Introduction to food and nutrition _ basics
- 1. Introduction to Food and Nutrition
- 2. Why Study Nutrition? • Nutrition = the science of food, nutrients, and their effect on health • Diet influences: energy, growth, disease prevention • Global issues: malnutrition, obesity epidemic, food insecurity
- 3. What is Nutrition • Nutrition (also called nourishment or aliment) is the provision, to cells and organisms , of the materials necessary (in the form of food ) to support life . • Processes of taking in and utilizing food substances. • Food generates energy and supplies materials used in body tissues and processes.
- 4. Nutrients • There are six major classes of nutrients • Macronutrients: (needed in relatively large amounts) – Carbohydrates, Proteins, Fats • Micronutrients: (needed in smaller quantities) – Vitamins, Minerals • Water: vital but not energy-yielding • Energy values: Carbs 4 kcal/g | Protein 4 kcal/g | Fat 9 kcal/g
- 5. Carbohydrates • Carbohydrates include sugars, starches and fiber • Main energy source (45–65% kcal) • Rice, noodles, bread, grains, etc. • Simple vs. complex carbs • Carbohydrates range from simple monosaccharides (glucose, fructose, galactose) to complex polysaccharides (starch). • Glycemic Index (GI) & blood sugar regulation • Fiber: gut health, satiety, cholesterol
- 6. Cellulose • Fruits and vegetables: high content of inedible material, or cellulose • Actually, it is edible—just not digestible • A substance found in the cell walls of plants • An important dietary component that aids in digestion • Sometimes called fiber or roughage, cellulose helps give food bulk as it moves through the digestive system • Aids the body in pushing out foods and wastes
- 7. Proteins • Proteins are the basis of many animal body structures (e.g. muscles, skin, and hair) • Functions: growth, enzymes, hormones, immune support • Each molecule is composed of amino acids – Amino acids: essential vs. non-essential • Complete vs. incomplete proteins – A complete protein source contains all the essential amino acids; – an incomplete protein source lacks one or more of the essential amino acids. • Nitrogen balance = intake vs. Excretion • Sources: meat, eggs, legumes, dairy etc.
- 8. Fats (Lipids) • Concentrated energy (20–35% kcal) • Types: saturated, unsaturated, trans fats – Saturated and some trans fats are typically solid at room temperature (such as butter or lard ), – unsaturated fats are typically liquids (such as olive oil or flaxseed oil ) • Essential fatty acids (Omega-3, Omega-6) • Cholesterol: HDL 'good' vs. LDL 'bad' • Fats are triglycerides , made of assorted fatty acid bound to glycerol backbone • Some fatty acids, but not all, are essential in the diet: they cannot be synthesized in the body.
- 9. Vitamins • Essential nutrients, necessary in the diet for good health • Organic, no calories, regulatory roles • Fat-soluble: A, D, E, K • Water-soluble: B-complex, C • Example: Vitamin D → calcium absorption • Deficiency vs. toxicity risks • Vitamin deficiencies may result in disease conditions: – goitre – scurvy – osteoporosis – impaired immune system – poor psychological health etc.
- 10. Minerals • Dietary minerals are the chemical elements elements required by living organisms • Inorganic, structural/regulatory roles • Often artificially added to the diet as supplements; the most famous is likely iodine in iodized salt which prevents goiter • Macro minerals (required in large quantity): Calcium, Magnesium, Phosphorus, Potassium, etc. • Trace minerals (Required in trace quantity): Iron, Zinc, Copper, Selenium • Examples: Iron → hemoglobin, Calcium → bones, Iodine → thyroid
- 11. Water • 60–70% of body weight • Functions: solvent, thermoregulation, transport, lubrication • Balance: intake vs. output • Deficiency: dehydration • Excess: hyponatremia
- 12. Balanced Diet • A balanced diet is one that provides all essential nutrients in the right amounts and proportions to maintain health, vitality, and wellbeing • It ensures the body has enough energy, nutrients for repair and growth, and protective elements to prevent diseases • Combines all nutrients in right proportions • Examples: Mediterranean, DASH diets • Role in disease prevention
- 13. Principles of Balanaced Diet • Adequacy: Provides sufficient energy and essential nutrients • Balance: Not too much of one nutrient at the expense of another • Variety: Includes foods from all groups (no single food has everything) • Moderation: Avoids excessive calories, sugar, salt, saturated fat, and alcohol • Proportionality: Carbs: 45–65%, Protein: 10–35%, Fat: 20–35% of daily energy intake
- 14. How to Attain a Balanced Diet • Follow dietary guidelines (e.g., MyPlate, Food Pyramid, WHO Healthy Diet) • Daily inclusion of: – Whole grains (energy, fiber) – Fruits & vegetables (vitamins, minerals, antioxidants) – Lean protein (meat, legumes, dairy, eggs) – Healthy fats (nuts, seeds, fish, oils) • Adequate water • Limit: ultra-processed foods, added sugars, excess salt, trans fats • Portion control & mindful eating (watch energy intake).
- 15. Why is a Balanced Diet Necessary • Supports growth & development (especially in children and adolescents) • Maintains body functions: metabolism, immunity, repair, hormonal balance • Prevents malnutrition: – Undernutrition → stunted growth, weakened immunity – Overnutrition → obesity, metabolic syndrome
- 16. Why is a Balanced Diet Necessary • Reduces risk of chronic diseases: diabetes, hypertension, cardiovascular disease, osteoporosis, some cancers • Enhances mental health & performance: diet linked to cognitive function and mood • Improves quality of life & longevity: healthy aging through good nutrition