.
Minerals are chemical elements (as opposed to organic compounds like vitamins) that are essential to normal body functions. Like other foods, minerals are divided into two groups; minerals which are elements that the body requires at least 100mg a day of and trace minerals which are needed in smaller amounts. There are seven major minerals. Calcium is needed for the formation of bone and teeth and nerve transmission, blood clotting, and muscle contraction. Vitamin D is needed to help calcium absorption. Phosphorus also helps with the formation of bone and teeth and requires vitamin D for absorption. Magnesium facilitates carbohydrate and protein metabolism, cell reproduction, and muscle action. Other major minerals include sodium, potassium, chlorine and sulphur. These minerals perform various functions from maintaining acid balance to digestive processing and carbohydrate metabolism and protein synthesis. Some trace minerals are considered "essential" such as iron, copper, fluorine, selenium and zinc.
When a person does not get enough of the food groups I have outlined above, they are at risk of dietary deficiency disease. Most dietary deficiency diseases are caused by a lack of protein, vitamins, or minerals Protein-energy malnutrition is a term used to describe conditions related to calorie and protein deficiency disorders. Such diseases are common in developing countries were food is in short supply. An example of one is the disease Kwashiorkor, This condition is caused when an infant is weaned off breast milk because a new infant has arrived but the infant does not receive a protein rich replacement. The baby experiences tiredness, muscular wasting, and edema (water retention). The hair and skin lose color, the skin becomes scaly, and the child may experience diarrhea and anemia.
www.humanillnesses.com/original/Conj-Dys/Dietary-Deficiencies.html#ixzz1HGJpZSEF
Lack of vitamins can produce a very wide range of dietary deficiency diseases. Vitamin A helps to protect the retina; a deficiency can cause night blindness in which the eyes fail to adjust to the dark because of problems with the retina. Vitamin C affects blood vessels, skin, gums, connective tissue, red blood cells, wound healing, and the absorption of iron. Scurvy is one disease that results from vitamin C deficiency. Its symptoms include bleeding under the skin, swollen or infected gums and a slow healing of wounds. Vitamin D helps to regulate the amounts of bone forming minerals such as phosphorous and calcium in the bloodstream so is vital for proper bone formation. Vitamin D deficiency can in a disease called rickets, which is characterized by bone deformities. It mainly affects children whose bones are still forming and can cause legs to bow and wrists and ankles to become thickened. Teeth can be affected too.
People with anorexia have problems with eating and this leads them to have deficiencies in all the main food groups. Anorexia is a serious eating disorder and mental condition. Typically those with anorexia will strictly control and limit what they eat and may also exercise excessively to lose weight. Others may binge eat and then purge the food from their body with laxatives or by vomiting. They may fear being fat, have a compulsion to be thin and or have an unrealistic idea of their body weight and size. The long term malnutrition associated with anorexia can cause a range of serious complications, such as kidney disease, cardio vascular failure or osteoporosis. Anorexia is not common but is the leading cause of mental health related death. www.nhs.uk/Conditions/Anorexia-nervosa/Pages/Introduction.aspx
Eating too much of a type of food can cause as many problems as not having enough. For example eating too much salt increases blood pressure. Too many people today eat too much fat and sugar and a consequence of this can be obesity. Weight depends on a balance between calories eaten and calories spent. Eating more calories than you need may be down to unhealthy food choices. For example, eating processed or fast food that is high in fat, not eating fruit and vegetables and complex carbohydrates, drinking too much alcohol which is high in calories, eating larger portions than are necessary or comfort eating. Lack of physical activity is another important factor that is related to obesity and some genetic conditions can increase your appetite. There are also genes that determine how much fat your body stores. A particular genetic variation could mean that your body is more likely to store fat than somebody else and medical conditions such as Cushing’s syndrome and an under active thyroid can cause weight gain, as can certain medicines. Obesity is an accumulation of fat in the body to the point that one is at risk of diseases that can damage your health and shorten your life, such as heart disease and diabetes. For medical purposes, the body mass index (BMI) is used to determine if body weight is in the healthy range.
BMI is calculated by,
Body mass (Kg) / Body height (m)2
So for example a person who weighs 58kg and has a height of 1.70 meters would be calculated as follows:
58kg/1.70m2= 20 BMI
A BMI of 20 is healthy; in fact 20 to 25 BMI is seen as healthy. Overweight is seen as 25 to 30 and anything over 30 is seen as obese.
However, BMI has some restrictions which make it invalid. This is because a BMI is only a measure of weight. This means that it doesn’t take in to account muscle, fat and water. Muscle, which is denser and therefore heavier than fat, is a good thing. A BMI test does not take this into consideration so a muscular person is likely to be judged as overweight according to a BMI. A bodybuilder, for instance, must be very fit and healthy due to their profession but a BMI test is likely to give a result that suggests otherwise.
