Diet and Health

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Diet and Health
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Health concerns of developed countries

• Infectious diseases
• Decrease in recent years due in part to better
  food handling and storage and water purification
• Chronic diseases
• Develop over time
• Reflect metabolic abnormalities
• Diet influences development of many chronic
  diseases

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Infectious disease

• Public health strategies help prevent spread
• Each individuals immune system provides a
  defense
• Properly functioning immune systems rely on
  proper nutrition

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Immune system

• Physical barriers
• Skin
• Mucous membranes that line body cavitites that
  open to the outside of the body
• White blood cells
• Antibodies
• Chemicals produced by white blood cells

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White blood cells

• Phagocytes
• Neutrophils and macrophages
• Ingest and destroy any type of bacteria
• T lymphocytes
• Many varieties of T lymphocytes
• Each type attacks a certain type of cancerous
  cell or a specific virus
• B lymphocytes
• Many varieties of B lymphocytes
• Each type produces antibodies (proteins) which
  disable specific bacteria

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Immunity and nutrition

• Immune system is the most sensitive to diet
• Disease and malnutrition are synergistic
• They work together to destroy health
• Impaired immunity is a hallmark sign of PEM
  (protein-energy malnutrition)

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HIV and AIDS

• AIDS is a viral infection caused by the human
  immunodeficiency virus (HIV)
• HIV is spread through body secretions
• HIV destroys the immune system
• The body cannot defend itself against infections,
  even those that would be mild in a normal person

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HIV and nutrition

• Good nutrition does not prevent or cure HIV
  infection
• Remember, the immune system itself is destroyed
• Good nutrition may improve responses to drugs and
  improve quality of life

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Nutrition and chronic disease

• Four of the top ten causes of death in U.S.are
  influenced by diet
• 1 Heart disease (a cardiovascular disease)
• 2 Cancers
• 3 Strokes (a cardiovascular disease)
• 6 Diabetes

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Other diseases influenced by diet

• Hypertension (a cardiovascular disease)
• Osteoporosis
• Atherosclerosis (a cardiovascular disease)
• Obesity
• Stroke (a cardiovascular disease)
• Diverticulosis
• Dental and oral disease

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Other risk factors

• Genetics
• Age
• Sedentary lifestyle
• Tobacco use
• Stress
• Environmental contaminants

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Multiple risk factors

• Often poor nutrition acts synergistically with
  other health risk factors to increase
  susceptibility to certain chronic diseases

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Atherosclerosis

• Known as hardening of the arteries
• Begins with soft fatty streaks on interior
  arterial walls, especially at points of branching
• Streaks enlarge and harden with accumulated
  cholesterol, other lipids and calcium
• Streaks that become encased in fibrous connective
  tissue are called plaques

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Plaques

• Stiffen arteries
• Narrow passages
• Well developed by age 30 in most people
• High amounts of dietary saturated fat contributes
  to development and progression of plaques
• Can become inflamed

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Inflammation

• A immunological response to cellular injury
  characterized by an increase in white blood
  cells, redness, heat, pain, swelling, and
  possible loss of function of body part

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Factors contributing to damage and inflammation
of blood vessels

• High LDL cholesterol
• Hypertension
• Cigarette toxins
• Elevated homocysteine (an amino acid)
• Some viral and bacterial infections

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Progression of inflammation

• Increased macrophages appear
• Smooth muscle of vessel wall tries to repair
• LDL particles become trapped in vessel wall
• LDL becomes oxidized by free radicals that are
  produced by the inflammatory process
• Macrophages ingest oxidized LDL and become part
  of plaque

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Consequences of inflammation

• Arterial damage plus inflammation contributes to
  the formation of blood clots, hardening of plaque
  by minerals and formation of fibrous connective
  tissue capsule

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Aneurysms

• Abnormal bulges of arterial walls weakened by
  inflammation of atherosclerosis
• Can rupture and lead to massive bleeding and
  possible death

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C-reactive protein

• Released by liver during inflammation
• A good marker of inflammation in blood vessel
  walls
• A better predictor of future heart attack than
  high LDL cholesterol

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Causes of plaque rupture

• Sudden vascular spasm
• Surge in blood pressure

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Factors contributing to plaque instability and
rupture

• Thin fibrous cap
• Large lipid core
• Large number of macrophages

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Response to plaque rupture

• Clot formation
• Thrombosis
• Embolisms

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Blood pressure and atherosclerosis

• Heart must beat harder to move blood through
  narrowed vessels
• Blood pressure increases
• Accelerates vessel wall damage
• Increases formation of plaques and clots in
  damaged areas

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Effects of atherosclerosis on heart

• Atherosclerosis can affect any artery, but most
  commonly affects coronary arteries
• Angina
• Restricted blood flow, due to atherosclerosis, to
  heart muscle resulting in pain and pressure
• Heart attack
• Cessation of blood flow to heart muscle,
  resulting in death of affected heart muscle

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Effects of atherosclerosis on brain

• Transient ischemic attack (TIA)
• Temporary reduction in blood flow
• Stroke-cardiovascular accident(CVA)
• Cessation of blood flow

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Risk factors for coronary heart disease

• By middle age most people have at least one risk
  factor for CHD

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Major risk factors for CHD nonmodifiable

• Increasing age
• 45 or older for males
• 55 or older for females
• Male gender
• Family history of premature heart disease

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Major risk factors for CHD modifiable and diet
related

• High blood LDL
• Low blood HDL
• High blood pressure
• Diabetes
• Obesity, especially in abdomen
• Atherogenic diet high in saturated fats and low
  in fruits, vegetables and whole grains

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Modifiable risk factors for CHD non diet related

• Physical inactivity
• Aerobic exercise strengthens heart, promotes
  weight loss, improves blood lipid and blood
  glucose levels
• Cigarette smoking
• Risk declines within a few months of quitting

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Metabolic syndrome

• Any three of the diet related risks that occur
  together
• Syndrome predicts risk of CHD, but no more so
  than when risks are considered separately
• Proposed new definition puts added emphasis on
  abdominal obesity
• High prevalence of syndrome in U.S.

