Post on 06-May-2015
FOOD ANDDIET
B M Subramanya Swamy M.Sc. B.Ed.
CIE Co ordinator & Examination OfficerKanaan Global School
Jakarta Indonesia
subramanyaswamy1591978@gmail.com
FOOD ANDDIET
B M S SwamyUniversal School Jakarta
F O O DF O O DSource of fuel for the bodyEaten in the right amount and types, it leads to good healthIt serves to :
- supply energy- promote body growth and repair of tissues- regulate body functions
Carbohydrates, fats and proteins are nutrients that provide energyVitamins, mineral salts and water are not digested. It is used to regulate body functionsDietary fibre is important in preventing constipation
CarbohydrateCarbohydrates contain compounds of carbon, hydrogen and oxygen in the ratio of 1 : 2 : 1
Carbohydrates Types Sources Function
Monosaccharide(single/simple sugar)
Disaccharide(double/complex sugar)
Polysaccharide
GlucoseFructose Galactose
Sucrose Maltose Lactose
StarchCellulose Glycogen
Fruits and vegetables
Sugar cane, beetroot, milk
Rice, cereal, bread
• Provide energy• Converted to glycogen for storageExcess is stored as fats
Used in synthesis of DNA
Fats_________________________ 1. Composed of carbon, hydrogen and oxygen2. Oils (fatty acids and glycerol) are liquid at room
temperature. They have a low melting point.3. Waxes are solid at room temperature.4. Fats provide twice as much energy as
carbohydrates. They are stored in the body as fats.5. There are saturated and unsaturated fats.
Fats Sources Function
Saturated
Unsaturated
ButterAnimal fats
Fish oil Vegetable oil
Provide energy Medium for intake of
vitamin A, D, E and K
Synthesis of cell membrane
Insulation layer under skin
Protects organs from physical injury
Proteins___________________
☺ Composed of carbon, hydrogen, oxygen and nitrogen. May contain sulphur or phosphorus.
☺ Protein molecules are composed of large numbers of amino acids linked together by peptide links.
☺ Lack of proteins lead to kwashiorkor.☺ Complete proteins come from animal sources.☺ Incomplete proteins come from plant sources.
Proteins Sources Function
Animal/plant
Human (9 essential and 11 non-essential protein)
Lean meatFish Liver Milk Cheese Soya beans Cereals
Growth of new tissue Replacement of cell component Build up body structure like hair and nails Function of muscles, tendons and ligaments Formation of enzymes and hormones Components of antibodies
Fibre______________________
Fibre in the diet consist of carbohydrates, mainly cellulose and ligninThey are not digested by the human body
Sources Function
Fruits, vegetables, whole meal bread and cereals
Stimulates peristalsis, moves waste along intestines Absorbs water, making wastes softer. Thus preventing constipation
Minerals___________________ ۩ Inorganic, chemical elements۩ Regulate body processes۩ Not stored in the body (except for iron)۩ Is quickly used or lost۩ Body requires calcium, phosphorous and
magnesium more than iodine, iron and zinc
Mineral Sources Function Deficiency Symptoms
Calcium Cheese, milk, oyster, green vegetables
• Development of strong bones and teeth• Blood clotting• Muscle contraction• Nerve/heart activity
• Soft bones• Osteoporosis (adults)• Rickets (children)• Slow blood clotting• Weakness • Wounds heal slowly
Iron Egg, lean meat, legume, green leafy vegetables
• Forms haemoglobin in RBC• Transport oxygen as oxyhaemoglobin
• Anaemia • Paleness of skin• Fatigue
Vitamins_____________________ ♣ Organic compounds, required on small
quantities♣ Water-soluble vitamins (B and C) are not
stored in the body. Excess of these vitamins are excreted
♣ Fat-soluble vitamins (ADEK) need not be consumed everyday, it is absorbed by the body and stored in the liver
Vitamins
Sources Function Deficiency Symptoms
A Fish liver oil, dairy products, green vegetables
• Healthy growth• Maintenance of skin tissue• Formation of visual pigment in the retina
• Poor skin• Night blindness
B1 Whole grains, egg, meat
• Promote cell respiration• Normal growth
• Lethargy • Retarded growth• Degeneration of nerves and muscles (beri – beri)
C Fruits (esp. citrus), potatoes, green vegetables
• Healthy epithelia• Strong gums• Helps heal wounds• Aids in iron absorption
(scurvy)• Bleeding gums• Loose teeth• Bleeding under the skin• Slow healing of wounds
D Fish liver oil, dairy products
• Absorption of phosphorous and calcium• Builds and maintains bones and teeth
(rickets)• Mainly in children• Leads to bowlegs and beaded ribs
Water________________________ 1. Makes up about 60 – 70 % of body weight 2. Lost in urine, perspiration and breathing3. If not replaced, the body gets dehydrated4. This leads to muscles cramps and weakness in
the body
Function of water in the human bodyFunction Mode of action
Transport • Main constituent of blood and body fluid• Medium for transport of nutrients, water, hormones, etc
Reactions • Solvent for chemical reactions• Hydrolytic reactions during digestion
Lubricants • Constituent of synovial fluids in joints and mucus in alimentary canal
Homeostasis • Evaporation of water from sweating cools the body. Thus preventing overheating.
