NTA Level 4 • Semester 1 • PST04102

Introduction to Human Nutrition

Disease Control and Prevention • Source Session/Topic 42

Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability.

Session 42: Introduction to Human Nutrition

Total Session Time: 120 minutes + 2 hours Assignment

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• Describe Sources of Different Food Substances

• Describe the Composition of each Class of Food (Carbohydrates, Proteins,

Fats And Oils, Vitamins And Minerals)

• Define Balanced Diet and Explain its Importance to Human Health

• Differentiate Between Fat Soluble and Water Soluble Vitamins

Resources Needed:

• Flip charts, marker pens, and masking tape

• Black/white board and chalk/whiteboard markers

• Computer and LCD projector

SESSION OVERVIEW

SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Sources of Different Food Substances (15 minutes)

|Activity: Brainstorming (5 minutes) |

|Ask students to brainstorm on the following question: |

|What are sources and classes of different food substances? |

|ALLOW few students to respond |

|WRITE their responses on the flip chart/ board |

|CLARIFY and SUMMARISE by using the content below |

Important terms

• Food: is what is eaten or taken into the body by parenteral routes for

the purpose of nourishing the body.

o Foods contain elements called nutrients.

• Nutrients: are a variety of chemical substances that, in nature, form

part of food. Nutrients are not the same, they can be quite be different

from one another.

• Nutrition: is the term standing for the sum of all processes involved in

food intake, assimilation and utilization by the body.

o Food must be available and accessible for consumption

o Body ingests, rearranges, assimilates and utilizes the nutrients

consumed in food, for the purpose of:

▪ Production of energy

▪ Growth

▪ Functioning of organs and systems

▪ Maintenance of life.

• Nutritional status: is the result of the body’s nutrient intake and

utilization, which may be good or bad.

• Malnutrition: literally means ‘bad nutrition’.

o It means any deviation from normal nutrition.

o Can be either under-nutrition or over-nutrition

Sources of different food substances

The main sources of different food substances are:

• Cereals: For example maize, rice, millet, wheat and sorghum

• Pulses: For example lentils, beans, soya beans and peas

• Nuts: groundnuts and cashew nuts

• Vegetables:

o Green leafy vegetables: cabbage, cauliflower, spinach and lettuce

o Roots and tubers: yams, cassava, potatoes, sweet potatoes, carrots and

beetroots

o Other vegetables: ladiesfingers, brinjals, pumpkins, green peas

• Fruits: pawpaws, mangoes, oranges, banana, tangerines, pineapples as

well as wild fruits such as baobab fruits and tamarind

• Foods of animal origin: meat, fish, eggs, milk and milk products

• Sugar, Honey, Fats and Oils

o Examples of fats and oils are:

▪ Ghee

▪ Butter

▪ Coconut oil

▪ Margarine

▪ Sunflower

▪ Palm oil

STEP 3: The Composition of each Class of Food (30 minutes)

|Activity: Buzzing (5 minutes) |

| |

|ASK students to pair up and buzz on the following question for 2 |

|minutes |

| |

|What is the composition of classes of food? |

| |

|ALLOW few pairs to respond and let other pairs to add on points not |

|mentioned |

| |

|WRITE their response on the flip chart/board |

| |

|CLARIFY and SUMMARIZE by using the content below |

Carbohydrates

• These are organic compounds composed of the elements carbon, hydrogen and

oxygen.

• Carbohydrates provide the main source of energy for the body.

• Carbohydrates are classified as:

o Monosaccharide (glucose, fructose, galactose and mannose) are the

simplest carbohydrates.

o For their absorption they can pass through the wall of the alimentary

tract without being changed by digestive enzymes.

o Disaccharides (sucrose, maltose and lactose) and oligosaccharides are

also simple carbohydrates.

▪ These have to be converted by the body into monosaccharides

before they can be absorbed from the alimentary tract.

o Polysaccharides, also called complex carbohydrates, are chemically the

most complicated carbohydrates. Examples are starch, cellulose and

glycogen.

▪ These are long chain molecules in which a large number of

monosaccharides are combined.

Lipids

• These are organic compounds made of the elements carbon, hydrogen and

oxygen but in different proportions and different structural arrangements

• Fats and oils provide the body with fuel with very high efficiency

• Dietary lipids transport the fat-soluble vitamins (vitamin A, D, E and K)

• Absorption of these vitamins does not take place very efficiently in the

absence of fat

• Lipids that are solid at room temperature (butter, beef fat) are referred

to as ‘fats’

• Lipids that are in liquid at room temperature are referred to as ‘Oils’

Proteins

• Proteins are organic molecules that contain the elements carbon,

hydrogen, oxygen and nitrogen.

• Frequently proteins contain sulphur and phosphorus and less frequently,

other elements such as iron, copper and iodine

• Nitrogen is the element characteristic of all amino acids and therefore

of proteins

• Amino acids are classified into two groups:

o Those amino acids which cannot be synthesized in the human body (or

synthesized in inadequate amounts) are termed essential.

o Those which can be synthesized in the body are non-essential amino

acids.

Importance of Protein in Nutrition

• Necessary for growth, development and repair of the body.

• Main structural constituents of the cells and tissues making up the

greater proportion muscles and organs.

• For producing metabolic and digestive enzymes

• Constituent of certain hormones such as thyroid hormones and insulin.

