© Livestock & Meat Commission for Northern Ireland 2015 Energy and Nutrients

© Livestock & Meat Commission for Northern Ireland 2015

Energy and Nutrients

Learning Objectives

The key learning objectives for this section are that you will:

• Know the main nutrients required for a healthy diet;

• Identify sources of these nutrients in the diet.


Energy and nutrients

We need nutrients to:

• Stay alive;

• Be active;

• Grow;

• Keep warm.


Energy and nutrients

Food provides a range of different nutrients. Some nutrients provide energy, while others are essential for growth and maintenance of the body.

There are two different types of nutrients:

• macronutrients;

• micronutrients.


Energy

A regular supply of dietary energy is essential for life.

We need energy to:• keep the heart beating;• maintain body temperature;• grow.

We also need energy for all the other activities we do. Energy requirements are different for different people.


Energy

Why do you think energy requirements are different?

Male/female Body composition

Activity levels

Physical activity levelsAge


Energy balance

Our weight depends on the balance between how much energy we consume from food and drinks, and how much energy we use by being active.

When we eat or drink more energy than we use up, we put on weight; if we consume less energy from our diet than we expend, we lose weight.

If we eat and drink the same amount of energy as we use up, we are in energy balance and our weight remains the same.


Macronutrients

There are three macronutrients that are essential for health.

These are:• carbohydrate;• protein;• fat.

Macronutrients are measured in grams (g).

They provide our bodies with energy and also the building blocks for growth and maintenance of a healthy body.


Carbohydrate

Carbohydrate provides energy for the body. 1 gram provides 3.75 kcal (16 kJ).

At least half the energy in our diets should come from carbohydrate, mostly as starchy carbohydrates.

The two types of carbohydrate that provide energy are sugars and starch.

Dietary fibre is also a type of carbohydrate found almost exclusively in plants. It is important to keep the digestive system healthy (fibre contributes 2 kcal (8.4kJ) per gram).


Sources of carbohydrate

Can you name some sources of starchy carbohydrate?


Sources of carbohydrate

Can you name some sources of sugar in the diet?


Protein

Protein provides energy; 1 gram provides 17 kJ (4 kcal).

Protein is essential for growth and repair of the body and maintenance of good health.

Different foods contain different amounts and different combinations of amino acids (the building blocks of proteins). Our bodies cannot make some of these amino acids therefore we need to obtain them from a balanced diet.


Protein

Protein from animal sources contains the full range of essential amino acids needed by the body, e.g. beef, lamb, salmon.

However, vegans and vegetarians can get all the amino acids they need by combining different plant sources of protein, e.g. pulses and cereals.


Sources of protein

Animal sources of protein include:• beef and lamb;• fish;• eggs;• dairy foods.

Plant sources of protein include:• nuts and seeds;• cereals; • pulses, e.g. beans, lentils;• mycoprotein; • soya products.


Fat

Fat is a concentrated source of energy: 1 gram of fat provides 9 kcal (37 kJ).

Fat provides essential fatty acids that we cannot make ourselves but need in small amounts.

Fat carries fat-soluble vitamins (A,D,E and K) and helps our bodies to absorb them.

Foods that contain a lot of fat provide a lot of energy.


Structure of fat

Fat is made up of fatty acids and glycerol.

Types of fatty acids include:• Saturated;• Unsaturated;

- Monounsaturated;- Polyunsaturated.

The structure of the fatty acids determines:• their effect on our health;• their characteristics, e.g. melting point.


Sources of fat

Saturated fat can be found in a variety of food including:• Meat and meat products;• Full fat dairy products (e.g. cheese);• Coconut oil, palm oil, butter, ghee, lard; • Cream, ice cream;• Pastries, cakes and biscuits.

Unsaturated fats can be found in:• Vegetable oil, e.g. rapeseed, olive and

sunflower oil;• Oily fish;• Avocado;• Nuts and seeds.


Micronutrients

There are two groups of micronutrients:• Vitamins; • Minerals.

