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Isnin, 22 Oktober 2012

NUTRIENTS



Nutrient can be classified into macronutrient and micronutrient.
  • Macronutrients : daily requirement of the nutrient is more than 1 g / day such as carbohydrate, protein and fat.
  • Micronutrients : daily requirement of the nutrient is less than 1 g / day such as itamin and mineral.

Calorie providing nutrient including carbohydrate, protein and fat while non energy providing nutrient include vitamin, mineral and water.

MACRONUTRIENTS
Carbohydrate
The majority of carbohydrate in the diet come from plants, an exception being milk. Carbohydrate are the most importance source of energy in the diet, being the primary energy source for exercising muscles, the brain and central nervous system. Carbohydrates are classified according to their structure into simple or complex carbohydrates.
  • Primary source of energy that provide glucose necessary for glycogen stores.
  • 1 g CHO = 4 kcal
  • CHO should contribute 55% – 70% from total energy intake
  • Recommendations: 6-10 g/kg body weight/day
  • Optimum CHO needs depend on:
  • Total energy
  • Body size
  • Duration, intensity and type of exercise
  • Glycemic Index ( a factor that rank food from 0 to 100 based on the rate at which a food raises the blood glucose level.

Types: sample and complex

Source of Carbohydrate 
Situation
CHO Recommendation
Low intensity @ training program less than 60-90 min/day
5-7 g/kg body weight/day
Training program more than 90-120 min/day
7-10 g/kg body weight/day
Extreme exercise program in between 6-9 hours/day (cross country cyclist
10-12 g/kg body weight/day
CHO loading for endurance & ultra endurance athletes
7-10 g/kg body weight/day
Rapid recovery after training session @ competition multiple day (duration in between session is less than 8 hours)
1 g/kg body weight (the first 30 min after competition) repeat intake of 1 g/kg body weight every 1-2 hours until actual requirement achieved
  •  Simple CHO or Sugars include table sugar, fruits and fruit juices, honey, milk and milk products, cola and breakfast cereals.
  • Complex CHO or starches include rice, bread, pasta,  sweet corn, pulses, potatoes, animal muscle and liver.
  • Carbohydrate recommendation according to situation.

Protein
Protein is needed to build and maintain all the cells in the body, a unique function that no other nutrient can fulfill. Cells are constantly being replaced and an intake of protein is therefore needed on a daily basis. During periods of growth and development there is an additional need for protein hence, children and adolescents will have a proportionally greater requirement than adults.

If carbohydrate and fats are not eaten in sufficient amounts, protein can be used to meet energy demands. Protein cannot be stored for later use like carbohydrate and fat, so if more protein is consumed than the body needs for growth, maintenance and repair, the excess protein is either broken down and used for energy or converted into fat and stored.

Proteins are made up of amino acids linked together in long chains. The body needs 20 different amino acids for its structure and function. Eight of these amino acids are essential, cannot be made by the body and must therefore be provided by the diet.

Functions:
  • Growth and maintenance
  • Structural components
  • Enzymes
  • Hormones
  • Antibodies

Types: Complete and incomplete protein

Requirement:
  • Sedentary adults – 0.8 g/kg bw
  • Active adults – 1.0 g/kg bw
  • Endurance athletes – 1.2 to 1.4 g/kg bw
  • Strength athletes – 1.4 to 1.8 g/kg bw


Sources of protein
  • Animal sources include meat, offal, poultry, fish, shellfish, eggs, milk and milk products. 
  • Vegetable source include beans, peas and lentils, nuts and seeds, tofu, soya and soya milk, textured vegetable protein.

Fat
Dietary fat is a vital nutrient and should be included in the diet. Although a large percentage of the population consumes too much fat, it is both unnecessary and unhealthy to try to exclude fat totally from the diet.
  •  Becomes the primary fuel source during endurance exercise events since the body’s supply of CHO (blood glucose and glycogen) is limited.
  •  1 g fat = 9 kcal
  • Recommendations: Endurance athletes: 20-25% of energy athletes, trying to lose weight : 20% of energy.
  •  Functions: (i) Provides essential fatty acids (linoleic and a-linolenic acid) and fat-soluble vitamins (A, D, E and K); (ii) Parts of structural components of cell membrane, brain,  and  spinal cord tissue; (iii)Body uses fat to store extra energy, which can be used to provide fuel to the working muscle; (iv) Stored as adipose tissue and protects the organs; (v) Satisfy hunger; (vi) Add taste to food
  •  Fat is less efficient than glucose as a source of energy since it requires more oxygen to be used
  •  Classification: visible vs. invisible
Visible fat include butter, margarine, ghee, oils, cream, fat on meat and poultry skin.
Invisible fat include fat present in all but the very lean cuts of meat, whole milk, eggs, meat products, chips, fried food and pastry, salad cream, chocolate and creamy sauces.

