diet and health

Whitney & Rolfes – Understanding Nutrition, 12th Edition

Diet and HealthDiet and Health

Chapter 18


Nutrition and Infectious Nutrition and Infectious DiseasesDiseases

Nutrition cannot directly prevent or cure infectious diseases Good nutrition can strengthen body’s

defenses Poor nutrition weakens the immune system


The Immune SystemThe Immune System

Body’s first line of defense Skin, mucous membranes, GI tract

Antigens Examples

Two types of white blood cells Phagocytes Lymphocytes



Phagocytes Scavengers of immune system First to arrive at the scene of an invader Phagocytosis

Engulf and digest antigen Secrete cytokines



Lymphocytes – B-cells Rapidly divide and produce antibodies

Travel through bloodstream to site of infection

Stick to surfaces of antigensMake it easy for phagocytes to ingest

Antibodies react selectivelyRetain a memory



Lymphocytes – T-cells Travel directly to invasion site Recognize antigens on surface of phagocyte

cellsT-cells multiply in responseRelease chemicals to destroy antigen

Signal to slow down immune response Highly specific Organ transplants


Nutrition and ImmunityNutrition and Immunity

Immune system responds to subtle changes in nutrition status Synergistic downward spiral

Protein energy malnutrition (PEM) Impaired immunity

Vitamin and mineral deficiencies & excesses Diminish immune response


Nutrition and ImmunityNutrition and Immunity


Effects of PEM on the Effects of PEM on the Body’s Defense SystemsBody’s Defense Systems


HIV/AIDSHIV/AIDS

Human immunodeficiency virus (HIV) Develops into acquired immune deficiency

syndrome (AIDS) Transmitted by direct contact with body fluids

No cure Prevention is best course

Nutrition benefits for HIV/AIDS patients Food safety is critical


Inflammation and Chronic Inflammation and Chronic DiseasesDiseases

Immune system response to infection or injury Acute inflammation

Phagocytes engulf microbesRelease of oxidative products to kill microbes Inflammation fights off infection and

promotes recovery Chronic inflammation

Harmful


Nutrition and Chronic Nutrition and Chronic DiseasesDiseases

Leading causes of death in U.S. Relationship with diet

Chronic diseases Interrelationships among chronic diseases Numerous disease associations with various

nutrients Multiple risk factors for each chronic disease

Modifiable risk factorsNonmodifiable risk factors


Ten Leading Causes of Ten Leading Causes of Death in the U.S.Death in the U.S.


Interrelationships among Interrelationships among Chronic DiseasesChronic Diseases


Risk Factors and Chronic Risk Factors and Chronic DiseasesDiseases


Cardiovascular DiseaseCardiovascular Disease

Major causes of death around the world Family history Lifestyle factors Coronary heart disease (CHD) is most

common formUsually caused by atherosclerosis



Atherosclerosis development Accumulation of fatty streaks along inner

arterial wallsStreaks enlarge and hardenEncasement in fibrous connective tissue

Plaques stiffen arteries and narrow passagesWell-developed plaques by age 30

Dietary factors



Atherosclerosis development Inflammation

Damage to cells lining the blood vessels elicits inflammatory response

Immune system sends in macrophagesLDL cholesterol becomes trapped and

engulfed by macrophagesMacrophages swell; eventually become cells

of plaque



Atherosclerosis development Inflammation

AneurysmC-reactive protein (CRP)Lipoprotein-associated phospholipase A(2) or

LP-PLA(2) Plaques

Plaque stability – rupture



Atherosclerosis development Blood clots

Platelets and other factors form blood clotsProstaglandins and thromboxanes Omega-3 fatty acids

Blood pressurePlaques increase pressureAtherosclerosis is a self-accelerating process



Atherosclerosis development The results

Heart attackTransient ischemic attack (TIA)


Risk Factors for Coronary Risk Factors for Coronary Heart Disease (CHD)Heart Disease (CHD)

By middle age, most adults have at least one risk factor

Regular screening and early detection



Age, gender, and family history Nonmodifiable risk factors

Older vs. younger peopleMen vs. womenEarly CHD in immediate family members



High LDL and low HDL cholesterol Total cholesterol LDL – most atherogenic lipoproteins

Plaque instability Inflammatory process

HDL indicate a reduced risk of atherosclerosis


Standards for CHD Risk Standards for CHD Risk FactorsFactors



High blood pressure (hypertension) Relationship with heart disease risk holds

true for men, women, young, and old Injures artery walls Accelerates plaque formation

