SACE Stage 2 Nutrition Flashcards

Comprehensive practice flashcards covering SACE Stage 2 Nutrition core concepts, energy calculations, digestive physiology, dietary guidelines, food safety, sustainability, technology, scientific inquiry, and exam command words.

Nutrition

The process by which the body obtains and uses nutrients from food to support energy, growth, repair and health.

Nutrient

A substance in food that the body needs for energy, growth, repair and normal functioning.

Six Major Nutrient Classes

Carbohydrates, protein, fats, vitamins, minerals and water.

Macronutrients

Nutrients required in relatively large amounts, including carbohydrates, protein, fats and water.

Micronutrients

Nutrients required in smaller amounts, including vitamins and minerals.

Nutrient vs. Food

A nutrient is a substance used by the body, while food contains nutrients and other components.

Units of Energy

Kilojoules ($\text{kJ}$) or kilocalories ($\text{kcal}$).

Kilocalorie to Kilojoule Conversion

Approximately $4.184\,\text{kJ}$ in one kilocalorie.

Energy Density of Carbohydrate

Approximately $17\,\text{kJ}$ per gram.

Energy Density of Protein

Approximately $17\,\text{kJ}$ per gram.

Energy Density of Fat

Approximately $37\,\text{kJ}$ per gram.

Energy Density of Alcohol

Approximately $29\,\text{kJ}$ per gram, although alcohol is not an essential nutrient.

Energy Density of Water

$0\,\text{kJ}$ per gram.

Main Function of Carbohydrates

To provide the body with an important source of energy.

Two Main Types of Carbohydrates

Simple carbohydrates and complex carbohydrates.

Simple Carbohydrates

Carbohydrates made from one or two sugar units that are generally digested relatively quickly.

Complex Carbohydrates

Carbohydrates made from longer chains of sugar units, including starch and many forms of dietary fibre.

Glucose

A simple sugar used by cells as a major source of energy.

Glycogen

The storage form of glucose in humans, found mainly in the liver and skeletal muscles.

Dietary Fibre

Carbohydrate material that is not fully digested by human digestive enzymes and supports digestive and other aspects of health.

Benefits of Dietary Fibre

It supports bowel regularity, helps maintain digestive health and can contribute to fullness and healthy blood cholesterol and glucose levels.

Sources of Dietary Fibre

Wholegrains, vegetables, fruit, legumes, nuts and seeds.

Amino Acids

The fundamental units that make up protein.

Main Functions of Protein

Growth and repair of tissues, formation of enzymes and some hormones, immune function and maintenance of body structures.

Essential Amino Acids

Amino acids that the body cannot make in sufficient amounts and must obtain from food.

Complete Protein Sources

Foods that provide all essential amino acids in adequate proportions, such as eggs, dairy, meat, fish and soy.

Plant Protein Sources

Legumes, tofu, tempeh, soy products, nuts, seeds and some wholegrains.

Main Functions of Fats

Providing energy, supporting cell membranes, insulating the body, protecting organs and helping absorb vitamins A, D, E and K.

Saturated Fats

Fats that contain no carbon-carbon double bonds; high intakes can raise LDL cholesterol.

Unsaturated Fats

Fats containing one or more carbon-carbon double bonds; they include monounsaturated and polyunsaturated fats.

Trans Fats

Unsaturated fats with a particular molecular structure; industrial trans fats can adversely affect blood cholesterol and cardiovascular health.

Omega-3 Fatty Acids

Essential polyunsaturated fats involved in cell function and other processes, including normal brain and cardiovascular function.

Sources of Unsaturated Fats

Nuts, seeds, avocado, olive oil and oily fish.

Functions of Vitamins

They regulate body processes and support functions such as immunity, energy metabolism, vision and tissue maintenance.

Fat-Soluble Vitamins

Vitamins A, D, E and K, which are absorbed with fat and can be stored in the body.

Water-Soluble Vitamins

Vitamin C and the B-group vitamins, which dissolve in water.

Vitamin A

Supports vision, immune function, growth and healthy epithelial tissues.

Vitamin D

Helps regulate calcium and phosphate absorption and supports bone health.

Vitamin C

Supports collagen formation, wound healing, antioxidant activity and iron absorption from plant foods.

B-Group Vitamins

Support energy metabolism and other functions such as red blood cell formation and nervous system function.

Vitamin K

Supports normal blood clotting and bone-related processes.

Calcium

Supports bones and teeth, muscle contraction, nerve signalling and blood clotting.

Iron

Helps form haemoglobin, which transports oxygen in the blood.

Sodium

Helps regulate fluid balance and supports nerve and muscle function; excessive intake can contribute to high blood pressure.

Potassium

Supports fluid balance, nerve signalling and muscle function, including normal heart function.

Iodine

Helps the thyroid gland produce hormones that regulate metabolism, growth and development.

Zinc

Supports immune function, wound healing, growth and normal enzyme activity.

Functions of Water

It supports transport, temperature regulation, digestion, chemical reactions and waste removal.

Dehydration

A condition in which the body loses more water than it takes in, affecting normal body function.

