Fat soluble vitamins are micronutrients that the body absorbs with dietary fat and can store, mainly in the liver and body fat. For AQA GCSE Food Preparation and Nutrition, you need to know the functions and food sources of vitamins A, D, E and K. Understanding how these vitamins work helps you explain the nutritional value of meals, compare ingredients and make better practical choices. This guide covers the key facts for AQA specification 3.2.2.1, Food, nutrition and health, and shows how to write clear, exam-ready answers.
What are fat-soluble vitamins?
Micronutrients are nutrients needed in small amounts. They include vitamins and minerals. Fat-soluble vitamins dissolve in fat rather than water. This means they are absorbed more effectively when a meal contains some fat and can be stored in the body.
Vitamins A, D, E and K are the fat-soluble vitamins. Unlike water-soluble vitamins, they are not simply removed in urine when there is more than the body needs. The body can store them, so taking high-dose supplements without appropriate advice may cause harmful levels to build up. In an exam, focus on the recognised functions, sources and deficiency effects in the specification rather than suggesting that more is always better.
Vitamin A
Functions
- Helps maintain normal vision, particularly in low light.
- Helps maintain healthy skin and the linings of parts of the body, such as the respiratory system.
- Supports the normal function of the immune system.
Sources
Preformed vitamin A, also called retinol, is found in animal foods such as liver, eggs, butter and full-fat dairy products. Some foods provide carotenoids, especially beta-carotene, which the body can convert into vitamin A. Useful plant sources include carrots, sweet potatoes, spinach and other dark green leafy vegetables.
A lack of vitamin A can affect vision and immune function. When discussing liver in a practical or written answer, remember that it contains a particularly high amount of vitamin A, so it should not be treated as an everyday food for everyone. Current healthy-eating and supplement guidance can change, so check the NHS or other relevant official guidance when needed.
Vitamin D
Functions
- Helps the body absorb and use calcium and phosphate.
- Contributes to the maintenance of healthy bones and teeth.
- Supports the normal function of the immune system.
Sources
Vitamin D is unusual because the body can make it when skin is exposed to sunlight. Food sources include oily fish, egg yolk and fortified foods, such as some spreads and breakfast cereals. Fortification means that a vitamin or mineral has been added to a food.
Too little vitamin D can contribute to poor bone health. The amount made from sunlight varies with factors such as season, time of day, skin covering and skin type. Do not present sunlight as a guaranteed food source or ignore sensible sun-safety advice. For current UK advice about vitamin D and supplements, use the NHS or GOV.UK.
Vitamin E
Functions
Vitamin E acts as an antioxidant. An antioxidant helps protect the body’s cells from damage caused by oxidation. This is a useful technical term to use when explaining vitamin E in an exam.
Sources
Good sources include vegetable oils, nuts, seeds, wheat germ and wholegrain products. Some green leafy vegetables also contribute vitamin E. In practical work, a salad containing seeds or a dish using a suitable vegetable oil could help increase the variety of vitamin E sources in a meal.
Vitamin E deficiency is uncommon in people eating a varied diet. Avoid claiming that vitamin E is a cure or that taking a large supplement will automatically improve health. A strong answer links the nutrient to its function and then gives accurate food examples.
Vitamin K
Functions
Vitamin K is needed for normal blood clotting. Blood clotting is the process that helps the body stop bleeding after an injury. It also contributes to maintaining healthy bones.
Sources
Important food sources include green leafy vegetables such as kale, spinach and cabbage, as well as broccoli and vegetable oils. A varied diet usually provides vitamin K. If you are writing about a person taking prescribed medicines, do not give medical advice: explain that their healthcare professional should provide individual guidance.
Comparing the four vitamins
| Vitamin | Main functions | Example sources |
|---|---|---|
| A | Vision, healthy skin and immune function | Liver, eggs, dairy foods, carrots and sweet potatoes |
| D | Absorption and use of calcium and phosphate; healthy bones and teeth | Sunlight, oily fish, egg yolk and fortified foods |
| E | Antioxidant protection of cells | Vegetable oils, nuts, seeds and wholegrains |
| K | Normal blood clotting and healthy bones | Leafy green vegetables, broccoli and vegetable oils |
Applying the knowledge to food preparation
When planning a practical dish, consider how a range of ingredients can contribute different micronutrients. For example, a vegetable-based meal containing spinach or broccoli could provide vitamins A and K, while a dressing made with vegetable oil could contribute vitamins E and K. An egg-based dish could provide vitamins A and D, although the exact amount depends on the ingredients and portion.
Cooking and preparation can affect nutrients. Use a suitable method, avoid unnecessary waste and consider whether vegetables need peeling. Do not assume that a food is a good source simply because it is colourful. Link your statement to a named ingredient and a specific vitamin function.
Teacher Tip: Encourage pupils to learn each vitamin as a three-part chain: vitamin, function, source. For example: “Vitamin D helps the body absorb calcium; sources include oily fish and fortified foods.” This is more useful than memorising a disconnected list.
Exam-ready retrieval checklist
- Can you explain what makes vitamins A, D, E and K fat-soluble?
- Can you give one accurate function and two food sources for each vitamin?
- Can you explain why vitamin D is linked to calcium and healthy bones?
- Can you define an antioxidant and connect the term to vitamin E?
- Can you identify vitamin K’s role in normal blood clotting?
- Can you apply the facts to a realistic dish or menu without making unsupported health claims?
For the exact wording and coverage of the course, compare your notes with the AQA Food Preparation and Nutrition specification. Health, supplement and nutrition guidance can change, so use current official NHS, Food Standards Agency or GOV.UK information where relevant.
Frequently asked questions
Why are vitamins A, D, E and K called fat-soluble?
They dissolve in fat, are absorbed alongside dietary fat and can be stored in the body. This is different from water-soluble vitamins, which are not stored in the same way.
Which fat-soluble vitamin is made by the body using sunlight?
Vitamin D can be made in the skin when it is exposed to sunlight. It is also supplied by foods including oily fish, egg yolk and some fortified foods.
What is the best way to revise these vitamins?
Use a table or flashcards with three columns: vitamin, function and source. Then practise applying the information to a dish, menu or short exam question.