1.1Carbohydrates are the body's main source of energy. they
provide energy that is needed for muscle contraction in exercise. Carbohydrates
contain 6 Carbon atoms, 12 Hydrogen atoms and 6 Oxygen atoms. Carbohydrates
come in two different types which are simple and complex carbohydrates.
Simple carbohydrates are carbohydrates that contain one or two units of
sugar. The carbohydrate with one unit of sugar is called a simple sugar known
as a Monosaccharide. It brings together the word Mono = one and saccharide =
sugar hence the word Monosaccharide. These are monosaccharides:
Fructose: It is the sugar found in fruit and honey
Glucose: Also known as blood sugar which is produced when you
digest carbohydrates
Galactose:Comes from the digestion of Lactose. It is known to be
the sweetest of the sugars.
The simple carbohydrates that contain two units or molecules of
sugar are called disaccharides. Three examples of disaccharides are:
Sucrose: This is sugar and it is found naturally in sugar cane or
sugar beets. Sucrose is the combination of fructose and glucose through condensation.
Sucrose provides the body with energy, however over consumption of sucrose can
lead to things such as tooth decay and high blood sugar.
Lactose: Lactose is a non sweet sugar and is found in things such
as milk. This plays a role in the absorption of calcium. In addition to this
Lactose also helps to make bacteria which are needed by the large intestines to
make vitamin K which is vital for the body to prevent blood clotting. Lactose
is made up of a molecule from both Galactose and Glucose and are linked
together by a Beta linkage.
Maltose:
Known as malt sugar and is found in small amounts in germinating seeds and corn
syrup. Maltose in the form of corn syrup is used by food companies to prolong
the shelf life of their food. Maltose is made up of two glucose molecules and
is linked together by an acetal oxygen bridge.
Complex carbohydrates are carbohydrates that have 10 or more
simple sugars which are called polysaccharides. Poly saccharides are broken
down into simple sugars so they can be used as energy later on.
Some examples of polysaccharides are:
Starch: This is mainly found in plants such as seeds, roots and in
fruits. Foods such as potatoes, grains and legumes contain a high level of
starch in them.
Glycogen- This is found in the liver and body muscles. This
converts into glucose and this then helps metabolism and maintaining a good
energy balance.
Foods containing starch is our main source of carbohydrates
because it provides us with energy and we can take in a variety of nutrients
that we need in our diet. Starch contain things such as , Fibre, Calcium, Iron
and B vitamins. Foods such as potatoes, pasta and bread (especially wholemeal)
are the best foods containing carbohydrates and they provide us with a variety
of other nutrients as well. These are:
For every gram of carbohydrates consumed, you take in four
calories. These calories are what provide you with the energy to do everyday
exercise and sport. If someone takes in more calories than what they burn off
in a day then they are more than likely going to be overweight. This doesn’t
mean they will be unhealthy as some overweight people may be body builders or
overweight for the sport they do.
The Recommended Daily Allowance (RDA) for carbohydrates is 130 grams
for both adults and children, which is based on the average minimum amount of
glucose utilized to the brain.(Williams,M.H,2005)
The acceptable macronutrient distribution range (AMDR) suggests
that between 45-65% of our daily consumption should be from carbohydrates. The
RDA for carbohydrates are different for athletes. For athletes doing high
intensity training it is recommended that
> 50% should be consumed. And for
athletes doing endurance training it is > 60%.
This is a protein structure:
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Protein is one of the best sources for Nitrogen and nitrogen is
very important to the human body as it is needed in compounds such as DNA.
The functions of protein fit into an anagram called ‘GETS HAM’.
Growth and repair
Enzymes
Transport
Support
Hormones
Antibodies
Movement
Protein is needed in the body for growth and repairing the body
muscles and tissue. The enzymes are made up of proteins and these enzymes speed
up reactions. They form almost every enzyme in the human body and they get them
to do various different things. These enzymes break down starches and turns
them into disaccharides and monosaccharides. As well as this an enzyme in the
stomach called Pepsin speeds up the process in which proteins are broken down
into amino acids. Protein is used to transport molecules. For example the red
proteins known as haemoglobins transport oxygen around the body. The main
source of protein is in the muscles and these muscles provide support the body
in movement. They form and support contractile muscles and these are known as
actin and myosin which help support muscle contraction. Different hormones in
the body are used to help regulate the body. For example insulin which is
produced in the pancreas and is used control the amount of glucose in the body.
