Nutrition

A balanced diet is essential for maintaining overall health and well-being. It should include a variety of foods from all the food groups, providing essential nutrients that support bodily functions. Regular consumption of fruits and vegetables is particularly important, as they are rich in vitamins, minerals, and antioxidants.

🍎 Chapter 2: Nutrition

1⃣ Classification of Nutrients

🥦 Macronutrients

• Carbohydrates — main source of energy (4 kcal/g). Includes simple (sugars), complex (starches & fiber).

• Proteins — growth, maintenance, repair of tissues (4 kcal/g).

• Fats (Lipids) — energy storage, insulation, protection of organs (9 kcal/g).

🥗 Micronutrients

• Vitamins — essential for metabolic processes (e.g. Vitamin A, C, D, E, K, B vitamins).

• Minerals — structural and regulatory roles (e.g. iron, calcium, potassium, sodium).

💧 Water

• Maintains hydration, transports nutrients and waste, regulates temperature.

2⃣ Additional Nutrients & Components

• Phytochemicals — beneficial plant chemicals (e.g. antioxidants like polyphenols in berries).

• Fiber — important for digestive health; includes soluble and insoluble fiber.

3⃣ Nutritional Value & Labeling

• Nutrient Density — ratio of beneficial nutrients to energy content (e.g. kale vs. white bread).

  • Example: Kale (NDI 1000) vs. cola (NDI 1).

• Nutritional Labeling — color-coded labels (Red, Amber, Green) indicate high, medium, low levels of fat, sugars, and salt.

• Reference Intake (RI) — guides daily intake recommendations (e.g. 2000 kcal/day for adults).

4⃣ Glycaemic Index (GI)

• Measures how quickly carbohydrates raise blood glucose.

  • High GI: white bread, sugary cereals (quick rise).

  • Low GI: whole grains, pulses (slower rise).

• Important for managing diabetes.

5⃣ Biological Value (BV)

• Measures the proportion of absorbed protein that becomes incorporated into body proteins.

  • HBV: eggs, meat, fish (complete proteins).

  • LBV: cereals, pulses (incomplete, need combination).

6⃣ Complementary Interactions of Nutrients

• Proteins: Combining LBV foods (e.g. beans & rice) provides all essential amino acids.

• Other Nutrients: Nutrients work synergistically (e.g. Vitamin C enhances iron absorption).

7⃣ Structure of Nutrients

🔬 Carbohydrates

• Monosaccharides: Glucose (brain fuel), fructose, galactose.

• Disaccharides: Sucrose (table sugar), lactose (milk), maltose.

• Polysaccharides: Starch (amylose & amylopectin), glycogen, cellulose (dietary fiber).

🔬 Proteins

• Composed of amino acids (20 total, 8 essential).

  • Peptide bonds formed via condensation.

  • Four levels of structure: primary, secondary, tertiary, quaternary.

• Denaturation: heat, pH, mechanical action can unravel protein structure.

🔬 Lipids

• Triglycerides: glycerol + 3 fatty acids.

  • Saturated (no double bonds) — solid at room temp (e.g. butter).

  • Unsaturated (one or more double bonds) — oils.

• Essential fatty acids: Omega-3, Omega-6.

🔬 Vitamins & Minerals

• Water-soluble: B vitamins, Vitamin C.

• Fat-soluble: Vitamins A, D, E, K.

• Minerals: e.g. calcium, iron, potassium.

🔬 Water

• Universal solvent, transports nutrients, removes waste.

8⃣ Food Production Methods & Their Effects

🏭 Processing Effects on Nutrients

• Processing: milling, refining, heating — often reduces vitamins/minerals.

  • Example: white flour lower in fiber and B vitamins than wholegrain flour.

• Fortification: adding nutrients back (e.g. iron in breakfast cereals).

🍳 Cooking Methods

• Boiling: major losses of water-soluble vitamins (e.g. Vitamin C, B vitamins).

• Steaming: best at retaining water-soluble vitamins.

• Frying: retains vitamins but can form harmful aldehydes.

• Microwaving: short time, minimal losses.

• Roasting/Baking: minimal vitamin losses; longer time may reduce B vitamins.

• Grilling/Broiling: losses due to dripping juices; risk of carcinogens (PAHs).

🥫 Preservation

• Canning, freezing, drying.

  • Freezing: preserves most nutrients.

  • Drying: preserves but can reduce Vitamin C.

  • Canning: loss of some vitamins, but preserves shelf-life.

🧪 Antioxidants

• Added to foods to prevent oxidation and spoilage (e.g. Vitamin E).

🥣 Fortification

• Adding nutrients to prevent deficiencies (e.g. iodine in salt, Vitamin D in margarine).

🥑 Cholesterol-Lowering Foods

• Plant sterols & stanols reduce cholesterol absorption (e.g. in fortified spreads).

