Welcome to Nutrition, Diet and Health Concerns!

Hey there! Ready to dive into one of the most important topics for your well-being? This chapter is all about understanding the food you eat, how it fuels your body, and how to make smart choices for a healthy, energetic life. It's not just about memorising facts; it's about learning practical skills that you'll use every single day. Let's get started!


Section 1: The Basics - What Are We Talking About?

First, let's get our key terms straight. Think of these as the foundation for everything else we'll learn.

What are these terms?
  • Nutrition: This is the science of food and how your body uses it for growth, energy, and repair. It’s the story of what happens to your lunch after you eat it!
  • Health: The World Health Organization (WHO) defines it as a state of complete physical, mental, and social well-being, not just the absence of disease. It's about feeling good, inside and out.
  • Food Science: This is the study of the physical, biological, and chemical makeup of food. It asks questions like, "Why does an apple turn brown?" or "What makes bread rise?"
  • Food Technology: This is the application of food science to the selection, preservation, processing, packaging, and distribution of food. It's how we get safe, long-lasting, and convenient food, like canned soup or vacuum-packed rice.
Key Takeaway

Nutrition is how your body uses food. Health is your overall well-being. Food Science is the study of food itself, and Food Technology is how we apply that science to make the food products we buy and eat.


Section 2: The Building Blocks of Food - Nutrients & Water

Food is made up of nutrients, which are substances that provide nourishment essential for life and growth. We can split them into two main groups: Macronutrients and Micronutrients.

Analogy Time! If you're building a house, Macronutrients (carbs, proteins, fats) are the bricks, cement, and wooden frames. You need a lot of them! Micronutrients (vitamins, minerals) are the screws, nails, and wiring. You need them in smaller amounts, but they are absolutely essential to hold everything together and make it work.

Part A: Macronutrients (The Energy Givers)

Your body needs these in large amounts. They provide calories, which are units of energy.

1. Carbohydrates (Carbs) - The Body's Main Fuel

These are your body's primary and preferred source of energy. They are made of Carbon (C), Hydrogen (H), and Oxygen (O). The basic molecular structure is:

$$C_6H_{12}O_6$$

Classification of Carbohydrates:

Memory Aid: Think of "saccharide" as a sugar block. "Mono" means one, "Di" means two, and "Poly" means many.

  • Monosaccharides (Simple Sugars - 1 block): These are absorbed quickly by the body.
    • Examples: Glucose (in fruits, honey), fructose (fruit sugar), galactose (in milk).
  • Disaccharides (Simple Sugars - 2 blocks): Two monosaccharides joined together.
    • Examples: Sucrose (table sugar = glucose + fructose), lactose (milk sugar = glucose + galactose), maltose (malt sugar = glucose + glucose).
  • Polysaccharides (Complex Carbs - many blocks): Long chains of monosaccharides. They release energy slowly, keeping you full for longer.
    • Examples: Starch (in rice, potatoes, bread), dextrin, cellulose (a type of fibre), pectin, and glycogen (the form of glucose stored in our muscles and liver).

Functions of Carbs in the Body:

  • Sugar & Starch: Main source of energy for the brain, muscles, and all body functions.
  • Dietary Fibre (like cellulose): Your body can't digest it, but it's super important! It helps with digestion, prevents constipation, and makes you feel full. Find it in vegetables, fruits, and whole grains.
2. Protein - The Body's Builder & Repair Crew

Proteins are made of smaller units called amino acids. There are over 20 different amino acids, but they can be grouped into two types:

  • Essential amino acids: The body cannot make these, so you must get them from food.
  • Non-essential amino acids: The body can make these on its own.

Functions of Protein in the Body:

  • For growth and repair of body tissues (like muscles, skin, and hair).
  • To make important substances like enzymes (which speed up chemical reactions) and hormones (which act as chemical messengers).
  • Can be used for energy if there aren't enough carbs or fats.
  • Helps to maintain fluid and pH balance in the body.
3. Lipids (Fats & Oils) - The Energy Reserve

Lipids are made of fatty acids and glycerol. They are a very concentrated source of energy.

