objectives: to define nutrition and related words.to define nutrition and related words. to identify...
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Objectives:
• To define nutrition and related words.To define nutrition and related words.
• To identify nutritional requirements.To identify nutritional requirements.
• To understand Food pyramid.To understand Food pyramid.
• To list types of nutrients and relation to health.To list types of nutrients and relation to health.
• To define malnutrition and its classification.To define malnutrition and its classification.
• To list main malnutrition problems. To list main malnutrition problems.
• To describe Obesity.To describe Obesity.
• NutritionNutrition is defined as the science of is defined as the science of
food and its relationship to health. Or, food and its relationship to health. Or,
• The process of making use of food.The process of making use of food.
• It is concerned primarily with the part It is concerned primarily with the part
played by nutrients in body growth, played by nutrients in body growth,
development and maintenance .development and maintenance .
• Dietetics is the practical application of the principles of nutrition; it includes the planning of meals for the well and the sick.
• Good nutrition means “maintaining a nutritional status that enables us to grow well and enjoy good health.”
• Nutrients are substances (specific dietary
constituents) that are crucial for human life,
growth & well-being.
• Macronutrients (carbohydrates, lipids, proteins &
water) are needed for energy and cell
multiplication & repair.
• Micronutrients are trace elements & vitamins,
which are essential for metabolic processes.
CLASSIFICATION OF FOODSCLASSIFICATION OF FOODS
• Classification by origin: - Foods of animal origin
- Foods of vegetable origin
• Classification by chemical composition: - Proteins
– Fats– Carbohydrates– Vitamins– Minerals
CLASSIFICATION BY PREDOMINANT FUNCTION
• Body building foods:
• -meat, milk, poultry, fish, eggs, pulses etc
• Energy giving foods:
• -cereals, sugars, fats, oils etc.
• Protective foods:
• -vegetables, fruits, milk, etc
• Community Nutrition:Community Nutrition:
Identification of nutritional needs of population
groups and available resources.
• Nutritional Epidemiology:Nutritional Epidemiology:
It is the investigation of the relationship
between diet and disease.
Nutritional requirementsNutritional requirementsRecommended Dietary Allowances (RDA):
The level of nutrients considered to be adequate to meet the
nutritional needs of all healthy persons.
Knowledge of RDA is necessary to:
• Assess the nutritional adequacy of diets for
growth of infants, children and adolescents.
• Maintain health in adults of both sexes and
during pregnancy and lactation.
The adequate diet & Food PyramidsThe adequate diet & Food Pyramids
Food Group System:Food Group System:
• Classifies food according to similarity in
nutrient content.
• Foods placed in each group have a high
nutrient density.
Daily Food guide with Nutrient Pattern and Recommended Quantity.
Group Group Key Nutrients Key Nutrients Quantity Quantity CommentsComments
Milk and CheeseMilk and Cheese Calcium, Calcium,
ProteinProtein
Phosphorus, Phosphorus,
riboflavinriboflavin
3 cups for 3 cups for children 4 cups children 4 cups for teenagersfor teenagers
2 cups for adults2 cups for adults
Low-fat milk products Low-fat milk products have generally all the have generally all the same nutrient content, same nutrient content, however they are however they are lower in calories and lower in calories and vitamin A. vitamin A.
Meats, poultry, Meats, poultry, fish, beans fish, beans
Protein, IronProtein, Iron
Niacin, ThiaminNiacin, Thiamin
Red meat -> ZincRed meat -> Zinc
Egg yolk and liverEgg yolk and liver
-> Vitamin A-> Vitamin A
Dry beans and NutsDry beans and Nuts
-> Magnesium -> Magnesium
2 servings2 servings
Serving size: 2-3 Serving size: 2-3 ouncesounces
1 ounce of meat 1 ounce of meat
= 1 egg = 1 egg
or ½ cup cooked or ½ cup cooked beansbeans
1 ounce = 30 gm 1 ounce = 30 gm
Legumes and nuts has Legumes and nuts has a lower biological a lower biological value than meat. value than meat.
They can be combined They can be combined with animal or grain with animal or grain products to increase products to increase protein quality. protein quality. Cholesterol and Cholesterol and vitamin B12 are found vitamin B12 are found only in animal only in animal sources. sources.
