L5 6 manlutrition

Nutrition and the

Physiology of

Malnutrition

• 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)

Contents

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)

Protein (g)

1940 – 2200

36 – 46

2550 – 2900

44 – 60

Fat 15 – 33% 15 – 33%

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

MineralsMajor “Bone” Minerals Trace Minerals

Calcium (bones) Iodine (thyroid function)

Phosphorus (DNA) Iron (hemoglobin)

Magnesium (bones) Zinc (enzyme, hormone)

Sodium (nerve impulse) Copper (abs. of iron)

Chloride (fluid balance) Flouride (bone & teeth)

Potassium (prot. syn) Chromium (energy rel.)

Sulfur (some a.a.’s) 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.

What is malnutrition?

World Health Organization definition:

The term is used to refer to a number of diseases, each characterized by cellular imbalance between nutrients and energy supply and the body's demand for them. ( to ensure growth, maintenance, and specific functions).

Types of Malnutrition

• Overnutrition

• Secondary malnutrition

• Micronutrient malnutrition

• Protein Calorie malnutrition

Overnutrition

• Too many calories leading to obesity,

diabetes, hypertension and

cardiovascular disease

• “Transition diets” now a consideration of

WHO due to increase worldwide in

chronic disease due to dietary change

• On a global basis 79 % of all deaths attributable to chronic disease are already occurring in developing countries

–Public health implications are “staggering”

• Overnutrition following fetal malnutrition has also been linked to chronic disease risk in adulthood

Summary: Definition of malnutrition

• Malnutrition is having the inappropriate

level of a micro- or macronutrient;

• 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.

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

• 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

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.

*

*

*

*

*At least 70%

of childhood

diseases are

related with

one of these

conditions

*

• Causes and correlates of Malnutrition

• Measurement and Types of Malnutrition

• Severe Malnutrition

• Mild/Moderate Malnutrition (Underweight and Stunting)

• Specific Nutritional Deficiencies (Iodine and Iron)

Child malnutrition

death and disability

Inadequate Disease

Diet

Insufficient

access to food

Inadequate

maternal and

child care

Poor water/ sanitation

inadequate health

services

Causes of malnutrition

Baby

Low Birth

Weight

Child

Stunted

Adolescent

Stunted

Woman

Malnourished

Pregnancy

Low Weight

Gain

Elderly

Malnourished

Higher

mortality rate

Impaired

mental

developmentIncreased risk of

adult chronic disease

Untimely/inadequate

weaning

Frequent

InfectionsInadequate

catch up

growth

Inadequate

food, health

& care

Reduced

mental

capacity

Inadequate

food, health

& care

Reduced

mental

capacity

Inadequate

fetal

nutrition

Inadequate

food,

health

& care

Inadequate

food, health

& care

Higher

maternal

mortality

Reduced

capacity

to care

for baby

Start here

Correlate: Unsafe Water

Source for photos: Overseas Aid: www.nat.uca.org.au, Statistics, UNICEF State of the World’s Children 2000

11% urban and 38% rural households do

not have access to safe water

http://www.nat.uca.org.au/

Correlate: Inadequate Sanitation


21% urban and 75% rural households do

not have access to adequate sanitation


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


Correlate: Poverty

28% of the population lives at below $1 per

day

Average GNP per capita is $1299

(compared with $29,080 in USA)



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


Correlate: Poor Public Health

About 30% of 1-year olds are not fully

immunized for TB, DPT (Diptheria,

Pertussis, and Tetanus), polio and measles



Correlate: No Breastfeeding

Source: Children’s Hospital Islamabad

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 study was

conducted.

56% babies in developing countries are not

breastfed from 0-3 months

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

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.

Summary: Measurement

• There are several types of malnutrition,

micro- and macro-malnutrition;

• Measurement of severe malnutrition and

micro-nutrient deficiency usually occurs

due to presence of critical signs.

• measurement of mild/moderate

malnutrition occurs with growth charts.

Kwashiorkor

Swollen

belly

Pellagra

Decreased

muscle

mass

Sparse

hair

Infection

Apathy

Severe Malnutrition

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

• 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

Severe Malnutrition: Consequences

Summary: Severe malnutrition

• Severe malnutrition is defined as > 3

s.d. away from median reference

standards;

• Key types of severe malnutrition are

kwashiorkor (low protein) and

marasmus (low calories);

• Severe malnutrition results in severe

deficits for children

Mild/Moderate Malnutrition

(Underweight and Stunting)

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 % <5 y.o.

Developing Countries 39%

Least Developed Countries 47%

Data for 1992-98, UNICEF State of the World’s Children 2000(India 52%, Bangladesh 55%, Cambodia 56%)

0%

10%

20%

30%

40%

50%

60%South Asia

Sub-SaharanAfrica

Middle Eastand NorthAfrica

Latin America& Caribbean

CEE/CIS &Baltic States

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

poor

nutrition

poor mental

development &

behavior

alterations in

development

of CNS

“functional

isolation”

emotional

reactivity,

impaired

stress response

Hypothesized Mechanisms

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.

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

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

Source:UN ACC-SCN-IFPRI - 4th

Report on World Nutrition Situation

Iron deficiency - anemia

%

Source: UN-ACC-SCN-IFPRI-4 Report on World Nutrition Situation

0

10

20

30

40

50

60

70

80

% pregnant women

South CentralAsia

West Africa

East Africa

Eastern Europe

Oceania

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

From UNICEF, State of the World’s Children: Adapted from Stuart Gillespie, John

Mason and Reynaldo Martorell, How nutrition improves, ACC/SCN, Geneva 1996.

Where do we go from here?

Improved child

nutrition

Increased

productivity

Enhanced human

capital

Poverty

reduction Economic growth

Social sector

investments