Human nutrition

• Balanced diet needs the right amount of


  CarbohydrateProteinLipid (Fat)VitaminMineralDietary Fibre
• Carbohydrates


  Carbohydrates provide the body with glucose, which is converted to energy used to support bodily functions and physical activity.Carbs are found in pasta potato rice bread etc
• Proteins

  Proteins help with the growth and repair of muscles.Proteins are found in animal products like meat, fish, cheese, milk and eggs. Vegetable sources include soya-bean products, pulses and nuts.
• Lipid (fat)


  This provides slow energy and insulation against the cold as it is stored beneath the skin. 25% of our diet should be fat.Lipids are found in Oils, dairy products, nuts and fish.
• Vitamin


  We have vitamins in very small quantities compared to the first three items. Some common vitamins and their purposes are:A - for visionB - for energy production and stress reductionC - to keep skin healthyD - to help bones and teeth
• Mineral


  We have minerals in very small quantitiesCalcium is a mineral and is found in milk, cheese, egg, etcCalcium helps with growth and for healthy teeth and bones
• Iron

  Iron is needed for the formation of red blood cells. Sources of iron include red meat, green vegetables, eggs, lentils and bread.
• Alimentary Canal


  The alimentary canal is the passage that food takes through our bodies.

  
• Ingestion


  Human ingestion mostly occurs by passage through the mouth - we eat and drink. We chew and swallow or just swallow.
• Digestion

  Digestion occurs through the alimentary canal, from the mouth to the stomach and small intestine. It is the process of breaking down the food, first into smaller pieces, by chewing and then into smaller molecules, with the assistance of enzymes and acids. These are small enough to pass through the wall linings of our digestive tract and pass into the bloodstream. Saliva glands, pancreas, liver and stomach are four organs that produce enzymes and/or acids.
• Absorption


  This is the process of smaller molecules being absorbed into the bloodstream through the walls of the digestive tract; primarily in the small intestine but also in the stomach. To increase the rate of absorption, the wall lining of the small intestine is lined with Villi which increases the surface area allowing more absorption to happen simultaneously. One villi is called a villus
• Assimilation


  This mostly occurs in the liver. After entering the bloodstream, nutrients can be converted into compounds usable by the cells of the body. For example, glucose is stored as glycogen while surplus amino acids are deaminated.
• Digestive enzyme


  We have talked about these before. They all have their own roles in the digestive process. A simple way to think about it is they all help digest a different part of our diet:AmylaseAmylase digests carbohydrates and breaks them down into smaller units and eventually into glucose which is easy to absorb. If people eat too much sugar and carbohydrates, it can cause a deficiency in their amylase.MaltaseMaltase does what amylase does but to sugars, like sucrose, eventually converting them into glucose for absorption.ProteaseProteins require protease and hydrochloric acid to break them down into amino acids which can then be absorbed. Illnesses can occur from not properly breaking down proteins before absorption.LipaseAs Lipids are fats so Lipase is used to break them down into fatty acids and glycerol. Not much digestion of fats occurs in the stomach. It is primarily that of emulsified fats such as in dairy products and egg yolks.BileAs mentioned, Lipase doesn't perform much digestion of lipids - this is where bile comes in. Produced in the liver, it is brown-green, stored in the gall bladder and then secreted into the small intestine. Lipids stick together, which makes them difficult to break down, hence enzymes are unable to react with them. Bile breaks down the groups of lipids so that Lipase can act upon them.