diet and health

Diet and HealthChapter 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

Hypertension(high bloodpressure)

Stroke andheart attack

Diabetes(insulin

resistance)

Atherosclerosis(abnormal

blood lipids)

Obesity(especially abdominal obesity)

Some cancers

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 thrombosis1.Insulin resistance2.Hypertension3.Dyslipidemia4.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 SmokingPowerful factor for increased risk Increases blood pressure and heart workloadRaises LDL while hardening arteries

http://youtu.be/-YjrkBYDDQMhttp://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 cellsChronic 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

Type 1 Type 2

No glucose enters the cells

Blood glucose rises (hyper- glycemia)

Some glucose enters the cells, but slowly

Cells break down protein and fat

Glucose spills into the urine (glycosuria)

Water moves into the blood (osmotic effect)

Hunger Hunger

Ketones produced for energy (ketosis)

Frequent urination (polyuria) and fluid losses

Excessive eating (polyphagia)

Weight loss

Excessive eating (polyphagia)

Dehydration (blood volume depletion and electrolyte imbalances) and excessive thirst (polydipsia)

Diabetic ketoacidosis manifested by: • Ketones in the breath (acetone breath) • Ketones in the blood (ketonemia) • Ketones in the urine (ketonuria)

Weight gain

Diabetic coma (can be fatal) Hyperosmolar

hyperglycemic state or comaa (can be fatal)

Hyperosmolar hyperglycemic state usually develops in the absence of ketosis and is most often associated with type 2 diabetes.

MetabolicConsequencesof UntreatedDiabetes

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: 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/Ris

k/obesity

Cancer Development

Normal cells

Mutagens alter the DNA in a cell and induce abnormal cell division.

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).

Malignant cellsNormal cells

Stepped Art

Initiation PromotionFurther tumor development

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