Transcript Slide 1

Diet and Health
Chapter 18
Nutrition and Infectious Diseases
• Nutrition cannot directly prevent or
cure infectious diseases
– Caused by bacteria, viruses, parasites or
other microbes and transmissable
– Good nutrition can strengthen body’s defenses
– Poor nutrition weakens the immune system
– Nutrition intervention can help prevent
malnutrition and minimize the wasting away of
tissues.
The Immune System
• Organs of the Immune System
– Spleen
– Lymph nodes
– Thymus
• Body’s first line of defense- the epithelium
– Skin, mucous membranes, GI tract
• Antigens- foreign substances that invite attack from
antibodies or inflammation
– Examples- bacteria, virus, toxin, allergen
• Two types of white blood cells
– Phagocytes
– Lymphocytes
White Blood Cells
• Phagocytes
– Scavengers of immune system
– First to arrive at the scene of an invader (antigen)
– Phagocytosis
• Engulfment and digestion of antigen
– Secrete cytokines, proteins that activate metabolic
and immune responses to infection
White Blood Cells
• Lymphocytes: B-cells
– Rapidly divide and produce antiBodies
• Travel through bloodstream to site of infection
• Stick to surfaces of antigens
• Make it easy for phagocytes to ingest
– Antibodies react selectively
• Retain a memory
• Are members of immunoglobin class of
proteins
White Blood Cells
• Lymphocytes: T-cells practice chemical warfare
– Travel directly to invasion site
– Recognize antigens on surface of phagocyte cells
• T-cells multiply in response
• Release chemicals to destroy antigen
– Signal to slow down immune response
– Highly specific: each T-cell can attack only one type of
antigen
– T-cells destroy cancer cells
– T-cells also like to reject organ transplants
Nutrition and Immunity
• Of all the body systems, immune system is
most vulnerable to subtle changes in nutrition
status
– Disease and malnutrition cause synergistic
downward spiral
• Protein energy malnutrition (PEM) + impaired
immunity always together
• Vitamin and mineral deficiencies & excesses
diminish immune response
Immunity and
infectious disease
increase nutrient
needs and lower
food intake.
Effects of PEM on
the Body’s Defense Systems
HIV/AIDS
• Human immunodeficiency virus (HIV)
– Develops into acquired immune deficiency
syndrome (AIDS)
– Transmitted by direct contact with body fluids
– Disables body’s defense systems against disease
• No cure
– Prevention is best course
• Nutrition benefits for HIV/AIDS patients
– Food safety is critical
– Good diet assists drug response, lengthens life
Inflammation and Chronic Diseases
• Immune system response to infection or injury
– Acute inflammation
• Increased blood supply to site, permeable blood vessels
so WBC’s get to the exact location
• Phagocytes engulf microbes
• Release of oxidative products like hydrogen peroxide
(H2O2) to kill microbes
• Acute inflammation fights off infection, removes
damaged tissue, heals wounds and promotes recovery
Chronic Inflammation
• Sustained, persistent inflammation is harmful
• Produce cytokines, oxidative products, blood
clotting factors, other bioactive chemicals
• Chronic inflammation results in tissue damage
• Sustained inflammation threatens health and
worsens all the chronic diseases
Nutrition and Chronic Diseases
• Four of the top ten causes of death in U.S., including the
top three are related to diet.
• These four account for 70% of the 2+ million deaths/yr, up
from 60% in 2007-2008
• Lifestyle risk factors are important and related to chronic
disease.
• Many of the nutritional factors in the treatment of chronic
disease are interrelated.
• Numerous disease associations with various nutrients
• Multiple risk factors for each chronic disease
• Modifiable risk factors (under your control)
• Nonmodifiable risk factors (genetics)
Ten Leading Causes of Death
in the U.S.