9⃣ Additional Key Concepts

🔑 Key Terminology

• Hydrolysis: water breaks down chemical bonds (e.g. digestion of carbs/proteins).

• Glycosidic bonds: links between sugar units in carbohydrates.

• Peptide bonds: links between amino acids in proteins.

• Triglycerides: main form of dietary fat.

10⃣ Summary: Healthy Eating Principles

• Eat a wide variety of mostly plant-based, whole foods.

• Stay hydrated.

• Limit saturated fats, sugars, and salt.

• Combine LBV proteins for complete amino acid intake.

• Balance energy intake with energy expenditure.

• Consider GI for blood sugar control.

Vitamins

Of course! Let’s tackle vitamins in detail, covering functions, sources, and side effects for each. Here’s a comprehensive breakdown:

Vitamins: Functions, Sources, and Side Effects

Fat-Soluble Vitamins

Vitamin A

• Function: Maintains healthy vision, immune system, skin, and mucous membranes; supports cell growth and reproduction.

• Sources:

  • Liver, fish liver oils

  • Eggs

  • Dairy (milk, cheese, butter)

  • Orange/yellow/red fruits & vegetables (carrots, sweet potatoes, pumpkins, mangoes)

  • Dark green leafy vegetables (spinach, kale)

• Side Effects:

  • Deficiency: Night blindness, dry skin, increased infection risk

  • Excess: Toxicity causing headaches, dizziness, nausea, liver damage, birth defects (in pregnancy)

Vitamin D

• Function: Aids calcium absorption, supports healthy bones and teeth, regulates immune function.

• Sources:

  • Sunlight exposure (skin makes vitamin D)

  • Oily fish (salmon, mackerel)

  • Egg yolk

  • Fortified milk and cereals

• Side Effects:

  • Deficiency: Rickets (children), osteomalacia (adults), muscle weakness

  • Excess: Hypercalcemia (too much calcium in blood) leading to kidney stones, nausea, confusion

Vitamin E

• Function: Antioxidant (protects cells from free radicals), immune function, skin health.

• Sources:

  • Vegetable oils (sunflower, safflower)

  • Nuts and seeds

  • Green leafy vegetables

  • Fortified cereals

• Side Effects:

  • Deficiency: Rare, but can cause nerve and muscle damage

  • Excess: Increased bleeding risk, especially if on anticoagulants

Vitamin K

• Function: Blood clotting, bone metabolism.

• Sources:

  • Green leafy vegetables (kale, spinach)

  • Broccoli, brussels sprouts

  • Liver

  • Some produced by gut bacteria

• Side Effects:

  • Deficiency: Bleeding disorders, easy bruising

  • Excess: Rare, but can interfere with blood thinning medications

Water-Soluble Vitamins

Vitamin C (Ascorbic Acid)

• Function: Collagen synthesis, wound healing, immune function, iron absorption.

• Sources:

  • Citrus fruits (oranges, lemons)

  • Berries

  • Peppers

  • Tomatoes

  • Broccoli

• Side Effects:

  • Deficiency: Scurvy (bleeding gums, fatigue, joint pain)

  • Excess: Diarrhea, stomach cramps

Vitamin B1 (Thiamine)

• Function: Energy metabolism, nerve function.

• Sources:

  • Whole grains

  • Pork

  • Legumes

  • Nuts and seeds

• Side Effects:

  • Deficiency: Beriberi (weakness, nerve problems), Wernicke-Korsakoff syndrome (confusion)

  • Excess: Rare, excess is excreted

Vitamin B2 (Riboflavin)

• Function: Energy production, healthy skin, vision, nerve function.

• Sources:

  • Dairy

  • Eggs

  • Green leafy vegetables

  • Lean meats

• Side Effects:

  • Deficiency: Cracked lips, sore throat, inflamed tongue

  • Excess: Harmless bright yellow urine

Vitamin B3 (Niacin)

• Function: Energy metabolism, skin health, nervous system function.

• Sources:

  • Meat, poultry, fish

  • Whole grains

  • Legumes

  • Peanuts

• Side Effects:

  • Deficiency: Pellagra (diarrhea, dermatitis, dementia)

  • Excess: Flushing, liver damage

Vitamin B5 (Pantothenic Acid)

• Function: Energy metabolism, hormone synthesis.

• Sources:

  • Whole grains

  • Meat, poultry

  • Eggs

  • Avocado

• Side Effects:

  • Deficiency: Rare, but may cause fatigue, numbness

  • Excess: Rare, may cause diarrhea

Vitamin B6 (Pyridoxine)

• Function: Protein metabolism, red blood cell formation, brain function.

