whether a diet
high in fat promotes cancer
– Comparisons among world populations reveal that high fat diets often
correlate with high cancer rates
• Saturated fat from red meats and high fat dairy foods are
implicated as a risk factor for breast cancer
• Studying the effects of high fat intakes in complicated
– Because fat is extremely calorie dense
– Researchers must untangle the effects of fat alone from those of the
energy content of the diet
• Dietary fat tends to oxidise when exposed to high cooking
temperatures
– When these oxidised fat compounds enter the body, they may set up a
condition of oxidative stress that may trigger cancerous changes in the
tissues of the colon and rectum
• The type of fat in the diet may be important
– Some evidence implicates omega6 polyunsaturated fatty acids in cancer
promotion
– Some evidence suggests that omega3 fatty acids from fish may protect
against some cancers and may support recovery during treatment for
cancer
• Moderation in fat intake and inclusion of several fish meals a week
remain sound principles
– If not for cancer protection, then for the prevention of obesity and
the protection of the heart
• Alcohol
– Cancers of the head and neck correlate strongly with the combination
of alcohol and tobacco use
• And with low intakes of green and yellow fruits and vegetables
– Alcohol intake alone is associated with cancers of the mouth, throat,
and breast
– Alcoholism often damages the liver and precedes the development of
liver cancer
• Smoked, Grilled, and well done Meats
– Evidence from population studies spanning the globe over a period of
more than 20 years links diets high in meat, usually red meat, with a
moderately elevated risk of developing cancer of the rectum and colon
• In particular, meats cooked to the crispy well done stage may
be at fault
– Especially in genetically susceptible male smokers
• Chemical reactions during the browning of meat at high temperatures,
which occurs in pan frying, broiling, or grilling, form known
carcinogens in the food
– Meat drippings that drip and burn on hot coals also generate
carcinogens that rise in smoke and stick to the food
• Eating smoked, grilled, charbroiled, or well browned, well cooked
meats introduces carcinogens into the digestive system and may cause
problems there
– Once the chemicals are absorbed and enter the body they are quickly
captured and detoxified by the liver
• Remember that correlation is not cause
– Although certain foods may appear at the scene of the colon cancer
crime, no one yet knows whether eating such foods actually causes
cancer or whether some other feature of a meat rich diet is at fault
• Acrylamide
– A chemical produced in carbohydrate rich foods, such as potatoes and
grains, when cooked at high temperatures
– A known animal carcinogen
– Toxic to the nervous system of both animals and humans
– Used in manufacturing and construction
– Results from a chemical reaction between the naturally occurring
sugars and an amino acid in the food
– No one yet knows if acrylamide in amounts common in foods affects
human beings
• fibre and Fluid
– Epidemiological studies often report links between eating plenty of
fruits and vegetables and a low incidence of many cancers
• The reason for this is not clear
• A prominent theory is that a fibre rich diet may protect against some
cancers by:
– increasing stool weight,
– diluting the colon's contents,
– stimulating bacterial fermentation,
– and speeding up the transit time of materials through the colon,
– thus minimising exposure of the colon walls to cancer causing
substances in the feces
– Bacterial fermentation produces fatty acids that nourish the cells
that line the colon
• Improving their resistance to cancerous changes
– A European study concludes that populations with lower than average
fibre intakes are at a greatly increased risk of cancers of the colon
and rectum and that they could reduce that risk by 40% by doubling
their fibre intakes from fruits, vegetables grain foods, and legumes
• High fibre, low fat foods may not only reduce the risk of some
cancers but may also protect health in these ways
– The breakdown of fibres of whole grains by digestive tract bacteria
yields short chain fatty acids though to offer some protection against
heart disease as well as cancer
– High fibre diets help to regulate blood glucose and blood insulin
• Factors that may also play roles in cancer development
• Whole grains are rich in antioxidants and other phytochemicals that
reduce oxidative stress and promote overall health
• Bladder cancer may be related to intake of fluids
– Men who drink about 10 cups of fluid a day have been reported to
develop substantially less bladder cancer than those drinking only
about half this amount
– A greater fluid intake dilutes the carcinogens that naturally form in
urine and causes more frequent urination
• Thus reducing the likelihood that carcinogens will interact
with tissues of the bladder