Balanced Diet

A diet that supplies adequate energy and essential nutrients in suitable amounts and proportions to support health.

Energy Equilibrium

When energy intake and energy expenditure are approximately equal over time.

Energy Balance

The relationship between energy consumed through food and drink and energy used by the body.

Positive Energy Balance

When energy intake exceeds energy expenditure over time.

Negative Energy Balance

When energy expenditure exceeds energy intake over time.

Basal Metabolic Rate (BMR)

The energy required to maintain essential functions at rest under specified conditions.

Factors Influencing BMR

Body size and composition, age, growth, sex-related physiological factors, genetics, hormones and some health conditions.

Physical Activity Energy Expenditure

The energy used during movement and physical activity, including exercise and everyday activities.

Thermic Effect of Food (TEF)

The energy the body uses to digest, absorb, process and store nutrients after eating.

Simplified SACE TEF Proportion

Approximately $10\%$ of daily energy intake, when the question specifies this assumption.

TEF Calculation Formula

$\text{TEF} = \text{daily energy intake} \times 0.10$.

TEF Calculation Example ($10{,}000\,\text{kJ}$)

$10{,}000 \times 0.10 = 1{,}000\,\text{kJ}$.

Total Energy Expenditure (TEE)

The total energy used by the body over a period, including resting metabolism, physical activity and the thermic effect of food.

Simplified TEE Formula

$\text{TEE} = \text{BMR} + \text{TEF} + \text{physical activity energy}$.

Simplified TEE Calculation Example

If BMR is $6{,}000\,\text{kJ}$, TEF is $1{,}000\,\text{kJ}$ and physical activity energy is $2{,}000\,\text{kJ}$, $\text{TEE} = 6{,}000 + 1{,}000 + 2{,}000 = 9{,}000\,\text{kJ}$.

Energy Intake vs Energy Expenditure

Energy intake is the energy consumed from food and drink; energy expenditure is the energy used by the body.

Digestion

The mechanical and chemical breakdown of food into substances that can be absorbed.

Mechanical Digestion

The physical breakdown of food into smaller pieces, such as chewing and stomach churning.

Chemical Digestion

The breakdown of large food molecules into smaller molecules through chemical reactions, often involving enzymes.

Absorption

The movement of digested nutrients from the digestive tract into the blood or lymph.

Digestive Role of the Mouth

Where digestion begins, as chewing and salivary enzymes begin digestion.

Saliva

Moistens food and contains amylase, which begins starch digestion.

Oesophagus

Moves food from the mouth to the stomach by peristalsis.

Peristalsis

Rhythmic muscle contractions that move food through the digestive tract.

Digestive Role of the Stomach

It churns food and uses acid and enzymes to begin substantial protein digestion.

Hydrochloric Acid in Stomach

It creates an acidic environment, helps denature proteins and supports the action of pepsin.

Pepsin

An enzyme in the stomach that breaks proteins into smaller peptides.

Small Intestine

Completes much of chemical digestion and absorbs most nutrients.

Villi

Finger-like projections in the small intestine that increase the surface area available for absorption.

Microvilli

Tiny projections on intestinal cells that further increase the surface area for absorption.

Pancreas in Digestion

It releases digestive enzymes and bicarbonate into the small intestine.

Liver in Digestion

It produces bile and processes absorbed nutrients.

Gallbladder

It stores and concentrates bile before releasing it into the small intestine.

Bile

It emulsifies fat into smaller droplets, increasing the surface area for lipase to act.

Lipase

An enzyme that breaks fats into fatty acids and monoglycerides.

Amylase

An enzyme that breaks starch into smaller carbohydrates.

Proteases

Enzymes that break proteins into smaller peptides and amino acids.

Large Intestine

It absorbs remaining water and electrolytes and supports the formation of faeces.

Transport of Glucose and Amino Acids

They enter blood capillaries and are transported through the bloodstream.

Chylomicrons

Particles into which most absorbed dietary fats are packaged to initially travel through the lymphatic system before entering the blood.

Acceptable Macronutrient Distribution Range (AMDR)

The recommended percentage range of total dietary energy that should come from a macronutrient.

AMDR for Carbohydrates

$45\text{--}65\%$ of total energy intake.

AMDR for Fats

$20\text{--}35\%$ of total energy intake.

AMDR for Protein

$15\text{--}25\%$ of total energy intake.

Percentage of Energy from a Nutrient Formula

$\text{Energy supplied by the nutrient} \div \text{total energy intake} \times 100$.

Energy from Carbohydrate Formula

$\text{Grams of carbohydrate} \times 17\,\text{kJ/g}$.

Energy from Protein Formula

$\text{Grams of protein} \times 17\,\text{kJ/g}$.

Energy from Fat Formula

$\text{Grams of fat} \times 37\,\text{kJ/g}$.

Body Mass Index (BMI)

Body mass index, a screening measure calculated using weight relative to height.

BMI Formula

$\text{BMI} = \text{weight in kilograms} \div (\text{height in metres})^2$.

Limitations of BMI

It does not directly measure body fat, distinguish fat from muscle, or account fully for individual differences; interpretation differs for children and adolescents.