BIOCHEM

• Nutrition


  The provision of needed energy and essential constituents that cannot be synthesized de novo
• Sound nutrition depends on food intake that includes


  • Carbohydrates
  • Proteins
  • Fats
  • Vitamins
  • Minerals
  • Water
• The science of nutrition seeks to define the qualitative and quantitative requirements of the diet necessary to maintain good health
• Amino acids required by the body


  • 20 amino acids to synthesize proteins and other nitrogen-containing compounds
  • 9 of which cannot be synthesized in the body
• Protein quality


  Measured by comparing the proportions of essential amino acids in a food with the production required for the good nutrition; the closer the two numbers are, the higher the protein quality
• Egg and milk proteins

  High-quality proteins used as reference standards against which other proteins can be compared
• Energy intake


  • Affects protein requirements because it spares the use of proteins as energy source
• Physical activity


  • Increases nitrogen retention from dietary protein
• Marasmus


  Generalized wasting due to deficiency of both energy and protein
• Kwashiorkor


  Characterized by edema (swelling) due to deficiency of both quantity and quality of protein
• Carbohydrates


  Glucose is needed by tissues, but does not have to be provided as such diet, since other dietary carbohydrates are readily converted to glucose
• Minimum daily carbohydrates intake

  50 -100g recommended to prevent ketosis and loss of muscle protein
• Fiber


  • Aids in water retention during passage of food along the gut thus producing softer feces
  • Associated with reduced incidence of diverticulosis, cancer of colon, cardiovascular disease, and diabetes mellitus
  • Slow stomach emptying and delay the rise in blood glucose
• Lipids


  • Increase the palatability of food
  • Produces a feeling of satiety
  • Acts a dietary vehicle for fat-soluble vitamins
  • Supplies the essential polyunsaturated fatty acids that the body cannot synthesis
  • High fat consumption especially of saturated fat correlated with coronary heart disease
• Provitamin


  A compound that can be converted in the body to a vitamin
• Fat-soluble vitamins


  • Vitamin A (retinol)
  • Vitamin D (calciferol)
  • Vitamin E (alpha-tocopherol)
  • Vitamin K (anti-hemorrhagic vitamin)
• Water-soluble vitamins


  • Vitamin B complex
  • Vitamin C (ascorbic acid)
• Vitamin B complex


  • Thiamine (B1)
  • Riboflavin
  • Niacin (nicotinic acid)
  • Pyridoxine (B6)
  • Folic acid
  • Pantothenic acid
  • Biotin
  • Cyanocobalamin (B12)
• Macrominerals


  • Calcium
  • Phosphorus
  • Sodium
  • Potassium
  • Chloride
  • Magnesium
• Microminerals (trace elements)


  • Chromium
  • Cobalt
  • Copper
  • Iodine
  • Iron
  • Manganese
  • Molybdenum
  • Selenium
  • Zinc
  • Fluoride
• Kilocalorie (kCal)

  The amount of heat necessary to raise 1 kg of water from 15 to 16 degree Celsius