biology - human nutrition (diet)

Describe what is meant by a balanced diet

includes all essential nutrients, such as carbohydrates, fats and vitamins, in the correct amounts

State the principal dietary sources and describe the importance of carbohydrates

• bread, pasta, potatoes

• energy source to carry out chemical reactions

• to move around

State the principal dietary sources and describe the importance of fats and oils (lipids)

• butter, oil, nuts

• provide long term store of energy

• keep us warm by insulating

State the principal dietary sources and describe the importance of proteins

• meat, fish, nuts, seeds, beans

• need to grow

• repairs damaged tissue

State the principal dietary sources and describe the importance of vitamins C and D

vitamin C:

• citrus fruit, green vegetables

• forms an essential part of collagen (makes up skin, hair and gums)

• prevents scurvy

vitamin D

• sunlight, eggs, oily fish

• to absorb calcium

• strong bones and teeth

State the principal dietary sources and describe the importance of mineral ions (calcium and iron)

calcium:

• milk, cheese, eggs

• strong bones and teeth

• can cause rickets if not eaten enough

iron:

• red meat, spinach, beans

• needed to make haemoglobin (helps red blood cells transport oxygen)

• can get anaemia if you don’t get enough (can’t transport as much oxygen to tissues)

State the principal dietary sources and describe the importance of fibre

• whole grains, fruits and vegetables

• helps move food through our intestines properly

• provides bulk

• stops us from getting diarrhoea or constipation

State the principal dietary sources and describe the importance of water

• drinks, strawberries, oranges

• for chemical reactions to take place in cells

• we continuously lose water from breathing, sweating and urinating so we have to replace it all

State the causes of scurvy

caused by a lack of vitamin C in the diet for over 3 months

State the causes of rickets

caused by a severe lack of vitamin D