This topic provides an introduction to the basic concepts of nutrition, including macronutrients, micronutrients, and the role of nutrition in maintaining overall health and well-being.
Overview of Nutrition – Study Notes
| Aspect | Definition |
|---|---|
| Nutrition | The process by which living organisms obtain, assimilate, and use food substances to support growth, repair, maintenance, and energy production. |
| Nutrient | A chemical compound in food that the body needs to function (e.g., carbohydrates, proteins, fats, vitamins, minerals, water). |
| Diet | The habitual pattern of food and drink consumption. |
| Malnutrition | Any deviation from optimal nutrition, including under‑nutrition (deficiencies) and over‑nutrition (excesses). |
| Nutrient Class | Primary Functions | Key Sources | Recommended Intake (Adults) |
|---|---|---|---|
| Carbohydrates | • Main energy source (glucose) • Spare protein for tissue repair • Provide dietary fiber for gut health |
Whole grains, fruits, vegetables, legumes, dairy | 45‑65 % of total calories |
| Proteins | • Build & repair tissues • Enzymes, hormones, antibodies • Transport molecules |
Meat, fish, eggs, dairy, soy, beans, nuts | 0.8 g/kg body weight (≈46 g for women, 56 g for men) |
| Fats | • Concentrated energy (9 kcal/g) • Essential fatty acids (omega‑3, omega‑6) • Fat‑soluble vitamins absorption, cell membranes |
Olive oil, nuts, seeds, fatty fish, avocados | 20‑35 % of total calories (≤10 % from saturated fats) |
| Vitamins | • Co‑enzymes & regulators of metabolism • Antioxidant protection (e.g., vitamin C, E) |
Fruits, vegetables, dairy, fortified foods | Varies by vitamin (e.g., vitamin C 75‑90 mg/day) |
| Minerals | • Bone & tooth structure (Ca, P) • Fluid balance, nerve transmission (Na, K, Cl) • Oxygen transport (Fe) |
Dairy, meat, leafy greens, nuts, whole grains | Varies by mineral (e.g., calcium 1000 mg/day) |
| Water | • Solvent for biochemical reactions • Temperature regulation, joint lubrication • Transport of nutrients & waste |
Drinking water, beverages, high‑water foods (cucumber, watermelon) | ≈2.7 L (women) / 3.7 L (men) total water intake |
| Concept | Description |
|---|---|
| Energy Intake | Calories supplied by foods (carbohydrate = 4 kcal/g, protein = 4 kcal/g, fat = 9 kcal/g). |
| Energy Expenditure | Sum of basal metabolic rate (BMR), thermic effect of food (TEF), and physical activity energy. |
| Positive Balance | Intake > expenditure → weight gain (potentially adipose tissue). |
| Negative Balance | Intake < expenditure → weight loss (utilization of stored energy). |
| Neutral Balance | Intake ≈ expenditure → weight maintenance. |