Vegetable and
fruits
Vitamin A
Vitamin C
Carbohydrate (fiber)
4 servings
Serving size: ½
Cup vegetable or fruit
1 Medium fruit
Include one good
vitamin C source
daily, include deep
yellow or dark green
vegetable frequently,
include unpeeled
fruits and vegetables
for fiber.
Bread and Cereal Carbohydrate
Thiamin
Niacin
Iron
4 servings
Serving size:
1 slice bread
½ cup rice
During processing,
some essential
nutrients are lost.
Less refined
products are
recommended
Fats and sweets Fats
Carbohydrate
Calories
Fats should not be
more than 35% of the
total calories with 10%
from polyunsaturated
fats. Sugars should
not be more than 10%
of the calorie intake.
Unenriched, refined
bakery products are
included here
because they
provide low levels of
nutrients compared
to calories
Food PyramidFood Pyramid
Lessons from Food Pyramid:Lessons from Food Pyramid:
1. Maintain a healthy weight.
Studies show that the healthiest range for body weight is when the body mass index (BMI) is about 17 to 22.
2.2. Eat good fats and avoid bad fats.Eat good fats and avoid bad fats.
• Good fats are the oils found in nuts, seeds, grains and fish.
• They are high in the unsaturated fats necessary for good health.
• Good fats should contribute 30 to 45% of the total fat.
• Avoid saturated fats (animal fats and tropical oils e.g. coconut) to minimize the risk of heart disease.
• Trans-saturated fats are mainly found in margarines and commercial baked foods.
3. Eat whole-grain carbohydrates.3. Eat whole-grain carbohydrates. Why?
• whole-grainwhole-grain are more nutritious than refined are more nutritious than refined
carbohydrates carbohydrates
• Being more slowly digestedBeing more slowly digested
• Place less stress on pancreatic insulin production. Place less stress on pancreatic insulin production.
• Sources of whole grain carbohydrates include Sources of whole grain carbohydrates include
whole meal bread, whole wheat, brown rice.whole meal bread, whole wheat, brown rice.
• Avoid white bread, baked goods and pasta made Avoid white bread, baked goods and pasta made
with white flour.with white flour.
4.4. Avoid red meat as a protein source Avoid red meat as a protein source and emphasize plant proteins.and emphasize plant proteins.
• Red meat consumption is linked to a variety Red meat consumption is linked to a variety of chronic diseases & increases the risk of of chronic diseases & increases the risk of hip fracture.hip fracture.
• Animal proteins are usually packaged with Animal proteins are usually packaged with saturated fat.saturated fat.
5. Eat plenty of vegetables and fruits. 5. Eat plenty of vegetables and fruits. • Potatoes are not included as a vegetable.
• Dark green leafy vegetables, and fruit are clearly beneficial.
• A diet high in fruits and vegetables lowers blood
pressure and cholesterol and reduces the risk of cancer.
6. Take a multivitamin daily. 6. Take a multivitamin daily.
• This recommendation is insurance against any inadvertent deficiencies.
Energy Supplying Nutrients:Energy Supplying Nutrients:• Protein• Lipids• Carbohydrates
• Vitamins• Minerals• Water
Non-Energy Supplying Nutrients:Non-Energy Supplying Nutrients:
Main types of NutrientsMain types of Nutrients
PROTEINSPROTEINS• Proteins are complex organic nitrogenous
compounds.• They also contain sulfur and in some cases
phosphorous and iron.• Proteins are made of monomers called amino
acids.• There are about 20 different aminoacids which
are found in human body.• Of this 8-9 aa are termed “essential” as they
are not synthesized in human body and must be obtained from dietary proteins.
Protein Needs:Protein Needs:• Adults: 0.8 gm/kg Adults: 0.8 gm/kg body weight per daybody weight per day
• Excess protein is Excess protein is not usednot used to build more muscle to build more muscle
– If the body needs energy, the extra amino acids If the body needs energy, the extra amino acids are used for energyare used for energy
– If the body does not need energy, the extra amino If the body does not need energy, the extra amino acids can be converted to fat and stored.acids can be converted to fat and stored.