Insulin in the body is important because a lack of it can lead to diabetes. White
blood cells are antibodies in the body and they require protein and these help
immunity in our body in your immune system.
There are two types of protein and these are complete and
incomplete proteins. Complete proteins are foods that contain a sufficient
amount of the nine essential amino acids and incomplete proteins are foods that
do not contain all nine of the essential amino acids.
Examples of complete proteins:
Meat
Fish
Poultry
Cheese
Eggs
Yoghurt
Milk
Examples of incomplete proteins:
Nuts
Beans
Seeds
Peas
Grains
There are two sources of proteins and these
are animal proteins and non-animal proteins.
Animal proteins Non-animal
proteins
Meat Tofu
Meat products nuts
Eggs cereals
Dairy products grains
Fish soya
Poultry pulses
The RDA of protein for adult males is 56g per
day and for adult women it is 46g per day. However this is not the case for
everyone as proteins takes into account your age, weight and the type of
exercise you do.
The
table below shows what you must multiply your weight by.
Grams
of protein/kg body weight
Sedentary 0.8
Strength-trained, maintenance 1.2-1.4
Strength-trained, gain muscle mass 1.6-1.7
Endurance-trained 1.2-1.4
Intermittent, high intensity training 1.4-1.7
Weight-restricted 1.4-1.8
1g of protein= 4 calories.
Fat:
Saturated fat is fully covered or better
still, saturated with hydrogen atoms.
Mono unsaturated and polyunsaturated are
unsaturated because they contain one or more double bonds and as a result of
this, hydrogen bonds get eliminated where there are double bonds.
The main function for fat is to provide
immediate energy to our body. This means that proteins are saved from being
used and enables them to perform the more important task which is building and
repairing muscles and body tissue. When we eat too much fatty food and not use
all the energy that was given by the fatty foods, the fat is stored under our
skin and this is known as subcutaneous fat. Fats also help in making the
material of the cells and tissue in our body. An example of this is the cell
membrane. Furthermore, some fats also supply us with the essential fatty acids
we need in our body. Fats also carry vitamins
A D E and K into our body. Fats help them get absorbed into our
intestines.
There are three types of fat and these are
saturated, mono unsaturated and poly unsaturated.
Saturated fat can be found in animal meats as well as dairy products and
contribute to getting high cholesterol as well as putting on weight. In
addition to this it can contribute to getting a high blood pressure due to the
fatty deposits that will be stored in your body clogging your arteries.
.
Mono-unsaturated and poly-unsaturated fats
however are the healthier fats which you tend to find in olive oil, fish nuts
etc.
Trans fats also known as hydrogenated fats.
Hydrogenated fat is where the hydrogen is added to the un-saturated fat to make
it hard at room temperature. Foods such as margarine, biscuits, processed meals
and cakes are some that have hydrogenated fat in them.
1g of fat =9 calories
RDA for fat:
For the average female it is 70g
For the average male it is 95g
RDA for different sports athletes: this is protein
Sedentary 0.8
Strength-trained, maintenance 1.2-1.4
Strength-trained, gain muscle mass 1.6-1.7
Endurance-trained 1.2-1.4
Intermittent, high intensity training 1.4-1.7
Weight-restricted 1.4-1.8
1.2The RDA of carbohydrates,fat and protein
for different sports athletes would be doing different things and will need
different mounts to support them. For example a marathon runner will need,
compared to the RDA will need more protein compared to an average sedentary
person. For example the average 70kg sedentary male is recommended to have 56g
of protein a day. Whereas the average 70kg marathon runner is recommended to
have between 67-78g. This added protein will repair the damaged muscle tissue. The
RDA doesn’t take into account that runners have rest days and that means they
will take in more protein,carbohydrates and fats depending on whether it’s rest
or running day. The marathon runners intake of carbohydrates will differ
depending on the day.
Eg:rest/recovery day- same amount of proteins
as the average person.
Day before/day of run- more carbohydrates for
energy.
The marathon runner will not have as much fat
in them compared to an average person. They will use have more fat foods such
as jaffa cakes as a form of immediate energy
The RDA of carbohydrates for a weight lifter
will need more protein than an average sedentary person. An average 70kg male
is recommended to have 56g of protein but a weight lifter is recommended to
have between 89-95g to repair damaged muscle tissue. Compared to a normal
person, they would need more carbohydrates to replenish your body as well as
provide lasting energy for weight training. They would use more fat than a
normal person because they use this as a quick source of energy.