Interrelationships among
Chronic Diseases
Some cancers
Obesity
(especially abdominal obesity)
Atherosclerosis
(abnormal
blood lipids)
Diabetes
(insulin
resistance)
Hypertension
(high blood
pressure)
Stroke and
heart attack
Risk Factors and Chronic Diseases
Cardiovascular Disease
• Major causes of death around the world
– Family history
– Lifestyle factors
– Coronary heart disease (CHD) is most common form of CVD
• Usually caused by atherosclerosis
• Atherosclerotic plaques can raise blood pressure, cause
abnormal blood clotting, and cause heart attacks and
strokes. Recommendations for prevention and treatment
include dietary interventions, quitting smoking, and
regular physical activity. The most common form of CVD is
coronary heart disease (CHD), which develops due to
atherosclerosis in the coronary arteries.
CVD- Atherosclerosis development
– http://youtu.be/zeS-0au8ij4
– http://youtu.be/w8wXdtoW-HQ
– Accumulation of fatty streaks along inner arterial
walls
• Streaks enlarge and harden
• Encasement in fibrous connective tissue
– Plaques stiffen arteries and narrow passages
• Well-developed plaques by age 30
– Dietary factor
• Diet high in saturated/trans fat
• Diet low in antioxidant-rich plant-based foods
CVD- Atherosclerosis development
– Inflammation
• Damage to cells lining the blood vessels elicits
inflammatory response
• Immune system sends in macrophages
• LDL cholesterol becomes trapped and engulfed by
macrophages
• Macrophages swell; eventually become cells of plaque
CVD- Atherosclerosis development
– Damage from high LDL or Hcy, toxins, infections
– Macrophages respond to and free radicals are produced
by inflammation. LDL gets oxidized, attacked by
macrophages and trapped in vessels walls.
• Aneurysm- abnormal bulging of blood vessel wall
• C-reactive protein (CRP): better marker of inflammation than LDL
• Lipoprotein-associated phospholipase A(2) or LP-PLA(2): highly
specific markers of plaque inflammation
– Plaques
• Plaque stability , then rupture
CVD- Atherosclerosis Development
– Blood clots
• Platelets and other factors form blood clots
• Prostaglandins and thromboxanes
• Omega-3 fatty acids
– Blood pressure
• Plaques increase pressure
• Atherosclerosis is a self-accelerating process
• http://www.4shared.com/video/Hh-vYomM/YouTube__progression_of_ather.html
CVD- Atherosclerosis Results
• Heart Attacks and Strokes
– Angina – pain or pressure feeling around
the area of the heart.
– Heart attack – restricted blood flow to the
heart.
– Transient ischemic attack or stroke –
restricted blood flow to the brain, aka
“mini-stroke”
Risk Factors for Coronary
Heart Disease (CHD)
• By middle age, most
adults have at least one
risk factor
• Regular screening and
early detection
Risk Factors for Coronary
Heart Disease (CHD)
Nonmodifiable risk factors
• Age, Gender, and Family History
–
–
–
–
Men higher risk than women
Men older than 45 years of age.
Women older than 55 years of age.
Immediate family history of premature heart
disease.
Modifiable Risk Factors for
Coronary Heart Disease (CHD)
• Excess LDL (low-density lipoproteins)
available for oxidation-inflammation
• LDL is most atherogenic lipoprotein
• High LDL = high risk
– Desirable: 100 mg/dL.
– Above optimum level: 100-129 mg/dL.
– Borderline: 130-159 mg/dL.
– High: 160-189 mg/dL.
– Very High: 190 mg/dL.
Modifiable Risk Factors for CHD
• HDL (high-density lipoproteins) represent
cholesterol being carried back to the liver,
reduced risk.
– Desirable: 60 mg/dL.
– Borderline: 59-40 mg/dL.
– High: 40 mg/dL.
 Total cholesterol [TC = LDL + HDL + (.2 x TG)]
– Desirable levels at  200 mg/dL.
– Borderline levels at 200-239 mg/dL.
– High levels at  240 mg/dL.
Modifiable Risk Factors for CHD
• Elevated triglycerides are a marker for other risk
factors studied in relation to CHD.
• Desirable levels of fasting triglycerides:
150 mg/dL.
• Borderline levels of fasting triglycerides:
150-199 mg/dL.
