Food and nutrients

The role of nutrients

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Function, maintenance and protection

Vitamins, minerals and fibre play an essential role in the function of the human body.

Water-soluble vitamins

Fat-soluble vitamins

B Vitamins: allow energy nutrients to be used.

Vitamin A: responsible for growth, sight and skin renewal.

Vitamin C: stimulates the immune system, allows iron to be used, antioxidant.

Vitamin D: allows the uptake of calcium.

Vitamin E: antioxidant.


Vitamin K: blood clotting.

Minerals have a chemical symbol (shown in brackets) and play numerous roles:

  • Calcium (Ca): building bones, regulating the pulse
  • Iron (Fe): transports oxygen, fights infections
  • Magnesium (Ma): protects against attack from disease, plays a role in protein synthesis.
  • Potassium (K): water regulation, muscle contraction

Fibre prevents constipation and regulates the digestive process.

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Function, maintenance and protection

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Vitamins and minerals do not provide energy but they play a basic role in how the body functions.

We do not synthesise vitamins, or at least not enough vitamins. So they must be included in our diet. Vitamins play a major role in protecting us and preventing illness. They also play a part in growth as they allow the body to use constituents of energy and minerals.

Vitamins are generally divided into two groups. Water-soluble vitamins dissolve in water and liposoluble vitamins dissolve in fat.


Keywords > Water-soluble vitamins: B, C

Vitamin C and the B vitamins are soluble in water. Vitamin C strengthens your immune system and helps with the absorption of iron. B vitamins enable your body to use energy nutrients.

Keywords > Fat-soluble vitamins: A, D, E, K

The other vitamins are fat-soluble. Vitamin A is vital for growth, sight and skin renewal. Vitamin D is produced by the action of the sun on our skin and allows the body to use calcium. Vitamin E is an important antioxidant. It protects body tissue and helps fight cell ageing. Finally, vitamin K allows blood to clot, i.e. to form blood clots to stop bleeding when a blood vessel is damaged.


Minerals also play an important role in body function and maintenance. We often identify calcium as an important component of bones and teeth, but it has plenty of other functions as well. For example, it helps to regulate the pulse.

Iron is an oligo-element as it is only present in traces in blood. It is often associated with transporting oxygen but it also plays a protective role as it helps our immune system to defend itself against infection.

Magnesium helps protect us against disease, bacteria and viruses. It also helps relax muscles and fight stress. More important still, it plays a role in protein synthesis and producing energy.

Potassium helps regulate the water in the body as well as blood pressure.

There are other minerals, but our aim is not to give you an exhaustive list with a detailed explanation of the role of each one. It is more important to remember that it is not enough to build up your body and give it energy; you also need to maintain and protect it for it to function correctly.


Keywords > Dietary fibre

A final word about the role of fibre. The human body is unable to digest or absorb fibre. It is passed along the intestine without being broken down by digestive enzymes. So it plays a role in regulating intestinal transit.

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