Transcript Document 7162778

Nutrition and the
Physiology of
Malnutrition
Lia Fernald, Ph.D., M.B.A.
Human Biology Lecture
May 14, 2002
Male, 17, Oakland, weekly diet
Mon
Tues
Wed
Sat
Sausage, egg
B cheese burrito
(McD)
Nothing
Frosted Flakes
Hot link with
mustard,
ketchup, Coke
Personal size
L pepperoni pizza
Double cheese
burger, fries,
Coke (BK)
Pepperoni pizza
(PH) and french
fries
Nation’s
cheeseburger,
large fries, Coke
Burrito from
S vending
machine, Lays
Banana nut
muffin and
carton of milk
2 ham & cheese
sandwiches and
can of soda
2 hot dogs,
blueberry muffin
Spaghetti, fried
D chicken, fruit
punch
Small round
pizza
Baked pork
chops, mac &
cheese, Pepsi
Fries, BBQ
bacon cheese
burger (McD)
3,045
(38%)
2,400
(41%)
2,739
(33%)
3,163
(36%)
Overweight 9th graders in the Bay Area
35%
Alameda
San Mateo
Napa
Solano
Sonoma
Santa Clara
Contra Costa
Marin
San Francisco
30%
25%
20%
15%
10%
5%
0%
% overweight
“Overweight” defined as more than 25% body fat for boys
and more than 32% for girls. Less than 1% of students
are out of shape because they are too thin.
Today’s Class
•
•
•
•
•
•
Overview of Nutritional Requirements
Definition of Malnutrition
Causes and correlates of Malnutrition
Measurement and Types of Malnutrition
Severe Malnutrition
Mild/Moderate Malnutrition (Underweight
and Stunting)
• Specific Nutritional Deficiencies (Iodine and
Iron)
Nutritional requirements
Macro v. micro nutrients
• Macro-nutrients
– Protein (amino acids)
– Energy (carbohydrates)
– Fat (fatty acids)
• Micro-nutrients
– Water soluble vitamins (assist in energy-release of
carbohydrates and red blood cell formation)
– Fat soluble vitamins (development & metabolism)
– Minerals
Macro-nutrients
• Energy
– Necessary for all bodily function
• Protein
– Necessary for structural development (muscle
and bone)
• Fat
– Necessary for cell membrane and skin cell
development
Dietary Reference Intakes
Macronutrient
F (19-30 y.o.)
M (19-30 y.o.)
Energy (Kcal)
1940 – 2200
2550 – 2900
36 – 46
44 – 60
15 – 33%
15 – 33%
Protein (g)
Fat
Water soluble vitamins
• Thiamin B
– nervous system function, enzymatic energy release of carbohydrates
(beef, pork, liver, legumes, breads)
• Riboflavin B2
– Participants in enzymatic energy release of carbs, fat & protein (milk,
dairy, dark green vegetables, yogurt)
• Niacin
– Participates in enzymatic energy release of energy nutrients (beef,
pork, liver, breads, nuts)
• Folate
– Red blood cell formation, new cell division (veg, seeds)
• Vitamin B12 (Cobalamin)
– Red blood cell formation, nervous system maintainance (animal prod)
• Pantothenic Acid
• Biotin (Vitamin H, CoEnzyme R)
• Vitamin B6 (Pyridoxine)
• Vitamin C
Fat soluble vitamins
• Vitamin A
– Essential to vision, fetal development, immune response
– Found in dairy products, fish liver oils; as B-carotene found
in many plants (e.g. carrots, mango)
• Vitamin D
– Bone formation, calcium metabolism and absorption
– Found in sunlight, egg yolk, dairy products and fish liver oil
• Vitamin E
– Cell membrane construction and maintenance
– In fats and oils, green leafy vegetables, poultry, fish
• Vitamin K
– Blood clotting, protein synthesis
– In green leafy vegetables, liver, cabbage
Minerals
Major “Bone” Minerals
Trace Minerals
Calcium (bones)
Phosphorus (DNA)
Magnesium (bones)
Sodium (nerve impulse)
Chloride (fluid balance)
Potassium (prot. syn)
Sulfur (some a.a.’s)
Iodine (thyroid function)
Iron (hemoglobin)
Zinc (enzyme, hormone)
Copper (abs. of iron)
Flouride (bone & teeth)
Chromium (energy rel.)
