Comprehensive Notes on Macronutrients

This lesson focuses on nutrition for health outcomes, specifically macronutrients.
It covers the function and food sources of major nutrients important for health outcomes, including carbohydrates (and fibre), fats, proteins, and water.

Macronutrients: Nutrients needed by the body in relatively large amounts.
- Carbohydrates (including fibre)
- Fats (monounsaturated, polyunsaturated, saturated, trans)
- Proteins
- Water
Micronutrients: Nutrients required by the body in small amounts.
- Vitamins: Vitamin C, Vitamin D
- Minerals: Iron, Calcium, Sodium, Folate

Definition: A naturally occurring food compound formed from carbon, hydrogen, and oxygen, providing the body with energy to function.
Function: The body's primary source of energy.
- 1 gram of carbohydrates = $16KJ$ of energy
- The brain and central nervous system need a continuous supply of carbohydrates to function.
How they work: Enzymes in saliva, stomach, and small intestines break down carbohydrates into glucose molecules, providing energy. When glucose is not used, it's stored in adipose tissue (fatty tissue), potentially causing weight gain, or used as energy stores when needed.
Food sources:
- Wholemeal bread, pasta, rice, breakfast cereals
- Fruits such as oranges, grapes, bananas
- Vegetables such as corn, potatoes
Note: While lollies and cakes contain carbohydrates, they are a poor choice due to high fat content.

Definition: Made up of the indigestible parts of plant matter that help regulate the functioning of the digestive system.
Function:
- Helps absorb water, adding bulk to faeces and assisting in waste removal.
- Helps move waste products through the digestive system.
- Provides a feeling of fullness to prevent overeating.
- Helps control blood glucose levels by reducing glucose absorption from the small intestine.
- Works to reduce the amount of cholesterol absorbed by the body.
Food Sources:
- Lentils
- Oats
- Bran
- Vegetables such as artichokes, brussel sprouts, green peas, broccoli
- Fruits such as avocado, raspberries, blackberries, pears and oranges
Note: Fibre is a type of carbohydrate.

Definition: A group of natural esters of glycerol and various fatty acids, which are solid at room temperature and are the main constituents of animal and vegetable fat.
Function:
- Third source of energy, with a greater concentration than carbohydrates.
  - 1g fat = $37KJ$ energy
- Stored in adipose (fatty) tissue for use when other energy sources are in short supply.
- Carries fat-soluble vitamins into the body (Vitamins A, D, E, and K).
- Involved in the development and maintenance of cell membranes.
- Slows down the emptying of the stomach, which can delay hunger sensations.
- Insulates the body against temperature extremes.
- Acts as a natural shock absorber.
Food Sources:
- Oils (olive, canola, peanut, flaxseed, sunflower)
- Meats (red meat, chicken, fish)
- Cakes, biscuits
- Milk, cheese, cream
- Eggs
Note: Fat is required in our diets but mono- and polyunsaturated fats should be consumed in place of saturated and trans fats.

Fatty acids that have a single double bond in the fatty acid chain, with the remainder of the carbon atoms being single-bonded.
Should equal the highest proportion of fat intake.
Liquid/soft at room temperature.
Can assist in lowering LDL (low-density lipoproteins) cholesterol.
- LDL (low density lipoproteins): Fatty sticky substance which may bind the walls of arteries causing blockages leading to high blood pressure and stroke.
Food Sources:
- Olive oil
- Avocado
- Canola oil
- Nuts
- Peanut butter

Fatty acids in which more than one double bond exists in the molecule.
Certain polyunsaturated fatty acids cannot be made by the body and therefore need to be consumed in the diet.
- Omega 3: Promotes elasticity of blood vessels.
- Omega 6: Essential for cell structure and growth
- Omega 3 and 6: Two families of essential fatty acids that must be consumed from a balanced diet as they play important roles in maintaining health.
Food Sources:
- Tuna, salmon
- Nuts, seeds
- Safflower
- Soy

Generally of animal origin.
Increases the amount of LDL cholesterol.
Associated with many chronic conditions such as high cholesterol, high blood pressure, heart disease, obesity, and stroke.
Usually solid at room temperature.
Food Sources:
- Fatty meats
- Full-cream milk
- Cream
- Cheese
- Fried take-away
- Most baked goods

Have more adverse effects on cardiovascular health than saturated fats.
Increases the amount of LDL cholesterol.
In most cases, trans fats are created by liquid oil being converted to solid fat via hydrogenation, used in cooking.
Food sources:
- Pies
- Pastries
- Cakes
- Margarines/butters

Definition: A nitrogenous compound that has large molecules comprised of amino acids that helps build and repair muscles and tissues in all living organisms.
Function:
- Made up of amino acids (building blocks) which are responsible for building, maintaining and repairing body cells (muscle, bone, organs and blood).
- 1 gram of protein = $17KJ$ of energy
- There are 20 different amino acids our body needs.
- Secondary source of fuel for energy.
- When amino acids are digested, they are eventually broken down into glucose. If the glucose molecules are not used, they are stored in adipose tissue (fatty tissue) causing weight gain or used as energy stores when the body requires glucose.
Food Sources:
- Lean meat, poultry, and fish
- Eggs
- Dairy products (milk, yoghurt, cheese)
- Beans and legumes (lentils, soybeans, tofu, and chickpeas)
- Nuts and seeds

Definition: A colourless, transparent, odourless liquid that forms the seas, lakes, rivers, and rain and is the basis of the fluids of living organisms.
Function:
- Provides balance in the body through hydration.
- Allows for the absorption of water-soluble vitamins (B-group and C).
- Transports nutrients to cells throughout the body.
- Helps with the excretion of waste products.
- Increases the body's metabolism.
Food Sources:
- Fruit such as watermelon, cucumber, tomatoes
- Vegetables such as spinach, watercress, carrots
Note: The human body is roughly 60% water, but this figure changes slightly with age, sex, and hydration levels!

Dehydration can impact physical health and wellbeing as it can lead to muscle fatigue, cramps, and decreased endurance, making it challenging to stay physically active and carry out daily tasks.
Dehydration can lead to cognitive impairment as it can affect concentration, memory, and mood leading to headaches and dizziness, resulting in trouble focusing, thinking, and processing information impacting on mental health and wellbeing.

Carbohydrates: Primary source of energy.
Fibre: Regulates the functioning of our digestive system.
Fat: Transports fat-soluble vitamins, insulates the body, protects vital organs, and slows emptying of the stomach.
- Mono- and polyunsaturated fats are beneficial.
- Saturated and trans fats should be limited.
Protein: Helps build and repair muscles and tissues in all living organisms.
Water: Allows water-soluble vitamins to be transported, hydrates the body, assists in excretion of waste, and increases metabolism.