• Bladder cancer may be related to intake of fluids
– Plain water seems most beneficial
– But most any kind of fluid will do
• With the exception of alcoholic beverages, which may increase
the risks of many cancers
• Folate and Other Vitamins
– Folate deficiency seems to make cancers of the cervix and colon more
likely
• Ample folate may ward off other cancers in certain populations
• Up to 10% of the U.S. population, and a much larger percentage
of people with low incomes, consume a diet low enough in folate
to cause breaks in DNA that make cancer likely to develop
• Vitamin A
– Regulates aspects of cell division and communication that go awry in
cancer
– Helps to maintain the immune system
• Immune system cells can often identify cancerous cells and
destroy them before cancer can develop
• Vitamin D and exposure to sunshine have long been suggested as
protective against cancers
– Other than skin cancer
– The relationship is not clearly defined
• Cancer opposing roles have been suggested for vitamin B6, vitamin
B12, and pantothenic acid
• Taking supplements has not been proved to prevent or cure cancer
• Antioxidants may do more harm than good according to a current line
of investigation
– Immune system cells normally release oxidative free radicals in an
oxidative burst to kill off potentially dangerous microorganisms and
cancer cells
– Some cancer cells may selectively stockpile antioxidants to defend
against oxidative assaults from the immune system
– When mice with brain tumours were fed antioxidant depleted chow, the
tumour growth slowed and cancer cells died off at a rapid rate
• Calcium and Other Minerals
– Laboratory evidence suggests that a high calcium diet may help to
prevent colon cancer
• Supplemental calcium seems to suppress changes in the lining of
the colon associated with the onset of cancerous changes
– In laboratory experiments, human colon cancer cells replicate
rapidly when deprived of calcium but slow their replication when
calcium is restored
– Studies have not yet proved that one can avoid colon cancer by
increasing calcium intake
• A recent review revealed that the majority of studies since 1990
conform an association between colon cancer and both increased dietary
iron intake and high body iron stores
– Whether iron increases a person's risk for colon cancer may depend on
• Whether the person has an inherited tendency to store too much
iron, the person's sex (being female may be protective) and the
degree of supplementation
• How iron may facilitate cancer remains unanswered
– Iron is a powerful oxidising substance
• Oxidation may damage DNA in ways that initiate cancer
– Alternatively, iron supplements are constipating
• Constipation raises a person's risk of colon cancer
– Meat is a generous supplier of iron
• High meat diets often correlate with colon cancer
– If the iron and cancer link holds up to further scrutiny, the
benefits of iron enrichment to iron deficient populations must be
weighed against the harm to those prone to colorectal cancer
• Other minerals in food, including zinc, copper, and selenium, are
thought to play roles in cancer prevention
– Perhaps by helping antioxidant enzymes defend against its initiation
• Foods and Phytochemicals
– Whole foods and whole diets composed of them, not single nutrients,
may be most influential on cancer development
• The phytochemicals in some fruits and vegetables are thought to
be anti-carcinogens
• Some of these may protect against cancer by acting as mild
toxins that force the body to build up its arsenal of carcinogen
destroying enzymes
– Almost without exception, population studies find that diets lacking
in green and yellow fruits and vegetables and citrus fruits correlate
with cancers of many types
• Some evidence suggests that a number of antioxidant nutrients
and phytochemicals from a diet rich in fruits, vegetables, and
whole grains may be necessary to minimise DNA damage from certain
types of radiation
– A low intake of fruits and vegetables may leave cells unprotected
against DNA damage in the initiation of bladder and other cancers
– Infrequent use of cruciferous vegetables broccoli, Brussels sprouts,
cabbage, cauliflower, turnips, and the like is common in colon cancer
victims
– One review of the literature found a perfect association between
reduced incidence of lung cancer and diets high in fruits and
vegetables
– Incidence of stomach cancer correlates with too few vegetables in the
diet
• In one study, with vegetables in general
• In others, with lettuce and other fresh greens or vegetables
containing vitamin C
• Foods that contain phytochemicals are believed to promote health and
fight diseases
– Such foods, often called functional foods, have been recognised as
potentially beneficial by the national Academy of Sciences
• Who have defined functional foods as "potentially beneficial
products [that include] any modified food or food ingredient that
may provide a health benefit beyond the traditional nutrients it
contains."