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Recommendations for reducing risk of CHD

• Cholesterol screening
• Lifestyle changes
• Diet
• Exercise
• Smoking

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Hypertension

• Rises in blood pressure increase risk associated
  with atherosclerosis
• Hypertension is the most consistent and powerful
  predictor of stroke
• Affects about 1/3 adult U.S. population
• Contributes to over a million heart attacks and
  1/2 million strokes per year in U.S.

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Development of hypertension

• Rise in cardiac output (volume of blood
  discharged by the heart/minute)
• Rises when blood volume or heart rate increases
• Rise in peripheral resistance (resistance to
  blood flow in arterioles)
• Affected by diameter of arterioles vessels
  blocked by plaque automatically increase
  resistance

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Organs affecting blood pressure

• Nervous system
• Regulates heart rate
• Regulates diameter of vessels
• Certain hormones
• Regulate blood volume
• Cause blood vessel constriction
• Kidneys
• Produce hormones that produce vessel constriction
• Regulate retention of sodium and water which
  increase blood pressure

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Risk factors for hypertension

• Age
• Genetics
• Obesity
• Alters kidney function
• Promotes insulin resistance which leads to vessel
  damage
• Increases blood volume and cardiac output
• Increases peripheral resistance by adding 200
  miles of vessels/pound of fat

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• Salt sensitivity
• Causes rise in blood volume
• Alcohol
• Over 2 drinks/day
• Can interfere with medications
• Associated with stroke independent of
  hypertension

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Diagnosis

• Frequent checks of blood pressure at rest

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Treatment

• Weight control
• Physical activity
• DASH diet (dietary approaches to stop
  hypertension)
• Fruits
• Vegetables
• Low fat dairy
• Nuts
• Low total and saturated fat
• Reduction in salt intake
• Drug therapy
• Diuretics
• Other drugs

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Diabetes mellitus

• 6th leading cause of death in U.S.
• Contributes to or is underlying cause of heart
  disease, stroke, blindness and kidney failure
• Diabetics are 2x more likely to develop heart
  disease

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Metabolism of diabetes

• Abnormally sustained high levels of blood glucose
• Insufficient or complete lack of insulin
• Inability of cells to respond to insulin in some
  cases

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Insulin

• Hormone produced by the pancreas
• Released into blood after nutrients have been
  absorbed from digestive tract
• Signals cells to absorb energy yielding
  nutrients, glucose, amino acids and fatty acids
• Stimulates glycogen synthesis in liver and
  muscle, and fat synthesis
• Insulin maintains glucose levels within
  homeostatic limits in a normal person

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Symptoms of diabetes

• High glucose levels in blood and urine
• Thirst
• High urine volume

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Types of diabetes

• Type I
• Type II

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Type I

• Only 5-10 of diabetic cases
• Age of onset is usually under 30
• Is considered an autoimmune disorder in which
  white blood cells mistakenly destroy the beta
  cells of the pancreas, which make insulin
• Insulin must be replaced through injection
• Insulin is a protein, and if taken by mouth, is
  digested as any other protein would be

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Type II

• 90-95 of cases
• Usually appears over 40, although it is now seen
  commonly in much younger people, including
  children
• Obesity, aging and genetic tendencies are
  implicated in the development of type II
• Insulin may be normal, increased or decreased
• Cells may be insulin resistant
• Depending on severity, treatments include from
  weight loss, dietary changes, oral medications or
  insulin

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Complications of diabetes

• Altered glucose metabolism
• Conversion of glucose to sugar alcohols
• Cell toxicity
• Cell distension, including cells of the lens of
  the eye
• Abnormal attachment of glucose to proteins,
  rendering them inactive
• Damage to nerves and blood vessels
• Increased susceptibility to infection

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Metabolic consequences of type I

• Weight loss
• Excessive hunger and thirst
• Excessive eating
• Ketone production (damage kidneys and other
  organs)
• Dehydration due to excessive urine formation
• Diabetic coma
• Death

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Metabolic consequences of type II

• Hunger
• Excessive eating
• Weight gain
• Excessive urine formation
• Dehydration
• Coma
• Death

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Diet and diabetes

• Diet is strictly regulated and coordinated with
  medication in both types
• In milder cases of type II, dietary and physical
  activity changes alone may normalize blood
  glucose

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Cancer

• Cancers are the second leading cause of death in
  the U.S.
• Mutations occur in the DNA of cells, causing
  abnormal function and allowing them to reproduce,
  unchecked, to produce tumors
• Tumor cells may break loose and metastasize in
  the body and produce new tumors in many locations
• Organs with cancerous tumors cannot function
  normally

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Causes of cancer

• Genetic defects
• Oxidants produced during metabolic reactions
• Interactions between genes and environmental
  carcinogens

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Diet and cancer

• Diets rich in fruits,vegetables, legumes and
  whole grains contain nutrients and phytochemicals
  that reduce the risk of some cancers

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Weight and cancer

• Obese people are at a higher risk for some types
  of cancer
• Colon
• Endometrial
• Breast
• Kidney
• Esophageal
• Possibly ovarian and prostate

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The End