• Amount exceeding the requirement for growth, cell and fluid replacement

and other metabolic functions is used to provide energy

• The body obtains this energy by changing the protein into carbohydrate

Vitamins

• Vitamins are organic compounds that perform specific metabolic functions

in the body Most of them are not synthesized in the body, must be

provided by dietary sources

• Vitamins, unlike carbohydrates, lipids and proteins, do not produce

energy.

• Vitamins differ widely from one another in terms of chemical structure

and biological functions

Minerals

• Minerals are naturally occurring, inorganic, homogenous substances.

• These substances are very important to keep the human body in a balancing

working order

• Minerals are constituents of the bones, teeth, soft tissue, muscle,

blood, and nerve cells.

• Minerals act as catalysts for many biological reactions within the body

• Mineral classification:

o Major minerals includes:

▪ Calcium

▪ Iron

▪ Sodium

▪ Potassium

▪ Magnesium

▪ Phosphorus

▪ Sulfur

o Trace minerals are:

▪ Zinc

▪ Copper

▪ Cobalt

▪ Manganese

▪ Iodine

▪ Chromium

▪ Chloride

▪ Fluoride

Water

• This is an essential component of healthy diet. About 60-70% of the total

body weight of a person is water

• It is important for transport of nutrients, removal of waste and assists

in metabolic activities of all cells and provides lubrication to moving

parts of the body and assist in regulating body temperature.

• Clean and safe water is essential for avoiding water-borne and water

related diseases.

• Water requirement of a person varies with climate, age, activity,

dietetics habits and body build.

STEP 4: Balanced Diet and Explain its Importance to Human Health (40

minutes)

|Activity: Small Group Discussion (10 minutes) |

| |

|DIVIDE students into small manageable groups |

| |

|ASK students to discuss on the following question |

|What is balanced diet? |

|What is the importance of balanced diet to human health? |

| |

|ALLOW students to discuss for 10 minutes |

| |

|ALLOW few groups to present and the rest to add points not mentioned |

| |

|CLARIFY and SUMMARIZE by using the contents below |

Balanced diet

• A diet that contains the proper proportions of carbohydrates, fats,

proteins, vitamins, minerals, and water necessary to maintain good

health.

• A balanced meal should contain at least one food from each of the food

groups

• Balanced diet is important for growth and development

[pic]

Figure 1: Nutrition and Diseases: Vicious Cycle

STEP 5: Fat Soluble and Water Soluble Vitamins (10 minutes)

Classification of Vitamins

• Fat soluble vitamins are vitamins A, D, E and K.

• They are soluble in fats and fat solvents

• They are utilized only if there is enough fat in the body.

• They have the following general properties:

o Consist of carbon, hydrogen and oxygen

o They are relatively stable during:

▪ Processing,

▪ Preservation

▪ Preparation

o They are stored in the liver and fatty deposits of the body therefore

do not have to be consumed on daily basis

o If consumed in excess can produce toxicity

• Water-soluble vitamins are vitamins C, folic acid and the B vitamins.

• They cannot be stored in the body therefore, a day to day supply is

essential

STEP 6: Key Points (5 minutes)

• The main sources of different food substances are: cereals, nuts, pulses

and vegetables

• The major nutrients in the bodies are carbohydrates, proteins, lipids,

vitamins and minerals.

• Balanced diet is important for growth and development

• Balanced diet contains the proper proportions of carbohydrates, fats,

proteins, vitamins, minerals, and water

• Water soluble vitamins are soluble in water whereas fat soluble are not.

STEP 7: Evaluation (5 minutes)

• What are sources and classes of different food substances?

• What is the composition of each class of food?

• What is balanced diet?

• What is the importance of balanced diet to human health?

• What is the difference between fat soluble and water soluble vitamins?

STEP 8: Assignment (10 minutes)

|Activity: Take Home Assignment (10 minutes) |

| |

|DIVIDE students in groups or individuals |

| |

|ASK the students to work on the following Assignment |

|Explain how water requirement of a person varies with climate, age, |

|activity, dietetics habit and body build |

|ALLOCATE time for students to do the assignments and submit |

| |

|REFER students to recommended references |

References

Beaton G.H. & Bengoa J.M. (1976).Nutrition in Preventive Medicine. Geneva:

WHO

King, S. F & Burgess, A. (2000). Nutrition for Developing

Countries.(2nded.) Oxford: Felicity Oxford University Press.

Kumar, P. & Clark, M. (2006).Clinical Medicine.(6thed.) Phidalephia:

Elsevier Limited.

Latham, M. C (1997).Human Nutrition in the Developing World.David Lubin

Memorial Library.

McLaren, S. (1992).A Colour Atlas and Text of Diet-Related

Disorders.(2nded.) Aylesbury: BPCC Hazells Ltd

Raheena Begum.(2006). A textbook of Foods, Nutrition and Dietetics.(2nd.

Rev.ed.) New Delhi: Sterling Publishers Private Ltd

Tanzania Food and Nutrition Centre.(2009). National Guidelines for

Nutrition Care and Support for People Living with HIV.(2nded.) Dar es

Salaam: TFNC

← Previous Topic Next Topic →View all Disease Control and Prevention topics Open Complete Full Notes

PDF / OFFLINE NOTES

Unataka kutumiwa notes hizi kupitia WhatsApp?Kwa notes zilizopangiliwa vizuri kwa kusoma offline au PDF, bonyeza kitufe hapa chini. Ujumbe wenye Level, Semester, Module na Topic utaandaliwa moja kwa moja.TUMIWA NOTES WHATSAPP

WhatsApp: 255620339260