biology B1 (5)

What makes a healthy diet?

• A balanced diet should contain the following items in the correct amounts: carbohydrates, proteins, fats, vitamins, minerals, fibre and water
• This provides you with the correct amount of energy to keep your body healthy
• If your diet is not balanced you will end up suffering from malnutrition
• This happens when you eat the wrong amount of each type of food nutrient
• This could be eating too much or too little
• This can lead to a person being overweight or underweight
• An unbalanced diet may lead to deficiency diseases to conditions such as type 2 diabetes
• Minerals:
• -are chemical elements such a calcium, sodium and potassium
• -you need more of some than others
• -those you need more of are called major minerals, those you need less of are called trace minerals
• -minerals are needed by teeth and bones
• -some help your heart to beat properly, and some help your nervous system and body cells to work efficiently
• -others form part of enzymes and hormones
• Fats:
• -are used as energy stores in the body and contain important vitamins
• -they contain more energy than carbohydrates
• -too much saturated fat in your diet is not good for you
• -any fat that is not used up is stored in fat cells around the body
• -this makes you put on weight
• -unsaturated fats mainly come from plants and fish
• -unsaturated fats are much better for you than saturated fats as they contain many essential vitamins and minerals
• Carbohydrates:
• -give you energy
• -examples are sugars and starches
• -sugars such as glucose can be used by the body straight away
• -starches are more difficult to digest
• -starch has to be turned into glucose before it can be used
• Fibre:
• -is important for a healthy digestive system
• -cellulose and fibre are also carbohydrates
• -cellulose is difficult for us to digest
• -it is often called fibre or roughage
• Proteins:
• -are used to build muscles, to repair damaged tissues and to help young bodies grow
• -they are also used to produce important chemicals such as enzymes and hormones
• Water:
• -essential for staying alive, 60% of the body is water
• Vitamins:
• -play a very important part in almost all bodily processes, including the immune system etc
• -there are many different vitamins and minerals so it is important to eat a wide variety of foods
• -some vitamins are lost in cooking
• -some vitamins are lost in urine

Deficiency diseases

• Shortage of energy foods such as fats and carbohydrates can make you too thin
• Shortage of proteins affects your growth
• The amounts of vitamins you need are small
• But if you don’t get enough certain processes in the body will stop working
• The problems caused by the lack of a particular nutrient is called a deficiency disease
• Lack of vitamin A: scurvy- weakness and bleeding gums and under skin
• Lack of vitamin D: rickets- soft bones due to lack of absorption of calcium
• Lack of iron: anaemia- tiredness owing to lack of haemoglobin in red blood cells
• Lack of…