Molybdenum (enzymes)
Manganese (enzymes)
Selenium (antioxidant)
Cobalt (part of B12)
Summary: Nutritional requirements
• In order to live and function, humans need
macro- and micro- nutrients;
• Macro-nutrients are fat, protein and
carbohydrates;
• Micro-nutrients are water-soluble vitamins,
fat-soluble vitamins, and minerals (bone
and trace); the most critical micro-nutrients
are iron, iodine, zinc, vitamin A and vitamin
D.
Today’s Class
•
•
•
•
•
•
Overview of Nutritional Requirements
Definition of Malnutrition
Causes and correlates of Malnutrition
Measurement and Types of Malnutrition
Severe Malnutrition
Mild/Moderate Malnutrition (Underweight
and Stunting)
• Specific Nutritional Deficiencies (Iodine and
Iron)
What is malnutrition?
World Health Organization definition:
The term is used to refer to a number of
diseases, each with a specific cause related
to one or more nutrients (for example, protein,
iodine or iron) and each characterized by
cellular imbalance between the supply of
nutrients and energy on the one hand, and the
body's demand for them to ensure growth,
maintenance, and specific functions, on the
other.
Countries at risk of malnutrition
Geneva Declaration
1924: Declaration of the Rights of the Child (also
known as the Declaration of Geneva).
• Adopted after World War I by the League of Nations
through the efforts of British child rights pioneer
• Marks the beginning of the international child rights
movement and is also the first international affirmation of
the right to nutrition.
• Affirms that "the child must be given the means needed
for its normal development, both materially and spiritually"
and states that "the hungry child should be fed."
Death from malnutrition
*
*
*At least 70%
*
of childhood
diseases are
related with
one of these
conditions
*
*
Source: WHO, based on C.J.L. Murray and A.D. Lopez, The Global Burden of Disease, Harvard University Press,
Cambridge (USA) 1996 and American Journal of Public Health 1993-83.
Summary: Definition of malnutrition
• Malnutrition is having the inappropriate
level of a micro- or macro- nutrient;
• In some cases (i.e. the US), malnutrition
can be associated with being grossly
overweight;
• In most of the world, malnutrition is defined
as a LACK of nutrients;
• Malnutrition contributes to over 50% of
deaths in children in the world.
Today’s Class
•
•
•
•
•
•
Overview of Nutritional Requirements
Definition of Malnutrition
Causes and correlates of Malnutrition
Measurement and Types of Malnutrition
Severe Malnutrition
Mild/Moderate Malnutrition (Underweight
and Stunting)
• Specific Nutritional Deficiencies (Iodine and
Iron)
Causes of malnutrition
Child malnutrition
death and disability
Inadequate
Diet
Disease
Inadequate
Insufficient Poor water/ sanitation
access to food inadequate health maternal and
child care
services
Higher
mortality rate
Reduced
capacity
to care
for baby
Elderly
Malnourished
Inadequate
food,
health
& care
Inadequate
fetal
nutrition
Woman
Malnourished
Start here
Pregnancy
Low Weight
Gain
Higher
maternal
mortality
Impaired
mental
development
Increased risk of
adult chronic disease
Baby
Low Birth
Weight
Inadequate
catch up
growth
Child
Stunted
Untimely/inadequate
weaning
Frequent
Infections
Inadequate
food, health
& care
Reduced
mental
capacity
Adolescent
Stunted
Inadequate
food, health
& care
Reduced
mental
capacity
Inadequate
food, health
& care
Correlate: Unsafe Water
11% urban and 38% rural
households do not have
access to safe water
Source for photos: Overseas Aid: www.nat.uca.org.au, Statistics, UNICEF State of the World’s Children 2000
Correlate: Inadequate Sanitation
21% urban
and 75% rural
households do
not have
access to
adequate
sanitation
Source for photos: Overseas Aid: www.nat.uca.org.au, Statistics, UNICEF State of the World’s Children 2000
Correlate: Poor Education
25% of girls and 19% of boys do
not enter primary school;
54% of girls and 45% of boys do
not enter secondary school
Source for photos: Overseas Aid: www.nat.uca.org.au, Statistics, UNICEF State of the World’s Children 2000
Correlate: Poverty
28% of the
population lives at
below $1 per day
Average GNP per
capita is $1299
(compared with
$29,080 in USA)
Source for photos: Overseas Aid: www.nat.uca.org.au, Statistics, UNICEF State of the World’s Children 2000
Correlate: Poor Stimulation
39% of females
and 21% of males
over the age of 15
cannot read or
write
199 radios per
1000 population;
154 TV’s per 1000
population
Source for photos: Overseas Aid: www.nat.uca.org.au, Statistics, UNICEF State of the World’s Children 2000
Correlate: Poor Public Health
About 30% of 1year olds are not
fully immunized
for TB, DPT
(Diptheria,
Pertussis, and
Tetanus), polio
and measles
Source for photos: Overseas Aid: www.nat.uca.org.au, Statistics, UNICEF State of the World’s Children 2000
Correlate: No Breastfeeding
Babies are twins (boy and
girl)
Mother was told that she
wouldn’t have enough
breast milk for both,
so should bottle feed girl . . .