Vitamins and minerals are only needed in small amounts, but are essential to keep us healthy.

These are measured in milligrams (1mg = 0.001g) and micrograms (1μg = 0.001mg).


Vitamins

Vitamins can be found in a wide range of food and drinks and have many uses in the body.

They are divided into two groups:• Fat soluble;• Water soluble.

Fat soluble vitamins A, D, E and K can be stored in the body.

Water soluble vitamins B and C cannot be stored in the body are readily excreted.


Fat soluble

Vitamin A

Vitamin A is important for the normal structure and functioning of the skin and body linings, e.g. in lungs. It also helps with vision in dim light as well as keeping the immune system healthy.

Sources of Vitamin A include liver, whole milk, cheese, butter, spreads, carrots, dark green leafy vegetables and orange-coloured fruits, e.g. mangoes and apricots.


Fat soluble

Vitamin D

Vitamin D is needed for the absorption of calcium and phosphorus from foods, to keep bones healthy.

Most of our vitamin D come from the action of sunlight on skin during the summer months.

Food sources of vitamin D include oily fish, eggs, meat, fortified cereals and spreads.


Fat soluble

Vitamin E

Vitamin E acts as an antioxidant to protect the cells in our bodies against damage.

Good sources of Vitamin E include vegetable and seed oils, spreads, nuts and seeds.

Vitamin K

Vitamin K is needed for the normal clotting of blood and is required for normal bone structure.

Good sources include green leafy vegetables, meat and dairy products.


Water soluble

Vitamin B group

This group includes: • vitamin B1 (Thiamin);• vitamin B2 (Riboflavin);• vitamin B3 (Niacin);• vitamin B6;• vitamin B12;• folate/folic acid.

The B vitamins can be found in a variety of foods, such as bread, cereals, milk, beef, lamb, eggs, and fortified breakfast cereals.B vitamins are needed for the release of energy from food.


Water soluble

Vitamin C

Vitamin C is needed to make collagen. This is required for the structure and function of skin, cartilage and bones. Vitamin C also acts as an antioxidant. It also helps the body to absorb iron from non-meat sources such as vegetables, as well as assisting the healing process.

Sources of vitamin C include fruit especially citrus fruits and berries; green vegetables, peppers and tomatoes. Vitamin C is also found in potatoes.


Minerals

Minerals are substances required by the body in small amounts for a variety of different functions.

The body requires different amounts of each mineral; people have different requirements, according to their age, sex, physiological state (e.g. pregnancy) and sometimes their health.


Calcium

Calcium is important for:

• The formation and maintenance of strong bones and teeth;

• The normal functioning of nerves and muscles;

• Normal blood clotting.

Sources of calcium include milk and milk products, cheese and other dairy products, some green leafy vegetables such as broccoli, fortified soya bean products, canned fish (if containing bones that are soft and can be consumed) and bread.


Iron

Iron is essential for the formation of haemoglobin in red blood cells to carry oxygen around the body.

It is also required for normal metabolism and the functioning of enzymes to remove waste substances from the body.

A lack of iron in the diet means that the stores in the body will run out. This can lead to anaemia.

There are two types of iron from:• Animal sources –red meat, liver, poultry,

fish;• Plant sources – beans, nuts, dried fruits,

wholegrains, dark green leafy vegetables. © Livestock & Meat Commission for Northern Ireland 2015

Sodium

Sodium is found in all cells and body fluids. It is needed for regulating the amount of water and other substances in the body. It is involved in the use of energy and the normal functioning of nerves.

Sodium is found in very small amounts in raw foods. It is often added as salt during processing, preparation, preservation and serving.

Sodium intakes in the UK are too high. Eating too much salt is associated with an increased risk of developing high blood pressure. People with high blood pressure are more likely to develop heart disease or have a stroke.



Acknowledgement

For further information, go to: www.food4life.org.uk © LMC 2015

Documents

© Livestock & Meat Commission for Northern Ireland 2015 Energy and Nutrients