Nutrition Notes Science Form 2

CHAPTER 2: NUTRITION

2.1

Classes of Food

Fats Carbohydrat es

Proteins

Classe s of Food

Minerals

Fibre

Classes

Vitamins

Water

Functions

Examples sugars: cakes, cholates, fruits

Carbohydrat es

Fats Proteins Vitamins Minerals Fibre

Water

starch: rice, bread, potatoes Supply main energy to body

Supply more energy & give heat to body For growth, repair and replace damaged cells Maintain good health For proper growth & development of body To stimulate peristalsis Medium for chemical reaction in the body Regulate body temperature Transport digested food & waste materials

cellulose: vegetables, fruit glycogen (stored in the liver & muscle) butter, cheese, margarine meat, fish, milk, eggs, beans, peas, nuts vegetables & fruits meat, milk, banana, seafood, eggs fruits & vegetables

water

 Excess carbohydrates stored as fat in the body.  Vitamins A, D, E, K – fats soluble  Vitamins B, C – Water soluble  Vitamins – required in small quantity for body

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Vitamin s A B C

D E K

Minerals Sodium Potassium Calcium Iron Iodine Phosphoru s

Functions To promote healthy skins & eyes Maintain healthy skin & nervous system To increase immunity against diseases Maintain healthy skin, teeth, gums Maintains healthy & strong teeth & bones Promotes calcium & phosphorus absorption Maintain healthy reproduction system Blood clotting

Examples carrot, tomatoes, green vegetables yeast, liver, vegetables guavas, grapes, tomatoes,

Deficiency diseases Dry skin , night blindness Beri-beri, Pellagra, Anaemia Scurvy

citrus fruit, vegetables milk, eggs, fish

Rickets, softening of bones & teeth

seeds, nuts, egg yolk, whole grain liver, egg yolk, green vegetables

Functions Maintain body fluid balance

Examples cheese, meat, table salt

For nerve & muscle activities

bananas, fish, meat

Maintain strong & healthy teeth & bones Helps blood clotting Formation of haemoglobin in red blood cell Make the hormones of the thyroid gland Help in muscle contraction, make healthy

milk, eggs, anchovies, green vegetables liver, egg yolk, meat

Sterility prolong bleeding

Deficiency diseases muscle cramps paralysis, weak muscles Rickets, Osteoporosis, prolong bleeding Anaemia

seafood, seaweed

Goitre

cheese, milk, eggs

Rickets, tooth decay,

bones, and teeth

weak muscle

Beri-beri (disease of nervous system)

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Pellagra (skin disease)

Anaemia (shortage of red blood cell) Scurvy (bleeding gums)

Rickets (stunted growth)

Goitre (swollen

neck)

Kwashiorkor (lack of protein)

Food Test 3

Classe s

Type of test

Reagent

Result

Starch

Iodin test

Iodine

brown colour Iodine change into blue black

Glucose

Benedict's test / Fehling's test

Benedict's solution

brick-red precipitate formed

Proteins

Millon's test

Millon's reagent

white precipitate - red colour

Etanol

milky solution or white emulsion formed

Filter paper

A translucent spot formed

Fats

Emulsion test

Factors affecting balanced diet  Balanced diet – Diet which contains all seven types of food classes in the right quantities & proportions. Factors Age

Gender

Explanation babies, children, & teenagers need more energy than adults Men need more energy than woman

Reason Babies, children, and teenagers more active & life process faster Men are more active than woman

of the same age & body size Body size Health conditio n Type of job Climate

Big size individuals need more energy than small size individual

Big size individual need more energy for life process

Patients’ needs more energy than

Patients need more energy to

someone who is healthy

recover from diseases.

Heavy work need more energy

Heavy work need more

than light work

energy to perform

Individual live in cold weather need more energy than individual live in warm weather

More energy required in cold weather to maintain body temperature

Calorific value of food

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Human digestive system

1. Digestion – process of breaking down large food molecules into smaller molecules that can be absorbed by body. 2. Physical digestion – breaking down food into smaller particles by teeth. 3. Chemical digestion – breaking down food by enzymes.

