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While macronutrients (carbohydrates, fats and proteins) provide energy, the body also needs vitamins, minerals and water to function properly. These are often called micronutrients (vitamins and minerals) because they are needed in smaller amounts. For AQA GCSE PE, you need to understand their general role in the body, why a balanced diet is important, and the definition and consequences of dehydration.
Vitamins are organic compounds that the body needs in small amounts to function correctly. They play essential roles in maintaining health and supporting body systems, but the body cannot make most of them — they must come from food.
Exam Tip: AQA does not require you to know specific vitamins and their individual functions at GCSE level. You need to know that vitamins are essential for body systems and health, and that they are obtained through a balanced diet. Do not waste time memorising vitamin A, B, C, D, etc. unless specifically asked.
| Role | Detail |
|---|---|
| Support immune function | Help the body fight infection and disease |
| Support growth and development | Essential during childhood and adolescence |
| Aid energy release | Some vitamins help the body convert food into usable energy |
| Maintain healthy skin, eyes and bones | Different vitamins contribute to the health of different tissues |
| Aid blood clotting | Essential for wound healing |
| Antioxidant protection | Some vitamins protect cells from damage caused by free radicals |
A varied, balanced diet that includes plenty of fruits, vegetables, whole grains, dairy and protein sources will provide all the vitamins the body needs. Key food groups include:
| Food Group | Vitamins Provided |
|---|---|
| Fruits and vegetables | Wide range of vitamins, particularly vitamins A and C |
| Dairy products | Vitamins A, D and B12 |
| Meat, fish and eggs | B vitamins, vitamin D |
| Whole grains | B vitamins, vitamin E |
| Sunlight | The body produces vitamin D when exposed to sunlight |
Minerals are inorganic substances needed in small amounts for a range of bodily functions. Like vitamins, they must be obtained from food.
Exam Tip: As with vitamins, AQA does not require detailed knowledge of individual minerals at GCSE. Know that minerals support body systems and health, and are obtained through a balanced diet.
| Role | Detail |
|---|---|
| Bone and teeth health | Minerals like calcium and phosphorus are essential for strong bones and teeth |
| Muscle and nerve function | Minerals like sodium and potassium help muscles contract and nerves transmit signals |
| Oxygen transport | Iron is a key component of haemoglobin, which carries oxygen in red blood cells |
| Fluid balance | Minerals like sodium help regulate the amount of water in the body |
| Immune function | Minerals like zinc support the immune system |
| Energy production | Some minerals are involved in the enzymes that release energy from food |
| Food Group | Minerals Provided |
|---|---|
| Dairy products | Calcium |
| Red meat | Iron, zinc |
| Green leafy vegetables | Iron, calcium |
| Fish | Iodine, phosphorus |
| Nuts and seeds | Magnesium, zinc, selenium |
| Whole grains | Iron, magnesium |
A balanced diet provides all the nutrients the body needs in the correct proportions. It includes:
| Component | What It Provides |
|---|---|
| Carbohydrates | Main energy source (55–60% of diet) |
| Fats | Energy at low intensity, insulation, organ protection (25–30%) |
| Proteins | Growth and repair of tissues (15–20%) |
| Vitamins | Support body systems and health |
| Minerals | Support bones, muscles, nerves and other functions |
| Water | Hydration, temperature regulation, transport of nutrients |
| Fibre | Supports healthy digestion and bowel function |
| Reason | Detail |
|---|---|
| Provides all essential nutrients | The body needs a wide range of nutrients; no single food provides them all |
| Supports growth and development | Especially important for children and teenagers |
| Maintains energy levels | The right mix of macronutrients ensures sustained energy throughout the day |
| Reduces disease risk | A balanced diet reduces the risk of obesity, heart disease, diabetes and some cancers |
| Supports immune function | Vitamins and minerals are essential for a strong immune system |
| Optimises sporting performance | Athletes need the right nutrients in the right proportions to train and compete effectively |
| Supports mental health | Good nutrition is linked to better mood, concentration and emotional wellbeing |
Exam Tip: AQA may ask you to explain why a balanced diet is important, either in general or specifically for athletes. Make sure you can give at least three reasons with clear explanations. Always link your answer to the specific nutrients and their roles.
Hydration refers to the process of maintaining an adequate level of water in the body. Water is essential for virtually every bodily function.
| Role | Detail |
|---|---|
| Temperature regulation | Water in sweat evaporates from the skin, cooling the body during exercise |
| Transport of nutrients | Water in blood plasma carries nutrients, oxygen and hormones around the body |
| Removal of waste products | Water helps the kidneys filter waste products and produce urine |
| Joint lubrication | Synovial fluid (largely water) lubricates joints, reducing friction |
| Chemical reactions | Many metabolic reactions take place in water (it is a solvent) |
| Maintaining blood volume | Adequate hydration ensures blood volume remains sufficient for effective circulation |
Water balance is the relationship between water intake and water loss:
| Water In | Water Out |
|---|---|
| Drinking water and fluids | Urine |
| Water content of food | Sweat |
| Metabolic water (produced during respiration) | Breathing out (water vapour in exhaled air) |
| Faeces |
The body must maintain a balance between water in and water out. During exercise, water loss through sweat increases significantly, meaning fluid intake must also increase.
Dehydration is a state in which the body loses more water than it takes in, resulting in insufficient water for normal bodily functions.
| Situation | Why Dehydration Occurs |
|---|---|
| During exercise | Sweating increases significantly, especially in hot conditions |
| In hot environments | The body sweats more to cool down, increasing water loss |
| Not drinking enough fluids | Inadequate fluid intake means losses are not replaced |
| Illness (vomiting/diarrhoea) | Rapid fluid loss that is difficult to replace quickly |
| Altitude | Breathing rate increases at altitude, losing more water vapour |
Exam Tip: The definition of dehydration is frequently tested. Learn it precisely: "A state in which the body loses more water than it takes in, resulting in insufficient water for normal bodily functions." Many students lose marks by giving an incomplete definition such as "not having enough water."
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