A 100m sprinter will not need as much
carbohydrates compared to a normal sedentary person. This is because it is a
short event in which carbohydrates will not be needed as much. Protein will
needed but not as much compared to the marathon runner, or the weight lifter.
The 100m runner will need protein after running and after training(during rest
days) to repair the body. The 100m runner will need more fats than the other
two sports people because fats provide immediate energy and that is what the
100m runner needs. These will be in the form of unsaturated fats.
The three individuals in different sports
require different amounts of each macronutrients because of the difference in
intensity, the time period they are doing it for, how much the body needs to
repair and when the body needs the energy.
1.3 An endogenous energy reserve is an energy
reserve from within. Here are some endogenous energy reserves:
Glycogen is in the form of digested starch
which is stored in the liver which can hold between 141-198g.
=1200-2000 calories
from glycogen
Muscle tissue can store about 141-283g
Broken down into glucose(carbohydrates) which
undergoes glycolysis to form energy known as ATP
Blood glucose/sugar these carry
carbohydrates(energy) into the blood and muscles.
Stored as glycogen
Normal range or transportation of
carbohydrates round the body is 70-120mg/ml.
Fat deposits(adipose tissue)- body tissue
that contains fat(triglycerides) that has been stored there ready to use as
energy. It is the major storage site for fat.
Found:
Between skin and muscles
Around the heart and kidneys
Around the joints
Inside the eye-socket
Functions: Insulates vital organs
Provides energy
Energy balance is the relationship between
the amount of foods with energy in that we take in and the amount of
exercise/work we give out. For example if I take in more energy(from
carbohydrates) than i burn off then this will be stored as fat. 
Positive energy balance is where you
consume more than what you burn off.
Could lead to:
Weight gain
Increase in blood pressure and
cholesterol
Diabetes
.
Negative energy balance is where you
burn more calories and use more energy than what you consume.
Could lead to:Decline in metabolism
Decrease in body weight
Reduction in testosterone levels
Poor concentration and decrease in
physical performance.
Methods to assess energy intake and
expenditure via oxygen intake during exercise:
The metabolic chamber helps researchers to
find out what genes, activity levels and foods affect metabolism. This is a
good way to assess metabolism as this means that researchers could give
specific diets and exercise plans that would more than likely work for that
person the test was done on.
Vo2 max test: this is where someone runs on a
treadmill/bike with an oxygen mask on and they run for 20minutes with each
stage getting harder therefore taking in more oxygen. Vo2 max is recorded on
the final minute of the test when the person is taking the maximum amount of
oxygen they can.
1.3+1.4 Metabolic pathways:
The body converts nutrients to energy both
aerobically(with oxygen) and anaerobically (without oxygen):
Anaerobic(without oxygen)
ATP-PCr- this provides the body with approximately
10seconds of energy. This is usually used by athletes doing short burst things
such as 100m sprinters. It uses the ATP in the muscles that provides 2-3
seconds of energy. It then has to use Creatine phosphate(CP) to reproduce ATP.
Creatine phosphate only lasts between 6-8seconds.
Once fully used anaerobic or aerobic metabolism will step
in to aid the ATP to carry on during exercise.
Anaerobic metabolism is also known as glycolysis. It gets
ATP directly from carbohydrates. Lactic acid is on hand as a secondary source
of energy. This process breaks down glucose without oxygen. This provides us
with enough energy to do high intensity activities for about 3minutes. 800m and
1500m athletes would use this.
Aerobic metabolism is where our body uses oxygen to
change nutrients into ATP. This isn’t as quick as the other two systems but it
lasts much longer and tends to be used in endurance events such as marathons.
2.1Vitamins
Fat soluble
Vitamins A, D, E, and K are needed in small
amounts to keep good health. These are found in fish,liver and dairy products. An
excess amount can lead to toxicity. They are stored in the liver and fatty
tissues for a long period of time. Their functions is to help regulate our
immune system as well as helping our vision in the dark. It also aids bone
growth and tooth development.
Water soluble
Vitamin C
and B vitamins are Water soluble vitamins and their main function is to
help keep nerves and muscle tissue healthy. They also make red blood cells.The
body does not store water solubles. They are found in fruit,vegetables and
grains.
If you have too much than what your body
needs the extra vitamins leave the body via urination. They can be destroyed by
the heat, eg cooking, the heat evaporates some of the water and this is why
grilling or steaming foods is a better alternative. Large amounts of these vitamins can be
harmful.