Sources:Sources:
• Complete proteins have all essential amino acids Complete proteins have all essential amino acids (animal sources)(animal sources)
• Incomplete proteins lack one or more essential amino Incomplete proteins lack one or more essential amino acids (plant sources)acids (plant sources)
Functions of ProteinsFunctions of Proteins
• Body buildingBody building
• Repair and maintenance of body tissuesRepair and maintenance of body tissues
• Maintenance of osmotic pressureMaintenance of osmotic pressure
• Synthesis of bioactive substances and Synthesis of bioactive substances and
other vital molecules e.g. other vital molecules e.g.
immunoglobulinsimmunoglobulins
Lipids
• Lipids include cholesterol and triglycerides• Fat is necessary for health
FunctionsFunctions1. Main source of energy (9Kcal/g). 2. Spare protein.3. Adipose tissue holds the body organs and nerves
in place.4. Maintain body temperature.5. Transportation of fat soluble vitamins.
Classification• Saturated fat:Saturated fat:
– Animal foods generally are rich sources– Palm and coconut oil also are rich sources
• Monounsaturated fatMonounsaturated fat– Olives, peanuts, and canola oil are rich sources
• Polyunsaturated fatPolyunsaturated fat– Corn, sunflower, cotton seed, and nut oils are rich sources
• Hydrogenated fatHydrogenated fat
Hydrogenated fat
• Hydrogenation process hardens liquid oils into more
solid margarine.
– It makes unsaturated fat in oil more saturated
– Also it produces an unhealthy type of fat called
“trans fatty acid”“trans fatty acid”
• Saturated fat and trans fatty acids may be harmful to
health
• Baked products and fried foods are often made with
hydrogenated fats
CholesterolCholesterol
• Cholesterol is necessary for cell membranes and the Cholesterol is necessary for cell membranes and the
production of vitamin D, bile, and certain hormonesproduction of vitamin D, bile, and certain hormones
• It is found It is found onlyonly in in animalanimal foods foods
• High blood cholesterol levels are associated with High blood cholesterol levels are associated with
increased risk of increased risk of heartheart disease disease
Fats yield fatty acids and glycerol on Fats yield fatty acids and glycerol on hydrolysis hydrolysis
• Fatty acid content of different fats ( in per cent)• Saturated Monounsaturated
Polyunsaturated
• Fats fatty acids fatty acids fatty acids
• Coconut oil 92 6 2• Palm oil 46 44 10• Cotton seed oil 25 25 50• Groundnut oil 19 50 31• Sunflower oil 8 27 65 • Corn oil 8 27 65• Soya bean oil 14 24 62• Butter 60 37 3
Fat requirementsFat requirements
• The WHO Expert committee on Prevention of The WHO Expert committee on Prevention of
Coronary Heart Disease has recommended Coronary Heart Disease has recommended
only only 20 to 3020 to 30 per cent of total dietary energy to per cent of total dietary energy to
be provided by fats. (<30%)be provided by fats. (<30%)
• At least 50 per cent of fat intake should consist At least 50 per cent of fat intake should consist
of of vegetablevegetable oils rich in essential fatty acids. oils rich in essential fatty acids.
CarbohydratesCarbohydratesFunctions:Functions:
1. Carbohydrate is the main source of energy, providing 4 Kcals per one gram
2. Carbohydrate is essential for the synthesis of certain non-essential amino acids.
3. Necessary for normal fat metabolism.
4. Necessary for integrity of nerve cells.
5. Lactose allow growth of beneficial bacteria in the intestine.
6. Important for normal elimination (excretion); fibers
Recommended carbohydrate intake is 55% to 65% of calories, primarily from starchy foods
Classification of Classification of CarbohydratesCarbohydrates
1.1. Monosaccharides: glucose &fractoseMonosaccharides: glucose &fractose2.2. Disaccharides: Sucrose (G + F)Disaccharides: Sucrose (G + F)3.3. Oligosaccharides (3-10).Oligosaccharides (3-10).4.4. Polysaccharides (11-1000)Polysaccharides (11-1000) a-Indigestable e.g. cellulosea-Indigestable e.g. cellulose b-partially digestable e.g.raffinoseb-partially digestable e.g.raffinose c-Digestablec-Digestable e.g. starch e.g. starch The inability of the body to metabolize The inability of the body to metabolize
carbohydrates properly =DMcarbohydrates properly =DM
FiberFiber
• Indigestible plant material e.g. cellulose
• Dietary fiber is mainly non-starch polysaccharide
• It is found in vegetables, fruits and grains.
