Download Nutrition RPL Course

NATURAL HEALTH TEACHING SERVICES
Core Course : Basic Nutrition
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1. Introduction
4.4 Genetically Modified Food
2. Goal
4.5 Food preparation
3. Objectives
5. Digestive System
4. Diet
5.1 Digestive Process
5.1.1 The Oral Cavity
5.1.2 Stomach
5.1.3 Small Intestine
5.1.4 Large Intestine
5.1.5 Rectum and Anal Canal
4.1 Food Groups
4.1.1 Protein
4.1.2 Fat
4.1.3 Carbohydrate
4.1.3.1 Glycaemic Index and Glycaemic Load
4.2 Other Essential Nutrients
4.2.1 Fibre
4.2.2 Water
4.2.3 Vitamins
4.2.4 Minerals
5.2 Organs Associated with the Digestive System
5.2.1 Pancreas
5.2.2 Liver
5.3 The Effect of Stress on Digestion
6. Summary
4.3 Organic Food
7. Bibliography
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1. Introduction
Nutrition is the digestion and absorption of the substances (nutrients) that promote body functions. Nutrition is linked to health and
well-being, because the quality and variety of food we eat determines the quantity and quality of nutrients our bodies receive.
There are two aspects to nutrition:
 Diet, which is the selection of food we eat.
 The physical processes of digestion in the digestive system.
2. Goal
This short course is a general introduction to nutrition and the digestive process. It provides an overview of the various food groups
and other nutrients, and how the digestive tract works.
3. Objectives
At the
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end of this course you will be able to
list the various food groups
describe the importance of each food group for the body
list which types of foods fall into each food group
explain the terms glycaemic index and glycaemic load
outline the importance to the body of
o fibre
o water
o vitamins
o minerals
explain the term organic food
outline the significance of GM food
list the organs and associated organs of the digestive system
describe the functions of each organ that is part of the digestive system, and other associated organs
explain in general terms the digestive process
describe the effects of stress on digestion
4. Diet
To understand a balanced diet, you need to know about nutrients, which are the substances in food that enable our bodies to
function. Determining and understanding what could be called a balance of all necessary nutrients is not a simple exercise. In part
this is because we each have different needs, but it’s also because the way food is produced can increase or decrease the quantity
and the quality of the nutrients it contains. However, there are some broad guidelines that are a starting place for determining our
particular nutritional needs.
The various food groups are
 proteins
 carbohydrates
 fats
The generally accepted norm for mixing the three food types is 70% carbohydrate, 15% protein, and 15% fat. Other essential
nutrients are vitamins and minerals, fibre and water.
 Vitamins and minerals are needed for digestion, absorption and conversion of food in our bodies, but they don’t constitute
specific food groups as they’re found across all the other food groups.
 Fibre is also not a food group as it’s found in the other food groups. Fibre is essential for good elimination of waste products
and toxins.
 Water is also not a food, but is essential for hydration, lubrication, and elimination.
4.1. Food groups:
4.1.1 Protein
Protein is made up of 20 amino acids, which are the building blocks of the body. Amino acids enable growth and repair of
body tissue, the manufacture of hormones, enzymes, antibodies, and neurotransmitters, and they help transport substances
around the body. The quality and the quantity of protein eaten influences health.
The best sources of protein are eggs, quinoa, soya, meat, fish, beans and lentils. Animal protein includes saturated fats and
is best eaten only 3 times a week. A lot of animal protein in the diet has a negative effect on health.
Vegetable protein contains beneficial complex carbohydrates and is less-acid forming than meat. Seed foods such as runner
beans, peas, corn, and broccoli, are high in protein content and they reduce acidity.
Proteins are essential components of all organisms. Most of the tasks performed by living cells require proteins. In humans,
proteins are the structural components of muscle, connective tissue, nails, and hair. Proteins are also involved in metabolic
regulation, transport, defense, and catalysis.
4.1.2
There
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Fat
are two kinds of fats:
saturated (hard) fat
unsaturated (soft) fat
The main sources of saturated fats are dairy products and meat. These are not essential in the human diet and should be
eaten in small quantities, or not at all.
There are two kinds of unsaturated fats:
 monounsaturated fats
 polyunsaturated fats
Olive oil is the most common source of monounsaturated fats. Nuts, seeds, and fish are good sources of polyunsaturated
fats. The polyunsaturated oils Omega 3 and Omega 6 are called essential oils because they are not manufactured by the
body. They must be obtained from the food we eat. They are necessary for the good health of the brain and nervous system,
immune system, cardiovascular system, and skin. They are easily destroyed by heat and exposure to oxygen so must be
obtained from fresh sources.
