human nutrition

• Balanced Diet: getting all the right nutrients in correct proportions
• Children Below 12: Require more calcium
• Teenagers: Highest calorie Intake
• Adults: Balanced meal with less calories
• Pregnant Women: more iron, calcium and folic acid
• Males: Generally, require more energy
• Malnutrition: A condition caused by eating an unbalanced diet
• Overnutrition: balanced diet but eating too much of everything
• Undernutrition: having too little food
• Eating foods in incorrect proportions
• Starvation: losing strength & finally dying because of lack of food
• Coronary heart disease: eating too much fats which are rich in saturated fatty acids and cholesterol, may lead to heart attack
• Constipation: lack of roughages in food causes constipation because roughages are indigestible and form bulks
• Friction between bulks and walls of intestine stimulate the peristalsis
• Obesity: Eating too much fats and carbohydrates leads to their storage in the body mainly in the forms of fats and causing an increase in body weight
• Nutrient Uses: Carbohydrates Energy, Fats Source of energy, building materials, energy store, insulation, buoyancy, making hormones
• Proteins Energy, building materials, enzymes, haemoglobin, structural material (muscle), hormones, antibodies
• Vitamin C Protect cells from ageing, production of fibres
• Vitamin D Absorption of calcium
• Calcium Development and maintenance of strong bones and teeth
• Iron Making haemoglobin
• Fiber Provides bulk for faeces, helps peristalsis
• Water Chemical reactions, solvent for transport
• Deficiencies: Vitamin C: Scurvy; loss of teeth, pale skin & sunken eyes
• Vitamin D: Rickets; weak bones and teeth
• Calcium: Rickets; weak bones and teeth, also poor clotting of blood, spasms
• Iron: Anaemia; Fatigue (less iron → less haemoglobin → less oxygen transported → less respiration → less energy)
• Human Alimentary Canal: Ingestion: taking substances (e.g food, drink) into the body through the mouth.
• Egestion: passing out of food that has not been digested, as faeces, through the anus.
• Digestion: the break-down of large, insoluble food molecules into small, water soluble molecules using mechanical and chemical processes
• Mouth: contains teeth used for mechanical digestion, area where food is mixed with salivary amylase & where ingestion takes place
• Salivary glands: produce saliva which contains amylase and helps food slide down oesophagus
• Oesophagus: tube-shaped organ which uses peristalsis to transport food from mouth to stomach
• Stomach: has sphincters to control movement into and also has pepsin (a protease) to break down proteins into peptides and kill bacteria with hydrochloric acid.
• Rectum is where faeces are temporarily stored.
• Liver is the site of breakdown of alcohol and other toxins.
• Gall bladder stores bile from liver.
• Amylase, which breaks down starch into maltose, is produced in the pancreas (but also in the salivary gland).
• Anus is a ring of muscle which controls when faeces is released.
• Prevention of tooth decay involves eating food with low sugar content, regular and effective teeth brushing, and finishing a meal with a crisp vegetable and a glass of water.