• SolubleSoluble fiber swells or dissolves in water
– Rich sources include apples, bananas, citrus fruits, carrots
• Importance:
– Reduces cholesterol absorption
– Slows absorption of glucose
FiberFiber
• InsolubleInsoluble fiber fiber remains unchanged in water
– Rich food sources include brown rice, wheat bran,
and whole grain products
• Importance:• High fiber diet reduces the risk of heart disease,
diabetes type II, diverticulosis, hemorrhoids, constipation, and possibly colorectal cancer
* Refined foods lose fiber-rich parts during processing
Vitamins
• Regulate growth,
• maintain tissues, and
• help carbohydrates, proteins, and fats release
energy
• Provide no calories (energy)
• Needed in very small amounts
Classes of VitaminsClasses of Vitamins
• Water SolubleWater Soluble: 8 different B vitamins and : 8 different B vitamins and
vitamin Cvitamin C
• Fat SolubleFat Soluble: Vitamins A, D, E, and K: Vitamins A, D, E, and K
• Most healthy people do not need supplements; Most healthy people do not need supplements;
vitamins can be obtained by eating a variety of vitamins can be obtained by eating a variety of
foodsfoods
– Supplementation can increase the risk of Supplementation can increase the risk of
consuming toxic high levels consuming toxic high levels
Vitamin AVitamin A
• «Vitamin A» covers both:
– a pre-formed vitamin, retinol, and
– a pro-vitamin, beta carotene, which is converted to
retinol in the intestinal mucosa.
Sources:
– Retinol in liver, code liver oil & eggs (animal sources)
– Beta carotene: Coloured plants e.g. carrot, mango,
apricot, pumpkin,….. (plant sources)
Fat soluble vitamins
Functions of Vitamin AFunctions of Vitamin A
• It is essential for It is essential for normal vision. normal vision.
• It is necessary for maintaining the It is necessary for maintaining the integrity and the integrity and the
normal functioning of glandular and epithelial tissue normal functioning of glandular and epithelial tissue
which lines intestinal, respiratory and urinary tracts as which lines intestinal, respiratory and urinary tracts as
well as the skin and eyes. well as the skin and eyes.
• It supports growth, especially It supports growth, especially skeletal growthskeletal growth
• It may protect against some epithelial cancers such as It may protect against some epithelial cancers such as
bronchial cancers.bronchial cancers.
Vitamin DVitamin D
• The nutritionally important forms of
Vitamin D in man are:
– Calciferol (Vitamin D2) and
– Cholecalciferol (Vitamin D3)
Functions of vitamin DFunctions of vitamin D
• Intestine: Promotes intestinal absorption of
calcium and phosphorus
• Bone: Stimulates normal mineralization,
Enhances bone reabsorption, Affects
collagen maturation
• Kidney: Increases tubular reabsorption of
phosphate
Deficiency of vitamin DDeficiency of vitamin D
Deficiency of vitamin D leads to:Deficiency of vitamin D leads to:
• Rickets in children
• Osteomalacia in adults
Vitamin E
• Antioxidant- Protects RBCs from haemolysis.
• Present in wheat germ and green leafy vegetables
Vitamin K
• Important for blood coagulation
• Present in leaves of plants + natural (flora).
• Deficiency causes haemorrhagic manifestations.
Water soluble vitamins
Thiamine (B1)
• Function: essential for the utilization of
carbohydrates.
• Present in brewer yeast, beans and legumes.
• Deficiency: Beri-beri
Deficiency of thiamineDeficiency of thiamine
• Beriberi may occur in three main forms:
– peripheral neuritis,
– cardiac beriberi,
– infantile beriberi, signs of peripheral
neuropathy.
Riboflavin (B2)Riboflavin (B2)
• Important for cellular metabolism, oxidation and
reduction.
• Present in milk, liver, meat, eggs, fish and
vegetables.
• Deficiency: angular stomatitis &magenta
tongue.