The processing of foods has created a third group of fats called trans-fats which are the result of chemical changes in foods.
They can be formed by high heat (heated oils) and hydrogenation (solidifying) of liquid polyunsaturated fats. An example of
hydrogenation is margarine. Trans-fats are best avoided as the body does not recognise them as food and cannot digest
them.
4.1.3 Carbohydrate
Carbohydrates are the main source of energy for the body. There are two types of carbohydrate:
 fast release
 slow release
Fast release carbohydrates are sugars - including sweets, honey and malt - and most refined foods such as white rice and
white flour.
Slow release carbohydrates are whole grains (e.g. brown rice), vegetables, and fresh fruit. These contain complex
carbohydrates which, in the digestive process, take longer to convert to glucose. They often have a high level of fibre which
also slows down the release of glucose into the bloodstream. This provides sustained energy levels which are better for daily
activity and health than the energy spikes produced by fast-release (simple) carbohydrates. These give a sudden energy
spurt followed by a drop in energy.
Refined foods such as white flour, white sugar, and white rice, have lost most of their nutritional value in the refining
process. They don’t supply the body with vitamins and minerals necessary for proper digestion and good health. It is best not
to eat them.
Slow release carbohydrates should make up two-thirds of our diet (70% of calories). This means a healthy diet contains
large amounts of dark green, leafy and root vegetables, as well as fresh fruit. Three servings per day of each of theses
groups is recommended. In addition we should eat four servings of whole grains. Recommended whole grains are rice, millet,
rye, oats, whole-wheat, corn, quinoa, whole-grain breads, pasta and pulses.
4.1.3.1 Glycaemic Index (GI) and Glycaemic Load (GL)
The glycaemic index is used to measure the level at which different foods cause blood sugar levels to rise. It’s a scale
that compares the levels to which different foods raise blood sugar with the level to which pure glucose raises it.
Glucose is used as the comparative measure because it’s the carbohydrate that’s released in the blood the most
rapidly. It requires no digestion because the body is able to use it in its natural form. A high GI rating indicates food
to avoid. The lower the rating the better the quality of the food.
Low GI foods are called slow-releasing carbohydrates as they take longer to digest. This is because their chemical
structure is more complex than that of the fast-release foods.
Fast-release foods are various forms of sugars and refined carbohydrates such as white bread, white rice, puffed rice.
Slow-release foods are unprocessed, and high in fibre. These include fresh vegetables, unhusked rice, and oats. The
longer a carbohydrate is cooked, the higher its GI rating as the cooking process breaks down the carbohydrates – it
‘pre-digests’ them.
The glycaemic index does not indicate nutritional value. Nor does it indicate the effect that eating a food will have on
weight management. A different measure for this has been developed i.e. the glycaemic load.
The glycaemic load is used to measure how much weight one will gain from eating a particular food. It is calculated by
multiplying the quantity of carbohydrate in a food by its glycaemic index (quality). Carbohydrates with a low
glycaemic load are both nutritious and good for effective weight management.
4.2. Other essential nutrients
4.2.1 Fibre
In the digestive tract, fibre absorbs water, making the digested food content bulkier and more easily passed through the
body. Good sources of fibre are whole grains, fruit, vegetables, nuts, seeds, lentils, and beans. A selection of these should be
eaten daily. Cereals are good for preventing constipation and putrefaction (rotting) of food. Many digestive problems are
caused by sluggish bowels that do not clear properly.
Population groups with diets high in fibre have the lowest rate of bowel diseases such as diverticulitis, colitis, appendicitis,
and cancer because regular bowel movements prevent putrefaction of faeces which happens when the colon is not cleared
properly. Raw food contains more fibre than cooked food, and overcooking food reduces the fibre content even more. Raw
and lightly cooked foods are best.
4.2.2 Water
Two-thirds of the human body is water. Drinking water helps establish a good alkaline balance in the body. Maintaining the
water level of the body is a vital part of good health management. We lose about 1.5 litres of water each day through the
lungs, skin, and colon, as well as the kidneys and bladder. When glucose is used for energy, water is a by-product. This
produces about a third of a litre per day. A diet high in vegetables and fruit also provides water.
