Topic 8 Human nutrition

• There are 7 types of food : Carbohydrates, Proteins, Lipids, Minerals, Vitamins, Fibres and Water.
• We need food for growth, source of energy and replacement of worn and damaged tissues.
• Importance of carbohydrates includes : storage and energy.
• Proteins supplies the body with amino acids to build up our body structures and the excess will be deaminated to become an amine group and glycogen.
• Importance of proteins includes : growth, tissue repairs, enzymes, hormones, cell membranes, hairs and nails and, can be broken down to release energy.
• Lipids are used to make part of cell membrane systems and can be oxidized in respiration to release energy.
• Importance of lipids includes : energy, insulation, hormones and cell membranes.
• Minerals such as calcium, iodine, iron and zinc.
• Calcium is needed to form healthy bones and normal blood clotting. Deficiency of calcium includes rickets and osteoporosis.
• Iodine is needed to make some hormones.
• Iron is needed for making haemoglobin in red blood cell. Deficiency of iron includes anemia.
• Zinc helps to heal wounds.
• Vitamins are needed for chemical reactions in cells (enzymes)
• Vitamins are not broken down for energy.
• Vitamins are not build into body structures.
• Vitamins : A- to fight infections, better vision & keeping skin healthy, B1- to release energy from food, B2- healthy skin, eyes and nervous system, B12 - make RBC, release energy from food, C - to fight infection, better vision, keeping skin healthy, deficiency ; scurvy, D- keep bones, teeth and muscles healthy, deficiency ; rickets, E - Healthy skin, eyes and immune system, K- healing wounds.
• Importance of fibres includes : increase content of the colon and help it retain water, soften faeces which makes it easir for undigested food to pass. Lacking of fibres might lead to constipation.
• Balanced diet is a diet that contains all the important nutrients in the correct proportion to maintain good health.
• Unbalanced diet is when you dont take the essential nutrients in the correct proportions.
• Mouth is the site of food ingestion, physical digesting by the teeth and chemical digestion by the amylase.
• Salivary glands produces saliva (amylase)
• Stomach produces gastric juice (pepsin & HCL)
• Duodenum is the site of chemical digestion of proteins, lipids and starch.
• Liver makes bile (fats physical digestion), assimilation and deamination.
• Gall bladder stores bile.
• Pancreas secretes pancreatic juice.
• Illeum is the site of absorption of digested food.
• Rectum is the site of faeces storage.
• Anus is the site of faeces egestion.
• Peristalsis happens in the oesophagus. It transfers food from mouth to the stomach.
• Colon digest water from undigested materials and the bacteria in colon can digest part of fibre to form fatty acids.
• Food must be digested to make them soluble and can be absorbed into the bloodstream. Blood will then deliver food to living cells of all tissues.
• There are 5 main processes in digestive system : Ingestion, Digestion, Absorption, Assimilation and egestion.
• Ingestion is the process of taking food in through the mouth.
• Digestion is the process of breaking food into smaller soluble substance that can be absorbed.
• Absorption is the movement of nutrients from the intestines into cells lining of the digestive system and then into the blood.
• Assimilation is the uptake and use of products of digestion by cells.
• Egestion is the process of passing out undigested food (faeces)
• There are 4 types of human teeth : Incisor, Canine, Premolar and Molar.
• Incisor is to bite off food, same as canine.