5. Definition of terms
Nutrition
o It is the study of nutrients in food, how our body uses these nutrients
and the relationship between diet, health and disease
It includes the processes by which the human organism ingests,
digests, absorbs, transports, and excretes food substances
Nutrition also involves studying the factors that influence our eating
patterns, making recommendations about the amount we should eat
of each type of food and maintaining food safety
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6. Definition of Terms
Food: - is any solid or liquid which when ingested will enable the body to
carry out any of its life function.
• Nutrients : Substances obtained from food that are vital for growth and
maintenance of a healthy body throughout life.
– Essential Nutrients (indispensable nutrients)
– Non-essential nutrients:
• Roughage: fiber which enable the body to get rid of waste products, which
would otherwise become poisonous to the body. It add bulk to feces
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7. Nutrition and health
Good nutrition prevents a number of NCD
• Important for physical growth and mental development,
• Allows people to reach their full potential e.g. In school and work
• Protects us from both communicable and non-communicable diseases.
– Therefore, it helps to prevent disease, promote health & prolong life
Poor nutrition can lead to reduced immunity, increased susceptibility to disease,
impaired physical and mental development, and reduced productivity.
Nutrition is a major, modifiable, and powerful factor in promoting health,
preventing and treating disease, and improving quality of life
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8. Healthy diet
• A diet that contains all the nutrients we need in the right quantity
• That contains foods from all the food groups in the right proportions,
prepared with healthy cooking methods
• That contains foods that are safe to eat and that do not have harmful
chemical or microbiological substances.
• That resembles a diet which in practice has made people healthy (e.g. the
Mediterranean diet).
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10. Learning objectives
• At the end of this session, the students will be able to:
– Identify the macro and micro nutrients
– Recognize their food sources
– Describe their functions and their deficiency states
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11. Nutrients & their classification
Nutrient:
is an active chemical component
in the food that plays specific
structural or functional roles in
the body’s lively activity
1. Macronutrients
Carbohydrates
Lipids
Proteins
2. Micronutrients
Vitamins
Minerals
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12. Macronutrients
Macronutrients: are nutrients that are required by our body in large
quantities. Macronutrients are nutrients that provide
calories/energy
Carbohydrate provides 4 kcal/gram
Protein provides 4 kcals/gram
Lipid provides 9 kcal/gram
Alcohol?
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13. 13
Macronutrients contribute to the energy pool of the body
Carbohydrates
(45-65%)
Fats
20% - 35%
Proteins
(10% - 35%)
Energy Pool
of the body
(100%)
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14. Carbohydrates
• Organic molecules, which are polyhydroxy aldehydes or ketones, or substances
that produce these compounds when hydrolyzed.
• Exist as monomeric units or as polymers.
• General formula = (CH2O)n
• Comprise two major classes: simple carbohydrates and complex carbohydrates.
• Simple carbohydrates include monosaccharides and disaccharides.
• Complex carbohydrates include oligosaccharides containing 3 to 10 saccharide
units and polysaccharides containing more than 10 units
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16. I. Monosaccharides
• Contain one CHO molecule
• Eg. Glucose, fructose, galactose
• Are water soluble, Have sweet taste, called sugars
A. Glucose (blood sugar, grape suger, dextrose)
• End product of digestion of glycogen, starch, disaccharides and other
carbohydrates
– After meal, glucose is converted to glycogen and excess glucose
will be converted to triacylglycerol
• It’s major source of fuel and that is oxidized by cells for energy.
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17. B. Fructose : the sweetest of the sugars
C. Galactose (milk sugar)
– Not found free in nature but is produced in the body during the
digestion of lactose.
II. Disaccharides
Have the same characteristics with monosaccharides but have two
CHO molecules
The most commons are
Maltose
Sucrose and
Lactose, 17
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18. Disaccharides…
1. Maltose(malt sugar)
Two glucose units. Produced whenever starch breaks down
found in sprouting grains, beer, infant formulas
2. Lactose (milk sugar)
– Glucose + Galactose
– Found naturally only in milk & milk products
– We can get 6.8 gm/100ml of human milk and 4.8 gm/100ml of cow’s
milk
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19. Disaccharides…..
3. Sucrose (table sugar, cane sugar, beet sugar)
Glucose + Fructose
It is the most widely distributed of the disaccharides and is the most
commonly used natural sweetener and preservative.
White and brown sugars are almost 100 % sucrose. Found also in maple
syrup, molasses, sorghum and corn syrups
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20. Complex carbohydrates
Oligosaccharides
• Some oligosaccharides occur naturally in plants:
o Stachyose and raffinose (soybeans and other legumes)
o Fructooligosaccharides (wheat, onions, bananas, and garlic).
Promote the growth of beneficial colonic microflora.