Our daily intake of water should be a bit more than a litre. A good personal average can be calculated as 30ml per kilogram
of body weight. More water is required after exercise and in hot weather, or any other time when there is increased sweating
or urination.
Alcohol, tea (including green tea) and coffee contain caffeine and tannin which are diuretics (cause water loss), so are not
good sources of fluid. Some herbal teas can be drunk as part of the daily water intake. Rooibos is caffeine free, but others
are diuretic.
4.2.3 Vitamins
Vitamins are organic chemical compounds needed by the body for normal growth, metabolism (creating energy at cellular
level), and general good health. Vitamins are needed to make enzymes and hormones, the body’s own chemicals which are
required for the chemical reactions that keep us alive, to take place. Although only small quantities are necessary, they are
essential in the diet as they are not manufactured by the body. They are not food as they don’t directly nourish the body or
provide energy. But without them the body would not be able to create nourishment and energy from the food we eat.
There are two kinds of vitamins:
 fat-soluble
 water-soluble
Fat-soluble vitamins are stored in the body, mostly in fatty tissues and in the liver. These are vitamins A, D, E, and K.
Because the body can keep a store of them, we don’t need to eat them every day, and eating too much of them can cause
problems as they build up in the tissues.
Water-soluble vitamins cannot be stored in the body for very long as water in the body is continually being excreted and
replenished. As these vitamins are dissolved in water, they are excreted along with the water. We therefore we need a daily
supply of water-soluble vitamins, and it’s difficult to overdose on them. These are vitamins B1 to B12, and C.
The traditional dosage of vitamins is called RDA (Recommended Daily Allowance). This is the minimum daily requirement for
the prevention of disease in healthy people. Many nutritionists and researchers advise much higher amounts for optimal
health and for the prevention of health problems such as heart disease. As modern farming methods and distribution
processes reduce the vitamin content of food, more people take vitamin and mineral supplements. Soil quality also affects
the vitamin and mineral content of food.
4.2.4 Minerals
Minerals are inorganic chemical elements required by the body for growth, metabolism, and the manufacture of enzymes and
hormones. Like vitamins they are required in small amounts, and must be obtained from food as the body cannot make
them. Inorganic elements required in smaller amounts than this are called trace elements or trace minerals. These trace
elements are just as essential for health as minerals.
Required minerals are: Calcium, Chloride, Fluoride, Magnesium, Phosphorus, Potassium, Sodium, and Sulphur. Sulphur is so
prevalent in the food we eat that deficiency is unlikely. These minerals are found in all the cells of the body and are
sometimes called cell salts. When taken as supplements they are usually called tissue salts.
4.3 Organic food
The trend towards organic food comes from the awareness that modern farming methods produce food low in nutrients and high in
pollutants. Commercial farming often denudes the soil of nutrients, and thus also the food grown in it. To overcome this, chemical
fertilisers are used, which, in addition to pesticides used to protect crops against insect damage, are absorbed by plants. There is
growing concern that the consumption of these chemicals over a life-time is what lies behind the increase in chronic and
degenerative illnesses in society today. This has given rise to the organic movement which supports farming methods with minimal
or no use of chemical fertilisers and pesticides.
4.4. Genetically Modified (GM) foods
Genetic modification (GM) is the process of changing the genetic makeup of organisms such as animals, plants, or bacteria.
Genetically modified or genetically engineered products contain genes from different organisms, e.g. genes from animals put into in
plants. Another term used for such products is “transgenic”. GM products include medicines and vaccines, foods and food
ingredients, animal feeds, and fibres.
Technologies for genetically modifying foods are believed by some to offer solutions to some of the current global challenges.
However, all new technologies pose a degree of risk. Some are known and some are unknown. In the case of GM foods and crops
there is opposition to them around issues of human and environmental safety, labelling and consumer choice, intellectual property
rights, ethics, food security, poverty reduction, and environmental conservation.
The benefits of GM Products are primarily an increased yield due to greater tolerance of factors that would otherwise negatively
impact on crops, such as frost, pests, disease, and herbicides. Crops may also mature more quickly. Animals improve their
resistance to disease, have greater productivity, and yield enhanced products. It is argued that GM products conserve soil, water
and energy, and improve natural waste management. GM processing can produce “friendly” bio-herbicides and bio-insecticides.
Overall they are seen as a means of providing food security, especially in poor countries.
