Diet and digestion

Wherever you live and whatever you eat, the right balance of food is of enormous importance to your health and well-being. A balanced dietbalanced diet
A diet which contains the correct amounts of carbohydrates, proteins, lipids, vitamins, minerals and fibre to provide your cells with the resources they need. contains enough of the major food groups to supply the energy and nutrients you need to grow and maintain the cells, tissues and organs of your body.

Some types of food are needed in large amounts. These are the macronutrientmacronutrient
Food molecules which are needed in large quantities in the diet. s which include carbohydratecarbohydrate
Energy producing organic compounds which are made of carbon, hydrogen and oxygen. Examples of food containing carbohydrate are rice, pasta, bread and potatoes s, lipids and proteins. Other substances are just as important in our diets but are only needed in tiny amounts. They are the micronutrientmicronutrient
Food molecules which are needed in very small quantities in the diet. s and they include minerals and vitamins.

The main components of a balanced diet are:

Carbohydrates provide us with easy-to-use energy. They contain the chemical elements of carbon, hydrogen and oxygen. All carbohydrates are made up of units of sugar. Some carbohydrates contain only one sugar unit. The best known of these is glucoseglucose
A type of sugar: a mono saccharide with 6 carbon atoms (a hexose sugar). . Some carbohydrates are made of two sugar units joined together. Sucrose, the compound we call sugar in everyday life, is an example. Complex carbohydratecomplex carbohydrate
Carbohydrates such as starch and cellulose made up of long chains of sugar molecules joined together. s such as starch and cellulosecellulose
A complex carbohydrate which makes up plant cell walls. are made up of long chains of sugar molecules joined together by condensation reactions.

Lipids are fats (solids) and oils (liquids). The molecules contain a lot of energy and are a very important source of energy in your diet. They are also an important part of your cell membranemembrane
A thin, flexible sheet-like structure that acts as a lining or a boundary in an organism. s, as hormones and in your nervous systemnervous system
The system which coordinates the actions of the body in response to changes in the environment using electrical signals travelling through a system of nerves. . Like carbohydratecarbohydrate
Energy producing organic compounds which are made of carbon, hydrogen and oxygen. Examples of food containing carbohydrate are rice, pasta, bread and potatoes s they contain the chemical elements of carbon, hydrogen and oxygen. A lipid is made up of three fatty acidfatty acid
Large molecule consisting of a carboxylic acid (RCOOH) with the 'R' being a long unbranched hydrocarbon chain.  molecules joined to a molecule of glycerol. The glycerol is always the same. It is the different fatty acids that affect the lipid and determine if it is a fat or an oil.

Proteins contain carbon, hydrogen and oxygen and also nitrogen. They are used for building the cells and tissues of your body, and enzymes are also made of protein. Protein molecules are made up of long chains of amino acidamino acid
The basic building blocks of proteins. There are twenty amino acids used, in different combinations, to make every protein required by the human body. s joined together. There are 20 amino acids and different arrangements of these various amino acids give us all the different proteins. The long protein molecules are often folded or coiled to give them unique three-dimensional shapes.

Minerals and vitamins are needed in your body in very tiny amounts, but they are vital for your body to grow and function healthily. A lack of them in the diet can lead to many different deficiency diseases.

Minerals include:

• Iron, needed for the haemoglobinhaemoglobin
  The protein that carries oxygen within red blood cells.  which carries oxygen in the red blood cellsred blood cells
  Carry oxygen in the blood. They are also known as erythrocytes. . Found in red meat, leafy green vegetables, apricots and eggs.
• Calcium, needed for strong bones and teeth. Found in dairy products, fish, bread and vegetables.

Vitamins include:

• Vitamin A, needed for a healthy retina and good vision. Found in fish liver oils, butter, liver and carrots.
• Vitamin B1, needed for cell respiration. Found in yeast extract and cereals.
• Vitamin C, needed for cell layers to stick together. Found in citrus fruits and fresh vegetables.
• Vitamin D, needed for healthy bones and teeth. Found in fish liver oils and made in the skin in sunlight.

Fibre (also known as roughage) is material which you cannot digest - for example the cellulosecellulose
A complex carbohydrate which makes up plant cell walls. in plant cell walls. It does not get broken down, but it is very important for the healthy working of the digestive systemdigestive system
The organ system in the body which breaks down large insoluble food molecules into small soluble molecules which can be used by the body. . It provides bulk which allows the muscles to contract and move food through the digestive system steadily.