Water levels vary in humans as well. Prior to periods females often have higher levels of water which means their mass would be greater. Also, water is lost through perspiration which again means someone would weigh less after sweating. Both water levels and muscle affect the weight aspect of a BMI test. Height also influences the outcome of a BMI test, but height is altered by the operation of gravity during the day. This would also affect the validity of a BMI test. People are generally taller after a night’s sleep than they are in the evening as, during the day, gravity acts to reduce height. Height also varies with age. All these things mean that BMI is not a valid way of determining if someone is overweight because the results of the test would be altered by the time of the day of the test and the age and sex of the person taking the test. Not only does it not determine if someone is of a healthy weight but it also isn’t an accurate test for a healthy lifestyle.
Due to the problems associated with using BMI as an indicator of obesity some experts now claim that the best way to measuring obesity is a measurement that divides waist circumference by hip circumference. In women the result should be no more than 0.8 and for men 0.95. Fat stored in the abdominal area is more likely “than fat stored in other spots to trigger changes in hormone levels and cause inflammation, which in turn leads to clogged arteries”, says Dr. Gordon A. Ewy, a professor and chief of cardiology at the University of Arizona College of Medicine, and director of the school’s Sarver Heart Centre. But, “fat on a woman’s hips doesn’t seem to increase risk, whereas a beer belly does,” Ewy says. The waist-to-hip measurement is believed to be a way to catch people at risk for fat-related diseases that might otherwise have a healthy BMI score.
The graph below was drawn to show the relationship between the occurrence of obesity in the United States and the occurrence of diabetes. The trend appears to show that as the prevalence of obesity in the United States has risen, so to has the prevalence of diabetes. However, no actual relationship between the two phenomena has been demonstrated by the graph as we don’t know how obesity has been measured and there could be a wide range of factors besides obesity that have affected the increase in the prevalence of diabetes. These problems and others are discussed below the graph.
There are some problems with this graph, however. The reliability and validity are in serious question. First of all, we wanted to find out the link between type 2 diabetes and obesity. This graph does not specifically show what type of diabetes the people have, so it is a combination of both type 1and 2 diabetes. To improve this I would only include people with type 2 diabetes in the graph so I could make a comparison easier. Another improvement in which a comparison could be made is easier is to have both the obesity and diabetes lines as lines of best fit as apposed to having one being a line of best fit and one being a curve of best fit. Another problem with this graph is that it does not indicate how the data of obesity was collected. This has serious implications for validity as it means that some people could have been tested for obesity in one way and others in a different way. It also means that perhaps BMI was used to test whether the people involved where overweight, as previously mentioned there are some serious problems with the validity of the BMI test as a means of testing if someone is of a healthy weight. To improve this I would have everyone tested for obesity the same way. I also don’t know if this data is for everyone in America or just a certain region of America, to deal with that issue I would test a broad sample of people from a representative range of areas.
In the UK there are 2.8 million people with diabetes and an estimated further 850,000 who have the condition but are unaware of it. It is a condition whereby the amount of glucose in the blood is too high because:
- Either the pancreas does not produce any insulin (which is a hormone and a protein)
- or it does not produce enough,
- Or the insulin that is produced does not work properly
With the result that the body cannot make proper use of the glucose it needs as fuel. Instead, it builds up in the blood. Glucose comes from digesting carbohydrates (as described earlier). When they are digested, carbohydrates form glucose which is transported in the blood to cells where it can be converted into energy. The presence of glucose in the bloodstream alerts receptors in the blood cells to send a message to the pancreas to produce more insulin. Inside the pancreas are clusters of cells called the islets of Langerhans that produce a variety of hormones. The islets are made up of at least five different cell types, 65-85% of which are the beta cells responsible for making insulin. It is damage to the beta cells that is the most common cause of diabetes 1. Insulin controls the uptake of glucose by the cells and any excess glucose is converted into glycogen (which is insoluble, an important factor when the body is 70% water). Glycogen is stored in the liver or in fat around the body. When the body needs energy another hormone called glucagon is secreted by the pancreas to convert the glycogen back into glucose to be carried by the bloodstream for cells to use. The body functions properly when the glucose levels are at an optimum point. The cycle described above balances out the levels of insulin and glucose in the body. The cycle is maintained by the food you eat and the actions of the pancreas and liver. In type 1 diabetes, the body does not make any insulin at all because of an auto immune response which has caused the body to destroy the beta cells in the islets of Langerhans. Why this happens is not entirely understood. Type 1 diabetes accounts for about 15% of all cases of diabetes, is most common in the under 40s and is also the most common form of childhood diabetes. The process of producing glucose from carbohydrate occurs as normal, but as no insulin is produced so glucose cannot be taken up by the cells and builds up in the body. The body then tries to eliminate the glucose through the kidneys which is why those with undiagnosed type 1 diabetes tend to urinate a lot. The constant urination also causes the sufferer to become thirsty. As the urine and blood contain a lot of glucose, bacteria can thrive and cause a number of problems in the body such as slow healing of wounds, urinary infection and even the liquid in front of the lens of the eye can become cloudy due to glucose build up. As the glucose cannot access the cells to provide energy someone with undiagnosed diabetes will become lethargic and the body will have to break down fat stores to gain energy, leading to weight loss. Once diagnosed, these symptoms can be reversed if treated with insulin
