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Human body


Starch granules, seen through a microscopeStarch granules, seen through a microscope Food contains several types of nutrients. They provide energy, the raw materials necessary for growth and repair, and the chemicals needed to make body cells work properly. During digestion these nutrients—proteins, fats, carbohydrates, minerals and vitamins—are absorbed by the small intestine into the bloodstream. Fibre, a nutrient found in plant foods, is not digested, but helps the digestive process work efficiently.

Proteins, fats and carbohydrates

Foods rich in proteins include meat, poultry, fish, eggs, beans, nuts and cheese. Proteins have numerous roles inside the body including building and running cells. Foods rich in fats, or lipids, include meat, oily fish, dairy products, some fruits such as olives and avocados, and nuts and seeds. Fats have many functions including building membranes around cells, making nerves work properly, and keeping us warm.

Foods that are rich in certain nutrientsFoods that are rich in certain nutrients
Carbohydrates include starches and sweet-tasting sugars. Starch is found in bread, pasta, rice and other grains, and potatoes. During digestion, starch is broken down into glucose, a sugar. This is the body’s main source of the energy that is needed for movement and all other life processes.

A molecule of cellulose, a kind of dietary fibreA molecule of cellulose, a kind of dietary fibre

Vitamins and minerals

The chemical elements humans consume in the largest quantities are: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulphur. They are collectively known as CHNOPS.

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