Nutrients in a Healthy Diet
Identify seven dietary components: carbohydrates, lipids (fats), proteins, vitamins, minerals, dietary fibre and water. Explain their sources and roles, including which supply energy.
What a learner can do afterwards
- Names the seven dietary components used in this model and gives a source for each
- Explains the roles of dietary components, including protein for growth and repair
- Identifies carbohydrates, fats and proteins as energy sources; distinguishes them from vitamins, minerals and water, and explains that gut microbes break down some fibre
1 · Read
Animals get nutrients from food. Your body uses nutrients for energy, growth and repair. This lesson uses seven dietary components: carbohydrates, fats, proteins, vitamins, minerals, fibre and water. These describe parts of a diet, not seven separate kinds of food. One food can contain several components.
Bread, rice and pasta supply carbohydrates, a main source of energy. Oils, butter and nuts supply fats, also called lipids. Fats provide energy. Stored body fat holds energy for later and helps cushion organs. Foods are mixtures: wholegrain bread supplies both carbohydrates and fibre.
These are examples of components in foods, not complete lists of everything each food contains.
Protein supplies material for building and repairing body tissues, including muscles and skin. Meat, fish, eggs and beans are protein sources. Protein can also supply energy. Carbohydrates, fats and proteins all provide energy, even though protein is often discussed mainly for its growth and repair role.
Vitamins and minerals do not themselves supply food energy. Vitamin C from oranges and peppers supports wound healing. Calcium from milk and yoghurt helps build and maintain bones. Some vitamins help release energy from food, but are not fuel. Water from drinks and foods such as cucumber supplies no energy. It carries dissolved substances around the body and helps cells work.
Fibre from wholegrains, beans, fruit and vegetables adds bulk and helps waste move through the gut. Humans do not digest fibre like starch. Gut microbes break down some fibre, and this provides a little energy. Human digestion and microbial breakdown are different processes, so saying that humans do not digest fibre like starch does not mean that nothing in the gut can break it down.
A varied diet supplies seven dietary components. Carbohydrates, fats and proteins provide energy. Components can have several jobs, and one food can supply several components.
Lesson, questions and study cards written for this dataset.
Readings and study cards written for this dataset. Supplied textbook records informed factual checks; these readings are independently written.
More to read
Foods and components are different
A nutrient name describes something in food. A food name describes the food itself. Beans, for example, contain protein, carbohydrates and fibre. Milk contains protein, water and calcium. Naming one component does not give a complete description of either food.
The seven-component model is a checklist for studying a diet: carbohydrates, fats, proteins, vitamins, minerals, fibre and water. It does not require seven separate foods at every meal. Nor does it mean that every component has just one job.
Protein can supply energy too
Think about two questions when studying a dietary component: what does it supply, and what does the body use it for? Protein provides material for making and repairing tissues. That is why protein appears in explanations of growth and muscle repair.
Protein can also provide energy. Carbohydrates and fats provide energy too. Learning a component's main role should not turn into a rule that it has no other roles. Stored body fat, for example, holds energy for later and helps cushion organs.
What happens to fibre?
Wholegrains, beans, fruit and vegetables are sources of fibre. Fibre helps waste move through the gut by adding bulk. Humans do not digest fibre in the same way as starch.
There are also microbes living in the gut. They break down some fibre, and this provides a little energy. The two statements fit together: human digestion of starch and microbial breakdown of fibre are different processes. It would be inaccurate to change the first statement into a claim that fibre can never provide energy.
Water is part of food too
Drinking water is one way to obtain water, but it is not the only way. Foods such as cucumber also contain water. Water carries dissolved substances around the body and helps cells work. Water itself supplies no food energy.
A component can be needed even when it supplies no energy. Calcium from foods such as milk and yoghurt helps build and maintain bones. Vitamin C from oranges and peppers supports wound healing. Their jobs differ from the fuel role of carbohydrates.
Helping the body use its fuel
Some vitamins help the body release energy from food. This does not mean that vitamins are the fuel. The energy comes from the food components being used, including carbohydrates, fats and proteins.
Vitamins have other roles as well, and different vitamins do different jobs. Vitamin C supports wound healing. Minerals also have varied roles, such as calcium's role in bones. Vitamins and minerals are needed in small amounts, but they remain parts of a healthy diet. They are still needed even though they supply no food energy.
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