Polysaccharides
• Contain as many as 10- 60, 000 simple carbohydrate molecules
• Are insoluble in water, and don't taste sweet;
• Three types of polysaccharides are important in nutrition: Starches, Glycogen, Fibers
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21. 1. Starches
• The most common digestible polysaccharide in plants
• Starch is the primary storage form of carbohydrate in plants
– Is the most abundant carbohydrate throughout the world in man’s diet.
– Two forms: Amylose(15-20%) and amylopectine(80-85%)
• Major sources of starch include
– Grains (such as rice, wheat, barley, and oats)
– Legumes (such as kidney beans, black-eyed peas)
– Tubers (such as potatoes), and root crops (such as cassava)
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22. 2. Glycogen: The major form of stored carbohydrate in animal tissues, which is
localized primarily in liver and skeletal muscle
• Provides a rapid release of energy when needed
– Two third is in muscle for energy needs of muscle cells and 1/3 is in the
liver, as source of energy for any body cells.
3. Fiber(non-starch polysachrides) : dietary fiber or roughage
Humans do not have the enzyme to digest it
Can be fermented to some extent by intestinal bacteria short chain fatty
acids
found in all plant-derived foods
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23. • Dietary fiber refers to non-digestible (by human digestive
enzymes) carbohydrates and lignin that are intact and intrinsic
in plants
• Functional fiber consists of non-digestible carbohydrates that
have been isolated, extracted, or manufactured and have been
shown to have beneficial physiological effects in humans
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24. Fiber…
• Diets that are low in fiber have been shown to cause problems such as
constipation and hemorrhoids and to increase the risk for certain types
of cancers such as colon cancer
• Diets high in fiber; however, have been shown to decrease risks for
heart disease, obesity, and they help lower cholesterol
– In the large intestine, fibers remain and attract water, soften stools and ferment
• Foods sources : fruits, vegetables, and whole grain products
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25. 25
How does fiber prevent different health problems?
• Prevents secondary bile acid circulation
• Decrease intestinal transit time
• Decrease contact of carcinogens with intestinal cells
• Decreases absorption of fats and sugars
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26. Digestion of carbohydrates
• Before dietary carbohydrates can be used by the body’s cells they must
first be absorbed from the gastrointestinal (GI) tract into the bloodstream
– Restricted to monosaccharides
– Poly and disaccharides must be hydrolyzed.
• By the hydrolytic enzymes /carbohydrases.
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29. Digestion of Disaccharides
• Digestion takes place almost entirely within the microvilli (the
brush border) of the upper small intestine via disaccharidase
Lactase (lactose to glucose and galactose)
Maltase ( maltose to 2 glucose units )
Sucrase(sucrose to fructose + glucose)
Isomaltase (isomaltose to 2 glucose units )
Trehalase (trehalose to 2 glucose units )
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30. 30
They get fermented in the
colon by anaerobic bacteria
Oligosaccharides (eg. Raffinose, Stachyose)
and non-starch polysaccharides resistant
starch
Escape digestion in the
upper gut (small intestine
Increased faecal Biomass
resulting in increased
peristalsis
Production of
short chain fatty
acids (SCFA)
Acetate
Propionate
Butyrate
Production of
gases likes co2,
methane and
hydrogen
sulphide
Digestion of oligosaccharides, resistant starch and non-starch polysaccharides
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31. Functions of carbohydrate
1. Energy supply:
The main function of CHOs is to meet immediate energy needs as
glucose,
Some is stored as glycogen in liver and muscles
The rest is converted to fat and stored as adipose tissue
CNS is entirely dependent on glucose for energy
2) Protein-sparing action:
3) Helping the body use fat efficiently:
4) Lactose enhances calcium absorption 31
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32. 5) As component of body substances and compounds:
Heparin, nervous tissue, ribose in RNA & DNA
6) Encouraging growth of useful bacteria:
Some CHOs like oligosaccharides promote the growth of important bacteria like
lactobacillus & bifidobacteria
7) Promoting normal functioning of the lower intestinal tract:
Dietary fiber promote peristalsis and normal mov’t of the food and waste products
along the GIT and prevent occurrence of diseases like constipation, hemorrhoids,
cancer and also coronary heart disease
8) Improving the palatability of food/drink:
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33. Recommended daily allowance
45% - 65% of calories should come from carbohydrate
Adult need 50 to 100gm/day, average intake of total sugar is 80gm/day
Excessively consumed CHOs could be converted to lipids and get stored
leading to obesity and related chronic diseases
Dental carries is the commonest problem that encounters frequent sugar
consumers
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34. Maintaining blood glucose levels
• The Regulating Hormones
• Increase in blood glucose causes release of insulin
• Decrease in blood glucose increases release of glucagon
– Glucagon facilitates the breakdown of glycogen in the liver and muscle
cells
– Insulin facilitates
• Glucose transport to the liver and muscle cells
• Formation of glycogen in the liver and muscle cells
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35. 35
Food sources of Carbohydrates
• Free sugars are found from: fruits, juices, confectionery, Soft drinks, milk, sugar,
sugar cane, honey, yogurt, Cereal grains, Legumes & dried fruits, vegetables,
processed foods (pasta), jams, pastries, breads, candies fruits like banana, date fruits,
and sweet potato
• Starch is found from: starchy foods (like cereals and legumes and potatoes), Other
foods like fruits, vegetables, beans, nuts, seeds
• OligoSacharides are found from : Garlic, onion, Whole grain cereals and legumes
(beans and peas)
• Non starch polysaccharides are found from: Fruits, vegetables, Whole grain
cereals and legumes
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36. Proteins
• Proteins are found throughout the body, with
– over 40% of body protein found in skeletal muscle,
– over 25% found in body organs,
– and the rest found mostly in the skin and blood.
