Role of Nutrition in Prevention of Disease Arline McDonald, Ph.D Preventive Medicine 9/25/01 Nutrition Economic Consequences of Preventive Nutrition Disease Reduction in Hospitalization Costs/Year, $ Cardiovascular Disease 22 B Cancer 1B Low birth weight 500 B Neural Tube Birth Defects 70 B Cataract 2B Nutrition 9/25/01 Nourishment Functions Common Nourishment vs Pharmacologic Functions of Nutrients Nutrition Pharmacologic Functions 9/25/01 Nourishment vs Pharmacologic Functions of Nutrients   Pharmacologic Functions Nourishment Functions – initiated by disequilibrium – involve growth and – are compensatory maintenance activities responses – include surveillance – may involve activities – reflect a steady state different from usual roles – rely on adequate reserves – require higher levels of for effectiveness intake – are sensitive to imbalances – can rapidly deplete in nutrient intakes reserves and interfere with – expressed by classic nutrient nourishment functions deficiency disease symptoms Nutrition 9/25/01 Nourishment Functions enzyme activation cell messengers gene induction production, storage, release Energ y Regulatory Functions enzymes hormones immune substances Lean Body Mass, Skeletal Mass Synthesis of Bioactive Compounds Nutrition Fluid, Electrolyte, Acid-Base Balance Structure, functional activities membrane potentials, neuromuscular activity, plasma & cellular fluid volumes 9/25/01 Pharmacologic Functions feedback control gene expression Detoxification Enzyme Induction & Inhibition enzymes scavengers biotransformation and conjugation Immune Function Antioxidant Activity Nutrition Inflammatory Response Mitogenic, microbicidal & phagocytic activities Modulation by cytokines, prostaglandins 9/25/01 Nutrients with Nourishment and Pharmacologic Functions  Nutrients that support immune function –  Nutrients that provide antioxidant protection –  amino acids, vitamin B6, fatty acids, selenium Nutrients involved in tissue synthesis – vitamin C, carotenoids, vitamin E, selenium Nutrients that support synthesis of enzymes and bioactive compounds –  zinc, vitamin C, protein, vitamin A, vitamin B6, folate protein, energy, zinc, vitamin A, vitamin C, iron Nutrition 9/25/01 Contribution of Nutrient Imbalances to Development of Chronic Diseases Habitual Nutrient Intakes UV Exposure Nourishment Genetics Functional Cell Environmental Pollutants Stress Smoking Inactivity Damaged Damaged Cell Cell Nutrition Poor Hygiene 9/25/01 Determinants of Nutrient Needs  Absorption Efficiency  Metabolic Demand  Excretion Levels Nutrition 9/25/01 Absorption Efficiency A b s o r p tio n E ffic ie n c y H e a lth B io a v a ila b ility Ir o n C a lc iu m Z in c 10 Im b a la n c e s C a :F e F e :Z n Z n :C u D is e a s e D e fic ie n c ie s B -F o la te D -C a lc iu m M g -C a lc iu m Nutrition D ia r r h e a E le c tr o ly te s G e n e l V o m itin g G e n e l Fat M a la b s o r p tio n V ita m in s A , D,E,K 9/25/01 Metabolic Demand M e t a b o lic D em and H e a lt h G ro w th I r o n , Z in c , F o la t e P y r id o x in e A , D , C a lc iu m 12 S tre s s T h ia m in A s c o r b ic A c id M a g n e s iu m D is e a s e D ie t a r y E x c e s s K , Z n , M g , C r, B P y r id o x in e A n t io x id a n t s Nutrition I n fe c t io n Ir o n , Z in c P y r id o x in e A, C A lc o h o lis m T h ia m in M a g n e s iu m Z in c , A M e d ic a t io n s V ita m in D F o la t e P y r id o x in e 9/25/01 Goals of Nutrition in Disease Prevention 13 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 Nutrition 9/25/01 Optimize Cellular Activity and Tissue/Organ Function   14 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 Nutrition 9/25/01 Nutrient Requirements (Recommended Dietary Allowances)  Based on mean level of intake – –  Includes a margin of safety – – 15 required to prevent classic deficiency symptoms maintain serum levels in absence of deficiency symptoms accounts for individual differences (+ SD) provides additional amount for reserves Nutrition Intake + Reserves Needs 9/25/01 Years to Depletion 16 Carbohydrate Nutrition Vitamin A Vitamin C B-12 Calcium Nutrient Reserve Capacity 9/25/01 Effects of Different Dietary Intakes on Functional Activity % Functional Activity 100% Optimal 75% 50% Marginal Marginal 25% Excess Deficient 0% Nutrient Intake 17 Nutrition 9/25/01 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 – 18 maximize efficiency by not exceeding capacity Nutrition 9/25/01 Blood glucose (mg/dL) Blood Glucose Response to Different Sources of Carbohydrate 220 200 180 Typical Simple Sugar Soluble Fiber Starch 160 140 120 100 80 60 15 30 45 90 120 150 180 Minutes 19 Nutrition 9/25/01 Determinants of Blood Pressure X=Dietary Effects A r t e r ia l B lo o d P r e s s u r e C a r d ia c O u t p u t T o t a l P e r ip h e r a l R e s is t a n c e Salt & WaterX VasoconstrictionX Retention Renin Angiotensin Heart rate Aldosterone Kidney (long term) X 20 Epinephrine Norepinephrine SNS (short term) X Nutrition 9/25/01 Bone Mass Density (BMD) Calcium Intake and Fracture Risk 100% 80% Female at 80% Fracture Risk Threshold 0-10 20-30 30-40 40-50 50-60 60-70 70-80 80-90 90+ Age (years) 21 Nutrition 9/25/01 Effect of Nutrient Imbalances on Calcium Homeostasis plasma Ca+2 Bone Osteoclastic Activity Surface ions plasma Ca +2 Mg+ + Mg PTH2 Na + Kidney plasma Ca 22 +2 PO4-2 1, 25 (OH)2D protein Intestines Transcellular Tubular (Saturable) and Paracellular Reabsorption (Concentration-Dependent) Transport Nutrition 9/25/01 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 –  23 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 Nutrition 9/25/01 Cooperative Nature of the Immune System Immunoglobulins B-cells Complement Platelets CD4 T-cells CD8 Phagocytes Leukotrienes (LT4 or LT5) Cytokines Prostaglandins (PG2 or PG3) 24 Nutrition 9/25/01 Detoxification Drugs Chemicals Alcohol Steroid H Vitamin D Phase I Activation Active Intermediates Phase II Conjugation Targeted Cellular Effects Excretion Deactivation 25 Nutrition 9/25/01 Antioxidant Protection C e llu la r A n t io x id a n t s E n z y m e S y s te m s M in e r a ls C a t a la s e P e r o x id a s e Fe 26 S c a v e n g e rs V it a m in s G lu t a t h io n e P e r o x id a s e S u p e r o x id e D is m u t a s e Se, AA Cu/Mn Polyphenols Isothiocyanates M e m b n e L ip id P r o t e c t io n E Non-nutrient Plant Chemicals Nutrition A queous C o m p tm ts C L ip id C o m p tm ts Carotenoids CoQ10 9/25/01