• High levels of fasting triglycerides: 200-499
mg/dL.
• Very high levels of fasting triglycerides:
 500 mg/dL.
Standards for CHD Risk Factors
Modifiable Risk Factors for CHD
• High blood pressure (hypertension)
– Relationship with heart disease risk holds true for
men, women, young, and old
– Injures artery walls and accelerates plaque
formation
– Accelerates plaque formation which in turn
increases blood pressure.
• Diabetes Type 2
– Increases risk of death from CHD
Blood Pressure Numbers
• Systolic and/or diastolic pressure
– Desirable: 120/80
– Borderline (prehypertension):
120-139/80-89
– High (Stage one hypertension): 140/90
– Stage two hypertension: 160/100
Modifiable Risk Factors for CHD
• Obesity and physical inactivity
– Increase risk for CHD
– Desirable BMI: 18.5-24.9.
– Borderline: 25-29.9.
– High: 30.
• Cigarette smoking
– Smoking damages the heart directly
– Toxins in cigarette smoke damages vessels
• Atherogenic diet
– Elevates LDL cholesterol
Modifiable Risk Factors for CHD
• Other risk factors
– Elevated VLDL
• Metabolic syndrome, a cluster of health risks,
includes markers of inflammation and thrombosis
1. Insulin resistance
2. Hypertension
3. Dyslipidemia
4. Abdominal obesity
Recommendations for Reducing CHD Risk
• Screening
– Cholesterol screening
• Total cholesterol, LDL, HDL, triglycerides
• Two measurements at least 1 week apart
• If family history exists, draw lipoprotein A, CRP
• Intervention
– Lifestyle changes
• Physical activity, dietary changes, lose weight, reduce
exposure to cigarette smoke
– Medications
As Bad as it gets:
Junky Diet plus Smoking
• Cigarette Smoking
 Powerful factor for increased risk
 Increases blood pressure and heart workload
 Raises LDL while hardening arteries
http://youtu.be/-YjrkBYDDQM
http://youtu.be/o_BF8l-tT0g
• Atherogenic Diet high in saturated fats, trans fats,
and cholesterol and low in fruits and vegetables
• Antioxidants in fruits and vegetables + omega-3 fatty
acids and other good fats lower the risk of CHD.
Hypertension
• Systolic and diastolic pressure with risk of
death from CVD (pre-, stage 1, 2)
• Physiological factors of hypertension
– Cardiac output
• Heart rate or blood volume increases
– Peripheral resistance
• Diameters of arterioles
– Blood pressure is regulated by nervous system &
hormones that act on the kidneys
Hypertension
• Risk factors
– Aging
– Genetics
– Obesity
– Salt sensitivity
– Alcohol
• Treatment
– Weight control
– Physical activity
– DASH diet
 Lowers LDL & total
cholesterol
– Salt/sodium intake
– Drug therapy
Diabetes Mellitus
• Incidence (new cases) risen dramatically
– Prediabetes
• Sixth among leading causes of death
• Underlies or contributes to several other
major diseases
– Heart disease is leading cause of diabetes-related
deaths
Prevalence of Diabetes among Adults
in the United States
Diabetes Mellitus
• Diabetes treatment involves the coordination
of diet and/or drugs and physical activity to
control blood glucose fluctuations and control
or lose weight.
