Role of Nutrition in Prevention of Disease

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Role of Nutrition in Prevention of Disease

• Arline McDonald, Ph.D.
• Preventive Medicine

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Economic Consequences of Preventive Nutrition
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Nourishment vs Pharmacologic Functions of
Nutrients
NourishmentFunctions
Pharmacologic Functions
Common
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Nourishment vs Pharmacologic Functions of
Nutrients

• Nourishment Functions
• involve growth and maintenance activities
• include surveillance
• reflect a steady state
• rely on adequate reserves for effectiveness
• are sensitive to imbalances in nutrient intakes
• expressed by classic nutrient deficiency disease
  symptoms

• Pharmacologic Functions
• initiated by disequilibrium
• are compensatory responses
• may involve activities different from usual roles
• require higher levels of intake
• can rapidly deplete reserves and interfere with
  nourishment functions

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NourishmentFunctions
Energy
Lean Body Mass, Skeletal Mass
RegulatoryFunctions
Synthesis of Bioactive Compounds
Fluid, Electrolyte, Acid-Base Balance
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PharmacologicFunctions
Detoxification
Enzyme Induction Inhibition
Immune Function
Inflammatory Response
Antioxidant Activity
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Nutrients with Nourishment and Pharmacologic
Functions

• Nutrients that support immune function
• zinc, vitamin C, protein, vitamin A, vitamin B6,
  folate
• Nutrients that provide antioxidant protection
• vitamin C, carotenoids, vitamin E, selenium
• Nutrients that support synthesis of enzymes and
  bioactive compounds
• amino acids, vitamin B6, fatty acids, selenium
• Nutrients involved in tissue synthesis
• protein, energy, zinc, vitamin A, vitamin C, iron

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Contribution of Nutrient Imbalances to
Development of Chronic Diseases
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Determinants of Nutrient Needs

• Absorption Efficiency
• Metabolic Demand
• Excretion Levels

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Absorption Efficiency
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Excretion Levels
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Metabolic Demand
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Goals of Nutrition in Disease Prevention

• Optimize cellular activity and tissue/organ
  function
• Reduce metabolic burden imposed by environmental
  factors on cardiac, pulmonary, renal, hepatic,
  and musculoskeletal systems
• Support cellular defenses that protect tissue
  integrity

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Optimize Cellular Activity and Tissue/Organ
Function

• Provide sufficient amounts to satisfy daily
  demands
• Adequacy of intake
• Balance and variety in food choices
• Maintain adequate reserves
• Habitual diet and dietary patterns
• Defensive approach

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Nutrient Requirements (Recommended Dietary
Allowances)

• Based on mean level of intake
• required to prevent classic deficiency symptoms
• maintain serum levels in absence of deficiency
  symptoms
• Includes a margin of safety
• accounts for individual differences ( 2 SD)
• provides additional amount for reserves

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Nutrient Reserve Capacity
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Effects of Different Dietary Intakeson
Functional Activity
Deficient
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Reduce metabolic burden on organ systems

• Minimize workload
• reduce stress on organ systems involved in
  transport, metabolism, and elimination of
  nutrients and metabolic waste
• promote functional efficiency
• Prevent need for compensatory responses
• maximize efficiency by not exceeding capacity

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Blood Glucose Response to Different Sources of
Carbohydrate
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Determinants of Blood Pressure
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Calcium Intake and Fracture Risk
Fracture Risk Threshold
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Effect of Nutrient Imbalances on Calcium
Homeostasis

PTH
Kidney
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Support cellular defenses that protect tissue
integrity

• Maintain immune system competence
• requires support for all components
• depends on balanced intake of nutrients
• Promote efficiency of detoxification systems
• controls levels of reactive chemical
  intermediates
• Prevent oxidative damage
• accumulation of damage involved in pathogenesis
  of most chronic diseases
• reduces efficiency of immune cell activities

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Cooperative Nature of the Immune System
Immunoglobulins
B-cells
Complement
Platelets
CD4
Leukotrienes (LT4 or LT5)
Phago-cytes
T-cells
CD8
Cytokines
Prostaglandins (PG2 or PG3)
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Detoxification
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Antioxidant Protection