girl died the day after
this photo was taken
56% babies in developing
countries are not breastfed
from 0-3 months
Source: Children’s Hospital Islamabad
Summary: Causes/correlates
• Malnutrition rarely exists in isolation, and many
other factors contribute to its detrimental impact;
–
–
–
–
–
Poor physical resources, and overcrowded homes
Poor sanitation and water supply
Low income
Parents with little education
Minimal interaction/stimulation in the home
• Malnutrition has repercussions throughout the life
cycle and is thus multi-generational (diagram with
lots of arrows)
Today’s Class
•
•
•
•
•
•
Overview of Nutritional Requirements
Definition of Malnutrition
Correlates of Malnutrition
Measurement and Types of Malnutrition
Severe Malnutrition
Mild/Moderate Malnutrition (Underweight
and Stunting)
• Specific Nutritional Deficiencies (Iodine and
Iron)
Types of malnutrition
• Severe Protein-Energy Malnutrition (>3 S.D.)
– Kwashiorkor (low protein)
– Marasmus (low calories)
• Mild/moderate undernutrition (>2 S.D.)
– Stunting
– Underweight
– Wasting
• Micro-nutrient deficiency
–
–
–
–
Iodine
Iron
Vitamin A
Vitamin D
Measurement of Malnutrition
• STUNTING: Height for age – height
compared to a reference population of the
same age.
= represents long term growth retardation
• UNDERWEIGHT: Weight for age – weight
compared to age in a reference population
• WASTING: Weight for height – weight
compared to a reference population of the
same height.
Growth Curves (0-3 years)
Length/
Height
Weight
Age
Summary: Measurement
• There are several types of malnutrition,
micro- and macro-malnutrition;
• Measurement of severe malnutrition (>3
S.D.) and micro-nutrient deficiency usually
occurs due to presence of critical signs (to
be discussed);
• Measurement of mild/moderate malnutrition
(>2 S.D.) occurs with growth charts.
Today’s Class
•
•
•
•
•
•
Overview of Nutritional Requirements
Definition of Malnutrition
Correlates of Malnutrition
Measurement and Types of Malnutrition
Severe Malnutrition
Mild/Moderate Malnutrition (Underweight
and Stunting)
• Specific Nutritional Deficiencies (Iodine and
Iron)
Severe malnutrition % <5 y.o.
20%
18%
16%
14%
12%
10%
8%
6%
4%
2%
0%
South Asia
Sub-Saharan Africa
Middle East and
North Africa
CEE/CIS & Baltic
States
Latin America &
Caribbean
%
Developing Countries
Least Developed Countries
12%
13%
(India 21%, Bangladesh 21%, Cambodia 18%)
Data for 1992-98, UNICEF State of the World’s Children 2000
Severe PEM: Real Numbers
Example: India
• 21% of all children under 5
• # children under 5 is 115,615,000
• 24M children severely malnourished (Bigger than
population of Texas 20M)
Example: All developing countries
• Total # <5 in developing countries: 536,105,000
and 12% of that is:
• 64M children under 5y.o. severely malnourished
(California & New York & Florida)
Example: World (total number is 603,449,000)
11% = 66M (France or England)
Kwashiorkor
Infection
Sparse
hair
Swollen
belly
Decreased
muscle
mass
Pellagra
Apathy
Kwashiorkor (low protein)
• Decreased muscle mass (failure to gain weight and of
linear growth)
• Swollen belly (edema and lipid build-up around the liver)
• Changes in skin pigment (pellagra); may lose pigment
where the skin has peeled away (desquamated) and the
skin may darken where it has been irritated or traumatized
• Hair lightens and thins, or becomes reddish and brittle.