• The basis of protein structure is the amino acid which makes them
nutritionally essential
• 20 AA have been recognized as constituents of most proteins in our body
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37. Amino aids
• Classification
• Amino acids: classified as
• Essential
• Nonessential
• Conditionally essential
– For adults there are 8 EAA
– For infants there are 9 EAA, including Histidine
• 11 are “non-essential” because our bodies are able to make them.
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39. Protein classification
• Based on nutritional value
• Chemical composition
• Based on conformation of the protein
• Based on their chemical structure
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40. Pro class…cont’d
I Based on nutritional value
Complete protein: contains sufficient amounts of all essential
amino acids.
Considered as “high quality” protein.
(e.g. proteins of animal origin- egg & milk).
Incomplete protein: does not contain all essential amino acids
(e.g.lysine in cereals, methionine in legumes and tryphtophan in
corn).
Not sufficient for growth and health
Considered a “low quality” protein
40
41. Pro…cont’d
II) Based on nutritional value
Complete protein: contains sufficient amounts of all essential amino
acids.
Considered as “high quality” protein.
(e.g. proteins of animal origin- egg & milk).
Incomplete protein: does not contain all essential amino acids (e.g.
lysine in cereals, methionine in legumes and tryphtophan in corn).
Not sufficient for growth and health
Considered a “low quality” protein
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42. Pro class…cont’d
Soya bean has the best quality protein from plant family
Most common food sources of proteins for the developing
countries are plants especially cereals and legumes
Mixing of cereals and legumes will give a better quality
protein(complementary protein)
E.g. Bread with peanut butter
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44. Pro…cont’d
Mouth & esophagus – None
In the stomach:
The major event in the stomach is the partial breakdown
(hydrolysis) of proteins.
HCl denatures each protein so that digestive enzymes can
attack the peptide bonds.
The HCl also converts the inactive form of the enzyme
pepsinogen to its active form, pepsin.
Pepsin cleaves proteins-large polypeptides-into smaller
polypeptides and some amino acids.
44
45. Pro…cont’d
In the small intestine:
Several pancreatic and intestinal proteases hydrolyze
polypeptides further into short peptide chains,
tripeptides, dipeptides, and amino acids.
Then peptidase enzymes on the membrane surfaces
of the intestinal cells split most of the dipeptides and
tripeptides into single amino acids.
45
46. Pro…cont’d
Cooking increases the digestibility of proteins
Over heating can destroy some amino acids
Cooking with water makes proteins more palatable
46
47. 47
WHY DO WE NEED PROTEIN ?
We need protein for:
Growth (especially important for children, teens, and pregnant women)
10% - 35% of calories should come from protein.
Tissue repair
Immune function
Energy when carbohydrate is not available
Synthesis of enzymes, hormones all antibodies
Control Fluid movement in the body
As components in body structures such as skin, muscles, and bones
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48. Protein quality
Biological value: proportion of protein retained in the human body for maintenance
and/or growth
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PROTEIN BV*
Protein source BV
Egg 93.7
Milk 84.5
Fish 76.0
Beef 74.3
Soybeans 72.8
Rice, polished 64.0
Wheat, whole 64.0
Corn 60.0
Beans, dry 58.0
*Biological Value[BV]=proportion of protein retained in the human body for maintenance and or
growth.
49. Food sources of proteins
Animal Sources: are high quality
E.g. meat, egg, poultry, milk, fish, lamb, beef etc
egg is a reference protein
Plant Sources: mostly incomplete.
e.g. cereals and legumes
RDA
0.8 g /kg body weight
% of energy that should come from protein is 10% to 35%
Protein needs are higher for children, adolescents, and pregnant/lactating women
Protein needs can also be higher for active people and for vegetarians 49
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50. 50
Lipids
Lipid: Are a group of organic compounds that are insoluble in water but soluble in
alcohol, ether, and other organic solvents.
Classification
Nutritionally important lipids are classified into 3 main groups on the basis of their
Chemical structure.