Phytochemicals
These have no nutrtional value but they have
protective and possibly disease prevention properties. They are known to be non
essential which means the body doesn’t find them necessary to have however they
can help protect humans against disease. Three well known phytochemicals are:
Flavanoids found in fruits.
Lycopene found in tomatoes
Isoflavones found in soy
Macro-minerals
There are seven macro-minerals and these are:
Calcium
Phosphorus
Magnesium
Potassium
Sodium
Chloride
Sulfur
The three main ones are calcium, phosphorus
and magnesium.
Calcium- The most abundant mineral in the
body and represents about 2% of human body weight.
Function:
Bone
formation
Bone activation: nerve impuls transmission
Muscle contraction
Food sources-
Dairy products
Dried beans
Leafy vegetables
Soy milk
Calcium fortified food products
Phosphorus- a non metallic element. Second
most abundant mineral in the body.
Functions:
Bone formation
Acid base balance
Cell membrane structure
B vitamin activation
Organic compound component
Food sources-
All protein products
Meat
Poultry
Fish
Eggs
Milk
Cheese
Whole grain products
Magnesium- fourth most abundant mineral in
the body
Functions:
Protein synthesis
Glucose metabolism
Smooth muscle contraction
Micro-minerals are needed in small quantities
which are less than 100mg per day.
These are 10microminerals and here are some
of the well known ones:
Iron is a metallic element and comes in two
forms, ferrous and ferric.
Functions:
Haemoglobin and myoglobin formation.
Essential in oxidative process
Helps in oxygen metabolism
Food sources: liver
Meat
Fish
Poultry
Dried beans
Peas
Copper is a soft grey metal and is and has a
similar function to iron when it comes to oxygen metabolism.
Functions
Helps in the formation of haemoglobin
Bone formation
Food sources:
Liver
Meat
Fish
Poultry
Nuts
Wholegrain breads
Figs
Zinc is a nutrient that is essential for
humans.
Functions: protein synthesis
Immune function
Food sources:
Meat
Fish
Poultry
Dairy products
Nuts
Functions of:
micronutrients supplementation to enhance
sports performance:
Zinc supplementation enhances immune functions, eg fights of
common cold which prevents exercise to be done.
Free radicals are unstable and often react
quickly with other compounds. When they find a molecule which is stable they
then take their electron and the molecule then turns to a free radical as well.
This has an effect in aging.
Antioxidants travel round the body and help
the free radicals by providing them with another electron and that makes them
stable and prevents tissue damage.
Enzymes are protein and their main function
is to alter the rate of chemical reaction without having assistance from
outside sources and without changing themseleves.
Coenzymes are vitamions and enzymes need
these so they can work properly. These are known as the loose cofactors.
Cofactors- enzymes need these to give them
the push to start them off to in chemical reactions.
2.2A gymnast who has low body fat will need
less vitamins and minerals compared to the RDA recommendations. Despite this they may
still take in a good amount of each micronutrient.
100m sprinters will need more of each
micronutrient compared to the RDA recommendations as they will want to stay
hydrated and keep all the energy inside them. On a hot day they may need even
more than they usually have so they don’t lose micronutrients through sweat. If
they don’t take in these extra micronutrients they could lose up to:
8%speed
10%of strength
20%of cognitive function
Bodybuilders will need a lot more than the
RDA recommendations as they want to gain muscle quickly. They use supplements
that provide them with extra energy, power and strength.
All three sports athletes need different
amounts of micronutrients because their body needs them for different things. If
a gymnast has the same amount as a bodybuilder then they will be taking in
excessive amounts and this will have an effect on them.
Deficiency is where you are not getting
enough of something and as a result could lead to change in your health and
body. For example if you have Iron deficiency you may suffer from fatigue and
be less immune to infections. A decrease
in intellectual performance is another symptom. Excessive iron deficiency may
lead to tachycardia. If you have copper deficency then it will have an effect
on iron absorption which will lead to amenia. Long term consequences of copper
defiency is diarrhoea. Kwashiokor is another one which is protein deficiency
and often occurs in young children and places in LEDC’s (less economically developed
countries).
2.3Female gymnasts have a low calorie intake
and so if they get an injury it would take them ages to recover as they would
want to keep their weight to elite standard.
References
Williams. M.H,Nutrition
for health, fitness & sport seventh edition, 0-07-111240-4,2005,library
of congress cataloguing in publications data
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