Nutrients are compounds found in food and drink that the body needs to function properly. They provide us with energy, building blocks for repair and growth, and substances necessary to regulate chemical processes. There are six essential nutrients:

  • protein
  • carbohydrates
  • fats
  • vitamins
  • minerals
  • fluid

Protein, carbohydrates and fats are macronutrients as they provide us with energy and we need them in substantial amounts (macro=large).

Vitamins and minerals are micronutrients. While they don’t provide us with energy and we need them only in small amounts (micro=small), micronutrients are involved in many chemical reactions in the body.

While fibre is technically not classified as a nutrient, it has been included in this section as it is also required for general health. People eat foods and not single nutrients so that’s why it is important to know which foods provide which nutrients. Our food choices determine the combination of nutrients we eat.


Protein is a source of energy but its main role in the body is growth and repair. It helps in the formation of muscles, hair, nails, skin and organs, such as the heart, kidneys and liver. We all contain a significant amount of protein. For example, a 76kg man is made up of 12kg of protein (16%).


In a similar way to protein being made up of amino acids, carbohydrates consist of building blocks called ‘saccharides or ‘sugars’. Glucose and fructose (found in fruit) are examples of monosaccharides, the simplest type of sugar. Two monosaccharides joined together are called disaccharides, the most common being sucrose or ‘white cane sugar.’ Another example is lactose, found in milk. When large numbers of saccharides are joined together, they form polysaccharides and are found in the foods we commonly think of as ‘carbohydrates’, e.g. bread, potatoes and pasta.


Fat is an essential nutrient with a host of important functions within the body. It is essential for supplying the body with omega 3 and omega 6 essential fatty acids, producing healthy cell membranes, and maximising the absorption of fat-soluble vitamins (Vitamin A, Vitamin D, Vitamin E, and Vitamin K) and fat-soluble antioxidants (such as lycopene and beta-carotene).  Fat is found in many foods and comes from both animal and vegetable sources.


Vitamins are compounds that are needed in small amounts by the body but are involved in a large number of chemical reactions. Vitamins can be separated into two groups; water-soluble and fat-soluble.


Although only small amounts – measured in milligrams (mg) or micrograms (μg) – of minerals are required in the diet, minerals have many important functions in the body including bone structure and regulating body fluids. Each mineral has a different function.


Fluids are essential to us. Water fills the spaces in and between our cells, as well playing a vital role in the digestion and absorption of all the food we eat. Fluids also help to keep our body temperature within safe limits.


Fibre has always been synonymous with ‘being regular,’ but it is also protective against bowel disorders and heart disease. Fibre is a type of carbohydrate, however, unlike other carbohydrates, our bodies are not able to break fibre down into simple sugars.

Last reviewed: 20/06/2022

Last modified: April 3, 2024