Explore the roles, sources, recommended intake, and health effects of macronutrients (carbohydrates, proteins, fats) and micronutrients (vitamins, minerals) in the diet.
Macronutrients & Micronutrients – Quick Reference Notes
1. Overview
| Category |
Primary Role |
Typical Sources |
Daily Requirement (Adult) |
| Macronutrients |
Provide energy & building blocks for growth, repair, and metabolism |
Carbohydrates, proteins, fats |
Varies by age, sex, activity level (see sections below) |
| Micronutrients |
Support enzymatic reactions, hormone synthesis, immune function, and cellular signaling |
Vitamins & minerals |
Measured in milligrams (mg) or micrograms (µg); specific RDA values per nutrient |
2. Macronutrients
2.1 Carbohydrates
- Function: Main energy source; 1 g = 4 kcal.
- Types
- Simple: monosaccharides (glucose, fructose) and disaccharides (sucrose, lactose).
- Complex: oligo‑ and polysaccharides (starches, dietary fiber).
- Recommended Intake
- 45–65 % of total calories.
- At least 25 g of dietary fiber per day (women) / 38 g (men).
- Key Food Groups
- Whole grains, fruits, vegetables, legumes, dairy, nuts, seeds.
2.2 Proteins
- Function: Structural components (muscle, enzymes, hormones), transport, immune defense. 1 g = 4 kcal.
- Amino Acid Classification
- Essential (9 for adults): histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine.
- Non‑essential: can be synthesized by the body.
- Recommended Intake
- 0.8 g kg⁻¹ body weight/day for sedentary adults (≈56 g for a 70 kg person).
- 1.2–2.0 g kg⁻¹ for athletes, pregnant/lactating women, or during illness/recovery.
- Key Food Groups
- Animal: meat, poultry, fish, eggs, dairy.
- Plant: legumes, soy products, nuts, seeds, whole grains.
2.3 Fats (Lipids)
- Function: Dense energy source (9 kcal g⁻¹), essential fatty acids, fat‑soluble vitamin absorption, cell‑membrane structure, hormone production.
- Classification
- Saturated fatty acids (SFAs) – solid at room temperature; limited intake recommended.
- Monounsaturated fatty acids (MUFAs) – olive oil, avocados.
- Polyunsaturated fatty acids (PUFAs) – omega‑3 (ALA, EPA, DHA) & omega‑6 (LA).
Essential fatty acids: α‑linolenic acid (omega‑3) & linoleic acid (omega‑6).
- Trans fats – industrially hydrogenated; avoid.
- Recommended Intake
- 20–35 % of total calories.
- ≤10 % from saturated fats.
- Omega‑3: 1.1 g (women) / 1.6 g (men) EPA/DHA equivalents per day.
- Key Food Groups
- Healthy oils (olive, canola, flaxseed), fatty fish,