Which minerals does the body need, what do they do, and why is water just as important?
The function, dietary sources and effects of deficiency or excess of the minerals calcium, iron, sodium and phosphorus, and the function of water in the body.
An SQA National 5 Health and Food Technology answer on minerals and water, covering the function, sources and deficiency or excess effects of calcium, iron, sodium and phosphorus, and the function of water in the body.
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What this dot point is asking
The SQA wants you to know the function and food sources of the minerals calcium, iron, sodium and phosphorus, what a deficiency or an excess of each causes, and the function of water in the body.
Calcium
Sources of calcium include milk, cheese, yoghurt, tinned fish eaten with soft bones (such as sardines), and green leafy vegetables.
Iron
Sources of iron include red meat, liver, eggs, pulses (beans and lentils), green leafy vegetables and fortified breakfast cereals.
Sodium (salt)
Most people in Scotland eat more salt than they need, so dietary advice is to cut down, especially on salty processed foods, and to taste food before adding extra salt.
Phosphorus
Phosphorus works together with calcium to make strong bones and teeth, and it also helps the body release energy from food. It is found in many foods, including milk, cheese, meat, fish and cereals, so a deficiency is rare.
Water
You need more water in hot weather, during exercise, and if you have a fever, because more is lost through sweating.
Examples in context
Example 1. Building bone in the teenage years. A teenager's bones are still growing, so a good supply of calcium (from milk, cheese and yoghurt) plus vitamin D to absorb it helps build strong bones that resist osteoporosis in later life.
Example 2. Cutting hidden salt. A family swaps salty processed ready meals and crisps for home-cooked meals seasoned with herbs and spices instead of salt. This lowers their sodium intake, helping to keep blood pressure down.
Try this
Q1. Name the mineral needed to make haemoglobin, and one food that supplies it. [1 mark]
- Cue. Iron, from a food such as red meat, liver, eggs, pulses or fortified cereal.
Q2. State one health problem caused by eating too much sodium (salt). [1 mark]
- Cue. High blood pressure (hypertension), which raises the risk of heart disease and stroke.
Exam-style practice questions
Practice questions written in the style of SQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
SQA N5 style4 marksDescribe the function of calcium and iron in the body, and state one food source of each.Show worked answer →
A 4-mark answer needs the function and a source for each mineral, so plan two function marks and two source marks.
Calcium is needed to build strong bones and teeth, and it also helps the blood to clot. A source is milk (also acceptable: cheese, yoghurt, tinned fish with soft bones, green leafy vegetables).
Iron is needed to make haemoglobin, the red pigment in red blood cells that carries oxygen around the body. A source is red meat (also acceptable: liver, eggs, pulses, fortified breakfast cereal, green leafy vegetables).
A further point that scores is that vitamin D helps the body absorb calcium, and vitamin C helps the body absorb iron, so these vitamins should be eaten alongside the minerals.
Markers reward each correct function and source. Saying a mineral "keeps you healthy" with no specific role earns nothing.
SQA N5 style3 marksExplain why a diet high in sodium (salt) can be harmful to health, and describe the effect of an iron deficiency.Show worked answer →
This question covers an excess (sodium) and a deficiency (iron).
A diet high in sodium can raise blood pressure (hypertension). High blood pressure makes the heart work harder and raises the risk of coronary heart disease and stroke. Much of the salt we eat is hidden in processed foods.
A deficiency of iron leads to iron-deficiency anaemia, because there is not enough iron to make haemoglobin. With less haemoglobin the blood carries less oxygen, so the person feels tired, weak and lacks energy, and may look pale.
A further point that scores is that eating a food rich in vitamin C with an iron source helps the body absorb the iron, which helps prevent anaemia.
Markers reward the blood-pressure mechanism for sodium and the haemoglobin/anaemia mechanism for iron.
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Sources & how we know this
- SQA National 5 Health and Food Technology Course Specification — SQA (2017)
- British Nutrition Foundation - Minerals and trace elements — British Nutrition Foundation (2023)