• Sources:

  • Meat, poultry, fish

  • Whole grains

  • Bananas

  • Nuts

• Side Effects:

  • Deficiency: Anemia, depression, confusion

  • Excess: Nerve damage (tingling, numbness)

Vitamin B7 (Biotin)

• Function: Metabolism of fats, carbohydrates, protein, healthy hair and skin.

• Sources:

  • Eggs (yolk)

  • Nuts

  • Soybeans

  • Whole grains

• Side Effects:

  • Deficiency: Rare, but can cause hair loss, dermatitis

  • Excess: No known toxicity

Vitamin B9 (Folate/Folic Acid)

• Function: DNA synthesis, cell division, red blood cell formation.

• Sources:

  • Green leafy vegetables

  • Fortified cereals

  • Legumes

  • Citrus fruits

• Side Effects:

  • Deficiency: Neural tube defects (in pregnancy), anemia

  • Excess: Masks vitamin B12 deficiency

Vitamin B12 (Cobalamin)

• Function: Nerve function, red blood cell formation, DNA synthesis.

• Sources:

  • Animal products (meat, fish, eggs, dairy)

  • Fortified plant-based milk and cereals

• Side Effects:

  • Deficiency: Anemia, nerve damage, fatigue

  • Excess: Rare, usually excreted in urine

📝 Food Tech Notes on Minerals

1⃣ Calcium

🔹 Function:

• Builds strong bones and teeth

• Blood clotting

• Nerve and muscle function

🔹 Sources:

• Milk, cheese, yogurt

• Green leafy vegetables

• Fish with bones (e.g. tinned sardines)

🔹 Catering Considerations:

• Essential for children, teens, pregnant women, and the elderly.

• Important in dairy-based desserts, sauces, and cheese toppings.

• Consider lactose intolerance: offer fortified plant milks or calcium-rich alternatives.

2⃣ Iron

🔹 Function:

• Carries oxygen in red blood cells (prevents anemia)

• Supports energy metabolism

🔹 Sources:

• Red meat, liver

• Pulses, spinach, fortified cereals

🔹 Catering Considerations:

• Offer both heme iron (animal) and non-heme iron (plant) sources for vegetarians.

• Pair with vitamin C-rich foods (e.g. orange juice) to aid absorption.

• Avoid tannin-rich drinks like tea with meals that reduce absorption.

3⃣ Sodium

🔹 Function:

• Maintains fluid balance

• Nerve and muscle function

🔹 Sources:

• Table salt, processed foods (ready meals, soups)

• Cheese, bread, cured meats

🔹 Catering Considerations:

• Too much sodium raises blood pressure—watch salt content.

• Use herbs and spices instead of excess salt to season dishes.

• Be aware of dietary requirements (hypertension, heart disease).

4⃣ Potassium

🔹 Function:

• Regulates fluid balance

• Nerve and muscle function (including heart)

🔹 Sources:

• Bananas, potatoes

• Tomatoes, leafy greens

🔹 Catering Considerations:

• Helps balance sodium levels.

• Important for athletes and those with high sweat losses.

• Use fresh fruits and vegetables generously in menus.

5⃣ Fluoride

🔹 Function:

• Strengthens tooth enamel

• Prevents dental cavities

🔹 Sources:

• Fluoridated water

• Some fish and tea

🔹 Catering Considerations:

• Not a major focus in menu planning, but water and dental health education are relevant for children’s menus.

6⃣ Iodine

🔹 Function:

• Makes thyroid hormones (controls metabolism)

🔹 Sources:

• Seafood, milk, eggs

• Iodised salt

🔹 Catering Considerations:

• Essential for pregnancy to prevent developmental issues.

• Important for vegetarians/vegans who might avoid seafood.

• Use iodised salt in recipes where appropriate.

7⃣ Phosphorus

🔹 Function:

• Builds strong bones and teeth

• Energy production

🔹 Sources:

• Meat, dairy, nuts, fish, eggs

🔹 Catering Considerations:

• Usually plentiful in balanced diets.

• Essential for growing children and pregnant women.

8⃣ Zinc

🔹 Function:

• Immune function

• Wound healing

• Growth and reproduction

🔹 Sources:

• Meat, shellfish, eggs

• Whole grains, legumes

🔹 Catering Considerations:

• Include for wound healing and immune support.

• Pay attention for vegetarians: plant sources are less bioavailable.

📌 General Points for Catering:

✅ Offer a variety of food sources to meet mineral needs (meat, dairy, plant-based).
✅ Consider cultural/religious dietary restrictions (e.g. halal, kosher, vegetarian).
✅ Balance menus to avoid too much salt, processed meats, or saturated fat.
✅ Highlight iron and calcium for children, teens, pregnant women, and elderly.
✅ Educate about pairing plant-based iron with vitamin C foods to aid absorption.
✅ Be mindful of allergens and intolerances that might limit mineral intake.