VITAMIN B6
• Pyridoxine (vitamin B6) plays an important role in the metabolism of amino acids, fats and carbohydrate.
• The requirement of adults vary directly with protein intake.
VITAMIN B12• Vitamin B12 is a complex organo-metallic
compound with a cobalt atom (Cyanocobalamine)
• Vitamin B 12 cooperates with folate in the synthesis of DNA.
• Vitamin B 12 has a separate biochemical role, unrelated to folate, in synthesis of fatty acids in myelin.
Vitamin B12 deficiency Vitamin B12 deficiency
• Vitamin B12 deficiency is associated with Vitamin B12 deficiency is associated with
megaloblastic anaemia (pernicous anaemia), megaloblastic anaemia (pernicous anaemia),
demyelinating neurological lesions in the spinal cord demyelinating neurological lesions in the spinal cord
and infertility (in animal species). and infertility (in animal species).
• Dietary deficiency of B12 may affect subjects who are Dietary deficiency of B12 may affect subjects who are
strict vegetarians and eat no animal product.strict vegetarians and eat no animal product.
Nicotinic acidNicotinic acid
• Important for nervous system and epithelium.
• Present in yeast, liver, peanut, meat and intestinal flora.
• Deficiency: – Pellagra:
• Dermatitis • Dementia• Diarrhoea
VITAMIN CVITAMIN C
• Vitamin C (ascorbic acid) is a water-soluble vitamin.
• It is the most sensitive of all vitamins to heat.
• Vitamin C has an important role to play in tissue
oxidation
• It is needed for the formation of collagen of
connective tissue, which accounts for 25% per cent
of total body protein.
• Present in vegetables and fruits.
Deficiency of vitamin C
• Deficiency of vitamin C results in scurvyDeficiency of vitamin C results in scurvy.
• Signs of scurvy are:
– Swollen and bleeding gums,
– Subcutaneous bruising,
– Bleeding into the skin or joints,
– Delayed wound healing,
– Anaemia and weakness.
MineralsMinerals
• Minerals are certain elements that may:
– regulate chemical reactions in the body
– be part of organic molecules
• Iron in hemoglobin
• Calcium in bone and teeth
• Small amounts are needed for health
CalciumCalcium
• Most plentiful mineral in the body
– Needed for strong bones and teeth
– Involved in regulating blood pressure, clotting
blood, and muscular movements
• Bones store calcium
– Osteoporosis
• Bones lose mineral density and strength
• Aging people, especially menopausal women, are at
risk
Iron
• Most of the body’s iron is in hemoglobin,
which is in red blood cells
– The iron in hemoglobin picks up oxygen in the
lungs and transports it to cells
• Iron deficiency is one of the most common
nutritional disorders worldwide
WaterWater
• Variety of functions:
– helps transport of materials in the body, and
– involved in many chemical reactions.
• Beverages and most foods, especially fruits
and vegetables, supply water
• Diuretics such as alcohol and caffeine
increase losses of water from body
Water
• To be properly hydrated, a person needs at
least 8 cups of water daily
• Dehydration can be deadly
• Sports drinks replenish minerals and water
that are lost during heavy exercise
Malnutrition
Definition:
Malnutrition is a pathological state resulting
from a relative or absolute deficiency or
excess of one or more essential nutrients.
The major forms of malnutrition are:
Under-nutrition:
It is a pathological state resulting when nutrient intake
does not regularly meet the nutrient needs for cell
activities and body maintenance. It includes:
1. Macronutrient deficiency e.g., protein-energy
malnutrition (marasmus &kwashiorkor).
2. Micronutrient deficiency e.g. iron deficiency
anaemia, vitamin A deficiency, Iodine
deficiency….etc.
The major malnutrition problems in
the world are:
1. Protein–energy malnutrition (PEM)
2. Iron deficiency anaemia
3. Iodine deficiency disorders (IDD)
4. Vitamin A deficiency (VAD)
• Over Over 2 billion 2 billion people suffer from some form of iron people suffer from some form of iron
deficiencydeficiency
• AnaemiaAnaemia linked to iron and/or folic acid deficiency is linked to iron and/or folic acid deficiency is
among the world’s major nutritional disordersamong the world’s major nutritional disorders
• Africa & South Asia have the highest overall Africa & South Asia have the highest overall
incidence of anaemia, followed by Latin America & incidence of anaemia, followed by Latin America &
East AsiaEast Asia
• Parasitic infestation Parasitic infestation contributes to high percent of contributes to high percent of
cases in developing countries.cases in developing countries.
