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Understanding Nutrition
Chapter 18
Diet and Health
A. Fellah, Ph.D.
Nutrition and Chronic Diseases
 Lifestyle factors that influence disease development:
 Diet
 Physical inactivity.
 Tobacco use.
 Alcohol and drug abuse.
 Overweight.
 Irresponsible sexual behavior.
 Some risk factors such as diet and physical activity,
are modifiable, meaning that they can be changed;
others, such as genetics, age and gender, cannot be
Ten Leading Causes of Illness and Death in U.S.
Diet influences the development of several chronic diseases—notably, heart
disease, some types of cancer, stroke, and diabetes. These four conditions
account for about two-thirds of the nation’s 2 million deaths each year.
Diet/Lifestyle Risk Factors and Chronic Diseases
The same risk factor can affect many chronic diseases.
Notice, for example, how many diseases have been linked to a
high-fat diet. A particular disease, such as atherosclerosis, may
have several risk factor.
Risk Factors for Chronic Diseases
Synergistic: multiple factors operating together in such a way that
their combined effects are greater than the sum of their individual
Many of these conditions are themselves risk factors for other
chronic diseases. For example, a person with diabetes is likely to
develop atherosclerosis and hypertension. These two conditions,
in turn, worsen each other. Notice how all of these chronic
diseases are linked to obesity.
Heart Disease and Strokes
 Cardiovascular disease is the leading cause of death
around the world today. It accounts for 1 million deaths
in the US and costs ~260 billions yearly.
 Coronary heart disease (CHD): the most common
form of cardiovascular disease, usually involves:
 Atherosclerosis: accumulation of lipids and other
materials in the arteries.
Hypertension: is high blood pressure.
Each makes the other worse.
 Read the glossary on page 605
How Atherosclerosis Develops
 Plaques Develop: Atherosclerosis begins with
the accumulation of soft fatty streaks along the
inner arterial walls.
These fatty streaks usually gradually enlarge
and become hardened with minerals, forming
Plaques stiffen arteries and narrow passage
through them.
 Blood Clots Form:
Platelets are small, disc-shaped bodies in the blood,
important in blood clot formation. Clots normally form and
dissolve in blood all the time.
In atherosclerosis, clots form faster than they dissolve
because the platelets respond to plaques.
The action of platelets is under the control of eicosanoids.
Eicosanoids: 20-C omega-6 & omega-3 fatty
acids, each helps to regulate:
Blood pressure
Blood clot formation.
Blood vessel contractions.
Immune response.
Nerve impulse transmissions.
 Blood Flow Diminishes:
 Plaques and blood clots restrict blood flow.
The loss of blood flow to the area supplied by the
blocked artery robs the tissue of oxygen and
nutrients, and die.
 Blood Pressure Rises:
 The heart must create enough pressure to push
blood through the circulatory system.
When arteries are narrowed by plaques, clots, or
both, blood flow is restricted, and the heart must
then generate more pressure to deliver blood to
Risk Factors for Cardiovascular Disease
 Major risk factors for CHD:
 High blood cholesterol.
 Hypertension.
 Diabetes (insulin)
 Obesity.
 Physical response.
 Smoking.
Insulin resistance:
the condition of which a normal amount of insulin
produces a subnormal effect; a metabolic
consequence of obesity.
 Metabolic syndrome:
a combination of four risk factors-insulin,
hypertension, abnormal blood cholesterol, and
obesity-that greatly increase a person’s risk of
developing coronary heart disease; also called
Syndrome X or insulin resistance syndrome.
 High Blood Cholesterol::
 Cholesterol is carried by several lipoproteins, chief
among them LDL and HDL.
 High LDL and low HDL indicate correlate directly
with heart attack.
 The higher the LDL, the greater the risk of CHD.
 Hypertension:
Chronic high blood pressure frequently
accompanied atherosclerosis, diabetes, and
The higher the blood pressure above normal the
greater the risk of heart disease.
 Diabetes:
Blood vessels become blocked and circulation
Atherosclerosis progresses rapidly.
Associated with high LDL, high triglycerides, low
HDL, hypertension, and obesity.
 Smoking:
 Low HDL associated with cigarette smoking.
 It deprived the heart of oxygen and damages
 In general men have higher blood cholesterol and a
greater risk of CHD than women.
 Cardiovascular disease occurs ~10 to 12 years later
in women than in men
HDL and LDL Compared
Risk factors for cardiovascular disease.
An LDL-to-HDL ratio > 5 indicates a risk for men, and a
ratio > 4.5 indicates a risk for women
Recommendations for Reducing
Cardiovascular Disease Risk
 Cholesterol Screening:
Measuring total cholesterol, LDL, HDL, and triglycerides.
 Population Goals:
Maintain a healthy body weight and limit intake of saturated
fat, total fat, and dietary cholesterol.
 Control Weight:
Aim for a healthy weight. With weight loss, heart disease risk
factors improve: blood pressure, blood cholesterol, and TG.
 Reduce Fat, Especially Saturated fat:
AHA recommends fat intake of less than 30% of daily
kcalories. Choose a diet that is low in sat. fat and cholesterol
and moderate in total fat.
Diets to Reduce High LDL
Dietary Factors Protecting Against CHD
Read also table 18-2 page 609
 Affect 50 million people in US, > 1/3 of adult
 Blood Pressure Regulation:
 The Arteries: The heart is pushing the blood into arteries
to ensure its circulation through the whole system.