• Simple lipids - include fats and oils (Triglycerides)
• Compound lipids - includes Phospholipids, lipoproteins
• Derived lipid - includes sterols and straight chain alcohols
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51. Fatty acids
– The fatty acids are the simplest of the lipids. They are composed of a
straight hydrocarbon chain terminating with a carboxylic acid group.
Therefore, fatty acids have a polar, hydrophilic end and a nonpolar,
hydrophobic end that is insoluble in water
• Physical property
– Length of carbon chain
– Degree of saturation.
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52. Classification of fatty acids
1. On the basis of the number of carbon-chain:
A. Short chain: 2-4 carbon atoms (e.g. Butyric acid)
B. Medium chain: 6-12 carbon atoms (e.g. Caprillic acid)
C. Long chain: 14-18 carbon atoms (e.g. Palmitic acid, stearic acid)
D. Extra long chain: ≥ 20 carbon atoms (e.g. Arachidic acid)
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53. 2. Depending on degree of saturation
• Saturated FA:
If all of the carbon atoms are “saturated” with all hydrogen atoms they
can hold, then No double bond can exist.
Foods high in saturated fats include fatty cuts of meat, full fat dairy
products including cheese and cream, butter, coconut and palm oil,
cakes, biscuits, pastries and chocolate.
Mostly animal foods. E.g. butter(60% ), beef(28%), lamb(46%).
The major saturated fatty acids are palmitic and stearic acids
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55. • Unsaturated FA:
– If all of the carbon atoms in a fatty acid are “ not-saturated” with hydrogen
atoms, then Double bond exists.
– Unsaturated fats are predominantly found in foods from plants, such as
vegetable oils, nuts, and seeds.
– Types
• MUFA
• PUFA
– Human breast milk is also rich in polyunsaturated fatty acids.
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56. Monounsaturated FA (MUFA): contain only one double bond between carbon atoms.
Found in:
Olive, peanut, and canola oils
Avocados
Nuts such as almonds, hazelnuts, and pecans
Seeds such as pumpkin and sesame seeds
Polyunsaturated FA (PUFA): They have two or more double bonds between carbon atoms.
Sunflower, corn, soybean, and flaxseed oils
Walnuts, Fish
Canola oil – though higher in monounsaturated fat, it’s also a good source of polyunsaturated fat.
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57. Essential Fatty Acids
• These are a type of polyunsaturated fats and known as omega-
3 and omega-6 fats.
• They cannot be produced by the body
• An excellent way to get omega-3 fats is by eating fish 2-3 times
a week.
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58. Omega-3 Fatty Acids
• Health Benefits:
Anti-inflammatory Properties
Increases HDL (good) Cholesterol
Reduces Risk of Blood Clots
Reduces Blood Pressure
Reduces Risk of Sudden Cardiac Death
Prevention and Rx of heart disease
For normal growth and dev’t, especially in the eyes & brain…
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59. 59
Hydrogenation/Trans fatty acids
• If an unsaturated vegetable fat is altered by adding hydrogen atoms, which did not
exist in nature, the fat molecule is said to be "hydrogenated."
• Hydrogenation transforms the shape of a fatty acid to a "trans" form and the body
has difficulty digesting it.
• This is the problem with margarine — it contains hydrogenated, trans-fatty acids.
• Studies show this type of molecule to be more associated with artery disease than
the saturated ("hard") fat found in butter.
• hydrogenated fat also is commonly associated with junk food: potato chips. cookies,
etc. It is very hard to digest and is strongly associated with vascular disease.
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60. Triglycerides/triacyglycerols
• Most stored body fat is in the form of triacylglycerols (TAG), which
represent a highly concentrated form of energy.
• Three fatty acids combine with a glycerol molecule to form
triglyceride.
• Triacylglycerols account for nearly 95% of dietary fat.
• May be solid (fat) or liquid (oil) at room temperature
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61. Cholesterol
• Cholesterol is the most common sterol in animals and is the precursor for other
important steroids in the body, including
– The bile acids
– Steroid sex hormones such as estrogens, androgens, and progesterone;
– The adrenocortical hormones
– And vitamin D (cholecalciferol, the animal form)
• cholesterol is an essential component of cell membranes, particularly the
membranes of nerve tissue.
• Meats, egg yolk, and dairy products, the common dietary sources of cholesterol61
63. Cont…
Cholesterol is the most studied sterol because of its
epidemiological linkage with atherosclerosis and
coronary heart disease
63
64. Cholesterol…
Atherosclerosis: a common arterial disease in w/c
raised areas of degeneration and cholesterol deposits
form on the inner surfaces of the arteries obstructing
blood flow.
Excessive consumption of cholesterol increases the
serum cholesterol level that in turn facilitates atheroma
(fatty deposit in artery) formation in the vascular
structures.