• Increased infections and increased severity of normally
mild infection, diarrhea
• Apathy, lethargy, irritability
 Death does not occur from actual starvation but from
secondary infection
Kwashiorkor – mechanisms
• Occurs in reaction to emergency situations
(famine)
• Kwashiorkor more likely in areas where
cassava, yam, plantain, rice and maize are
staples, not wheat
• Increased carbohydrate intake with
decreased protein intake eventually leads
to edema (water) and fatty liver
Marasmus (low calories)
Ravenously
hungry
Gross
weight
loss &
no fat
Marasmus
• Deficit in calories – “marasmus” comes
from Greek origin of word “to waste”
• Gross weight loss
• Hyper-alert and ravenously hungry
• Children have no subcutaneous fat or
muscle
 eventually starve to death (immediate
cause often is pneumonia)
Marasmus – mechanism
• Energy intake is insufficient for body’s
requirements – body must draw on own stores
• Liver glycogen exhausted in a few hours –
skeletal muscle protein used via gluconeogenesis
to maintain adequate plasma glucose
• When near starvation is prolonged, fatty acids are
incompletely oxidized to ketone bodies, which
can be used by brain and other organs for energy
• High cortisol and growth hormone levels
 Mechanism is same as anorexia
Severe Malnutrition: Consequences
•
Mental development
–
–
•
Lower IQ levels
Poorer school performance
Behaviors of recovered severely malnourished
children
–
–
–
–
–
shy, isolated, withdrawn
decreased attention span
immature, emotionally unstable
fewer peer relationships/reduced social skills
played less/stayed nearer to mothers
Summary: Severe malnutrition
• Severe malnutrition is defined as > 3 s.d.
away from median reference standards;
• 66M children under the age of 5 are
severely malnourished (64M of these in
developing countries);
• Key types of severe malnutrition are
kwashiorkor (low protein) and marasmus
(low calories);
• Severe malnutrition results in severe
deficits for children
Today’s Class
•
•
•
•
•
•
Overview of Nutritional Requirements
Definition of Malnutrition
Correlates of Malnutrition
Measurement and Types of Malnutrition
Severe Malnutrition
Mild/Moderate Malnutrition (Underweight
and Stunting)
• Specific Nutritional Deficiencies (Iodine and
Iron)
Stunting – Height for Age
• Height for age reflects pre- and post- natal
linear growth
• “Stunting” refers to shortness that is not
genetic, but due to poor health or nutrition
• Most standard definition < 2 S.D.
• Stunting is good cumulative measure of
“well-being” for populations of children
(because not affected by weight recovery)
Stunting
These girls are:
From same school
and the same
neighborhood
Both have the
same birthday
Stunting % <5 y.o.
South Asia
60%
50%
40%
30%
20%
10%
0%
Sub-Saharan
Africa
Middle East
and North
Africa
Latin America
& Caribbean
CEE/CIS &
Baltic States
Developing Countries
39%
Least Developed Countries
47%
(India 52%, Bangladesh 55%, Cambodia 56%)
Data for 1992-98, UNICEF State of the World’s Children 2000
Stunting: Real Numbers
India where 52% of all children under 5 (total <5 is
115,615,000) are stunted
60M children in India are stunted (as many
people live in the MidWest)
Example all developing countries, where 39% of all
children under 5 (536,105,000)
209M children in dev world
In world, the total # of children <5 is 603,449,000
and 37% of that is
223M children in world (US popn 272M US
minus California and Texas)
Stunting: Causes
• Poor nutrition plays major role
• Role of environment: improvements in
average height shown by populations over
last century (impact of genetic influence
subsumed by level of socio-economic
development)
In 1833, British children were as tall as
children today from India and Guatemala
All immigrant populations have same
height after 3 generations in US
Stunting: Timing
• Age of onset varies, but usually in first 2-3
years of life
• First few months, infants in developing
countries grow just as quickly as children in
reference populations
– Growth retardation starts from 2-6 month of life
(often associated with weaning)
– Infants at risk during this time because of high
nutritional requirements and high rates of
infections (breast fed infants often protected)
Stunting: Consequences
• Cross-sectional associations – Low height
for age associated with:
– Reduced cognitive development
– Poor motor skills
– Poor neuro-sensory integration
– Quiet, reserved, withdrawn, timid, passive
– Difficulty making decisions
– Decreased involvement with environment,
toys, tasks
– Less able to deal with stressor such as hunger
or parasites
Hypothesized Mechanisms
alterations in
development
of CNS
poor
nutrition
emotional
reactivity,
impaired
stress response
“functional
isolation”
poor mental
development &
behavior
Summary: Mild/moderate maln.