Diabetes Increases risk of death from CHD



Obesity and physical inactivity Increase risk for CHD

High LDL, low HDL, hypertension, & diabetes

Cigarette smoking Smoking damages the heart directly Toxins in cigarette smoke damages vessels

Atherogenic diet Elevates LDL cholesterol



Other risk factors Elevated triglycerides

VLDLMeasurement of triglycerides

Metabolic syndrome Cluster of health risks Markers of inflammation and thrombosis


Recommendations for Recommendations for Reducing CHD RiskReducing CHD Risk

Screening Cholesterol screening

Total cholesterol, LDL, HDL, triglyceridesTwo measurements at least 1 week apart

Intervention Lifestyle changes

Physical activity, dietary changes, lose weight, reduce exposure to cigarette smoke

Medications


HypertensionHypertension

Systolic and diastolic pressure with risk of death from CVD

Physiological factors of hypertension Cardiac output

Heart rate or blood volume increases Peripheral resistance

Diameters of arterioles Regulated by nervous system & hormones

Kidneys


HypertensionHypertension

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 MellitusDiabetes Mellitus

Incidence has 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 Prevalence of Diabetes among Adults in the among Adults in the

United StatesUnited States



Diabetes development Characteristics

High blood glucose concentrationsDisordered insulin metabolism

Two main typesType 1Type 2


Features of Type 1 and Features of Type 1 and Type 2 DiabetesType 2 Diabetes



Type 1 diabetes Less common type

Autoimmune disorder Pancreas loses ability to synthesize insulin Commonly occurs in childhood &

adolescence Energy metabolism changes

May threaten survival Need insulin injections or external pump



Type 2 diabetes Most prevalent form of diabetes

Exact cause is unknownRisk factors

Insulin resistanceHyperinsulinemiaAmount of insulin is insufficient to

compensate for diminished effect in cells Chronic inflammation



Complications Acute Chronic

Conversion of glucose to sugar alcoholsLoss of circulation and nerve function InfectionsDiseases of large blood vesselsDiseases of small blood vesselsDiseases of the nerves


Metabolic Consequences Metabolic Consequences of Untreated Diabetesof Untreated Diabetes



Recommendations for diabetes Total carbohydrate intake Carbohydrate sources

Fiber and sugarGlycemic index

Dietary fat Protein

Kidney function



Recommendations for diabetes Alcohol

Moderation Type 1 diabetes

Adjust insulin to accommodate meals, physical activity, and health status

Nutrition therapy Type 2 diabetes

Diet and regular moderate physical activity


CancerCancer

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 Causes


Cancer DevelopmentCancer 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

Fig. 18-6, p. 626


CancerCancer

Development of cancer – carcinogenesis Environmental factors

Sun, water, air pollution, and smokingObesityExposure to estrogen


CancerCancer

Development of cancer – carcinogenesis Dietary factors – cancer initiators

Alcohol and tobacco useCooking meats at high temperaturesGrilling meatsDiets high in red meats & processed meatsPresence of acrylamide


Cancer Cancer

Development of cancer – carcinogenesis Dietary factors – cancer promoters

Types of fat in diet Dietary factors – antipromoters


Factors Associated with Factors Associated with Cancer at Specific SitesCancer at Specific Sites


CancerCancer

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 Recommendations for Chronic DiseasesChronic Diseases

Comparison with Dietary Guidelines for Americans

Healthy Eating Pyramid Links between diet and health

Weight control Diet Individualized recommendations

Human genome


Dietary Guidelines & Dietary Guidelines & Recommendations for Chronic Recommendations for Chronic

Diseases ComparedDiseases Compared


The Healthy Eating The Healthy Eating PyramidPyramid


Highlight 18Highlight 18

Complementary and Alternative Medicine


Defining Complementary Defining Complementary and Alternative Medicine and Alternative Medicine

(CAM)(CAM) Insufficient evidence regarding safety Variety of approaches, philosophies, &

treatments Alternative Complementary

Integrative medicine


Sound Research, Loud Sound Research, Loud ControversyControversy

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 Sound Research, Loud ControversyControversy

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 riskSome therapies are innocuous

Benefits with significant, unknown, or debatable risks


Nutrition-Related Nutrition-Related Alternative TherapiesAlternative 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


Nutrition-Related Nutrition-Related Alternative TherapiesAlternative Therapies

Herbal remedies Beneficial compounds from wild species Herbal precautions

“Natural” does not mean safe or beneficialNot regulated or evaluated by the FDALack of consumer information regarding

herbal preparations


The Consumer’s The Consumer’s PerspectivePerspective

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

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