Biochemistry

• Nutrition


  The science of food and nutrients and other substances contained in food. It is the study of their actions, interactions and balance in relation to health and disease.
• Nutrition


  The composition and quantity of food intake and the utilisation of the food by living organism.
• Study of human nutrition

  • Under nutrition
  • Over nutrition
  • Ideal nutrition
• Healthy diet


  • Includes preparation of food and storage methods that preserve nutrients from oxidation, heat or leaching and that reduce risk of food borne illnesses
• Purpose of food


  To provide energy for muscular activity and also to supply basic body building materials such as essential amino acids
• Nutrients


  Necessary constituents of food required by organisms for growth and maintenance of life
• Nutritional requirement


  The amount of each nutrient needed by the organism
• Seven major classes of nutrients

  • Carbohydrates
  • Fats
  • Protein
  • Fibre
  • Vitamins
  • Minerals
  • Water
• Types of nutrients


  • Macronutrients
  • Micronutrients
• Macronutrients


  Needed in relatively large amounts. Provide structural material and energy.
• Micronutrients


  Needed in small amounts. Needed for normal growth and maintenance of body.
• Proximate principles


  Protein, fat and carbohydrate. They are oxidised in the body to yield energy.
• Principle foods


  • Cereals
  • Pulses
  • Vegetables
  • Fruits
  • Nuts
  • Milk
  • Egg
  • Meat
  • Fish
• Cereals


  • Important sources of fibre, B vitamins, and minerals. Help maintain optimum health due to phytochemicals.
• Pulses


  • Provide substantial amounts of vitamins, minerals, and protein. Help manage blood sugar levels and reduce risk of heart disease.
• Vegetables


  • Low in fat and calories, supply dietary fibre, and are important sources of essential vitamins, minerals, and antioxidants. Reduce risk of chronic diseases.
• Fruits


  • Good source of vitamins, minerals, and phytochemicals. Reduce risk of chronic diseases. Provide potassium, folate, and other important nutrients.
• Nuts


  • Packed with beneficial nutrients that may reduce risk of many diseases. Good sources of healthy fats, fibre, and protein.
• Milk


  • Nutrient-rich, provides benefits for growth, energy, biosynthesis, essential fatty acids, vitamins, and minerals.
• Eggs


  • Rich in high-quality protein, vitamins, minerals, and heart-healthy nutrients like choline and betaine.
• Meat


  • High in protein, containing all essential amino acids, and good source of various vitamins and minerals.
• Fish


  • Good source of high-quality protein and heart-friendly omega-3 fatty acids. Provides vitamins and minerals.
• Calorific value


  The energy content of food materials, expressed as the amount of heat energy obtained by burning 1.0 gram of food stuff completely in the presence of oxygen.
• Calorie


  The amount of heat required to raise the temperature of 1 gram of water through 1 degree Celsius. Kilocalorie (Kcal) is 1000 calories.
• Kilojoule


  The energy required to lift 1 kilogram to 1 metre by 1 Newton. 1 Kcal is equal to 4.2 kJ.
• Average energy values when metabolised: Carbohydrates 4 calories/g, Fats 9 calories/g, Proteins 4 calories/g
• Respiratory Quotient (RQ)


  The ratio of volume of CO2 produced to the volume of O2 consumed during a given time.
• RQ values


  • Carbohydrates 1
  • Fats 0.7
  • Protein 0.8
• Importance of RQ


  • Indicates type of food being oxidised in the body, decreases in diabetes mellitus and starvation
• Basal Metabolic Rate (BMR)


  The minimum amount of energy required to maintain life or sustain vital functions like the working of heart, circulation, brain function, respiration etc.
• Normal value of BMR is 24 Kcal/Kg body weight/day
• Factors affecting BMR


  • Age
  • Sex
  • Surface area
  • Environmental temperature
  • Racial variations
  • Exercise
  • Starvation
  • Fever
  • Thyroid hormones
• Biological Value (BV) of proteins

  Measures the quantity of dietary protein used by animal for growth and maintenance of body function. It is defined as percentage of absorbed nitrogen that is retained by the body.
• Biological value of some proteins


  • Values provided
• Basal Metabolic Rate (BMR)


  The amount of energy required by the body at rest to maintain vital functions
• BMR is directly proportional to the body surface


  BMR increases
• Environmental temperature is cold

  BMR increases as a compensatory mechanism to maintain body temperature
• Racial variations are noted when BMR of different racial groups is compared, with high values 33% above normal reported in Eskimos
• Exercise


  Increases BMR due to increased cardiac output
• Starvation


  Lowers BMR