UNIT 2

NUTRITION

AND HEALTH

2.1FOOD AND

NUTRITIONAL

SUBSTANCES

MACRO-NUTRIENTS:SugarsLipidsProteinsWater

MICRO-NUTRIENTS:VitaminsMinerals

NUTRIENTS: they are the substances we

need for obtaining energy and for making

our own living matter. There are two kinds

of nutrients:

MACRO-NUTRIENTS: they are the major

components in food.

MICRO-NUTRIENTS: they are substances

which are present in small quantities in

food but which are also necessary for us.

Sugars or carbohydrates: their main

function is to provide energy. The most

common sugars in our diet are starches.

Fibre which comes from vegetables is also a

sugar. It is necessary for helping the food to

pass through the intestine.

Lipids or fats: these have many functions,

but the most important is to provide energy.

They can be found in vegetable oils and in

animal fats.

Proteins: these are necessary

for building the matter that

forms our cells.

Water: it is a fundamental

component of living matter.

Vitamins: these have many functions.

We need very small quantities of these

substances, but their absence causes

serious disorders.

Minerals: these are chemical elements

that do not form a part of living matter

by themselves but which we need in

small quantities.

FOOD PYRAMID

2.2 ENERGY

NEEDS

The energy value of a food is

proportional to the energy that is

released when the food is burnt. This

energy is measured in calories.

A calorie is the amount of heat

required to increase the temperature

of a gram of water by one degree

centigrade.

Sugars and lipids are the nutrients which

provide us energy. The human body

stores both types of nutrients so as to be

able to have constantly available energy

reserves. Lipids contain far more energy

than sugars.

Basal Metabolic Rate (BMR) is the

amount of energy which is consumed by

human body when it is totally at rest and

with a constant temperature.

2.3 A COMPLETE

AND BALANCED

DIET

An optimum diet is a complete and

balanced diet, complete because it

uses foods from every group and

balanced because we eat the

correct proportion of each food.

Criteria for an adecuate diet:

Food should provide just the right amount of energy for

carrying out our activities and for the development of the

body.

Diet should supply sufficient proteins, vitamins and

minerals.

With regard to the distribution of the foods which

provide energy, this should be done in accordance to:

Food rich in sugars →50-60% of total number of calories

Food rich in fats→ 25-30% of total number of calories

Food rich in proteins → 15-20% of total number of

calories

Disorders caused by food:

Obesity: The organism does not expel the

excess sugars but transforms them into

fats. The accumulation of fats in tissues is

the cause of obesity.

Anorexia: It is characterised by extreme

thinness due to a lack of food. People with

anorexia reject food.

Bulimia: People with bulimia eat all the

time without control and vomit almost

immediately all that they have ingested.

2.4FOOD

PRESERVATION

Ways of preserving food at

home:

Drying, salting and smoking.

Refrigeration:

Freezing

The oldest way of preservation

are drying, salting and smoking.

Refrigeration: Keeping foods in a

cold environment. When the

temperature is lowered, the action

of micro-organisms is slowed down.

Foods can be conserved for several

days.

Freezing: Keeping foods in a cold

environment (-10ºC). The action of

micro-organisms is detained almost

completely. Frozen foods can be kept for

long periods of time provided that the

cold chain is not interrupted. If a food

defrost, it must not be frozen again, it

must be eaten immediately or thrown

away.

EXPLAIN REFRIGERATION

AND FREEZING BY

COMPARING THEM.

REFRIGERATION FREEZING

Keeping foods in a cold

environment

Keeping foods in a cold

environment (-10ºC)

The action of

microorganisms is

slowered down

The action of

microorganisms is

detained almost

completely

Food can be conserved

for several days

Frozen foods can be kept

for long periods of time

provided that the cold

chain isn´t interrupted

Industrial forms of preservation:

Traditional forms of preservation

Additives

Sterilisation techniques

All the traditional forms of preservation

are used in industry (but these processes

are not always apt for all foods).Additives: They are various substances

which are added to food in small

quantities and following strict health

standars. They have different functions:

improve the flavour, improve the

appearance…

Preservatives: They are additives which

make food last longer.

Sterilisation techniques:

sterilisation consists of killing the

micro-organisms in the food by

heat. Pasteurisation consists of

heating the food (milk) to 72ºC for

15 seconds.

Use-by date: It is the day or

month after which the food can not

be used. After this date, the food

will not be at peak quality from a

health standpoint.

2.5 FOOD

TECHNOLOGY

Handling food:

Besides industrial processes, it is necessary

for people who handle food, both industrially

and at home, to follow some

recommendations:Be careful with personal hygiene. Wash

your hands frequently.Use appropriate and clean clothes (a cap,

an apron, a mask and gloves).Be careful with the hygiene of instruments

used for working.

Professionals in the food industry

receive the proper training to

ensure they work appropriately.

This training is necessary for them

to obtain a food handler´s

certificate.

New ways of obtaining food:

One of the concerns of the food

industry is to obtain the necessary

amount of food to satisfy the

demand. Different techniques have

been developed to obtain food

more efficiently than by using

traditional methods.

Agricultural techniques:

Use greenhouses in which it is

possible to obtain up to three anual

harvests for some vegetables.

Use of pesticides and herbicides to

prevent the crops from suffering the

attack of insects or the presence of

competitive weeds.

Intensive farming:

These techniques meant that

animals are fattened in relatively

short periods of time by improving

the feeding of animals and by

selection of breeds with rapid

growth.

Fish factory installations:

In these installations is where

various kinds of fish are reared. This

mean that it is possible to obtain a

good quality food in a short period of

time by using species with different

nutritional requirements.

Transgenic food:

Advances in the knowledge we

have of hereditary matters has

brought about the appearance of a

new generation of food,

genetically modified food.

New bio-technological techniques and

genetic engineering mean that it is

possible to manipulate the genetic

information of an organism. A bacteria,

a plant or an animal can be created

containing the normal genetic

information of its species but also with

new information in all the cells, these

organisms are known as transgenic.

However, genetically modified

foods are still being studied and

they will not be generally used until

it has been proven that they do not

cause any undesirable side effect to

the people who consume them.

VOCABULARY

NutrientsCalorieBasal Metabolic Rate (BMR)AdditivesPreservativesUse-by dateTransgenic

Nutrients: they are the substances we need for

obtaining energy and for making our own living

matter. There are two kinds of nutrients: macro-

nutrients and micro-nutrients.

Calorie: It is the amount of heat required to

increase the temperature of a gram of water by

one degree centigrade.

Basal Metabolic Rate (BMR): It is the amount of

energy which is consumed by human body when

it is totally at rest and with a constant

temperature.

Additives: They are various substances which are added to

food in small quantities and following strict health standars.

They have different functions: improve the flavour, improve

the appearance…

Preservatives: They are additives which make food last

longer.

Use-by date: It is the day or month after which the food

can not be used. After this date, the food will not be at peak

quality from a health standpoint.

Transgenic: It is a bacteria, a plant or an animal that is

created containing the normal genetic information of its

species but also with new information in all the cells using

new bio-technological techniques and genetic engineering.

UNIT MAP