• Diabetes development characterized by
• High blood glucose concentrations
• Disordered insulin metabolism
– Two main types
• Type 1
• Type 2
Diabetes Mellitus
• Type 1 diabetes
– Less common type
– Autoimmune destruction of pancreas β-cells
– Pancreas loses ability to synthesize insulin EARLY
– Commonly occurs in childhood & adolescence
– Energy metabolism changes
• May threaten survival
– Need insulin injections or external pump
Diabetes Mellitus
• Type 2 diabetes
– Most prevalent form of diabetes
• Worn out pancreas β-cells, impaired sensitivity to
serum glucose
• Risk factors – obesity, CVD/CHD risk factors, certain
ethnicities
– Insulin resistance
• Hyperinsulinemia
• Amount of insulin is insufficient to compensate for
diminished effect in cells
 Chronic inflammation correlates with ↑glucose, ↓insulin
effectiveness
Type 2 Diabetes
•
•
•
•
•
•
90-95% prevalence in diabetic population
Occurring in children and adults
Relatively moderate symptoms
Cells are resistant to insulin
Associated with obesity, heredity, and aging
Sometimes insulin is required
Diabetes Mellitus
• Complications
– Acute- Events! (hyperglycemic and hypoglycemic)
– Chronic
• Conversion of glucose to sugar alcohols
• Loss of circulation and nerve function
• Infections
• Diseases of large blood vessels- earlier and
more severe atherosclerosis
• Diseases of small blood vessels- loss of kidney
function & vision
• Diseases of the nerves- neuropathy
Metabolic
Consequences
of Untreated
Diabetes
Blood glucose
rises (hyperglycemia)
No glucose
enters the
cells
Cells break
down
protein
and fat
Ketones
produced
for energy
(ketosis)
Type 2
Type 1
Hunger
Glucose spills
into the urine
(glycosuria)
Weight loss
Diabetic ketoacidosis
manifested by:
• Ketones in the breath (acetone breath)
• Ketones in the blood (ketonemia)
• Ketones in the urine (ketonuria)
Excessive
eating
(polyphagi
a)
Diabetic
coma (can
be fatal)
Hyperosmolar hyperglycemic state usually develops in the
absence of ketosis and is most often associated with type 2
diabetes.
Water moves
into the
blood
(osmotic
effect)
Frequent
urination
(polyuria) and
fluid losses
Dehydration
(blood
volume
depletion and
electrolyte
imbalances)
and
excessive
thirst
(polydipsia)
Hyperosmolar
hyperglycemic
state or comaa
(can be fatal)
Some
glucose
enters the
cells, but
slowly
Hunger
Excessive
eating
(polyphagia)
Weight
gain
Diabetes Mellitus
• Recommendations for diabetes
– Total carbohydrate intake spread out over the day
– Carbohydrate sources
• Fiber slows sugar absorption and rise in glucose
• Glycemic effect high from refined starch, rice, corn
– Saturated fat limit to <7% (10% for healthy people)
– Protein
• Declining kidney function indicates need for lower
protein intakes
• NIDDK the best website
Diabetes Mellitus
• Recommendations for diabetes
– Alcohol
• Moderation
– Type 1 diabetes
• Adjust insulin to accommodate meals, physical activity,
and health status
• Nutrition therapy, exchange system
– Type 2 diabetes
• Diet and regular moderate physical activity
Metabolic Syndrome
or Syndrome X
• (Insulin resistance is a risk factor.)
•
•
•
•
•
Diagnosed by any three of the following factors:
Abdominal obesity
• Men- Waist circumference 40 inches.
• Women- Waist circumference 35 inches.
Triglycerides: 150 mg/dL.
HDL: 40 mg/dL in men, 50 mg/dL in women.
Blood pressure: 130/85 mm Hg.
Fasting glucose: 100 mg/dL.
Cancer
• Second leading cause of death in U.S.
• Development of cancer – carcinogenesis
– Mutations in genes that control cell division
• Effects of mutations
– As tumor develops, a network of blood vessels
develops
– Metastasis- proliferation of malignant cells from
one organ to another
• Cellular DNA altered by alcohol & heavily
smoked foods. Saturated/trans fat
promote cancer development.
Cancer
• Development of cancer – carcinogenesis
– Environmental factors
• Sun, water, air pollution, and smoking
• Obesity
• Exposure to estrogen
– Obesity and unhealthy diet
– http://www.cancer.gov/cancertopics/factsheet/Ri
sk/obesity
Cancer Development
Normal cells
Malignant cells
Normal
cells
Initiation
Promotion
Mutagens alter the
DNA in a cell and
induce abnormal
cell division.
Further tumor
development
Promoters enhance
the development of
abnormal cells,
resulting in
formation of a tumor.
