Essential Nutrition & Digestion Revision
Essential Nutrition & Digestion Revision
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Essential Nutrition & Digestion Revision
What do you already know about how our body digests nutrients?
Learning Intension
At the end of the lesson you will be able to describe the roles of carbohydrates, proteins, fats and vitamins, explain key aspects of their digestion, and apply this knowledge to a range of scenario-based questions.
Carbohydrates: Role & Importance
Carbohydrates provide the body’s main source of energy. When dietary carbohydrates are insufficient, the body starts producing glucose from proteins (gluconeogenesis), impacting overall protein availability.
How Carbohydrates Are Digested
Carbohydrate digestion begins in the mouth (amylase enzyme), continues in the small intestine, and results in glucose absorption. If not enough carbs are consumed, glucose must come from protein.
Essential Proteins
Proteins build and repair tissues and act as enzymes for vital chemical reactions. Essential amino acids must come from food; they cannot be made in the body.
Mutual supplementation occurs when two incomplete protein sources combine to form a complete protein.
(eating a dish of black beans and rice)
Mutual supplementation
Protein Digestion Explained
Protein digestion starts in the stomach with hydrochloric acid and pepsin, and continues in the small intestine by other enzymes. Reduced stomach acid slows this process, leaving more intact proteins.
Fats: Sources & Functions
Fats are energy-dense (9 kcal/g) and help absorb fat-soluble vitamins (A, D, E, K). Healthy (unsaturated) fats lower heart disease risk, while too much saturated fat can cause arterial plaque.
How Fats Are Digested
The gallbladder releases bile to emulsify fats, making them digestible in the small intestine. Without bile, fat and fat-soluble vitamin absorption are severely impaired.
Vitamins: Vital Micronutrients
Vitamins help regulate metabolism, support immunity, and aid tissue repair. Fat-soluble vitamins (A, D, E, K) need dietary fats for absorption. Water-soluble vitamins are not stored long-term.
Vitamin Digestion & Absorption
Fat-soluble vitamins dissolve in fats and are absorbed with dietary lipids, while water-soluble vitamins travel in water and pass quickly through the system. Fat intake influences vitamin absorption.
Types of Fats & Cardiovascular Health
Omega-3 Fats
Saturated vs Unsaturated
Saturated fats contribute to arterial plaque and higher LDL cholesterol, raising cardiovascular risk.
Found in foods like salmon, they are heart-healthy and anti-inflammatory.
Vitamins & Their Key Functions
Vitamin K helps with blood clotting.
Vitamins A, D, E, K need fats for absorption and storage, while all support critical bodily functions.
Soybean Nutrition
Soybeans are protein-rich legumes that provide all essential amino acids, have high unsaturated fat, and are cholesterol-free.
Tofu and soy milk are popular high-protein alternatives.
Soy Digestion & Health
Soy products are easily digested and rich in phytochemicals.
Soy protein may lower heart disease and osteoporosis risk by improving lipid profile and bone health.
Protein Structure
Classify as primary, secondary, tertiary, or quaternary structure.
Protein in Special Scenarios
RDA: 1.3–1.5g/kg. 70kg × 1.3–1.5 = 91–105g protein/day needed for endurnce.a
If carb intake is low, body uses protein for glucose, reducing protein for its main functions.
Protein Deficiency
Vegetarian Athletes
Enzyme Activity & Digestion
Pepsin needs stomach acid to work. If acid is reduced, protein digestion slows. Digestion can be measured by the Biuret test (violet = more intact protein).
Interpreting Biuret Test Results
A stronger violet colour = more protein present (less digestion). Weak colour = greater digestion.
Enzymes like those in pineapple juice break proteins down effectively.(Bromelain)
Nutrition in Clinical Scenarios
Fatty stools and vitamin deficiencies after bile duct block? Bile is needed for fat and vitamin absorption. Blockages reduce this, leading to symptoms.
Jaundice, pale stools, and abdominal pain are health issues might arise as a result of a bile duct blockage
Apply Your Knowledge
You should now be able to: - Describe nutrient types and functions - Explain digestion for each class - Apply knowledge to real-life scenarios and exam questions Review this presentation until you feel confident.
Write down 3 things you learned in this lesson.
Write down 2 things you want to know more about.
Ask 1 question about something you haven't quite understood yet.