Peripheral resistance: resistance to the flow of blood
caused by the reduced diameter of the vessels at the
extremities of the body-the smallest arteries and
Blood Volume contributes to blood pressure.
The Kidneys: depend on blood pressure to help them
filter waste out of the blood into the urine.
 Another determining factor is the volume of fluid in the
circulatory system, which depends in turn on the
number of dissolved particles in that fluid.
 (1) Pumping pressure from the heart forces blood into
the arteries.
 (2) Fluid cannot cross the thick wall of the arteries.
 (3) Capillary walls are very thin and porous, allowing
fluids and small substances such as ions, glucose,
and amino acids to easily cross, primarily by the
process of diffusion.
 (4) Blood proteins and red blood cells
that remain become more concentrated.
Blood presume decreases.
 (5) Blood is now so concentrated that it
attracts fluid back into the capillary.
Small molecules (waste products)
accompany the fluid. The pressure that
draws fluid back into the vein is osmotic
How Hypertension Develops
 When blood flow to the kidneys is reduced, the kidneys
expanding blood volume and constricting peripheral blood
vessels, result in high blood pressure.
 Obesity: more of extra capillaries through which the blood
must be pumped.
 Insulin Resistance: high blood insulin signals kidneys to
retain sodium.
 Hypertension is 2—3 times in people with type 2 diabetes.
 Consequence of Hypertension:
Stain on the heart’s pump until it gradually fails (heart
Risk Factors for Hypertension
High blood lipids.
Recommendations for Reducing Hypertension Risk
 Weight Control:
 aim for a healthy weight.
 Increase physical Activity.
 Alcohol:
 if you drink alcoholic beverages, do so in
 Sodium/Salt Intake:
 choose and prepare foods with less salt.
 Diseases that result from the unchecked
growth of malignant tumors.
 It is not a single disorder. There are many
cancers, that is, many different kinds of
 Carinogens: substances or agents that are
capable of causing cancer.
 Antipromoters: factors that oppose the
development of cancer.
Read glossary, page 616
Steps in the development of cancer. Antioxidants, other
substances in food, and the body’s protective mechanisms may
repair damage to cells and halt the progression of cancer.
Repair of Cellular Damage
Promotion of Cancer
Progression of Cancer
Tumor Formation: 1 of 3
How cancer develops?
Tumor Formation: 2 of 3
Tumor Formation: 3 of 3
Food Sources of Antioxidants
Vegetables rich in
fiber, phytochemicals,
and the antioxidant
nutrients (betacarotene, vitamin C,
and vitamin E) help to
protect against
Recommendation for Reducing Cancer Risk
 Choose a diet rich in a variety of plant-based food.
 Maintain a health weight and be physically active.
 Drink alcohol in moderation.
 Select food low in fat and salt.
 Prepare and store foods safely.
 Do not smoke or use tobacco in any form.
Diabetes Mellitus
 Ranks 6th among the leading causes of death.
 It is a chronic disorder characterized by high
blood glucose and either insufficient or
ineffective insulin.
 Type I Diabetes:
less common, the pancreas can not synthesize
insulin. (5-10% of all diagnosis)
Insulin dependent diabetes mellitus.
 Type 2 Diabetes: predominant form
It develops in people over 40 years old, seen
in obese children
Cells are less sensitive to insulin.
Blood glucose rises high which stimulate
pancreatic cells to make insulin, exhausting
these cells and reducing their ability to function.
Obesity-Diabetes Cycle
Complication of Diabetes
 In both types, glucose fails to gain entry into the cells
and consequently accumulates in the blood.
 Diseases of the Large Blood Vessels:
 Atherosclerosis tends to develop early, progress rapidly,
and be more severe in people with diabetes.
 Diseases of the Small Blood Vessels:
Microangiopathies are disorders of the small blood vessels.
Loss of kidney function and retinal degeneration.
 Disease of the Nerves:
Gangrene is the death of tissue due to deficient blood
Consequences of Diabetes
Nutrition and Immunity
Regardless of
where a
person enters
the spiral,
illness, and
interact to
and worsen
Disease and malnutrition create a synergistic downward
spiral that must be broken for recovery to occur.
Human Immunodeficiency Virus (HIV)
 The virus that causes AIDS. The infection progresses
to become an immune system disorder that leaves its
victims defenseless against numerous infection.
 Opportunistic infections: infections from
microorganisms that normally do not cause disease in
the general population but can cause great harm in
people once their immune systems are compromised.
 Wasting syndrome: an involuntary loss of more than
10% of body weight , common in AIDS and cancer.
 Heart disease, strokes, cancers and diabetes are
leading causes of death in the United States.
 Reducing fat intake, saturated fat intake and
cholesterol intake can reduce risk.
 Regular physical exercise and cessation of smoking
are also important in reducing risk.
 Obesity and hypertension have a direct relationship to
cardiovascular disease.
 Weight control is the most effective treatment of
 Alcohol and heavily salted and smoked foods
may initiate cancer development.
 Fiber and antioxidant nutrients and nonnutrients
serve as antipromoters that protect against the
development of cancer.
 It is wise to eat foods that contain these
 Diabetes mellitus characterized by high blood
glucose with insufficient or ineffective insulin.
 Coordination of diet, insulin injections, and physical
activity all help to control blood glucose.
 There are many significant complications with
 Nutrition plays a key role in keeping people healthy
and reducing the risk of chronic diseases.
 Nutrition interventions can help prevent
malnutrition and minimize wasting that occurs with
the progression of AIDS