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65. Cholesterol…
When the coronary blood vessels are involved,
there may be ischemia of the myocardium
resulting in ischemic heart disease.
Ischemia: an inadequate supply of blood to a part
of the body, caused by partial or total blockage of
an artery.
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66. Cholesterol…
If the ischemia is excessive, it may result in violent
myocardial infarction and sudden death of the subject.
Limiting the consumption of foods rich in cholesterol
such as: egg yolk, butter, cream, cheese, animal fat is
very important besides regular exercise to avert the toll
of morbidity and mortality resulting from such a
problem.
66
67. 67
Lipoproteins
• Compound lipids that contain both protein and various types and amounts of lipids.
• They are 25-30 % proteins and the remaining as lipids.
• They are made mostly in the liver and are used to transport lipids throughout the blood
• Classification
– Low density Lipoprotein(LDL)
– High density Lipo protein(HDL)
– VLDL
– Chylomicrones
HDL Transports lipids from tissues to the liver and decreases the risk of Chronic degenerative
diseases
LDL transports lipids from the liver to the tissues and increases the risk of Chronic
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68. Lipoproteins…
Based on their density, the lipoproteins are classified as:
a) High Density Lipoprotein (HDL):
Primarily contain protein with small amounts of
triglycerides and cholesterol.
HDL transports cholesterol from the tissues to the
liver to be metabolized.
High serum levels of HDL are protective against
atherosclerosis.
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69. Lipoproteins…
b) Low Density Lipoprotein (LDL):
Composed mainly of cholesterol.
LDL transports cholesterol from the liver to tissues.
High serum level of LDL greatly increases the risk of
atherosclerosis.
Diets that are high in saturated fatty acids are associated
with elevations in LDL cholesterol.
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70. Lipoproteins…
C) Very Low Density Lipoproteins (VLDL):
Contain primarily triglycerides with some protein and
cholesterol.
VLDL are hepatically derived particles that mediate the
transport of fat from the liver to peripheral tissue
High serum level of VLDL increases the risk of
atherosclerosis.
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71. Lipoproteins…
D) Chylomicrons: composed mainly of triglycerides
encased in a protein and phospholipid coating.
Transport absorbed triglycerides from the intestine to
the liver through the lacteals
High serum chylomicrons levels do not increase the
risk of atherosclerosis???
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74. Functions of Lipids
• Sources of energy (9 kcal/gm)
• Reserves (storage forms) of energy in animals
• Vehicle for the absorption of fat-soluble vitamins
• Support the viscera organs.
• Subcutaneous fat function as insulator of heat and cold
• Help to achieve desirable weight in case of underweight
• Improve the palatability of food
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75. Lipid function cont’d….
• Phospholipids are important structural materials in the
formation of cell membranes
• Cholesterol is important in the synthesis of bile salts in
the liver.
• Lipoproteins are important to transport lipids
• They form myelin sheath of nerves
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76. 76
Food Sources Fats
• There are three main types of fat, saturated fat, unsaturated fat, and trans fat.
High Risk for CHD
– Saturated fat (found in foods like meat, butter, lard, and cream) and
– trans fat (found in baked goods, snack foods, fried foods, and margarines) have
been shown to increase your risk for heart disease.
Low Risk for CHD
– Unsaturated Fat (FUFAS & MUFAS) (found in foods like olive oil, avocados, nuts,
and canola oil,vegetable oils, fish)
*Replacing saturated and trans fat in your diet with unsaturated fat has been shown
decrease the risk of developing heart disease.
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77. Dietary recommendations
• ~ 30% of total calories from fat
• Minimize saturated fatty acids
• Incorporate monounsaturated, Ω3 & Ω6
• Fish & nuts are good sources
• Nonfat dairy products
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79. Learning objectives
• To understand
• The types of major micronutrients
• Their biological roles, food sources
• Public health significance of their deficiency states
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80. Vitamins
• They are indispensable, non-caloric organic nutrients needed in tiny amounts in
the diet and most of them cannot be synthesized in the body.
• Function
– Help the process by which other nutrients are digested, absorbed and
metabolized or built into the body structures
– Help liberate energy contained within the macronutrients
• Classified as:
– Water soluble vitamins
– Lipid soluble vitamins
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81. Water-soluble vitamins
• Dissolve in water
• Cannot be stored in body
• Excess is excreted in urine
• Unstable to heat and light, leach into cooking liquids. (Folate, thiamine, vitamin C)
• Vitamin B-complex and Vitamin C.
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82. Fat-soluble vitamins
• Dissolve in fat before they are absorbed in the bloodstream to carry out
their functions.