Classification of Lipids:

  • Based on Molecular Structure:
    • Saturated fatty acids: Usually solid at room temperature. Examples: butter, fat on meat.
    • Monounsaturated fatty acids: One "double bond" in their chemical structure. Examples: olive oil, avocados.
    • Polyunsaturated fatty acids: Two or more "double bonds". Examples: corn oil, fish oil (Omega-3 fatty acids are in this group!)
  • Based on Physical State:
    • Fats: Solid at room temperature.
    • Oils: Liquid at room temperature. (Did you know? Hydrogenation is an industrial process that turns liquid oils into solid fats, but this can create unhealthy trans fats).

Lipids in Your Diet:

  • Cholesterol: A waxy substance needed to build healthy cells. But too much can be a problem!
    • LDL (Low-Density Lipoprotein): The "bad" cholesterol. It can build up in your arteries.
    • HDL (High-Density Lipoprotein): The "good" cholesterol. It helps carry LDL away from the arteries.
  • Trans fatty acids: Often found in processed foods. They raise your bad (LDL) cholesterol and lower your good (HDL) cholesterol. Best to avoid these!

Functions of Lipids in the Body:

  • Provide a concentrated source of energy.
  • Help absorb fat-soluble vitamins (A, D, E, K).
  • Provide insulation to help with body temperature regulation.
  • Protect vital organs.

Part B: Micronutrients (The Helpers)

Your body needs these in smaller amounts, but they are vital for good health. Deficiencies can cause serious problems.

1. Vitamins - The Spark Plugs

These are organic compounds that help regulate many body processes.

Memory Aid for Fat-Soluble Vitamins: Remember the word ADEK.

  • Fat-Soluble Vitamins (Stored in body fat):
    • Vitamin A: Good for vision, immune system. (Sources: carrots, sweet potatoes)
    • Vitamin D: Helps absorb calcium for strong bones. (Sources: sunlight, fatty fish)
    • Vitamin E: An antioxidant that protects cells. (Sources: nuts, seeds)
    • Vitamin K: Important for blood clotting. (Sources: leafy green vegetables)
  • Water-Soluble Vitamins (Not stored in the body, need to be replenished):
    • Vitamin B complex (B1, B2, Niacin, B6, Folate, B12): Help release energy from food. (Sources: whole grains, meat)
    • Vitamin C: Good for the immune system and skin, helps heal wounds. (Sources: oranges, bell peppers)
2. Minerals - The Nuts & Bolts

These are inorganic elements that come from the earth and are absorbed by plants. They have many different roles.

  • Calcium: Builds strong bones and teeth. (Sources: milk, tofu, leafy greens)
  • Iron: Helps make red blood cells that carry oxygen around your body. A deficiency can cause anaemia. (Sources: red meat, beans, spinach)
  • Phosphorus: Works with calcium for strong bones and teeth. (Sources: meat, dairy)

Part C: Water - The Unsung Hero

You can't live without it! About 60% of your body is water. It doesn't provide energy, but it's essential.

Functions of Water:

  • Transports nutrients and oxygen to cells.
  • Regulates body temperature.
  • Helps get rid of waste products.
  • Lubricates joints.

Part D: Nutrient Teamwork (Interrelationships)

Some nutrients work together in a "buddy system". Understanding this can help you eat smarter!

  • Iron and Vitamin C: Vitamin C helps your body absorb iron from plant-based sources much more effectively. (Example: Squeezing lemon juice (Vit C) over spinach (iron) in a salad).
  • Calcium and Vitamin D: Your body needs Vitamin D to be able to absorb and use calcium properly. (That's why milk is often fortified with Vitamin D!)
  • Calcium and Phosphorus: These two work together to form strong bones and teeth. A good balance is important.
  • Things that block absorption:
    • Iron and fibre: Too much dietary fibre can sometimes reduce the absorption of iron.
    • Calcium and dietary fibre: Similarly, high fibre intake can interfere with calcium absorption.

Part E: The Journey of Food in the Body

What happens after you swallow? Here's the simple version:

  1. Digestion: The process of breaking down large food molecules into smaller ones that the body can use. This starts in your mouth and continues in your stomach and small intestine.
  2. Absorption: The small nutrient molecules pass through the walls of the small intestine into the bloodstream.
  3. Assimilation: The body's cells use the absorbed nutrients for energy, growth, and repair.
  4. Excretion: The body gets rid of waste products it can't use.
Key Takeaway

A healthy diet needs a balance of macronutrients (carbs for fuel, protein for building, fats for reserves) and micronutrients (vitamins and minerals for helping everything work). Don't forget water! And remember that some nutrients work best as a team.