The arguments against GM products focus on the unknown and potentially long-term implications for human health and the
environment, and especially the unknown effects on microbial and other organisms, insects, and loss of biodiversity. There are also
controversies around economic domination, exploitation, the ethics of mixing genes across species, labeling, and mixing GM food
with non-GM food.
4.5 Food preparation
The way food is prepared and cooked affects its nutritional value. Any form of heating reduces the vitamin content of food. The
longer the food is cooked, and the higher the temperature used, the more vitamins are destroyed. Frying is particularly bad as the
temperature is so high that many nutrients are killed. Not only is the food affected but also the oil. The high temperature causes
chemical changes to the oil that renders it dangerous to human health. Heating the same oil again is even more detrimental to
health.
Microwave cooking not only reduces the vitamin value in food, but also destroys the enzymes that help the digestive processes, so
our bodies are less able to absorb nutrients from this food.
The least detrimental forms of cooking food are
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steaming, where nutrients are not leeched into the cooking water
slow cooking, which keeps the cooking temperature low
grilling in which the fat content is drained off
The more time food spends being transported from one place to another, and sitting on a shelf, the more nutrients are lost through
oxidation (exposure to oxygen). When foods are cut, peeled or chopped, oxidation speeds up. This means that conveniencepackaged “fresh” fruit and vegetables have reduced nutritional value. Some producers and traders try to keep raw foods looking
good by irradiating them with low voltage x-rays. This slows the ripening process and lengthens their shelf life. It also sterilises the
food but in the process it destroys some of its vitamin content. Fresh raw food is best, and locally produced foods are the most
nutritious.
5. The digestive system
The digestive system consists of all the parts of the body associated with nutrition. The processes involved are
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ingestion (taking in food and liquid through the mouth)
digestion (processing by mechanical and chemical means)
absorption (of simple dissolved substances into the bloodstream)
assimilation (usage of absorbed nutrients by the body’s cells)
Mechanical digestion is the breaking down of food by chewing in the mouth and the churning action of the stomach. Chemical
digestion is effected by the enzymes in saliva secreted in the mouth and the secretions of the stomach and intestines. Proteins are
broken down into amino acids. Carbohydrates break down into glucose. Fats are broken down into fatty acids.
The alimentary canal (also called the gastro-intestinal tract or GIT) is a continuous tube about 9m long. Most of its length is coiled
up in the abdominal cavity. The GIT consists of
 the mouth
 the pharynx
 oesophagus
 stomach
 small intestine – duodenum, jejunum, ileum
 large intestine – caecum, appendix, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anus.
Associated organs with ducts that lead into the GIT are the pancreas and the liver via the gallbladder.
The main function of the GIT and the associated organs is the preparation of food for absorption by the cells lining the tract and the
surrounding capillaries.
5.1 The digestive process
Digestion is facilitated by
 eating meals at regular times
 eating in proper quantities
 chewing food well.
Breakfast is important as it literally breaks the fast between the evening and morning meals. Ideally this ‘fast’ should be about 1012 hours as this is the time the body completes many of its processes, and repairs tissues
5.1.2 The oral cavity
The mouth, teeth and tongue pulverise the food with the aid of saliva secreted by the salivary glands and the secretions of
thousands of tiny mucous glands in the lining of the oral and pharyngeal cavities. Food is broken down by the teeth, moved
around the mouth by the tongue and cheek muscles, mixed with saliva and formed into a soft mass (bolus) for swallowing.
The tongue pushes the bolus into the pharynx. A reflex action stimulates the pharynx muscles to contract and push the bolus
into the oesophagus. The act of swallowing stimulates peristaltic action in the oesophagus. This action pushes the bolus
through the oesophagus into the stomach.
5.1.3 The stomach
Further mechanical and chemical digestion takes place in the stomach and small intestine. After a meal, food collects in the
stomach in layers. The build-up of gastric secretions (hydrochloric acid) takes about an hour to reach maximum level, during
which the alkaline saliva continues to act on the food, breaking down carbohydrates.
The 3 layers of muscle in the stomach wall create a churning movement as each layer of muscle runs in a different direction.
The churning breaks down the bolus as well as mixing it with the secretions of the stomach – hydrochloric acid, pepsinogens
(which become pepsins to break down proteins), intrinsic factor (necessary for the absorption of vitamin B12), and mucous
which protects the stomach wall from injury. Peristalsis pushes the churned up food, called chime, towards the pyloric
sphincter (the valve between the stomach and small intestine).