Controversy: The Obesity Epidemic - How Can We Gain Control?
• 97 million obese people
– Are at increased risk of serious illnesses associated with obesity
• Heart disease, diabetes, arthritis, cancer, and others
• There are 3,000,000 early obesity related deaths per year
• $60 billion spent on obesity related health care
• Why Has Our Society become Obesity Prone?
– Today, many people regularly overeat on large portions of inexpensive
high calorie foods
• Consuming about 500 calories more than in 1970
• At the same time they have grown accustomed to leisure time in
front of television sets; labour saving devices such as
automobiles and elevators; and jobs requiring more sitting than
moving
• Most people do not exercise enough to maintain health and fitness
– A full quarter of people get little or no physical activity
– As they gain weight and lose fitness, stress and sleep disturbances
creep into their lives
• And they feel increasingly exhausted and less motivated to move
• The problem can worsen if a chronically tired person seeks relief by:
– self medicating with caffeine,
– medicines, weightless pills,
– high calorie "energy" foods and drinks,
– and other inappropriate supplements, alcohol, tobacco, or other drugs
– Some of these drugs may provide relief in the short term, but none
solve the problem
• Some people's genetic inheritance lays the foundation for obesity
– But such tendencies remain silent unless conditions are right to
support weight gain
– The obesity prone individual makes freewill choices each day
• Personal choices leading to overweight may be heavily
influenced by societal conditions and they become less free than
most people assume
• Changing Physical Activity
– Technological advances have relieved people of much of the labor of
planting and harvesting food, walking or running long distances,
hauling water, and performing most of life's basic physical tasks
– Some researchers assign the lion's share of blame for increasing
national body weights on decreasing energy expenditure
– While laborsaving advances have liberated many human hours for
intellectual and leisure pursuits
• Their costs in terms of human health are only now being counted
in full
• Changing Home Life
– Changes in the family structure have influenced people's food intakes
over the past four decades
– By one estimate, the diet has changed more over the past 40 years
than in any other comparable period of human existence
– As more women have entered the workforce and as the hours worked by
all wage earners have increased, families have less time for the
traditional activities of homemaking
• Including meal planning, grocery shopping, and the labor
intensive preparation of meals of fresh foods
– Consequently, more and more people rely on prepared or partially
prepared foods to save time and effort
– Meals are influenced more by which foods are familiar, readily
available, moderately priced, and easy to prepare than by the nutrient
needs of the purchasers
• Along with convenience, manufacturers often include flavourful
ingredients such as salt, sugar, and fat and remove constituents
such as fibre
• Thus, in exchange for convenience, the purchaser relinquishes
to the food industry responsibility for the calorie and nutrient
content of food
• The Changing Food Supply
– Consumers now spend 45% of their food budget on foods purchased and
eaten outside the home
– An amount expected to rise more rapidly than any other food expense
category
• The Changing Food Supply
– Overall, the easiest, most accessible, most inviting, and oftentimes
least expensive U.S. consumer options encourage unhealthy behaviors
• Especially where food choices are concerned
• Fast foods are now readily available in most areas of the
nation and account for the largest segment of the growing "away
from home" food category for U.S. consumers
• On average, U.S. consumers now eat three hamburger meals each week
• Consumption of French fries far outweighs green vegetable intakes,
and soda sales have more than doubled in the past 40 years
• Food Advertising
– The food industry spends more than $33 billion each year on
advertising, trade shows, special product promotions, fees to
supermarkets to ensure prominent product placement, attractive
packaging, games and prizes, and other efforts to attract consumer
dollars
• Compare this to the $1 billion spent by the National Cancer
Institute to promote fruit and vegetable intake
• The "Buy More" Strategy
