The smallest unit of a protein is an amino acid. Proteins are made up of long chains of amino acids which are formed into structures. Amino acids are the smallest unit of a protein and there are 20 amino acids in total. Amino acids can be seen like the English Language, we have 26 letters in the alphabet that can make up millions of words. The 20 amino acids can make up to approximately 50,000 different proteins in the body.
When we eat protein it is digested in the digestive system and then delivered to the liver as individual amino acids. The liver then rebuilds the amino acids into long chains to make up proteins. The proteins that the liver produces depend upon the needs of the body at that time. If we need to replace muscle the liver will produce the relevant proteins to replace the muscle tissue.
Proteins have three specific roles in the body:
- To build structures (structural)
- To perform functions (functional)
- To provide fuel
Protein forms a part of the following structures:
- Muscle (skeletal, smooth and cardiac)
- Bone
- Internal Organs (heart, kidneys, liver etc)
- Connective tissue (tendons and ligaments)
The average daily intake of protein is the UK is 85g for men and 62g for women. The recommended daily amount of protein for healthy adults is 0.8g per kilogram of body weight; therefore a 70kg male will require 56g of protein per day. Protein needs are higher for children, infants and in many athletes.
The amount of protein recommended is dependent upon the activity in which the person is involved.
(Adapted from Franklin, 2000)
Therefore if you had a body builder weighing 90kg they would need to intake 180g of protein per day.
Recently there has been a boom in the use of protein shakes being used as a supplement for athletes during training. They are employed by athletes who want to gain more muscle mass, and to gain more muscle mass you need more protein on a daily basis. Protein shakes are usually high in protein because it contains high levels of the three amino acids that are broken down the most during training. Protein shakes contain powerful supplies of amino acids and are quick and convenient to use. However, there are several issues to consider:
- The human body has evolved to gain its protein from natural sources than processed sources (meats rather than powders)
- They often contain additives such as sweeteners, sugars and colourings
- The process of drying the proteins into powder from damages the structure of the amino acids, making them unusable by the body
- They are often very expensive
Fats
Fats are often perceived as being bad or a part of the diet to be avoided. In fact, fats are vital to health and perform many important functions in the body. The intake of certain fats does need to be minimised and excess consumption of fats will lead to health problems.
The functions of fats are as follows:
- Formation of cell membranes
- Formation of the myelin sheath which coats the nerves
- A component of the brain and nervous system
- Protection of internal systems (brain, kidneys, liver etc)
- Production of hormones (oestrogen and testosterone)
- Transportation and storage of vitamins A, D, E and K
- Constant energy source
- Store of energy
Fats and oils belong to a family called ‘lipids’ which perform a variety of different roles in the body. Predominantly fats supply energy for everyday activities and movement. They are described as being ‘energy-dense’ because they contain the most energy out of fats, carbohydrates and proteins. 1g of fat provides 9kcals:
The smallest unit of fat is called a ‘fatty acid’. There are different types of fatty acids present in the foods we eat. In particular, a fatty acid can be saturated or unsaturated. Saturated fats have always been given a bad name until recently when people realised that it is an important part of the diet. Due to their stable nature they always retain their structure. This is important because when they enter the cells, they recognise them and know what to do with them. Saturated fats are always stored as fat in fat cells. Naturally, occurring unsaturated fats, such as olive oil, have very beneficial effects when they are stored in fat cells. They can improve circulation, lower cholesterol levels and improve the health of skin, hair and nails.
The problem comes when unsaturated fats are heated because they change their structure and start to look like saturated fats. They become ‘hydrogenated’ or altered structurally and when they enter the body they are accepted into the fat cells because they look like saturated fats. Once inside the fat cells they start to cause damage to the cell and stop positive reactions occurring. The two most dangerous types of fats are:
- Hydrogenated Vegetable Oil
- Trans Fats
These have been linked to heart disease and cancer and are present in processed and deep fried foods.
The body can make all the fatty acids it needs except for two, the essential fatty acids (EFA’s), which must be supplied in the diet. These fatty acids are omega 3 and omega 6. sources of omega 3 and 6 are as follows:
Omega 3 fatty acids:
- Oily Fish (salmon, mackerel, herring etc)
- Flax Oils
- Walnuts
- Soya Beans
Omega 6 fatty acids:
- Sunflower Oil
- Pumpkin Seeds
- Sesame Seeds
- Safflower Oil
Research into omega 3 has shown that eating oily fish protects against heart disease. This is because the omega 3 acids may prevent the formation of blood clots on the artery walls and the levels of fats circulating the blood stream. The essential fatty acids are also thought to improve the function on the brain and promote learning as well as being beneficial for arthritics because they reduce swelling to the joints.
Fat intake should make up no more that 30 percent of the daily intake of calories, and only 10 percent of that should be kilocalories should come from saturated fats. There are many health problems related to eating an excess of fat, especially saturated fats. These problems include:
- Obesity
- High Blood Pressure
- Coronary Heart Disease
As fats provide just over twice the amount of energy per gram as carbohydrates sports performers may benefit from the energy burst that fats give them. If the fat is consumed a few minutes before their event the performer will receive a sudden burst of energy. However a diet high in fat can make over-consumption more likely. It is thought that excess dietary fat may be converted into body fat much more easily than either carbohydrate or protein.
Research shows that more people are more obese people today than ever before. Obese people are more likely to suffer from a range of illnesses including coronary heart disease, diabetes, gallstones, arthritis, high blood pressure and some types of cancer. However, most of the health problems associated with obesity are all removed once the extra weight is lost.
Vitamins and Minerals
Vitamins are organic substances that the body requires in small amounts. The body is incapable of making vitamins for its overall needs, so they must be supplied regularly by the diet. Some examples of Vitamins are Vitamin A, B1, B2, B3, B5, B6, C, D, and E.
There are several minerals required to maintain a healthy body. Some are needed in moderate amounts others only in very small amounts; the latter are referred to as trace minerals. Some examples of Minerals are: Calcium, Magnesium, Phosphorus, Potassium, Sodium, Copper, Iron, Selenium, and Zinc.
Water
One of the major chemicals essential to life is water although it has no nutritional value in terms of energy. Water is used by the body to transport other chemicals. It also plays a major role in maintaining the body at a constant temperature. About 2.5 litres a day are needed to maintain normal functions in adults. This amount depends heavily on environmental conditions and on the amount of energy expenditure. In the heat a greater amount of water is needed, and exercise requires an increased intake of water due to the loss of fluid via sweating. Only half of the body’s water requirement comes in the form of liquid. The other half is supplied from food (especially fruit and vegetables) and metabolic reactions (the breakdown of food results in the formation of carbon dioxide and water).
The Benefits of Healthy Eating
Athletes should aim to optimise their glycogen stores before exercise ("carbo-loading") as well as eating during exercise. This maximises the glucose availability in your blood which can be used by your working muscles. As a general guideline your intake of glucose should be between 30-60g per hour during a prolonged event. These glucose requirements can be met simultaneously with fluid needs by consuming glucose-electrolyte drinks.
Remember glucose and fluid must be ingested well in advance of fatigue (approx. 30mins). Therefore, as a general rule, start drinking early and continue drinking throughout the event.
