EXAM
Lisa
ch4.pptxMeasuring Undernutrition Chapter 4
From Chapter 3 What we Learned
Biggest problem, Over- & under-nutrition
Total Calories
Protein
Micronutrients
Common methods of assessing undernutrition
Clinical Assessment: Looking for physical signs of nutritional disorders
Biochemical: Examine blood and urine looking for metabolic changes that accompany nutritional disorders
Common methods of assessing undernutrition (cont.)
Dietary Assessment: Track what the person eats
Anthropometric Assessment: Measuring the human body and its parts. It is the most common method of assessing nutritional disorders
Clinical Assessment
Look at:
Hair color (lighter and thinner)
Ankle swelling
Enlarged necks
Poor eye sight
Clinical Assessment (cont.)
What is each an indicator of?
Hair color (Lighter and thinner)
Protein deficiency
Ankle swelling
Protein deficiency causing circulation problems
Enlarged necks
Goiter, iodine deficiency
Poor eye sight
Vitamin A deficiency
Clinical Assessment (cont.)
Be aware that other things can cause these symptoms
When these symptoms show to this extent then the problem is advanced
Used to analyze:
most severe cases
Specific types of malnutrition
Biochemical Assessment
Blood and urine tests
Show micronutrient deficiencies
Accurate but relatively expensive
Dietary Assessment
2 Methods:
Survey – recall by the person, after-the-fact
Review dietary records
Dietary Assessment (cont.)
Problems with both methods
People can’t recall exactly
People lie
People adjust their eating habits when they are in a study
Breast feeding – difficult to determine how much the baby eats
Seasonal variations (price & availability)
Dietary Assessment
Useful in:
Doing comparisons of diet and income
Also useful to track food allocations within the family
Anthropometric Assessment
Most commonly-used method
Size – indicator of calories & protein intake
Anthropometric (cont.)
Acute undernutrition
Short-term inadequate food
Caused by famine or war
People can recover
Chronic undernutrition
Long-term inadequate food
Even moderate, effects are permanent
Stunting
Def.: low height-for-age
Shows that the person has experienced chronic undernutrition during growth years
It is a symptom of past undernutrition
Stunting (cont.)
People born in 1910 were 4 cm (1.6 in) shorter than those born in 1930
People born in 1950 1 cm (1/2 in) taller than those in 1930
What does that tell you?
Wasting
Def.: low weight for height
This is a symptom of current undernutrition
Under weight
Def.: low weight for age
A symptom of present undernutrition
What about Inheritance?
Part of people’s height is determined by their genes
Are there ethnic differences?
These factors are less important than other factors
Nature vs. nurture
Other Factors
Poverty
Poor food intake
Infectious & parasitic diseases
Other environmental factors
Use of Antropometry
Most useful in comparisons of infants
Older children, less so
In developed countries useful in measuring overnutrition of adults
Antropometry (cont.)
What is measured?
Height
Weight
Arm circumference
One of the better measures of fat in the body
Skin-fold thickness
Antropometry (cont.)
Measurements are easy and cheap
Need:
Scale
Tape measure
Calipers (know what they are)
Antropometry (cont.)
Training someone to recognize undernutrition by clinical means takes a lot more time
Comparisons to a Reference Group
“You are shorter than average”
“You weigh less than average”
What is the purpose of all this?
Identify those in need of help
Either those who are undernourished
Or Those who are overnourished
Method 1 Measuring Large Groups
(Note: Method 1 is not labeled, but is described in the paragraph on p. 51 Drawing Inferences from a sample)
A continent?
A country?
A region?
Among demographic groups
Def: characteristics of a population or segment of the pop.
Among ethnic groups
Measuring (cont.)
Cannot measure everyone
Statistics – Sampling
If our sample is representative then inferences can be made of the whole population
Method 2 Examine Aggregate Data
Look at data on:
Birth weight
Infant mortality
Morbidity
Def.: the rate of incidence of a disease
These are not direct measures of nutritional status
Method 3 Aggregate Nutrient Intake
Or: average nutrient intake
FAO keeps such data on each country
FAO Food and Agriculture Organization
Part of the UN
These food-balance sheets show sources and types of food – over 100 different foods
Aggregate (cont.)
FAO keeps stats on sources of food:
Beginning stocks
Production
Imports
Aggregate (cont.)
FAO keeps stats on uses of food:
Ending stocks
Export
Animal feed
Consumption
Aggregate (cont.)
They use the word balance sheet because sources and use are in balance
Aggregate data: These measures imply undernutrition in a region
High IMR
Low birth-weights
High morbidity (illness) rates
Look at food availability to infer the existence of undernutrition
Food balance sheets estimate human consumption
1. Add up the supply of a specific food
beginning stocks + production + imports
2. Subtract the amount used for:
exports + livestock feed + seed + ending stocks
What about food stocks used for fuel?
What is left can be assumed to go for human consumption
3. Convert this to calories
do for all foods, to calculate available calories per capita per day (a widely used measure of malnutrition)
Remember: Carbohydrate and protein has 4 calories/gram & Fats and oils have 9 calories/gram
This is a mean, it could be that some people are consuming above the average and some people are undernourished
a. Studies of individuals need to be done to infer the percentage of the population that have inadequate food intake
IV. Undernutrition & child health
A. Undernourished mothers are likely to produce malnourished babies
1. Low birth weight
2. 40 times more likely to die before their first year
B. Undernutrition leads to high under-five mortality rates
Worldwide average (1999) = 78 per 1,000 live births
Industrialized countries = 7
Developing countries = 85
Least developed countries = 161
(Sub-Saharan Africa)
C. Undernutrition results in a weakened immune system which leads to death from childhood diseases
Infant mortality rate (IMR; children who die before their 1st birthday per 1,000 live births) goes up as a child’s percent of the median weight-for-age goes down
IMR in the U.S. is 2.1%
– before five = 2.5%
IMR in Guinea = 21.6%
– before five = 36.7%
V. Effects of undernutrition
A. Mental development impaired in undernourished children
B. Educational achievement lowered
C. Childhood undernutrition results in smaller adults who can do less physical work & who earn less money
D. Undernourished adults are less productive when working and lose more work time to sickness and so have less money to buy food
(note the cycle)
Measuring nutritional status for large groups
A. Draw inferences from a sample using statistics
1. Use info from a subset of the population to infer characteristics of the whole population
2. Sample must be representative
B. Use aggregate data on the effects of undernutrition to infer how much undernutrition exists
Aggregate data: data compiled from several measurements