– Everyone already eats some kind of food everyday
– To increase food sales marketers must convince us to buy their brand
over others
• Or, if we already choose it, to buy more of it – A proven
strategy for prodding consumers to buy more is to appeal to their
economic sense
• The fight for brand loyalty is fierce
– Much of it is aimed at children
• Thanks largely to technological advances in agriculture, a restaurant
often spends less on the food it serves than on most other expenses,
such as personnel, facility, or monthly expenses
• The strategy of offering more food for just a little more money
at each selling opportunity therefore pays off in greater profits
– To a consumers, a deal seems sweeter if significantly more food
can be obtained for just a few cents more
• Portion sizes and obesity rates have increased proportionately over
the years
• Along with restaurant food, prepared food has also gotten larger, and
most common portions exceed recommended portion sizes
– Sometimes by huge margins
• For example, a store bought chocolate chip cookie was reported
to exceed the USDA standard for a cookie by 700%
• Once source of this trend may be some recent initiatives by marketers
to stimulate consumers to buy more food
– Thus increasing company profits
– A study reports that larger pasta packages prompt consumers to cook
more pasta at a meal
• A good result for those selling pasta
• Sales of candy and popcorn work the same way
• Food super sizing strategies seem to be a tremendous financial
success wherever they are employed
– As consumers gradually adapt to larger portions, they put pressure on
the food industry to supply more and more food per serving to remain
competitive
• Marketing to Children
– The food industry spends almost $12 billion annually promoting high
calorie fast foods, fried snack foods, high sugar cereals, candies, and
soft drinks during children's television viewing hours and in other
media
• Children spend up to $6 billion of their own pocket money each
year and $132 billion more in annual family spending
• Techniques used to sell foods and other products to youth include
– Manipulating children's emotional and physical needs
• Such as their needs for per acceptance, love, safety, and
security and their desire to be independent, to act older, and to
develop an identity
• Some children are a captive audience for commercials brought into
their classrooms by a media service that provide "free" programming to
schools
– Paid for by selling children's classroom time to advertisers
– Such companies market fried snack food, fast food, and high calorie
soft drinks to students
• 8 million of whom are forced to watch two minutes of such ads
at school each day
• The ads work
• The Food Industry Speaks Out
– The food industry has much to fear from accusations that its high
calorie products and selling tactics are fueling the obesity epidemic
• Public sentiment that the industry is harming consumers for the
sake of profits could direct consumer dollars elsewhere
• Many food companies fear lawsuits that could force them to pay
enormous settlements if they are found culpable in causing harm
to consumers
• Many long established food companies take pride in their traditions
and products
– Providing the best to consumers who are eager for them
– Such companies hold that their primary goal is to meet the changing
desires and demands of their customers
• Does The Food Industry Cause Obesity?
– Is the food industry akin to tobacco companies in harming people's
health?
• The evidence against tobacco smoke as a cause of diseases is
ironclad, even when the products are used as intended
• Individual foods are unlikely to be found to cause obesity
because many people eat them in moderation and remain lean
• Tobacco smoke is a toxic, addictive, and unnecessary hazardous
substance
• Food is necessary for life
– Even fast food provides some nutrients and seems tolerable by the
healthy body when taken in moderation
– The fast food industry provides a service of preparing foods for
today's families who cannot or choose not to prepare foods at home
• The arguments in defense of the food industry were summed up this way
by the president of the national association representing restaurant
owners
– "Restaurants have a wide variety of choices on their menus, and
people make the choice to eat what they want and when they want every
day. This is all about personal responsibility and moderation."