A carbohydrate meal takes about 2-3 hours to leave the stomach, a protein meal takes longer, and a fatty meal takes the
longest.
The functions of the stomach:
 temporary storage while the digestive enzymes act
 chemical digestion
 mechanical digestion
 limited absorption of water, alcohol, some fat-soluble drugs
 dissolving of iron from the food, for absorption in the small intestine
 production of intrinsic factor necessary for the absorption of vitamin B12 in the small intestine
 provides some defence against microbial organisms.
5.1.4 The small intestine
The small intestine lies in the abdominal cavity, surrounded by the large intestine. It is about 5 metres long and has 3
undivided sections. The first section is the duodenum which is about 25cm long and separated from the stomach by the
pyloric sphincter (valve). The common bile duct enters this part of the intestine, feeding bile from the gall bladder and the
digestive juices from the pancreas into the chime as it passes through this section of the intestine.
The central part of the intestine is called the jejunum and is about 2 metres long. The last part is called the ileum. It is about
3metres long and ends at the ileocaecal sphincter which controls the flow of chime from the ileum into the caecum, which is
the first part of the large intestine.
The functions of the small intestine are:
 movement of the chime by peristalsis
 secretion of intestinal juice (digestive enzymes)
 completion of chemical digestion of carbohydrates, protein and fats
 protection against infection by microbes by the lymph follicles
 secretion of the hormones and enzymes
 absorption of nutrients
Most absorption of nutrients is done through the lining of the small intestine into the capillaries serving it. Only water,
minerals, and some vitamins are absorbed from the large intestine. Once absorbed, the nutrients are transported by the
blood to the liver where many of them are altered and stored, or metered out into the general circulation via the hepatic
veins. Nutrients are retrieved by the body’s cells in the capillary circulation.
5.1.5 The large intestine
This is also called the colon, and is about 1.5 metres long and is wider than the small intestine. The ileocaecal valve lies
between the small and large intestines and controls the flow between them. Its functions are to keep in the contents of the
small intestine long enough for the digestive process to be completed, and to prevent the bacteria in the large intestine from
entering the small intestine. It also prevents backward flow form the large to the small intestine.
The first part of the large intestine is a short dilated section called the caecum which lies near the pelvic bone. The appendix
opens into it. The next section, called the ascending colon runs up the body between the caecum and the liver where it
curves to the left and becomes the transverse colon. The transverse colon runs across the body from under the liver and
below the stomach to the spleen where it bends downwards to form the descending colon. The descending colon passed
down the left side of the abdominal cavity and then curves towards the midline. In the pelvic area it is called the sigmoid
colon. The sigmoid colon lies in an S-shaped curve in the pelvic area, and opens into the rectum.
The contents of the ileum are fluid when they pass into the caecum. The faeces (contents of the colon) become semi-solid as
water is reabsorbed into the body as they move through the colon. If insufficient water has been drunk, the amount of water
reabsorbed will increase, leaving the faecal matter very dry and difficult to pass through the colon, causing constipation.
Mineral salts, vitamins, bile constituents, and some drugs are absorbed into the blood through the capillaries surrounding the
colon. Microbes in the colon synthesize vitamin K and folic acid. Gases in the colon consist of the constituents of the air
swallowed with food and drink (mostly nitrogen). Gas production can also be the result of stress as it interferes with the
digestive processes, and also fermentation of unabsorbed nutrients, especially carbohydrates.
The peristaltic movement in the transverse colon pushes faecal matter into the descending and sigmoid colons. This occurs at
long intervals, usually stimulated by the entry of food into the stomach, so ideally, we should defecate after each meal.
Faecal matter entering the sigmoid colon stimulates the need to defecate. Repeated repression of this impulse may cause
habitual constipation. Mucous provides lubrication, and fibre in the diet gives the bulk needed to stimulate defecation.
5.1.6 The rectum and anal canal
The rectum is a slightly dilated area of the colon, and is about 13cm long. It terminates in the anal canal which is about
3.8cm long in adults, and opens to the exterior through the anus. The anus is controlled by 2 sphincter muscles. The inner
one is under the control of the autonomic nervous system (involuntary action). The outer one is under voluntary muscle
control. If the urge to defecate is habitually ignored, constipation will result.
