In order for our bodies to stay healthy there are seven key nutrients which we should involve in our every day diet. Carbohydrates Carbohydrates (CHO) are important to our bodies as they give us energy for our working muscles. They are named carbohydrates due to their characteristic content of carbon, hydrogen and oxygen with the general formula of Cx(H2O)6. The liver turns carbohydrates into glucose and this is used by the body for energy. Carbohydrates are found in starchy foods such as pasta, bread, rice and cereal; these are known as complex carbohydrates.
CHO can also be found in sugary foods such as confectionary which includes food stuffs such as lollipops, sweets and chocolate; these are known as simple carbohydrates. Simple CHOs are easily digested by the body which gives us a very fast energy release, which can be known as a 'hit'. This is because straight after digestion it appears in the circulatory system in the form of glucose, it goes straight to the cells to be used as energy More Help. As the molecules are small they can be metabolized quickly therefore producing the quickest form of energy.
Complex CHOs are larger molecules and they can only be broken down by using the enzyme amylase, which is found in the salivary glands and the pancreas. This means that it takes longer for all the complex CHOs to be metabolized so energy is released slowly and lasts for longer periods of time. Carbohydrates have different structures depending on if it is a monosaccharide, disaccharide or a polysaccharide. (A) Monosaccharides They are a group of sweet, soluble, crystalline molecules which are the simplest forms of carbohydrates and the basic building blocks for other saccharides.
They are monomers and are considered monosaccharides if they have about 5 or 6 carbons within them. Once 2 monomers have been linked together it is then called a disaccharide. As a result of the reaction a Glycosidic bond is formed, at the point where the molecules have joined together. A Glycosidic bond is formed through the oxygen of one molecule and the carbon of another; if this formation is repeated more than 3 times the chain of molecules are called a polysaccharide. (A) Polysaccharides These are very complex carbohydrates and are made up of many simple sugars.
They consist of 1000s of repeating units of glucose and make up a very large molecule; because of their size they can store large quantities of glucose known as glycogen. This glycogen can be broken back down when the muscles need more energy, normally during exercise. This process is called glycogenolysis, in which the repeating units of glucose are broken down in to individual simple sugars which can travel in the blood to the muscles that require more energy. The diagram below shows the polysaccharide, glycogen. (A) The bonds in a polysaccharide are also glycosidic and formed by a condensation reaction.
In order for glycogenolysis to take place these bonds need to be broken; to do this the reverse of a condensation reaction has to take place, known as hydrolysis. The enzyme amylase weakens the bond allowing for the insertion of the water molecule and for two monomers to be produced. (A) Carbohydrates are very important in our diet as they are the main source of energy. It is particularly vital for athletes to have a high carbohydrate diet as it will help increase their performance. The amount of carbohydrates they need in their diet however, is dependant upon the build and sport they compete in.
If an endurance athlete increases his dietary intake a few days before a performance his glycogen levels are enhanced which allows them to deliver sufficient amounts of glucose (energy) to the muscles during the performance. If an athlete ingests carbohydrates 3-4 hours before a competition then it increases the liver and muscles glycogen, again this raises the level of endurance and performance. (B) Dieticians recommend that the average person's diet should be made up of about 47% carbohydrates, with the majority of these coming from starchy foods (complex CHOs).
However, an athlete should increase the amount of calories coming from carbohydrates in their diet to about 55-65% according to some sport nutrition experts. Having this much in their diet allows them to have large storages of glycogen which allows them to exercise at their optimum level and meet the muscles energy requirements. Energy requirements are dependant upon the sport the athlete is participating in. For example, short-burst, high intensity sports such as sprinting, jumping and pole vaulting only use 100% carbohydrates as their main energy source.
For longer events such as, long distance, the body uses carbohydrates and fats are used as fuel sources. (B) During endurance events such as the marathon it is important to keep glucose levels high as that the athlete does not become fatigued. In order to do this it is recommended that every hour that they are exercising they should be receiving 50 - 60g of carbohydrates. However, instead of using starchy CHOs, sugary ones will also do the trick, as they are faster releasing and can be given in the form a fruit drink.
This is why during the London marathon there are regular intervals of drink stations where the runners can grab a drink usually made up of one part fruit juice to one part water. (B) Fats Fats are also another source of energy; these however, release energy much slower than carbohydrates. We tend to use fat as a reserve energy store after burning all of our carbohydrates. Fat also helps our body in other ways such as protecting our vital organs, regulating our body temperature and keeping our skin in a good condition. The majority of fat sources in foods come from things such as, butters, creams, vegetable oils, nuts and flesh of animals.