• Other spokespeople argue that the cause of obesity is the Americans'
lack of exercise, rather than the availability of certain food products
or the prevalence of advertising
• New Menu of Choices
– Many food companies have recently added lower fat, lower calorie
products to their lines
• While a few others have eliminated the largest of the overlarge
portion options
• Unfortunately, a comparison of the fat and calories among the
new offerings reveals little improvement
• Reasonable choices other than salads are available
– One sandwich chain has built its reputation on making available some
low calorie sandwiches that can be used to support weightless efforts
– Other establishments, when asked, will omit fatty toppings from
sandwiches and salads to produce a reasonable nutritious meal
• The food industry states that such choices have always been available
• But most people entering a fast food restaurant associate these
establishments with a chance to indulge
• Only a few have the willpower to order slimmed down offering when
familiar full calorie treats are within view and are the path of least
resistance
• Can Government Actions Reverse Obesity Trends?
– Many government resources and much private money have been spent over
the years on developing initiatives to reverse obesity in the U.S.
• Since 1950, at least 35 consumer education reports have
specified sound weight control practices as essential to
maintenance of good health
• Not one of these public health efforts has succeeded in slowing
obesity rates in this country
– So it seems unlikely that more reports and documents would be
effective
• The FDA is planning enhancements of food labels and launching a
"Calories Count" education campaign
• Previous initiatives that focused on individual responsibility failed
to acknowledge the societal factors that erect barriers in the path of
those who try to follow health promoting advice
• Individuals are ultimately responsible for their own behavior, but in
the current social environment, few are prepared to choose behaviors
that support health when doing so is difficult
• Nutrition Education
– Part of the blame for unheeded dietary advice is placed on inadequate
education in today's schools
– A law passed in 1977 mandates that federal funds be supplied to
states for training teachers and school food service workers and to
teach basic nutrition science to the nation's schoolchildren
• Although the law still exists, money to deliver nutrition
information is inadequate
• The Healthy People 2010 report sets a goal of increasing the
proportion of schools that provide a minimum of three years nutrition
education for the nation's children
– Including such skills as balancing food intake with physical activity
• New Ideas for Change
– When healthy foods cost less, people choose them more often
• One suggestion is to use monetary incentives to encourage food
producers and consumers to make healthier food and exercise
choices
• This plan would raise taxes on high calorie, high fat, high
salt foods, sugary sodas, candies, and fried snack foods
• These tax revenues could then subsidise purchases of health
promoting foods
• As consumers chose more and more of the less costly items,
manufacturers would respond by making then available in greater
varieties and by marketing them more heavily
– According to this construct, taxing automobiles and other labor
saving devices that rob people of the exercise they need could yield
needed price incentives for purchasing and using bicycles, exercise
equipment, and walking shoes
• This could lead to a healthy restructuring of our whole society
into one that promotes fitness rather than obesity
• Conclusion
– On hearing of economic plans such as the one just outlined, many
people react with scepticism and resistance
• They believe that in a free market society, citizens are
capable of making decisions in their own best interest and do not
need the government to step in and restructure their lives
• Consumers can choose to live right now, today, as though such
incentives were already in place
• Turn off the television and take up a physically active recreation
• Choose to live close enough to shopping, work, and school to allow
walking as an option
• Park farther away than usual and walk through the parking lot
• Lobby for laws that require landscaping, trees, and walkways in
parking lots to make them safe and inviting
• Seek out and use stairways instead of elevators
• Take walks and get to know the neighbours
• Write letters to building owners, asking them to improve stairwells
and access to them
• Obtain an inexpensive pedometer and vow to walk 10,000 steps each day
• Choose to consistently follow the advice of the experts offered in
Chapters 1 and 2 of this text
– Even if it means paying more for food and making time to prepare
foods at home
• Make a point to remember standard portion sizes and use them to
decide how much to eat at a sitting
• Take some of the food home for another meal when restaurant portions
are too large
• Save enticing fatty and sugary fast foods and snacks for special
occasions
– While choosing healthier choices as staple, everyday foods
• Teach the children in our lives to think differently about food
• Lobby lawmakers to fund nutrition education classes, physical
education classes, and eliminate from the classroom all commercials for
high fat, high calorie foods
• Pressure schools to replace candy and soda with fruit and low fat
milk options and to reverse the trend toward hiring fats food companies
to provide school lunches for children