The different types of fats in the diets
Dietary fats are made up of different mixtures of fatty acids which may be saturated, monounsaturated or polyunsaturated. Fat containing a high proportion of saturated fatty acids tend to be solid at room temperature while those that contain high proportions of unsaturated fatty acids are usually liquid at room temperature.

Saturated fats e.g. meat and poultry, dairy product.
Monounsaturated fats e.g. olive oil, peanuts, almonds, avocado, pears, rapeseed oil.
Polyunsaturated fats e.g. sunflower, corn, soya bean, cottonseed and safflower oils, only fish and lean meat.

Essential fatty acids which the diet must supply include the omega-6 (linolenic acid) and omega-3 (alpha linolenic acid). The are vital for the development of cell membranes and are involved in the regulation of immune responses and blood clotting.

Cholesterol is an essential part of cell membranes. It is involved in protecting nerve fibres and plays a role in the production of vitamin D. Dietary sources of cholesterol are of animal origin only, namely egg yolks, liver and kidney, fish roes and shellfish. However, the main source of cholesterol in the blood is not directly from diet cholesterol. Cholesterol is made in the liver and high intakes of saturated fats are associated with increased levels of blood cholesterol. A raised level of blood cholesterol is a risk indicator for heart disease.

MICRONUTRIENT
Vitamins and minerals are found naturally in food and are vital in the maintenance of all body functions. They help to maintain health and prevent disease. Different foods supply different vitamins and minerals in varying amounts and therefore a wide range of foods must be includes in a diet if requirements for these essential nutrients are to be met. The Recommended Nutrient Intakes (RNI) Malaysia (NCCFN,2005) provides the amount of nutrient that is sufficient for almost every individual. If an individual consumes the RNI of a nutrient, that person is most unlikely to be deficient in that nutrient.

Vitamins
Vitamins do not provide energy, although some are involved in the release of energy from food. The requirements, functions and food sources of water-soluble and fat-soluble vitamin are as follows:

Water Soluble Vitamins  
Vitamins
Recommendations
Functions
Food Sources
Vitamin B1 (Thiamin)
1.0      1.5 mg
Needed in energy  metabolism and growth. Supports muscle, nerve and cardiovascular function
Fortified cereals, legumes nuts, organ meats, molasses and yeast.
Vitamin B2 (Ribofalbin)
1.2 -1.7 mg
Essential for energy metabolism; growth and tissue repair
Cereals, liver, milk, green leafy vegetable, nuts, whole grains
Vitamin B3 (Niacinamide, Nicotinic acid)
13 – 19 mg
Essential for energy metabolism and nerve function
Lean meat, seafood, milk, yeast, enriched cereals, whole grains
Vitamin B5 (Pantothenic acid)
4 – 7 mg
Essential for energy metabolism and nerve function
Legumes, meat, fish, poultry, wheat germ, whole grains
Vitamin B6 (Pyridoxine acid)
2 mg
Essential for carbohydrate and protein metabolism, immune function, red blood cell production, nerve function.
Oatmeal and cereals, banana, plantain, poultry, liver
Folate (Folic acid, Folacin)
400 µg
Vital for red blood cell synthesis, Essential for the proper division of cell, Maternal folate deficiency may result in an infant with birth defects
Fortified cereals, green leafy vegetables, liver, lentils, black eyed peas, orange juice
Vitamin B12 (Cobalamin)
2 µg
Required for red blood cell production, energy metabolism, and nerve function.
Ground beef, lever. Seafood, milk, cheese
Biotin
30 – 100 µg
Participates in energy metabolism, fatty acid formation and utilization of the B vitamins.
Legumes, whole grains, eggs, organ meats
Vitamin C (Ascorbin acid, Ascorbate)
60 mg
Antioxidant, role in growth and repair of tissue, increases resistance to infection and supports optimal immune function.
Cantaloupe, citrus fruits, strawberries, asparagus, cabbage, tomatoes, broccoli.