5.2 Organs associated with the digestive system
5.2.1 The pancreas
This gland lies in the abdominal cavity behind the stomach between the duodenum and the spleen. It produces 2 different
kinds of substances:
 Pancreatic juice which contains enzymes that digest carbohydrates, proteins and fats. These enzymes are secreted
into the pancreatic duct which takes them to the duodenum.
 The hormones insulin and glucagon. These are produced by specialised cells called the Islets of Langehans. They are
secreted directly into the blood where they control the blood glucose (sugar) level.
5.2.2 The Liver
The liver is in the upper abdominal cavity on the right side under the diaphragm. It is connected to the digestive system
through the gall bladder which stores the bile produced by the liver. The liver has many functions:
 Carbohydrate metabolism: It converts glucose to glycogen for storage and back to glucose when we need extra energy.
This is an important part of the regulation of blood glucose levels.
 Protein metabolism: It breaks down amino acids (protein building blocks) not needed by the body into urea which is
excreted in the urine. Proteins from worn out cells are broken down into uric acid which is also excreted in the urine. It
also builds new proteins from amino acids, and makes blood proteins and blood clotting agents.
 Detoxifying: it breaks down drugs (including alcohol) and toxic substances.
 Inactivates hormones the body is not using at the time.
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Makes vitamin A from carotene in food.
Produces heat through all its chemical processing. This is the main source of body heat.
Secretion of bile: it makes bile from the blood. Bile is stored in the gall bladder from where it is secreted into the
duodenum to help digest fats.
Storage of fat soluble vitamins A, D, E, K, some water soluble B vitamins, and the minerals iron, and copper.
Fat metabolism: stored fat can be converted to a form in which it can be used to provide energy.
5.3 The effect of stress on digestion
Stress interferes with the digestive process, so it’s important to eat slowly in a pleasant, calm atmosphere. The body interprets the
signs of stress as danger signals and take us into ‘flight or fight’ mode. This primitive response prepares the body to literally fight or
run for our lives. This level of physical activity means the muscles need extra energy. The cells make energy from oxygen which is
transported to them by the blood, so when we are under stress they need access to more blood so they can get more oxygen.
When we’re in fight-or-flight mode, the body increases production of adrenalin. One of the effects of adrenalin is to expand the
blood vessels so more blood can be carried faster to the muscles. This extra blood has to come from somewhere, and as the body
presumes we will not be eating while fighting or running, it takes it from the biggest user of blood - the digestive system. As a result
the digestive system is in ‘slow mode’ while the heart, circulation, respiratory, and skeletal-muscular systems are all in ‘extra fast
mode’. This is why people who are highly stressed for long periods of time often develop digestive disorders. It is also why we are
told not to eat when we are upset, as our adrenalin levels are high then too, and food is not digested properly.
6. Summary
Good nutrition is based on a balanced diet, i.e. one that contains all the nutrients needed for good health. This requires eating a
variety of foods in appropriate proportions taking into account one’s energy requirements. Food production methods often leave, or
add, chemical substances to foods. Over time these can cause health problems. Increasing awareness of this has created increasing
consumer desire for organic foods and resistance to GM foods.
The digestive system is the term used to describe the alimentary canal and collection of organs and associated organs involved in
the digestive processes. These processes include the mechanical and chemical breakdown of food into its chemical components.
These components are used by the body for cellular maintenance and repair, the manufacture of hormones and enzymes as well as
the energy required for these processes to take place, and for the elimination of body wastes.
7. Bibliography
Essortment – all the information you want to know http://www.essortment.com/all/irradiationof_rwkc.htm
Glenville, Marilyn 1999, Kyle Cathie Ltd: Natural Alternatives to Dieting
Holford, Patrick 1998, Piatkus: The Optimum Nutrition Bible
1999, Piatkus: The 30 day Fat Burner Diet
2005, Piatkus: The Holford Diet
Human Genome Project Information website http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml
Pressman, Alan H and Buff, Sheila 2000, Alpha Books: The Complete Idiot’s Guide to Vitamins and Minerals
McKeith, Gillian 2004, Michael Joseph: You are What You Eat
Seeley, Rod R, Stephens, Trent D, Tate, Philip 2000, McGraw-Hill: Anatomy and Physiology 5th ed.
Waugh, Anne, Grant, Allison 2006, Elsevier: Ross and Wilson Anatomy and Physiology
McKee, Trudy, McKee, James 1999, WCB McGraw-Hill: Biochemistry: An Introduction 2nd ed.
Wikipedia: http://en.wikipedia.org/wiki/