Section 3: Health, Diet and Common Concerns

Now that we know about nutrients, let's see how they relate to our overall health and diet.

Part A: Health, Wellness and Your Body

  • Wellness: A broader concept than health. It's about actively making choices towards a healthy and fulfilling life.
  • Basal Metabolism (BMR): The amount of energy (calories) your body needs to perform basic, life-sustaining functions at rest, like breathing and keeping your heart beating.
  • Human Digestive System: The pathway food takes, including the mouth, stomach, and intestines, where digestion and absorption happen.
  • Energy Consumption: The total calories you burn in a day, which includes your BMR plus the energy used for physical activity.

Part B: The Balanced Diet Blueprint

A balanced diet provides all the necessary nutrients in the right amounts to keep you healthy.

  • Dietary Guidelines: Tools like the Food Pyramid help us visualise how much of each food group we should eat. Generally, it recommends more grains, vegetables, and fruits, and less fat, oil, and sugar.
  • Nutrition Labelling: The nutrition facts label on packaged foods is your best friend! It tells you about the calories, macronutrients, and some micronutrients in a serving, helping you make informed choices.

Part C: Common Health Concerns

When our diet is out of balance, it can lead to health problems.

  • Malnutrition: A general term for a diet that is not balanced. This includes both under-nutrition (not getting enough nutrients) and over-nutrition (getting too many calories, leading to excess weight).
  • Obesity: A condition of being very overweight, with a high degree of body fat. It increases the risk of many other diseases. Prevention involves a balanced diet and regular exercise.
  • Anorexia Nervosa: A serious eating disorder characterised by an intense fear of gaining weight and a distorted body image, leading to self-starvation. It requires professional medical and psychological help.
  • Constipation: Difficulty passing stools. It can often be prevented by drinking enough water and eating enough dietary fibre.
  • Diabetes (Type 2): A disease where the body cannot regulate blood sugar levels properly. A healthy diet, weight management, and exercise are key for prevention and management.
  • High Blood Pressure (Hypertension): When the force of blood against your artery walls is too high. Reducing salt (sodium) intake is a crucial preventive measure.
  • Coronary Heart Disease: Occurs when arteries that supply blood to the heart become narrowed or blocked, often by cholesterol. A diet low in saturated and trans fats can help prevent this.
Key Takeaway

A balanced diet, guided by tools like the Food Pyramid and nutrition labels, is crucial for preventing diet-related diseases. Be aware of the signs of these health concerns and know that lifestyle choices make a big difference.


Section 4: Diet and Meal Planning for Real Life

Everyone is different, so their nutritional needs are different too! Good meal planning considers who you are cooking for and the situation.

Part A: Determinants - What to Consider?

(i) Target Groups
  • Sex: Generally, males require more calories than females due to differences in body size and muscle mass.
  • Age groups:
    • Babies/Toddlers: Need energy and protein for rapid growth.
    • Adolescents: Growth spurts mean they need more calories, protein, and calcium.
    • Adults: Needs vary based on activity level.
    • The Elderly: May need fewer calories but still need nutrient-dense food, especially calcium and Vitamin D for bone health.
  • Occupation: A manual worker (e.g., construction worker) will need far more calories than a sedentary worker (e.g., office worker).
  • Health concerns and specific needs:
    • Pregnant women: Need extra nutrients like folic acid, iron, and calcium.
    • Vegetarians: Need to ensure they get enough protein, iron, and vitamin B12 from plant-based sources.
(ii) Climate Factor

Where you live and the time of year can influence what you eat. For example, on a cold winter day, you might crave a hot, hearty soup, while on a hot summer day, a light salad and fruit might be more appealing.

(iii) Occasions

We eat differently depending on the event! A meal for a birthday party will be very different from a regular daily family meal.

Part B: Principles of Meal Planning

When you plan meals, you're trying to balance several things:

  • Nutritional Needs: Is the meal balanced and appropriate for the person eating it?
  • Lifestyle Needs: Is it a quick meal for a busy weeknight (efficiency)? Does it bring the family together (social needs)?
  • Financial Constraints: Does it fit within the family's budget?
  • Resource Constraints: What time do you have to cook? What cooking facilities (e.g., oven, microwave, steamer) are available?
Key Takeaway

Good meal planning is a puzzle. You need to fit together the needs of the person, the occasion, the budget, and the available resources to create meals that are both healthy and enjoyable.