Introduction to Minerals and Water
Welcome! We have already looked at macronutrients (the "big" nutrients like protein and fat) and vitamins. Now, we are diving into minerals and water. Think of minerals as the "building blocks" and "spark plugs" that keep your body’s systems running smoothly, while water is the essential "transport system" that keeps everything moving. Even though we only need minerals in small amounts, they are vital for staying healthy!
Part 1: The Essential Minerals
The AQA syllabus requires you to know about six specific minerals. Let’s break them down one by one.
1. Calcium
What does it do? (Functions): Calcium is famous for keeping bones and teeth strong. It also helps your blood to clot after a cut and helps your muscles and nerves work properly.
Where do we find it? (Sources): Milk, cheese, and yogurt are the main sources. It is also found in green leafy vegetables and fortified white flour (in the UK, calcium is added to white flour by law!).
What happens if we don't get enough? (Deficiency): A lack of calcium can lead to rickets in children (where bones become soft and deformed) and osteoporosis in older age (where bones become brittle and break easily).
2. Iron
What does it do? (Functions): Iron is needed to make haemoglobin in our red blood cells. This is what carries oxygen around your body to give you energy.
Where do we find it? (Sources): Red meat (like beef and lamb), liver, kidney, and dark green vegetables like spinach. It is also found in fortified breakfast cereals.
What happens if we don't get enough? (Deficiency): You might develop iron deficiency anaemia. This makes you feel very tired, pale, and short of breath because your body isn't getting enough oxygen.
3. Sodium (Salt)
What does it do? (Functions): Sodium helps maintain the balance of fluids in your body and helps your nerves and muscles function.
Where do we find it? (Sources): Most of the sodium we eat is already in processed foods (like bread, crisps, and ready meals) or added as table salt.
What happens if we have too much? (Excess): This is a common problem! Too much sodium is linked to high blood pressure, which increases the risk of heart disease and strokes.
4. Fluoride
What does it do? (Functions): Fluoride is the "shield" for your teeth. It strengthens tooth enamel and helps prevent tooth decay.
Where do we find it? (Sources): It is found in drinking water (some areas have it naturally, others have it added), tea, and fish. Most of us get it from toothpaste too!
5. Iodine
What does it do? (Functions): Iodine is needed to make hormones in the thyroid gland. These hormones control your metabolism (how quickly your body uses energy).
Where do we find it? (Sources): Seafood, seaweed, milk, and dairy products.
6. Phosphorus
What does it do? (Functions): Phosphorus works closely with calcium to maintain strong bones and teeth. It is also involved in how the body stores and uses energy.
Where do we find it? (Sources): It is found in almost all foods, but especially high-protein foods like meat, fish, dairy, and nuts.
Quick Review Tip: Remember that Calcium and Phosphorus are "teammates" — they work together for bone health!
Part 2: Water and Hydration
Water makes up about \(60\%\) of our body weight. We can survive for weeks without food, but only a few days without water!
Why do we need water? (Functions)
1. Hydration: It keeps our cells plump and healthy.
2. Temperature control: When we get too hot, we sweat. As the sweat evaporates, it cools us down.
3. Waste removal: It helps the kidneys flush out waste products in urine.
4. Digestion: It helps us swallow food and keeps things moving through the digestive system (preventing constipation).
5. Blood volume: It is the main ingredient in blood, helping transport nutrients and oxygen.
How do we lose water?
We lose water constantly throughout the day through:
- Sweating (especially during exercise).
- Breathing (we exhale water vapour).
- Urination and faeces.
Daily Fluid Needs
Health guidelines suggest we should drink about 2 litres (roughly 6 to 8 glasses) of fluid every day. This can include water, lower-fat milk, and sugar-free drinks like tea or coffee.
When do we need EXTRA fluids?
Sometimes, 2 litres isn't enough. You need to drink more during:
- Physical Activity: When you exercise, you sweat more to stay cool, so you must replace that lost fluid.
- Hot Weather: High temperatures cause more sweating.
- Illness: If you have a fever, vomiting, or diarrhoea, your body loses fluids much faster than usual.
Did you know? Dehydration can make you feel a "brain fog" or give you a headache. If you feel thirsty, you are already slightly dehydrated!
Key Takeaways for Your Exam
Common Mistake to Avoid: Don't confuse Minerals with Vitamins. In an exam, if a question asks for a mineral involved in bone health, write Calcium, not Vitamin D (even though they work together!).
Important Links:
- Calcium deficiency = Rickets / Osteoporosis.
- Iron deficiency = Anaemia.
- Excess Sodium = High Blood Pressure.
- Fluoride = Dental Health.
The "Water Rule": We need water for temperature control and waste removal. Always increase intake during exercise or hot weather.