Sign up to access the complete lesson and track your progress!
Unlock This CourseWater and dietary fibre might not seem as exciting as vitamins or proteins, but they're absolutely vital for keeping your body working properly. Without enough water, you'd be in serious trouble within just a few days. And without enough fibre, your digestive system would struggle to function normally. Let's explore why these two nutrients are so important for human health.
Key Definitions:
You can survive weeks without food, but only about 3-5 days without water. Every single cell in your body needs water to function properly. It's like the oil in a car engine - without it, everything grinds to a halt.
Water isn't just something you drink when you're thirsty - it's actively involved in almost every process happening inside your body right now. From helping your blood carry oxygen to your muscles, to removing waste products through your kidneys, water is constantly at work.
Think of water as your body's ultimate multitasker. It's working 24/7 to keep you alive and healthy, often in ways you don't even notice.
Water carries nutrients, oxygen and hormones around your body through your blood. It also helps remove waste products like carbon dioxide and toxins.
When you get hot, you sweat. This water evaporation cools your body down, preventing dangerous overheating during exercise or hot weather.
Water keeps your joints moving smoothly by maintaining the synovial fluid that acts like oil between your bones.
Your brain is about 75% water, your muscles are 75% water and even your bones are 22% water! A 2% drop in body water can cause noticeable tiredness and difficulty concentrating. Athletes can lose up to 3 litres of water per hour during intense exercise.
The old "8 glasses a day" rule isn't quite right for everyone. Your water needs depend on your age, size, activity level and the weather. Generally, teenagers need about 2-2.5 litres per day, but this includes water from all sources - not just what you drink.
You might be surprised to learn that about 20% of your daily water comes from food. Some foods are particularly water-rich and can help keep you hydrated.
Fruits: Watermelon (92% water), oranges (87%), apples (84%)
Vegetables: Cucumber (95%), lettuce (94%), tomatoes (94%)
Other: Milk (87%), yoghurt (85%), soup (84%)
Dietary fibre is the tough, stringy parts of plants that your body can't digest. While that might sound useless, it's actually incredibly important for your health. Think of fibre as your digestive system's best friend - it helps everything move along smoothly and keeps your gut bacteria happy.
Not all fibre is the same. There are two main types and each does different important jobs in your body.
This type dissolves in water to form a gel-like substance. It helps lower cholesterol levels and controls blood sugar. Found in oats, beans, apples and carrots.
This type doesn't dissolve in water. It adds bulk to your stool and helps food pass through your digestive system. Found in whole grains, nuts and vegetables.
Fibre might not be digested, but it's definitely not wasted. As it travels through your digestive system, it's doing several important jobs that keep you healthy.
Fibre prevents constipation by adding bulk to stool and helping it move through your intestines more easily.
Soluble fibre helps lower cholesterol levels, reducing the risk of heart disease later in life.
High-fibre foods make you feel full for longer, helping prevent overeating and weight gain.
In developed countries where people eat lots of processed foods low in fibre, rates of bowel cancer, heart disease and diabetes are much higher than in countries where people eat traditional diets rich in plant foods. Studies show that people who eat 25-30g of fibre daily have significantly lower risks of these diseases.
Both water and fibre deficiencies can cause serious health problems. Understanding these helps you appreciate why these nutrients are so important.
Dehydration can happen faster than you think, especially during hot weather or when you're ill.
Headaches, tiredness, difficulty concentrating, dark yellow urine, dry mouth and feeling thirsty.
Dizziness, rapid heartbeat, confusion, very dark urine or no urination and can be life-threatening.
Not getting enough fibre can cause both immediate discomfort and long-term health risks.
Constipation, feeling bloated, irregular bowel movements and digestive discomfort.
Higher risk of heart disease, type 2 diabetes, bowel cancer and weight gain.
Getting enough water and fibre doesn't have to be complicated. Many delicious foods can help you meet your daily needs for both.
Aim for 25-30g of fibre daily. Here are some excellent sources that teenagers actually enjoy eating.
Porridge oats (4g per bowl), wholemeal toast (3g per slice), bran cereal (10g per bowl)
Apple with skin (4g), banana (3g), handful of almonds (4g), popcorn (3g per cup)
Baked beans (7g per half can), brown rice (4g per cup), broccoli (5g per cup)
Start your day with a glass of water and keep a water bottle with you. Choose wholemeal bread instead of white, eat fruit with the skin on and add beans or lentils to soups and stews. Small changes like these can make a big difference to your water and fibre intake.