• Can be stored in body
• Can accumulate to toxic levels if large amounts ingested
• Fairly stable at normal cooking temperatures
• Vitamins A, D, E and K
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83. Vitamin A
• Vitamin A is a fat-soluble vitamin which is provided in the diet in two forms
Retinoids (preformed vitamin A)
– Found in foods from animal sources specially liver and dairy products (including
whole milk, cheese, and butter) as well as fish and eggs
Carotenoids (provitamin A) They are found in fruits, vegetables, and other plant-
based products
– main provitamin A carotenoids are eg β-carotene, α-carotene, β- cryptoxanthin
– Other carotenoids in food, such as lycopene, lutein, and zeaxanthin, are not
converted into vitamin A and are referred to as non-provitamin A carotenoids
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84. • Both provitamin A and preformed vitamin A must be metabolized
intracellularly to retinal and retinoic acid, the active forms of
vitamin A
• Retinal (used in vision)
• Retinoic acid (used for growth and genetic differentiation)
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86. Vit…cont’d
Food sources summary of vitamin A
A) Plant sources:
Provitamin Vit-A is generally found in GLV, yellow, orange, red (brightly
colored) fruits and vegetables such as spinach, sweet potatoes, carrots,
broccoli, Papaya, mango, Pumpkin, kale, watermelon, tomatoes
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88. Functions of vitamin A
Essential for normal function of retina
Essential for normal function of retina by combining with purple pigment
of retina (opsin) to form rhodopsin,(necessary for sight in partial darkness)
• Cell differentiation (especially as retinoic acid)
• Reproduction Vitamin A, as retinol but not as retinoic acid, is essential for
reproductive processes in both males and females
– Normal fetal development
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89. Functions….
Maintenance of the immune system
Vitamin A is used as an immune enhancer in viral diseases. Eg . Supplementation
with vitamin A leads to a 50% decrease in mortality from measles in developing
countries
Builds body's resistance to respiratory infections
Helps form and maintain healthy skin, hair, and mucous membranes.
Helps to treat acne, impetigo, boils, and carbuncles, open ulcers when applied
externally
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90. Functions…
Antioxidant, cancer protection
Alpha-carotene and lycopene have well-noted anti-cancer effects
• Growth
Promotes bone growth and teeth development
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92. Epidemiology
VAD is the most common preventable cause of corneal
ulceration and blindness in the developing world
Children who are at risk of VAD include
6 – 59 months old
Those with PEM, measles, diarrhea and ARI diseases
Infants < 6 months who are not breast fed
Children with VAD are at increased risk of more frequent
and sever episodes of diarrhea, ARI and measles
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93. Epid…
Improving vitamin A status
Improves resistance to common child hood
illnesses
Decreases the severity of infections
Decreases child hood mortality by 50% and 40%
from measles and diarrheal diseases respectively
Over all mortality in children 6 – 59 months can be
reduced by 23%
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94. Deficiency of vitamin A
Night blindness
Lack of tear secretion (goblet cell)
Changes in eyes with eventual blindness if deficiency is severe and untreated.
• Susceptibility to respiratory infection, Increased severity of infection (e.g.
measles, diarrhea, or malaria)
Dry, rough skin
Changes in mucous membranes
Weak tooth enamel
Weight loss, poor bone growth, slow growth
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95. Vitamin A Deficiency disorders –Xerophthalmia
• Night blindness: The child cannot see in the partial darkness. He/she has to go
in to the house early in the evening
• Conjuctival xerosis: The Conjuctival covering, the white surface of the eyeballs
become dry and rough instead of being moist, smooth and shining. The child
cannot open and close his/her eyes because it is painful
• Bitot’s spots: A foamy or cheesy accumulation, which forms in the inner
quadrant of the cornea in the eyes. The cornea the central transparent part of the
eye becomes cloudy. It reflects more advanced vitamin A deficiency, but tends
to be reversible with treatment.
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96. Xerophthalmia…
• Corneal ulceration: An ulcer on the cornea may leave scar, which can
affect vision.
• Keratomalacia: The eyeballs become opaque and soft, jelly like
substance; hereafter there will be a rapid destruction of the eyeball and
no hope of recovery after the condition reached the stage of
keratomalacia
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99. Cont…
According to the WHO , VAD is considered as a significant
public health problem based on the prevalence of the clinical
signs in the community.