• Stunting refers to growth retardation (>2
S.D.) secondary to malnutrition;
• Almost 40% (223M) of children <5 in the
developing world are stunted;
• Children are most at risk for stunting in the
first 2-3 years of life;
• Stunting is associated with poor mental
development and altered behavior.
Today’s Class
•
•
•
•
•
•
Overview of Nutritional Requirements
Definition of Malnutrition
Correlates of Malnutrition
Measurement and Types of Malnutrition
Severe Malnutrition
Mild/Moderate Malnutrition (Underweight
and Stunting)
• Specific Nutritional Deficiencies (Iodine,
Iron, Vitamin A, Vitamin D)
Specific Nutritional Deficiencies
•
•
•
•
Iodine Deficiency
Iron Deficiency
Vitamin A
Vitamin D
Iodine deficiency - thyroid
“Simple goiter is the easiest of all known diseases to prevent . . .
It may be excluded from the list of human diseases as soon as
society determines to make the effort” David Marine 1923
Iodine Deficiency Disorders
Source: State of the World’s Children, 1998
Causes of Iodine Deficiency
• Mountainous areas at risk (soils leached by
high rainfall, melting snow, flooding)
• Culturally induced behavioral change
– Tasmanian Aboriginals migrated every season
until European invasion, became sedentary
and had incidence of thyroid problems
Iodine Deficiency: Severe
• Goiter: most commonly recognized
consequence (enlarged thyroid)
– Occurs when thyroid gland is unable to meet
the metabolic demands of the body through
sufficient hormone production – thyroid
compensates by enlarging (works in short
term)
• Cretenism: proximal pyramidal signs,
intellectual impairment, primitive reflexes
– Only occurs with severe fetal iodine deficiency
Iodine Deficiency: Moderate
• Studies comparing 2 Villages
– Consistent results: meta-analysis showed 13.5
IQ point difference between groups
• Intervention Studies
– Prenatal supplementation (esp. 1st trimester):
clear impact – prevents cretenism, and affects
mental development in children
– Childhood supplementation: many mediocre
studies, but positive impact
Iron deficiency - anemia
80
70
60
%
50
40
South Central
Asia
West Africa
East Africa
30
Eastern Europe
20
10
Oceania
0
% pregnant women
Source:UN ACC-SCN-IFPRI - 4th
Report on World Nutrition Situation
Source: UN-ACC-SCN-IFPRI-4 Report on World Nutrition Situation
Iron Deficiency
• Iron is critical for body:
– Carries oxygen to tissues from lungs
– Transports electrons within cells
– Integral part of important enzyme reactions
• Anemia is caused most commonly by iron
deficiency (anemia is found in 40-60% of
women and children in developing
countries)
Iron Deficiency Consequences
• Iron deficiency results in:
– Decreased work capacity and work productivity
– Permanently impaired development
• Psychomotor development of anemic children will
be reduced by 5-10 IQ points
– Increased morbidity and mortality from
infections
– Decreased growth
Vitamin A Deficiency
• Vitamin A is important
because it is
essential to vision,
fetal development,
immune response
• 250 million children of
pre-school age lack
sufficient Vitamin A in
their diet.
• 350,000 become blind
each year, and half of
them die within a year
of becoming blind….
Vitamin A Deficiency
• Associated
with blindness and increased
severity of infections such as measles and
diarrhoeal disease
• WHO estimates that 2.8 million children
under 5 years old have signs of clinical
xerophthalmia (childhood blindness)
• WHO estimates that 14 million pre-school
children already have some eye damage
from Vitamin A deficiency
Vitamin D Deficiency: Rickets
http://www.spoilheap.co.uk/rickets.htm
Summary: Micronutrient deficiency
• Iodine is critical for thyroid function –
deficiency results in cretinism & goiter
• Iron is critical for blood and muscles –
deficiency results in anemia
• Vitamin A is critical for visual development
– deficiency results in blindness
• Vitamin D is critical for bone development –
deficiency results in rickets
Where do we go from here?
Increased
productivity
Poverty
reduction
Economic growth
Improved child
nutrition
Social sector
investments
Enhanced human
capital
From UNICEF, State of the World’s Children: Adapted from Stuart Gillespie, John
Mason and Reynaldo Martorell, How nutrition improves, ACC/SCN, Geneva 1996.