Lecture 3

Question 1

Intervention Trials: Characteristics

Answer 1

Placebo: Dummy treatment given to control to eliminate participation expectations
Blinding of Study: Unknown which participant is assigned to which group
Single Blind Study: Participant or researcher
Double Blind Study: Both parties

Question 2

Intervention trials Strength and Weakness

Answer 2

Strengths: Shows causation, Evidence considered stronger than observation studies
Weakness: Difficult to measure disease outcome
Difficult to sustain trial if there is heavy diet change

Question 3

Nutrition Research

Answer 3

Use results from both intervention and observational studies to make dietary recommendations

Question 4

Seven Countries Study

Answer 4

One of earliest nutrition studies
Looked at relationship between lifestyle factor and cardiovascular disease
Looked at: Agre, BP, serum cholesterol, smoking, exercise, resting HR, Overweight + Obesity
Die: Sat and Poly fat intake, sugar and protein intake

Question 5

Seven Countries Study Properties

Answer 5

Observational
Hypothesis: Lifestyle factors affects heart disease
Studied 13,000 middle age men - more likely to get cardio disease
Picked several cities from countries to develop range of data

Question 6

The Core of Seven countries study

Answer 6

Dietary intake evaluated at start
Data obtained from participants for 5-10 years with follow ups up to 40 years
Outcome: Incidence of heart disease and death from heart disease determined

Question 7

Seven Countries Results

Answer 7

+ correlation between serum cholesterol and cardiovascular disease
+ correlation between Saturated Fat and cardiovascular disease
- Correlation between PUFA and serum cholesterol

Question 8

Seven Countries Paradox

Answer 8

Same levels of cholesterol but different mortality between the countries
Other factors affect heart disease

Question 9

Mediterranean Diet Pyramid

Answer 9

Gold Standard of Diet
Mostly vegetables
Little animal product but enough to get its esstential nutrients

Question 10

Nutrition Recommendation for Canadian Diet

Answer 10

Nutrient-Based Approach - Nutrient required to maintain health
Food-Based - types and amount of foods to maintain health
Translate nutrient to food so its easier for people to understand

Question 11

Today’s Canadian Diet recommendation

Answer 11

Use Dietary Reference Intake (DRIs)
Institute of Medicine determines intake
IOM changes diet to new data

Question 12

Dietary Reference Intakes

Answer 12

Planning and assessing diets of healthy individuals
Values change for different sex and life stages
Estimated Energy Requirement (EER)
Acceptable Macro nutrient Distribution Range (AMDR)
Estimated Average Requirement (EAR)
Recommended Dietary Allowance (RDA)
Adequate Intake (AI)
Tolerable Upper Intake Level (UL)

Question 13

Estimated Average Requirement (EAR)

Answer 13

Nutrient intake that meets 50% required of people in a group
Estimate probability than an individual meets his requirement
Estimate what proportion of a group meets their requirements

Question 14

Determining EAR

Answer 14

Find biochemical criteria that allows you to measure how much an individual needs
Find requirement distribution from a sample population

Question 15

Establishing EARs

Answer 15

Physiological Criteria:
Vitamin X requirement is met when serum is saturated with Vitamin H
Not universal criterion for all nutrients
DO depletion-repletion experiment on population of healthy adults

Question 16

EAR Depletion

Answer 16

Feed Vitamin X free diet
Vitamin X serum levels tracked
Levels decline until Vitamin x is no longer detected
Individual is deficient

Question 17

EAR Repletion

Answer 17

Re-feed Vitamin X
Vitamin serum levels rise
Reaches a point where there is no increase in levels
That intakes is individual’s requirement

Question 18

Difference between Nutrient Requirement and Intake

Answer 18

Requirement:
Experimentally determine nutrient requirement
Amount needed to maintain health
How much Vitamin X needed to maintain in blood
Intake:
Amount of nutrient consumed
Determined by diet composition
How much Vitamin X is consumed

Question 19

Dietary Reference Intakes EAR

Answer 19

EAR represents average daily intake nutrients requirement needed by half the people in a group
If nutrient intake = EAR there is 50% an individual is meeting his requirement

Question 20

Recommended Dietary Allowance (RDA)

Answer 20

EAR + 2 Standard Deviations

Ensures there is 98% your intake is meeting your requirements

Question 21

EAR cut point method

Answer 21

Use EAR cut point to find what proportion of a group is meeting their requirements
Proportion of population not meeting their requirement

Question 22

Two Population with same EAR cutpoint

Answer 22

Not the same proportion of population meets requirements

Portion of population depends on median intake and standard deviation of intake distribution

Question 23

How EAR cut point is used

Answer 23

Health Canada: Population is well if 10% or less is below EAR
Canadian Community Healthy Survey: Measure nutrient intake and use EAR cur point to determine adequacy of nutrient intake

Question 24

Adequate Intake

Answer 24

Not enough data to calculate an EAR
Usually based on estimate average nutrient intake by healthy population
Used when EAR not available

Question 25

Adequate Intake (2)

Answer 25

Your intake > AI, intake ok
AI a good personal target
Intake < AI, may or may not be ok