These indicators are
Night blindness > 1.0%
Bitot’s spot > 0.5%
Corneal xerosis > 0.01%
Corneal scar > 0.05%
Biochemical deficiency
(serum retinol<0.7micromol/lit) > 5%
In Ethiopia 27% of < 5 children have sub clinical VAD
According to the 2010 EHNRI report, the overall prevalence of Bitot's spots
and night blindness in Ethiopia was 1.7% and 0.8%, respectively
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100. Causes of Vitamin A deficiency
Inadequate intake
• Poor bioavailability
• Low fat diets (Low fat diets < 5 to
10 g daily) impair the absorption of
provitamin A carotenoids)
Mal-absorption
• HIV, Measles, parasitic infections
• Cause low serum retinol
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101. RDA
RDA for vitamin A is expressed in retinol equivalents (RE)
One RE = 1 mcg retinol or 6 mcg beta-carotene
Age Retinol Equivalents (IU)
0-6 months 375RE (2,100IU)
6-12 months 375RE (2,100IU)
1-3 years 400RE (2,000IU)
4-6 years 500RE (2,500IU)
7-10 years 700RE (3,300IU)
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103. Prevention
Breast feeding
Adequate vitamin A source for the first 6 months of age
Vitamin A supplementation
Disease targeted supplementation of at risk children:-
Measles,diarrheal diseases,ARI and sever PEM
Universal supplementation for at risk groups
(6 – 59 months)
Food fortification
Dietary diversification
103
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105. Minerals
• Major minerals, also called macrominerals, are distinguished from the microminerals
by their abundance in the body.
• The macrominerals are typically required by adults in amounts greater than 100 mg
per day.
• The trace elements are required by adults in amounts between about 1 mg and 100
mg per day
• The ultratrace minerals are required by adults in amounts less than 1 mg per day
105
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107. Iodine
• Iodine: is an ultratrace element that combines with the amino acid tyrosine to
create the thyroid hormone.
• The human body contains about 15 to 20 mg of iodide, most (70–80%) of which is
found in the thyroid gland
• These hormones regulate numerous functions
Biochemical reactions (e.g., protein synthesis, enzyme activities)
Influence early organ development (e.g., brain)
• Thyroid hormones play a major role in the growth and development of the
brain and central nervous system in humans from the 15th week of
gestation to 3 years of age. 107
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108. Additional Functions of Iodine
• Keeps skin, hair and nails healthy.
• Protects thyroid gland after accidental exposure to
radiation.
• Protects against breast cancer and goitre.
108
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110. • Health consequences of iodine deficiency….
Cretinism is a congenital disease characterized by mental
and physical retardation and commonly caused by
maternal iodine deficiency during pregnancy.
The most damaging effect of inadequate intake of
iodine is on the developing brain
Iodine deficiency alone lowered mean IQ scores by
0.9 SD or 13.5 IQ points
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113. Male from Ecuador about
40 years old, deaf-mute,
unable to stand or walk.
Use of the hands was
strikingly spared, despite
proximal upper-extremity
spasticity.
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115. Causes of IDD
Soil devoid of iodine
– Erosion of the land
– Crops growing in this type of soil
– Animal products from animals grazing grass growing in this soils
– Water will also be deficient
Poor consumption of sea foods
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116. Cause…..
Increased consumption of goitrogens
– These are factors in the food that interfere with iodine uptake by
the thyroid gland.
– Ex. cabbage, cassava, spinach, lettuce, turnips (beets), kale.
• Deficiency of other micronutrients (Iron, selenium, and Vit A)
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117. Risk factors for IDDs in Ethiopia
Marine foods are rarely consumed
Staple diets are of plant origin
Most of the Ethiopian cereals grow in
iodine deficient soils
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118. • Dietary sources of iodine
– The richest dietary sources of iodine are seafood, seaweed and
iodized salt
– Foods of animal origin including meat and milk can also
constitute a significant source of iodine if animals have grazed
on iodine sufficient soils.
– Similarly, crops from iodine sufficient soils may supply some
dietary iodine
– Iodine fortified foods like salt, bread and milk
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119. • Recommended intakes
(WHO/UNICEF/ICCIDD, 2001)
• At a level that assures 150 µg/day is safe
for all populations (WHO, UNICEF,
FAO, ICCIDD, IAEA)
Category Intake (µg/day)
Infants, 0 – 59 months 90
School children, 6 – 12 years 120
Children > 12 years and adults 150
Pregnant and lactating women 200
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120. Zinc
• Is another important mineral which is found in every
cell of the body and is a part of over 200 enzymes
• The human body contains about 1.5 to 3.0 g of zinc.
• Zinc is found in all organs, tissues, and body fluids
120
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122. Functions of Zinc
Functions as antioxidant
Maintains normal taste and smell( part of gustin)
Aids wound healing
Promotes normal fetal growth
Helps synthesize DNA and RNA
Promotes cell division, cell repair and cell growth
Maintains normal level of vitamin-A in blood
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123. • Animal
– Rich sources: meat (beef, pork), poultry, organ meats, fish
and shellfish and
– lesser amounts in eggs and dairy products
• Plant
– Cereals and legumes contain a modest amount of Zn, but their
high phytate content reduces the amount absorbed.