Iron deficiencyIron deficiency
Consequences of iron deficiency
• Reduces work capacity, thus productivity,
earnings
• Associated with 50% of maternal deaths
• Retards fetal growth, causes low birth weight
(LBW) & increases infant mortality
• Impairs ability to resist disease; in childhood,
reduces learning
Improving Iron statusImproving Iron status
• Iron tablets
• Iron fortification of basic foods (bread)
• Increased consumption of iron rich foods &
factors which enhance absorption
• Control of parasitic infections
Iodine deficiency disorders (IDD)Iodine deficiency disorders (IDD)
• In 1990: 1.6 billion people worldwide at risk of
IDD
• At least 655 million with goitre
• 43 million with some degree of mental
impairment
• 11 million with cretinism
• Moderate Iodine deficiency is associated with
average reduction of over 13 IQ points
Prevention of IDDPrevention of IDD
• Adequate intake of Iodine can prevent all IDD
• make milder forms of goiter disappear
• improve development of older children mildly affected
• Severe forms of IDD such as cretinism, cannot be
reversed; But,
• can only be prevented by adequate intake of Iodine during pregnancy
• Now, iodizing salt is all over the world
Vitamin A deficiency (VAD)Vitamin A deficiency (VAD)
• May be subclinical, severe or moderate
• Clinical (xerophtalmia)
– 2.8 million children 0-4 years old
• Blindness, total or partial
– at least half a million children a year
– about half die within a few months
Deficiency of vitamin ADeficiency of vitamin A
The signs of vitamin A deficiency are:The signs of vitamin A deficiency are:
• Follicular hyperkeratosis,
• Night blindness
• Conjunctival xerosis
• Bitot's spots
• Corneal xerosis
• Keratomalacia
Improving vitamin A statusImproving vitamin A status
• Increased intake of vitamin A rich foods e.g.
eggs, butter, whole milk, liver, red palm oil,
dark green, yellow & red fruits & vegetables
• Fortification of basic foods with vitamin A
• Supplements e.g. 2 capsules of Vitamin A
per year to young children
Over-nutrition:
It is a pathologic state resulting when nutritional
intake exceeds the body needs, which leads
to caloric excess over an extended period of
time.
Definition
Obesity is Disorder of Body Regulatory Systems leads to Excess Body Fat
Assessment: Body Mass Index (BMI) Waist Circumference (WC)
Waist to Hip ratio (WHR)
Causes & Associated FactorsCauses & Associated Factors
•Genetic: Complex PolygenicGenetic: Complex Polygenic
•Environmental and BehavioralEnvironmental and Behavioral
•Signaling factors:Signaling factors:• HormonalHormonal• NeurologicNeurologic• PsycologicalPsycological
Assessment of ObesityAssessment of Obesity• The international standard for assessing body
size in adults is the body mass index (BMI).
• BMI is computed using the following formula:
BMI = Weight (kg)/ Height (m²)
• Evidence shows that high BMI (obesity level) is
associated with type 2 diabetes & high risk of
cardiovascular morbidity & mortality
BMI (WHO - Classification)BMI (WHO - Classification)
BMI < 18.5 = Under Weight
BMI 18.5-24.5= Healthy weight range
BMI 25-30 = Overweight (grade 1 obesity)
BMI >30-40 = Obese (grade 2 obesity)
BMI >40 =Very obese (morbid or grade 3
obesity)
Waist circumference
Waist circumference predicts mortality better than any other anthropometric measurement.
It has been proposed that waist measurement alone can be used to assess obesity, and two levels of risk have been identified
MALES FEMALE
LEVEL 1 > 94cm > 80cm
LEVEL2 > 102cm > 88cm
Waist circumference
Level 1 is the maximum acceptable waist circumference irrespective of the adult age and there should be no further weight gain.
Level 2 denotes obesity and requires weight management to reduce the risk of type 2 diabetes & CVS complications.