Nutritional needs

📝 Chapter 3: Nutritional Needs of Humans

📌 LO3: Understand the relationship between nutrients and the human body

🔹 AC3.1: Functions of Nutrients in the Body

1⃣ Growth and Development

• Food provides building blocks for growth:

  • Increase in number of cells (hyperplasia) and size of cells (hypertrophy).

  • Formation and development of body tissues (bones, muscles, organs).

  • Supports brain and nervous system development — essential in children.

2⃣ Energy Production

• Food is converted into energy through respiration:

  • Aerobic respiration (oxygen + glucose) → energy + CO₂ + H₂O.

  • Energy used for:

    • Movement (physical activity)

    • Thinking (mental exertion)

    • Physiological processes (heartbeat, breathing)

    • Metabolic reactions (growth, repair, digestion).

  • Vitamin B group supports energy metabolism.

3⃣ Regulating Metabolism

• Nutrients regulate body processes:

  • Enzymes and hormones control metabolic reactions.

  • Catabolism: breaks down nutrients for energy.

  • Anabolism: builds and repairs tissues.

  • Metabolic rate influenced by:

    • Body size, muscle mass, age, genes, thyroid hormones, mental state, activity level, pregnancy, body temperature, diet.

🔹 AC3.2: Characteristics of Unsatisfactory Nutritional Intake

Visible Conditions:

• Obesity: Excess body fat.

• Skin disorders: Acne, eczema, rashes.

• Dental disease: Tooth decay from high sugar intake.

Non-Visible Conditions:

• Nutritional deficiencies/excesses: Anemia (iron), vitamin deficiencies.

• Digestive disorders: Constipation, IBS, coeliac disease.

• Metabolic issues: Diabetes.

• Dental issues: Tooth decay, gum disease.

🔹 AC3.3: Nutritional Needs of Specific Groups

👶 Life Stages

• Infancy (0–5 yrs): Growth, brain development — high energy and protein.

• Childhood (6–12 yrs): Growth, bone development — calcium, vitamin D.

• Adolescence (13–19 yrs): Growth spurts, iron needs (esp. girls).

• Adulthood (19+): Maintenance, pregnancy and lactation (increased iron, folate).

• Older adulthood (65+): Less energy, more calcium, vitamin D.

🩺 Medical Conditions

• Diabetes: Balanced carbs, avoid sugar spikes.

• Hypercholesterolemia: Low saturated fat, more fiber.

• Anemia: More iron (meat, green veg).

• Lactose Intolerance: Avoid dairy, use alternatives.

• Coeliac Disease: Gluten-free diet.

🌍 Culture

• Religious beliefs: Halal, kosher, vegetarian/vegan.

• Lifestyle choices: Vegetarian, vegan, pescatarian.

⚖ Food Environments

• Food Deserts: Limited access to healthy food.

• Food Oasis: Good access to fresh produce.

🔢 Calculating Nutritional Needs

• EAR: Average requirement for a group.

• RNI: Enough for almost all (97.5%).

• LRNI: Enough for few (2.5%).

• Safe Intake: For uncertain data.

• Use BMR and PAL to estimate energy needs.

🏃‍♂ Activity Levels and Sports Nutrition

• More activity → higher energy needs.

• Protein for muscle repair.

• Carbohydrates for energy.

🔹 Unsatisfactory Nutritional Intake – Detailed Examples

🍩 Obesity

• Causes:

  • High-calorie diets, sedentary lifestyle, genetics.

  • Aetiology: energy intake > energy expenditure.

• Consequences:

  • Diabetes, heart disease, hypertension, sleep apnea, depression.

❤ Cardiovascular Disease (CVD)

• Heart attack, angina, stroke.

• Risks: high saturated fat, smoking, inactivity.

🍬 Diabetes

• Type 1: Insulin injections.

• Type 2: Lifestyle and diet control.

• Complications: heart, eyes, kidneys, nerves.

🦷 Dental Disease

• Sugar intake → cavities, gum disease.

🦴 Rickets/Osteoporosis

• Lack of vitamin D and calcium → weak bones.

🩸 Anemia

• Lack of iron → fatigue, pale skin.

🧴 Skin Disorders

• Nutrient deficiencies → dry skin, rashes.

🔹 Additional Notes

🏘 Community Food Environments

• Healthy: Fresh produce, community kitchens.

• Obesogenic: Fast food, high-calorie snacks.

📊 Nutritional Numbers

• Energy: 2000 kcal/day.

• Carbs: 260g/day.

• Protein: 50g/day.

• Fat: <70g/day (saturates <20g).

• Fiber: 30g/day.

• BMI: 18.5–24.9 = healthy.

📐 BMR and PAL

• BMR calculated by weight, height, age, gender.

• For men its (10 x weight (kg) + (6.25 x height in cm) - (5 x age in years) + 5, and for women it’s (10 x weight (kg) + (6.25 x height in cm) - (5 x age in years) - 161). This calculation provides a baseline for understanding daily caloric needs based on individual characteristics.

• PAL (Physical Activity Level) is then multiplied by the BMR to estimate total daily energy expenditure (TDEE), taking into account various activity levels ranging from sedentary to very active.

• PAL varies from <1.4 (sedentary) to >2.4 (extremely active).

✨ Plenary Q&A

• Name 3 common allergies? (milk, nuts, gluten).

• How does dietary knowledge help caterers? Prevents health risks, ensures safe meals.