FatSoluble Vitamins 
Vitamins
Recommendations
Functions
Food Sources
Vitamin A (Retinol, Retinolds, Carotene)
800 – 1000 µg RE or 5000 IU
Growth and repair of body tissues, immune function, night vision, carotene is the water soluble from with antioxidant properties.
Oatmeal, green and yellow fruits and vegetable, liver, milk
Vitamin D
5 – 10 µg or 200 - 400 µg
Regulates calcium metabolism and bone mineralization.
Fortified milk, egg yolk, salmon and sunlight.
Vitamin E (Alpha, Tocopherol)
8 – 10 mg
Antioxident, protects cell, membranes and enhances, immune function
Fortified cereals, nuts, wheat germ, shrimp and green vegetable.
Vitamin K
60 – 80 µg
Assists in blood clotting and calcium metabolism
Green and leafy vegetable

Minerals
Minerals also do not provide energy, although some are involved in the process of energy production like vitamins.

Minerals can be classified into :
Macro minerals: minerals that required in relatively large amounts. (Celcium, chloride, magnesium, phosphorus, potassium and sodium).
Micro minerals : Minerals that also required but in small amounts that knows as trace elements. (iodine, chromium, copper, fluoride, iron, manganese, molybdenum, selenium and zinc).

Macro Minerals 
Minerals
Functions
Food Sources
Calcium (Ca)
Bone formation, enzyme activation and nerve impulse transmission and muscle contraction.
Milk, cheese, yogurt, dried beans and peas, dark green leafy vegetable, calcium –fortified products.
Fluoride (F)
Helps from bones and teeth
Milk, egg yolk, drinking water and seafood.
Magnesium (Mg)
Protein synthesis, glucose metabolism, smooth muscle contraction, and bone component.
Milk and yogurt, dried beans, nuts, whole grain products, fruits and green leafy vegetable.
Potassium (K)
Ion in intracellular fluid, glucose transport into cell.
Banana, citrus fruit, fresh vegetable, milk, meat and fish.
Sodium (Na)
Ion in extra cellular fluid, nerve impulse conduction, muscle contraction, acid-base balance, blood volume homeostasis.
Salt, canned and processed food, soy sauce.


Micro Minerals

Minerals
Functions
Food Sources
Ferum (Fe)
Hemoglobin and myoglobin formation, electron transfer, essential in oxidative process.
Meat, internal organ, fish, poultry, whole grain products, green leafy vegetable and dried fruits.
Copper (Cu)
Proper use of iron and hemoglobin in body.
Organ meat, meat, fish, nuts, eggs, whole grain bread, bran cereal and banana.
Zinc (Zn)
Cofactor of many enzymes, involved in energy metabolism, protein synthesis, immune function, sensation of taste and smell.
Organ meat, meat, fish, poultry, shellfish, dairy products, whole grain products.
Chromium (Cr)
Enhances insulin function
Organ meat, oyster, cheese, whole grain products, asparagus.
Selenium (Se)
An antioxidant enzyme
Meat, fish, poultry, organ meats, seafood, whole grain and nuts.

Water
Up to 55% to 65% of the adult body is made up of water, equivalent in volume up to 40 liters.
Function and importance of water:
  • Transporting nutrients and oxygen around the body and excrete metabolic waste via kidneys in urine.
  • Body temperature regulation through sweating mechanism.
  • Medium for chemical reaction during digestion
  • To keep joints and eye well lubricated.

Fluids intake and fluids loss
  • Fluids intake: Water, food and drinks.
  • Fluids loss: Urine, breathe, sweat, faces.

General Recommendation for Athletes
It is no coincidence that the diet that is currently being promoted for better health and reduced risk for a long term disease and premature death forms the foundation of the diet for sporting performance. A good diet will contain a wide variety of foods in other to ensure that all the nutrients are present in the required amounts. There are no “good” or “bad’ foods. All foods can fit in to overall diet, but the frequency with which some foods are consumed and infrequency of other being consumed will lead to one diet being good while another will be not so good.

General Eating Rules:
  • Eat 5 – 6 times a day (3 meals plus 2 – 3 snacks) every 3 hours. Do not allow more than 5 hours between meals.
  • Eat within one hour of awakening. Start your day with breakfast.
  • Eat a small snack in the afternoon and before bedtime.
  • Eat before you become hungry.
  • Distribute calories during the day. Eat dinner by 7.30 pm to 8.00 pm and keep supper light.
  • Drink 200 ml of water  10 minutes before each meal. Drink 1.5 liter of water or preferably sports drinks for every hour to training.
  • Take time and sit down in a calm environment to eat. Enjoy your food.
  • Carbohydrate rich foods and drinks should make up at least half of all meals and snacks.
  • Follow the food Pyramid Guide. Keep each meal as close to its recommendation.

 Food Pyramid Guide



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