GRADE 12 CONSUMER STUDIES TERM 2 REVISION MATERIAL UPDATED

Nutrients and Their Functions

Proteins

• Structural role: basis of all body cells; build new muscle cells; repair & maintain tissue.
• Functional role: enzymes, antibodies, control of body functions.
• Energy: provide energy; excess stored as fat.

Carbohydrates

• Primary energy source; provide heat; spare protein.
• Dietary bulk/fibre for satiety and gut health.
• Types & food sources:
  • Starch: grains, pasta, breakfast cereals, starchy vegetables.
  • Sugar: intrinsic & added.
  • Cellulose/Fibre: skins of fruit; stimulates peristalsis.

Lipids (Fats)

• Concentrated energy; absorption of fat-soluble vitamins; insulation & protection.
• Types:
  • Unsaturated fats (liquid @ r.t.): sunflower, olive oil.
  • Saturated fats (solid @ r.t.): butter, visible animal fat.
  • Trans / hydrogenated fats: formed via hydrogenation; present in fried foods, doughnuts, some margarines.

Fibre Terminology

• Soluble fibre: dissolves in water forming gel; slows $\text{glucose}$ entry.
• Insoluble fibre: binds water; accelerates peristalsis.

Vitamins & Minerals

• Vitamin C: aids iron absorption.
• Vitamin B$_{12}$: formation of red blood cells; nervous-system function.
• Iron: component of haemoglobin transporting $O_2$.
• Folic Acid: formation of red blood cells.

South African Dietary Guidelines (Robot Format)

• RED: "Use salt, fats, sugar & alcohol sparingly/ sensibly."
• ORANGE: "Make starchy foods the basis of most meals."
• GREEN:
  • Be active.
  • Drink 6–8 glasses of safe water daily.
  • Eat plenty of fruit & vegetables every day.
  • Enjoy a variety of foods.
  • Eat dry beans, peas, lentils, soya regularly.
  • Chicken, fish, meat, milk or eggs can be eaten daily.

Food- and Nutrition-Related Health Conditions

High Blood Cholesterol & Coronary Heart Disease (CHD)

• Cholesterol: soft, white, waxy substance produced by liver.
• LDL = “bad”, deposits plaque; HDL = “good”, removes LDL.
• Plaque narrows arteries → $\text{↓ blood flow}$ → risk of angina, myocardial infarction, stroke, gangrene.
• Causes: high intake of saturated & trans fats, genetics, inactivity, stress, alcohol, excess salt.
• Dietary prevention/management:
  • Limit red meat to 2–3 small portions / week.
  • Increase oily fish (omega-3).
  • Replace saturated fats with mono-/poly-unsaturated oils (olive, canola).
  • ≥5 portions fruit & veg (antioxidants, fibre).
  • Emphasise legumes; beware hidden fats; read labels.
• Therapeutic options: dietitian-prescribed low-cholesterol diet, medication (e.g. Lipitor).
• Foods that naturally lower cholesterol: fibre-rich produce, whole-grain bread, nuts, seeds, avocado, olive oil.
• Consequences if unmanaged: hypertension, thrombosis, MI, stroke.

Atherosclerosis

• Definition: build-up of fatty plaque inside artery walls causing them to harden, thicken, narrow, clog.
• Initiated by endothelial damage (smoking, high LDL).
• Risk factors: high cholesterol, hypertension, inactivity, diabetes, male sex, age, obesity, high alcohol, genetics, ↑ triglycerides.
• Sites & sequelae: coronary (CAD), cerebral (CVA), peripheral (PVD).
• Prevention/management:
  • (\le 200\,\text{mg}) dietary cholesterol/day.
  • High-soluble-fibre foods absorb cholesterol.
  • Omega-3 fish oils – anti-inflammatory, antithrombotic.
  • Eliminate trans fats; limit saturated fat, sodium, sugar.
  • Eat antioxidants (vit A, C, E), garlic; include mono-unsaturated fats.
  • Lifestyle: HeartMark products, regular exercise, healthy weight, no smoking, stress control.

Hypertension (High Blood Pressure – “Silent Killer”)

• Normal reading: $120/80\,\text{mmHg}$; Hypertensive: $\ge 140/90\,\text{mmHg}$.
• Causes: inactivity, high salt, smoking, alcohol, genetics, obesity, stress, high cholesterol.
• Dietary prevention:
  • Increase avocado, oily fish, blueberries, whole grains, yoghurt, fruit & veg, plain rice/pasta/potatoes.
  • Restrict sodium ((<120\,\text{mg} /100\,g on labels), fatty meats, full-fat dairy, sugar-sweetened beverages.
• Lifestyle: regular exercise, healthy sleep, no smoking/alcohol; medication (e.g. beta-blockers) when indicated.

Anaemia

• Condition: too few red blood cells/haemoglobin ⇒ tissue O_2 shortage.
• Aetiology: iron, vitamin B$_{12}$, folic-acid deficiencies; hereditary disorders; blood loss (menstruation, ulcers, cancer); chronic disease; alcohol excess.
• Risk groups: pregnancy, chronic illness, post-menopausal women, ≥65 yrs.
• Prevention & management:
  • Iron sources: beef, poultry, fish, legumes, dark leafy greens, prunes.
  • Folic acid: fruit, juices, leafy veg, kidney beans, peanuts.
  • Vitamin B$_{12}$: meat, dairy, soy.
  • Vitamin C-rich foods enhance iron uptake (citrus, peppers, strawberries).
  • Adequate hydration; restrict caffeine & alcohol.
• Example case (Nancy – vegetarian athlete): prescribed fresh fruit, muesli & yoghurt, hard-boiled eggs, orange juice to supply iron, B$_{12}$, folate, vitamin C.

Foodborne Diseases

Exam expectations: identify transmission routes in food environments and state incubation periods.

Food Additives

• Definition: substances added to food intentionally in small quantities to improve quality or shelf life.
• Reasons for use: nutritional enrichment, flavour, colour, texture, preservation, antioxidant protection.
• Categories:
  • Nutrient additives.
  • Emulsifiers & stabilisers.
  • Bleaching & colouring agents.
  • Chemical preservatives.
  • Antioxidants.
  • Flavour enhancers.
• Safety & health: regulated limits, potential allergies, long-term effects debated.

Food Labelling

• Four information sections: (1) Serving size, (2) Calories, (3) Macro- & key nutrients, (4) Vitamins & minerals.
• Interpretation skills required:
  • Assess type of fat (saturated vs mono/poly-unsaturated) rather than total fat.
  • Detect trans fats via “partially hydrogenated oils”.
  • Check cholesterol, sodium ((<120\,\text{mg}/100\,g = low).
  • Evaluate fibre & added sugars in total carbohydrates.
• Nutrient content claims must meet prescribed conditions (energy, fat, sat-fat, cholesterol, sodium, fibre, protein, vitamins, minerals). Learners must judge if claims are misleading.

Food-Related Consumer Issues

• Genetically Modified (GM) Food: definition, examples, potential benefits (yield, pest resistance) & environmental/economic concerns (biodiversity, dependency on seed companies).
• Organically Grown Food: produced without synthetic fertilizers/pesticides; perceived health & environmental advantages; higher cost.
• Irradiated Food: exposed to ionising radiation to destroy pathogens & extend shelf life; safety affirmed by regulators; consumer acceptance issues.
• **Food