Minerals and Trace Elements: Function, Sources, Deficiency

What are Minerals and Trace Elements?

Minerals and trace elements are micronutrients. They are chemical elements that do not contain carbon and are needed by the body for a variety of jobs.

Minerals are needed by adults in quantities of between 1mg and 100mg per day and they include calcium, iron, magnesium, phosphorus, potassium, sodium chromium, copper, manganese, selenium, sulphur and zinc.

Trace elements are needed by adults in quantities of less than 1mg a day (which is very small) and they include fluoride, iodine, cobalt, molybdenum and silicon.

All of the minerals and trace elements are essential for the body, but in this topic we are going to study just five of them: calcium, iron, sodium, fluoride and iodine.

This article tells you:

  • why the body needs these minerals and trace elements
  • the foods which give us these minerals and trace elements
  • what happens if we do not have enough (a deficiency) of these minerals and trace elements
  • what happens to these minerals and trace elements when foods are processed
    and cooked.

Calcium

Function (its job in the body):

  • It is needed for normal growth in children
  • It is the main mineral in bones and teeth and gives them strength and hardness
  • It is needed to help the blood to clot after an injury
  • It is needed to help the nerves and muscles work properly.

Sources (the foods it is found in):

Vitamin D is needed to help the body absorb calcium from food. It is found in milk and dairy products such as cheese and yogurt. It is found in plant foods such as wholegrain cereals, seeds, nuts, green leafy vegetables and lentils.

Calcium is added to some foods to enrich them – white bread has calcium added by law and some products such as milk, soya milk, fruit juices and yogurt have extra calcium added to them.

Deficiency (what happens if we do not have enough):

As we grow, our bones gradually get bigger and stronger as calcium and other minerals are laid down in them. Physical, load-bearing exercise such as running, jumping and walking stimulates the bones to take up minerals, so it is essential for children and teenagers to be physically active to help this process.

It is essential that we have enough calcium in our diets to allow the bones to reach their peak bone mass (this is when they are hardest and have the most minerals in them and is particularly important during adolescence).

If the bones do not reach peak bone mass, they gradually become weaker as we grow older and will be more likely to break.

If a pregnant woman does not have enough calcium in her diet, calcium will be removed from her bones to enable the bones of the unborn baby to grow. This will weaken the woman’s bones and teeth.

If there is not enough calcium in the blood, the blood will not clot properly after an injury and the nerves and muscles will not work properly, leading to a condition called ‘tetany’ in which the muscles become rigid and will not relax.

Calcium is not affected by normal cooking processes.

Iron

Function (its job in the body):

Iron is needed to make a red-coloured protein called haemoglobin in red blood cells (which is why blood is red), which take oxygen around the body.

Sources (the foods it is found in):

Vitamin C is needed to help the body absorb iron from food. Good sources of iron include red meat, liver, kidney, dried apricots, lentils, corned beef, curry spices, cocoa and plain chocolate. There is also some iron in egg yolk

Bread and many breakfast cereals are fortified with iron. 

Green leafy vegetables, e.g. spinach, contain some iron but not all of it may be available to the body.

Deficiency (what happens if we do not have enough):

Newborn babies have a supply of iron that lasts about three months (milk is a poor source of iron) until the baby starts to be weaned on to solid foods.

Adolescent girls and women must make sure they have enough iron in their diet to cope with the loss of iron during their periods.

Pregnant women must have enough iron in their diet to supply their own increased blood volume and the baby’s store.

A deficiency of iron leads to low iron stores in the body and eventually to iron deficiency anaemia. Symptoms of anaemia include:

  • tiredness, weakness, lack of energy
  • a pale complexion, pale inner eyelids – weak and split fingernails.

Effects of processing and cooking:

Iron is not affected by normal cooking processes. It is a good idea to eat foods rich in vitamin C with iron-rich foods to help the absorption of iron.

Sodium

Function (its job in the body):

Sodium is needed to control the amount of water in the body. It is also needed to help the body use energy and to control the nerves and muscles.

Sources (the foods it is found in):

Salt is sodium chloride. Most raw foods contain very small amounts of sodium chloride (salt). During the processing, preparation, preservation, and serving of many foods salt is added – snack foods (crisps, roasted salted nuts) ready meals, and instant foods such as dried soups and pasta pot meals, takeaway foods, cheese, yeast extract, canned fish, smoked flavour foods such as bacon, ham and fish.

Sodium is also found in sodium bicarbonate which is used as a raising agent in baked foods such as cakes and biscuits.

Sodium is also found in a food additive called monosodium glutamate which is used to increase the flavour in many takeaway foods and ready meals.

Deficiency (what happens if we do not have enough):

A deficiency of sodium will cause muscle cramps and is sometimes seen in people who work or take part in sports in very hot conditions because they lose sodium in their sweat. The body can also lose too much sodium if someone has sickness and diarrhoea.

Many people have too much salt in their diet. If you have too much salt, you may develop high blood pressure which puts a strain on the heart and other parts of the body.

Too much salt can also damage the kidneys, especially in babies and young children.

Sodium is not affected by normal cooking methods.

Fluoride

Function (its job in the body):

  • help strengthen the bones and the enamel part of the teeth.

Sources (the foods it is found in):

  • sea water fish
  • tea
  • naturally in some water supplies.

Deficiency (what happens if we do not have enough)

  • the teeth may be more likely to develop cavities (holes) if they are not cared for properly.

Fluoride is not affected by normal cooking processes.

Iodine

Function (its job in the body):

  • It is needed to make thyroid hormones in the thyroid gland in the neck
  • Thyroid hormones control the metabolic rate of the body – the rate at which chemical reactions take place inside the body.

Sources (the food it is found in):

  • It is found in seafoods
  • It is also found in milk and dairy foods and some plant foods depending on how
    rich in iodine the soil is in the area in which the cows or plants have grown.

Deficiency (what happens if we do not have enough):

  • The person will feel tired, lethargic (does not want to do anything), and will gain weight
  • The thyroid gland in the neck will swell up to form a goitre 

Iodine is not affected by normal cooking processes.

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