– Fruits and vegetables are low in Zn
Dietary Sources
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124. – Growth retardation
– Delayed sexual maturation & impotence
• Impaired testicular development
– Hypogonadism & hypospermia
– Immune deficiencies
– Night blindness
– Impaired taste (hypoguesia)
– Delayed healing of wounds, burns
– Impaired appetite & food intake
Clinical manifestations of Zn Deficiency
124
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126. – The RDA for
– Adult men:11 mg/d
– Adult women: 8 mg/d
– During pregnancy: 11 mg/day to cover the calculated need
for growth of the fetus and placenta
– lactating women: 12 mg/day
Recommended dietary allowance
126
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127. Zinc Intervention Programs
The three major categories of nutrition-
focused zinc intervention strategies
• Supplementation
• Fortification
• Dietary diversification/modification
Key target groups:
o IYC
o Pre-pregnant women
o Pregnant women
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128. Iron
is trace element found in functional forms (hemoglobin and
myoglobine, enzymes) and in transport & storage forms
(transferrin, ferritin, and hemosiderin).
It is a needed to transport oxygen from the lungs to body tissue
and to bring carbon dioxide from body tissues to the lungs
The human body contains about 2 to 4 g of iron. Over 65% in
hemoglobin, about 10% in myoglobin, 1% to 5% is found as
part of enzymes, and the remaining body iron is found in the
blood or in storage.
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129. Food sources of iron
• Found as heme and nonheme.
• Heme iron is found in animal products, especially meat, fish, and
poultry.
o About 50% to 60% of the iron in meat, fish, and poultry is heme
iron.
• Nonheme iron ( Ferric form, Fe3+) ) is found primarily in plant foods
(nuts, fruits, vegetables, grains, tofu) and dairy products (milk, cheese,
eggs)
Note: While non-heme iron makes up over 85% of the iron in our diet,
heme iron is more easily absorbed.
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131. Factors enhancing and inhibiting
absorption of non-heme iron
Enhancers
• Vitamin-C
• Amino acids
• High altitude
• Hydrochloric acid
• Fermentation
• Alcohol
• Deficient stores
Inhibitors
• Phytates
• Tanins
• Polyphenols
• Heavy metals
• Fibers
• Low altitude
• Replete stores
• Achlorhydria
7/2/2023 131
132. Functions of Iron
Prevents and treats iron-deficiency anemia
Stimulates bone marrow production of hemoglobin
Replace iron lost during menstruation.
Iron is an essential component of hemoglobin, myoglobin
and a co-factor of several essential enzymes.
The heme compound myoglobin is an iron-protein complex
in muscles. This complex helps muscles get extra energy
when they work hard.
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133. Deficiency of Iron
• Iron deficiency is the most common nutrient deficiency worldwide.
• It occurs most often due to inadequate iron intake and is the most common
cause of anaemia .
• Iron intake is frequently inadequate in four population groups:
Infants and young children (6 months to about 4 years) Because of the
low iron content of milk and other preferred foods,
rapid growth rate, and
insufficient body reserves of iron to meet needs beyond about 6
months
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134. Cont…
adolescents in their early growth spurt
Because of rapid growth and the needs of expanding red blood cell
mass
females during childbearing years
Because of menstrual iron losses
pregnant women
Because of their expanding blood volume, the demands of the fetus
and placenta, and blood losses that are incurred in childbirth
PLWHA
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135. Iron Deficiency Anemia/Nutritional
Anemia
• Occurs when Hgb production is considerably
reduced leading to a fall in its levels in the
blood
• Serum transferrin receptors are high
7/2/2023 135
136. Iron deficiency anemia..
• May develop under many circumstances:-
– Increased demand as in the case of pregnancy,
lactation, rapid growth etc
– Decreased intake of a nutrient
– Decreased absorption of a nutrient from food
– Chronic blood loss resulting in iron deficiency(
e.g. in hook worm and schistosoma infection)
7/2/2023 136
137. Symptoms of IDA
• Shortness of breath
• Lethargy, fatigue, headache
• Disturbance in taste
• Pallor of the conjunctiva, tongue, nail beds and soft palate
• Enlargement of the spleen (splenomegally)
• Behavioral changes
• Impairment of cognitive function
• Short attention spans…..etc
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138. Causes of iron deficiency
The main causes for failure to meet iron needs could be:
Dietary
Inadequate intake of both heme and non-heme
iron rich diets
Regular consumption of high phytate plant-based
meals
Inadequate intake of iron absorption enhancers
Inadequate intake of vit A, B- 12, folic acid, &
possibly B-6
7/2/2023 138
139. Non dietary factors
Increased physiological requirements such
as menstruation
Frequent parasitic infections including
• Malaria
• Hookworm
• Trichuriasis
• Schistosomiasis
Abnormal blood cell production (sickle cell)
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140. Diagnosis, IDA
• Measuring hemoglobin concentration
– Children 6m-6yr 11g/100ml
– Children 6-14yr 12g/100ml
– Adult male -13g/100ml
– Adult females, non-pregnant -12 g/100ml
– Adult females, pregnant -11 g/100ml
• Red blood cell morphology
• Complete Blood count
• Stool exam
7/2/2023 140