World Food Supply
There has been a dramatic increase in world populationThere has not been an increase in natural resources to feed the increasing populationMalnutrition is a world wide problem.
It takes many forms.
Types of Malnutrition
Malnutrition Form
Starvation • Insufficient food to supply daily requirements of the individual
Eating disorder Anorexia nervosa
Bulimia
• May be genetic or environmental• Constant dieting with rapid weight loss• Psychological condition influenced by fashion trends
Eating too much food, and then getting rid of food by vomiting or use of laxatives
Marasmus • General starvation• Both energy and protein are insufficient• Affects children less than 1 year old who have been weaned too early or given poor substitutes for mother’s milk
Kwashiorkor • Children displaced from breast feeding after arrival of new baby• Develops protein deficiency diseases• Body is dwarfed
Obesity • Being 20% above ideal weight• May be caused by thyroid problems, or low metabolic rate
Overeating saturated fats
• Increases level of cholesterol in the blood• Is deposited on walls of arteries where they harden• May cause clots to form, leading to heart attack and high blood pressure
Constipation • Difficult bowel movement• Could be caused by lack of exercise, emotional stress, misuse of laxatives, diet low in dietary fibre• May cause vessels in rectum to produce haemorrhoids, resulting piles• Can cause pain and bleeding
Causes of food supply shortage
Causes
Form
Population explosion
• World population on the rise• Poverty, starvation and depletion of natural resources also on the rise
Famine • Extreme shortage of food• Industrial nations have food surplus• Under-develop nations with no means to pay for the expensive food
Drought • Severe climatic change• Extreme crop damage• Destruction of farm animals
Flood • Rivers overflow their banks, monsoon rains, tidal waves etc.• Destruction of agricultural lands and crops• Lands destroyed by tidal waves not suitable for farming anymore
Solution to world food supply shortageSolution Form
Green revolution New strain of crops to enhance food yields
Farming the sea Culturing fish, lobsters, prawn and crabs, and plants like seaweed and algae
Genetically modified food Genes altered to improve quality of foodIncrease shelf life, size, nutrient content
Distribution of food World Red Cross organizations supply food surplus to over populated third world countries
Farming technique Improve output of farmsUse machinery and fertilizers
Enriched foods Basic foods with increase in nutrients to improve quality of foodAddition of vitamins and minerals
Pest control Reduce quantity of food lost during storage or growth
Increase land under cultivation
Increase food productionUse of arid, semi – arid and desert areas with irrigation methods for farming
Diet Balanced diet♦ Food intake and energy required varies with
sex, age and occupation♦ Good nutrition involves selecting food from
the various food groups♦ Eat grain, vegetables, fruits, dairy protein-rich food, fatty food
Basic food group
Food group Sources Nutrients
Grain Whole grain, enriched flour
Carbohydrates, fibre, vitamin B, iron and protein
Fruits and vegetables
Dark green vegetable, deep yellow vegetable
Carbohydrates, fibre, various vitamins and minerals
Dairy Milk and milk products
Main source of calcium, protein, vitamin A, B and B2
Protein-rich Poultry, eggs, red meat, legumes
Rich in protein, vitamin B, magnesium and zinc
Fats and sweets Candy, pastry, oil, coffee
Low in nutrient value
Energy A balanced diet supplies all the essential nutrients in the correct proportionsBasal metabolic rate (BMR) and physical activity determines the energy to maintain BMR to sustain activitiesBMR varies by sex, age and state of health of the individual
Energy supplied by the various food types
1 g of food type Energy (kj)
Carbohydrate 2.2
Fat 8.5
Protein 7.2
Food AdditivesAdditives substances added to foods in small quantities for a variety of reasons.
Function Examples Advantages Disadvantages
Flavorings • Monosodium Glutamate (MSG) (an amino acid)• Salt
• Chocolate flavour• Sugar
Improves taste
Improves taste
Improves taste
High doses can cause sweating and hyperactivity.
Contributes to high blood pressure.
The sugar in chocolate provides an excellent substrate for growing bacteria which produce acids which can cause tooth decay, also fattening.
Function Examples Advantages Disadvantages
To improve nutritional quality
• Lysine is added to flours in places where diet is poor. • Vitamin D is added to white flours
Enriches poor diet
Colouring Annatto Improves appearance, by replacing colour lost in processing
Some people are allergic to annatto
Sweeteners Nutrasweet Food can taste sweet without being so fattening
Unsuitable for some people.Gives a bitter aftertaste.
Function Examples Advantages Disadvantages
Preservatives Vinegar, salt, sugar
Reduces bacterial spoilage on ready – made meals. E.g. salad
Vitamin content of food declines with storage.
Anti-oxidant Sodium ascorbat
Stops fat spoiling and becoming rancid in pre – cooked meats
Stabilisers Carragheen Stops food textureseparating
Thickeners Guar gum Gives a thicken consistency and better sensation in the mouth.