Mouth

Oesophagus

Stomach

Duodenum 5

Anus

Rectum

Large intestine

Small intestine

Organs

Functions

Mouth

Cut & chews the food into smaller molecules

Oesophagus

Channels food (bolus) to stomach through peristalsis action

Stomach

Begins the digestion of protein

Duodenum

Secret pancreatic juices to digest protein, carbohydrate, & fats

Small intestine

Complete the food digestion and absorb end product of digestion

Large intestine

Reabsorb water & minerals from indigested food

Rectum

Store the faeces

Anus

Removes faeces from body

Salivary glands

Produce saliva which contain amylase enzyme

Liver

Secrets bile to emulsify fats

Gall bladder

Store bile which is secreted by liver

Pancreas

Produce digestive enzymes (amylase, protease, lipase)

4. Peristalsis – Contraction & relaxation of digestive tract to channel the food throughout the digestive tract.

Organs

Juices

Mouth

Saliva (alkaline)

Amylase

Starch - Maltose

Gastric juice

Protease

Protein - Polypeptide or Peptone

Casein/Rennin

Liquid milk protein - Solid form

Hydrochloric acid

Kills bacteria in the food

Pancreatic juice

Amylase

Starch - Maltose

(secreted by pancrease)

Protease

Protein - Polypeptide or Peptone

Lipase

Fat - Fatty acid + Glycerol

Stomach

Duodenum

(acidic)

(Alkaline)

Enzyme

Bile (alkaline greenish fluid secreted by liver) Small intestine

Intestinal juice

Functions

Emulsify fats & oils into globules Maltase

Maltose - Glucose

Protease

Peptone - Amino acid

Lipase

Fat - fatty acid + Glycerol

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 Water, minerals, vitamins are need not to be digested because these food are very small and simple molecules that can be absorbed into body.

Food class Carbohydra te Protein

End product Glucose

Fat

Glycerol + fatty acid

Amino acid

Absorption of digested food

1. Absorption of end product take place in small intestine through the diffusion process. 2. Length of small intestine – 6 metre. Walls of small intestine is folded to increase its surface area. 3. Features of small intestine: a. Have many finger-like projections known as villi (singular: villus). b. Have many blood capillaries to facilitate absorption. c. Very long about 6 m allows greater absorption. d. Very thin so that small molecules can enter the blood capillaries. e. Moist lining enables food molecules to dissolve easily. 4. Vilus or Villli – the surface of small intestine covered with millions of tiny finger-like projections. 5. Functions of vilus – Absorb digestion food effectively.

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Reabsorption of water & defecation 1. Undigested food enters the large intestine. 2. Reabsorption of water & minerals from undigested food (e.g cellulose, fibre) take place. 3. Defecation – process where faeces removed from body. 4. Faeces is formed and stored in the rectum. Then, removed through anus.

Good eating habits 1. Good eating habits – Eating nutritious food in right quantities & proportion. 2. Healthy eating habits: a. Eat plenty of vegetables & fruit. b. Consume less sugar & salt c. Eat in moderation d. Drink plenty of water e. Chew food thoroughly before swallowing f.

Eat nutritious food

g. Avoid junk food 3. Unhealthy eating habits: a. Consume high sugar lead to diabetes b. Consume high salt lead to blood pressure c. Consume too much fat lead to high blood cholesterol and heart diseases 4. Constipation – difficulty to defecate hard faeces from body. 5. Causes of constipation – lack of water & roughage in diet. To avoid constipation, must eat food such as fruits, vegetables, and grains. 6. Over weight/ Obesity – Excess body fat which can cause health problem such as diabetes, hypertension, heart diseases, cancer, & failure in respiratory and excretory systems. 8

7. Causes of obesity – Genetic, lack of exercise, unbalanced nutrition 8. Saturated fat is bad for body because fat will accumulate in the blood stream and cause blockage of blood vessels and lead to heart attack and stroke.

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