What are minerals and why does the body need them, and why is water so important in the diet?
Minerals as micronutrients (calcium, iron, sodium) and water: their functions, food sources, deficiency and excess effects, and the importance of hydration.
A focused answer to the WJEC Food Preparation and Nutrition principles of nutrition topic on minerals and water, covering calcium, iron and sodium, their functions and sources, deficiency and excess effects, and why water and hydration matter.
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What this dot point is asking
You need to know what minerals do in the body (focusing on calcium, iron and sodium), their food sources and deficiency or excess effects, and why water and good hydration are important.
Minerals as micronutrients
Calcium
Function: with vitamin D, builds and maintains strong bones and teeth, and helps muscles and nerves work. It is especially important during growth and in older people, to reduce the risk of brittle bones (osteoporosis).
Sources: milk, cheese, yoghurt, fortified plant milks, green leafy vegetables and tinned fish with soft bones.
Deficiency: weak bones and teeth; in children, poor bone development; in later life, osteoporosis.
Iron
Function: makes haemoglobin in red blood cells, which carries oxygen around the body.
Sources: red meat, liver, eggs, and plant foods such as lentils, beans and dark green vegetables. Vitamin C helps the body absorb iron, especially from plant foods.
Deficiency: anaemia, causing tiredness, pale skin and breathlessness. Teenage girls and women need more iron because of monthly blood loss.
Sodium
Function: sodium (from salt) helps control the amount of water (fluid) in the body and helps nerves and muscles work.
The problem: most people eat too much salt, much of it hidden in processed foods. Too much sodium raises blood pressure, increasing the risk of heart disease and stroke. The advice is to cut down on salt (no more than about 6 g a day for adults).
Water and hydration
Water makes up a large part of the body and is vital:
- it forms much of the blood and transports nutrients,
- it removes waste in urine,
- it helps control body temperature through sweating,
- it is needed for digestion.
Dehydration (not drinking enough) causes headaches, tiredness, poor concentration and dark urine, and if severe, dizziness. The advice is to drink 6 to 8 glasses (about 1.5 to 2 litres) of fluid a day, more in hot weather or when exercising. Water, lower-fat milk and sugar-free drinks all count; sugary drinks are best limited because of the free sugars they contain.
Other minerals to be aware of
Besides calcium, iron and sodium, the body needs small amounts of other minerals. Fluoride helps protect teeth from decay and is added to some water supplies and toothpaste. Phosphorus works with calcium in bones and teeth. You will not be tested in detail on these, but it is worth knowing that a varied diet normally supplies all the minerals the body needs, which is why no single food group should be cut out without good reason.
Exam-style practice questions
Practice questions written in the style of WJEC exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
WJEC style4 marksExplain why calcium and iron are important in the diet, naming a good source of each.Show worked answer →
A 4-mark question. Award marks for the function and a source of each mineral.
Calcium is needed, with vitamin D, to build and maintain strong bones and teeth, and it helps muscles and nerves work. Good sources are milk, cheese, yoghurt and fortified plant milks. Iron is needed to make haemoglobin in red blood cells, which carries oxygen around the body. Good sources are red meat, liver, and plant foods such as lentils, beans and dark green vegetables. Too little iron causes anaemia, which makes a person tired and pale.
Markers reward: calcium for bones and teeth with a source; iron for haemoglobin and carrying oxygen with a source; and ideally the anaemia link.
WJEC style3 marksDescribe why drinking enough water each day is important, and give two effects of dehydration.Show worked answer →
A 3-mark question on water and hydration.
Water is needed to keep the body hydrated; it makes up much of the blood, helps transport nutrients, removes waste in urine, helps control body temperature through sweating, and is needed for digestion. If a person does not drink enough they become dehydrated, which causes effects such as headaches, tiredness, poor concentration, dark urine and, if severe, dizziness.
Markers reward: a reason water is needed (transport, temperature control, removing waste or digestion) and two correct effects of dehydration such as headache, tiredness, poor concentration or dark urine.
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Sources & how we know this
- WJEC Eduqas GCSE Food Preparation and Nutrition specification (from 2016) — WJEC Eduqas (2016)