The cancerous tumor
releases cells into the
bloodstream or lymphatic
system (metastasis).
Stepped Art
Cancer
• Development of cancer – carcinogenesis
– Dietary factors – cancer initiators
•
•
•
•
•
Alcohol and tobacco use
Cooking meats at high temperatures
Grilling meats
Diets high in red meats & processed meats
Presence of acrylamide
– Acrylamide forms naturally when certain carbohydrate-rich
foods are fried, baked, or roasted at high temperatures.
– Overheated oils used in sauteeing/frying
Cancer
• Development of cancer – carcinogenesis
– Dietary factors – cancer promoters
• Types of fat in diet
• High-fat diets correlate with high cancer rates
in animals
• Antipromoter Foods:
– Omega-3 fatty acids may be protective
– Fruits and Vegetables
– Fiber-rich foods
Cancer
• Recommendations for reducing cancer
risks
– Fruit and vegetable intake
• Phytochemical protective benefits
– Rich sources of fiber
• Fruits, vegetables, legumes, & whole grains
– Maintenance of healthy body weight
– Physical activity
Recommendations for
Chronic Diseases
• Comparison with Dietary Guidelines for
Americans
• Healthy Eating Pyramid
– Links between diet and health
• Weight control
• Diet
• Individualized recommendations
– Human genome
Dietary Guidelines & Recommendations
for Chronic Diseases Compared
The Healthy Eating Pyramid
Recommendations for
Reducing Cancer Risk
 DON’T SMOKE!!!
1. Maintain a healthy body weight.
2. Be physically active.
3. Limit consumption of energy-dense foods.
4. Consume five or more cups of fruits & vegetables per day.
5. Limit the consumption of red meat.
6. Limit consumption of alcoholic beverages.
7. Limit consumption of salt.
8. Try to meet nutritional needs through the diet rather than
supplements.
Highlight 18
Complementary and Alternative
Medicine
p. 636
Defining Complementary and
Alternative Medicine (CAM)
• Insufficient evidence regarding safety
• Variety of approaches, philosophies, &
treatments
– Alternative
– Complementary
• Integrative medicine
Sound Research, Loud Controversy
• Scientific evidence is lacking
– Safety and effectiveness
• Sound research – the questions
– Does treatment offer better results than doing
nothing or giving a placebo?
– Do the benefits clearly outweigh the risks?
Sound Research, Loud Controversy
• Placebo effect
– Placebo brings about healing effect in people who
believe they are receiving the treatment
• Risks versus benefits
– Ideally, benefits with little or no risk
• Some therapies are innocuous
– Benefits with significant, unknown, or debatable
risks
Nutrition-Related
Alternative Therapies
• Use of foods, vitamin and mineral
supplements, and herbs to prevent & treat
illness
• Foods
– Examples
• Vitamin and mineral supplements
– Can be either conventional or alternative
Ginger may relieve
nausea and vomiting
due to motion sickness
or pregnancy.
Ginkgo may slow the loss
of cognitive function
associated with age.
St. John’s wort may be
effective in treating mild
depression.
American ginseng may
improve glucose control
in people with type 2
diabetes.
Saw palmetto may
improve the symptoms
associated with an
enlarged prostate.
The gel of an aloe vera
plant soothes a minor
burn.
Nutrition-Related
Alternative Therapies
• Herbal remedies
– Beneficial compounds from wild species
– Herbal precautions
• “Natural” does not mean safe or beneficial
• Not regulated or evaluated by the FDA
• Lack of consumer information regarding herbal
preparations
Herbal Variability Issues
•
•
•
•
•
•
•
•
•
True identification of herbs
Purity of herbal preparations
Appropriate uses and contraindications of herbs
Effectiveness of herbs
Variability of herbs
Accuracy of labels
Safe dosages of herbs
Interactions of herbs with medicines and other herbs
Adverse reactions and toxicity levels of herbs
The Consumer’s Perspective
• Use of alternative therapies
– In line with beliefs about health and life
• Alternative therapies are most often used in
addition to conventional therapies
• Important to inform physician of alternative
therapy use