Which minerals does the body need, what do they do, and why is water essential?
Minerals as micronutrients: calcium, iron, sodium and other minerals, their functions, food sources and bioavailability, the effects of deficiency and excess, and the functions and importance of water in the diet.
A CCEA A-Level Nutrition and Food Science answer on minerals and water: the functions and sources of calcium, iron and sodium, mineral bioavailability and absorption, the effects of deficiency and excess, and the functions and importance of water in the diet.
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What this dot point is asking
CCEA wants you to describe the main dietary minerals (especially calcium, iron and sodium), their functions and food sources, the factors that affect how well minerals are absorbed (bioavailability), the effects of deficiency and excess, and the functions and importance of water in the body.
The main minerals
Calcium builds and maintains bones and teeth and is needed for blood clotting, nerve function and muscle contraction. Its absorption requires vitamin D and is reduced by phytates (in wholegrains) and oxalates (in spinach and rhubarb). Sources are milk, cheese, yoghurt, tinned fish with bones, and fortified bread and plant drinks. A deficiency leads to poor bone development and, in later life, osteoporosis.
Sodium, eaten mainly as salt (sodium chloride), controls the body's fluid balance and is needed for nerve and muscle function. However a high salt intake raises blood pressure and the risk of stroke and heart disease, so adults are advised to eat no more than 6 g of salt (about 2.4 g sodium) a day. Most dietary salt is hidden in processed foods such as bread, sauces and ready meals.
Water and hydration
Too little water causes dehydration, with headache, tiredness, concentrated urine and, if severe, a dangerous fall in blood volume. Needs rise with heat, physical activity, breastfeeding, and illness involving vomiting or diarrhoea, which connects hydration to the life-stage content of the module.
Examples in context
Example 1. Salt reduction in processed food. Because most salt is hidden in bread, processed meat, sauces and ready meals rather than added at the table, public-health campaigns ask manufacturers to reformulate with less salt. A family swapping ready meals for home-cooked dishes and checking labels can cut well below the 6 g target, lowering blood-pressure risk. This links sodium directly to the diet-and-health content.
Example 2. Calcium and vitamin D for bone health. A teenager building peak bone mass needs both calcium (for the bone mineral) and vitamin D (to absorb it). A diet with dairy or fortified plant drinks plus some sunlight or a supplement supports strong bones and reduces the later risk of osteoporosis. This shows how a mineral and a vitamin work as a pair, a recurring CCEA theme.
Try this
Q1. Explain why vitamin D is needed for calcium to be useful in the diet. [2 marks]
- Cue. Vitamin D is needed for calcium to be absorbed from the gut; without it, calcium uptake is poor however much is eaten.
Q2. State the recommended maximum daily intake of salt for an adult. [1 mark]
- Cue. No more than 6 g of salt a day.
Q3. Name two functions of water in the body. [2 marks]
- Cue. Any two of: medium for reactions, transport in blood, temperature control by sweating, removing waste in urine, lubrication.
Exam-style practice questions
Practice questions written in the style of CCEA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
CCEA AS 20186 marksExplain the importance of calcium in the diet and discuss the factors that affect how well it is absorbed.Show worked answer →
A 6-mark answer needs the functions of calcium and the factors that raise or lower its absorption.
Calcium is needed for the formation and maintenance of strong bones and teeth, where most of the body's calcium is stored. It is also essential for normal blood clotting, the working of nerves, and the contraction of muscles including the heart. Requirements are high during growth, in pregnancy and breastfeeding, and again in later life to protect against osteoporosis.
Absorption is improved by vitamin D, which is essential for calcium uptake from the gut, and by the body's greater need during growth and pregnancy. Absorption is reduced by phytates in wholegrain cereals and by oxalates in foods such as spinach and rhubarb, which bind calcium and make it unavailable, and an excess of fibre can also reduce uptake.
Markers reward at least two functions (bones and teeth plus clotting, nerves or muscles), the role of vitamin D in absorption, and named factors that reduce absorption (phytates, oxalates, excess fibre).
CCEA AS 20204 marksDescribe the functions of water in the body.Show worked answer →
A 4-mark answer needs four separate functions of water.
Water makes up about two thirds of body mass and is the medium in which the chemical reactions of metabolism take place. It is the main component of blood and lymph, transporting nutrients, oxygen and waste products around the body, and it carries waste out in urine.
Water regulates body temperature through sweating, in which heat is lost as sweat evaporates, and it acts as a lubricant in joints, the eyes and the digestive tract. It is also needed for the digestion and absorption of food, and it gives moisture and turgor to cells and tissues.
Markers reward four distinct roles from: medium for reactions, transport in blood, removal of waste in urine, temperature regulation by sweating, lubrication, and a role in digestion.
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Sources & how we know this
- CCEA GCE Nutrition and Food Science specification — CCEA (2016)
- Salt and health (SACN report) — Scientific Advisory Committee on Nutrition (2003)