SBM NutrDisease Prevention

Role of Nutrition in Prevention of
Disease

Arline McDonald, Ph.D.
Preventive Medicine

1

9/25/01

Nutrition


Economic Consequences of
Preventive Nutrition
Disease

2

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

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Nourishment
Functions

3

Common

Nourishment vs Pharmacologic
Functions of Nutrients

Nutrition

Pharmacologic
Functions

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Nourishment vs Pharmacologic
Functions of Nutrients


4

 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

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Nourishment
Functions
enzyme activation
cell messengers
gene induction

production,
storage, release

Energ
y
Regulatory
Functions

enzymes
hormones
immune substances

5

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

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Pharmacologic
Functions
feedback control
gene expression

Detoxification
Enzyme
Induction &
Inhibition

enzymes
scavengers

6

biotransformation
and conjugation

Immune
Function

Antioxidant
Activity

Nutrition

Inflammatory
Response

Mitogenic,
microbicidal &
phagocytic
activities

Modulation by
cytokines,
prostaglandins

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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
–

7

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

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Contribution of Nutrient Imbalances to
Development of Chronic Diseases
Habitual Nutrient Intakes
UV Exposure

Nourishment
Genetics
Functional
Cell

Environmental
Pollutants

Stress

8

Smoking

Inactivity

Damaged
Damaged
Cell
Cell
Nutrition

Poor Hygiene

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Determinants of Nutrient Needs

9



Absorption Efficiency



Metabolic Demand



Excretion Levels

Nutrition

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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 1 2 -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 ra l

V o m itin g
G e n e ra l

Fat
M a la b s o r p tio n
V ita m in s A ,
D,E,K

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Excretion Levels
E x c r e tio n L e v e ls

11

H e a lth

D is e a s e

Im b a la n c e s
Na>Ca
Na>K

M e d ic a tio n s
D iu r e tic s -K
S e q u e s tr a n ts -F o la te

Nutrition

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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 1
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

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Goals of Nutrition in Disease Prevention

13

1.

Optimize cellular activity and tissue/organ function

2.

Reduce metabolic burden imposed by environmental factors on
cardiac, pulmonary, renal, hepatic, and musculoskeletal systems

3.

Support cellular defenses that protect tissue integrity

Nutrition

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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

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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 (+ 2 SD)
provides additional
amount for reserves

Nutrition

Intake
+ Reserves

Needs

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Years to Depletion

16
8
7
6
5
4

3
2
1
0
Carbohydrate

Nutrition
Vitamin A

Vitamin C

B-12

Calcium

Nutrient Reserve Capacity

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Effects of Different Dietary Intakes
on Functional Activity
% Functional Activity

100%
Optimal

75%
50%

Marginal

Marginal

25%

Excess

Deficient

0%

Nutrient Intake

17

Nutrition

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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
–

18

maximize efficiency by not exceeding capacity

Nutrition

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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
0

15

30

45

90

120

150

180

Minutes

19

Nutrition

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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

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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

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Effect of Nutrient Imbalances on
Calcium Homeostasis
plasma Ca+2

Bone

Osteoclastic Activity

Surface ions

plasma Ca

+2

Mg+

+
Mg
PTH2

2

Na
+
Kidney
plasma Ca

22

+2

PO4-2
1, 25 (OH)2D
protein

Intestines

Transcellular
Tubular
(Saturable) and Paracellular
Reabsorption
(Concentration-Dependent)
Transport

Nutrition

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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
–



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

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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

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Detoxification
Drugs
Chemicals
Alcohol

Steroid H
Vitamin D

Phase I

Activation

Active
Intermediates

Phase II

Conjugation

Targeted
Cellular
Effects

Excretion

Deactivation

25

Nutrition

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