In type 2 diabetes the pancreas can still make some insulin, but either it does not make enough, or the insulin produced does not work properly. A number of factors influence the development of diabetes but genetic predisposition seems to be the strongest factor followed by obesity and high calorific intake and about 20% of people with type 2 diabetes have antibodies to the cells of their islets of Langerhans as a result of an autoimmune response whereby the islet cells are seen as ‘foreign’ and are destroyed (as in the case of diabetes 1). However the most significant factor seems to be genetic predisposition, approximately 38% of siblings and one-third of children with one or more parents with type 2 diabetes will go on to develop diabetes or abnormal glucose metabolism. Studies with identical twins showed that 90-100% of the time when diabetes developed in one it would also develop in the other compared with 50% in type 1diabetes. In type 2 diabetes glucose is produced as normal from the digestion of carbohydrates, but the insulin which ‘unlocks’ the cells allowing the glucose to be taken up only partly unlocks the cells (this can be because the ‘locks’ have become furred up due to fat deposits). This gives rise to a build up of glucose in the blood and in response, the pancreas produces more insulin, leading to a rise in the insulin AND glucose levels in the body. This situation is exacerbated by energy hungry cells sending emergency signals to the liver to release stored glucose. The symptoms of type 2 diabetes are similar to type 1 but their onset is slow and some people have no symptoms at all. In fact, people can live for up to 10 years before they realise they have the condition. This type of diabetes is more commonly found in the over 40s among white people and in the over 25’s in those of South Asian and African heritage. It is beginning to appear more commonly amongst children, teenagers and young people of all ethnic backgrounds. Type 2 diabetes accounts for about 85% of all people with diabetes. It can be treated with a healthy diet, increased exercise and loss of weight but most people will need some form of expensive medication to treat it.
Doctors use two main tests to diagnose diabetes. The first is the direct measurement of glucose levels in the blood after a fast of at least 8 hours. This is called the Fasting Plasma Glucose test (FPG) . It is inexpensive and easy to administer so is the preferred test but it can miss some diabetes or pre diabetes that can be found with the second test I discuss below, the Oral Glucose Tolerance Test (GTT). The reliability of the FPG test is improved if it is performed in the morning after an overnight fast. Results and implications are shown in the table below:
*Confirmed by repeating the test on a different day.
http://diabetes.niddk.nih.gov/dm/pubs/diagnosis/
The second test for diabetes is to measure the body’s ability to process the excess sugar resulting from drinking a high glucose drink, the GTT test. This test is more sensitive but less convenient and more expensive to administer. The person taking the test has nothing to eat or drink except water for at least 8, but not more than 16, hours. An initial blood sugar level is taken and then the person drinks a high glucose drink (75 grams of glucose or 100 grams for pregnant women) and has their blood tested straight away and then 30 minutes, 1 hour, 2 hours, and 3 hours later (5 times in total). A person without diabetes will experience a rise in blood glucose levels after consuming the drink, but these will then fall quickly back to normal as insulin will have the effect of reducing blood glucose. In a diabetic, blood glucose levels will rise to higher than normal levels after consuming the glucose drink and fall far more slowly as insulin is either not produced or the body does not respond to it. The test may lead to the following diagnoses:
Blood glucose measurements during the GTT test can vary so a mildly elevated blood glucose level may result in the test having to be run again to check the diagnosis. Any kind of illness that a person taking the test has will affect the results, as will some drugs, so validity depends on the person being in good health (apart from possibly having diabetes) and not taking medication that may alter blood glucose levels, such as steroids or diuretics. A further factor that may interfere with the validity of the GTT test is race. A study by the The American College of Obstetricians and Gynaecologists found that the thresholds for correct diagnosis of diabetes needed to be adjusted for different racial groups.
PUT TABLE OF RESULTS, PATIENT DATA GRAPH AND DISCUSS HERE, IMPROVEMENTS?
In 1941 two scientists (Beadle and Tatum) carried out experiments that proved genes govern the ability to synthesize amino acids. As more came to be understood about the nature of DNA more progress was made and the relationship between DNA and the synthesis of proteins came to be understood. Insulin and glucagon are proteins produced through protein synthesis so understanding this process is important in understanding diabetes. DNA stands for deoxyribonucleic acid. It takes the form a double twisted helix, or a twisted ladder shape. The struts of the ladder have a backbone made of sugar and phosphate. Attached to each sugar and phosphate, forming the rungs, is one of four types of molecules called bases. The bases have the letters A, C T and G. These bases join together following rules which mean that A and T always match and C and G always match. The DNA letters stand for Adenine (A), Thiamine (T), Cytosine (C) and Guamine (G). Transcription is the first stage in protein synthesis. It occurs in the nucleus of the cells in the islets of Langerhans. The DNA uncoils to expose the relevant bases (see below)
mRNA (messenger Ribonucleic Acid) which is in the cytoplasm enters the nucleus through nucleic pores. The mRNA aligns with the exposed bases of DNA. However, mRNA cannot produce Thiamine so to compensate for this mRNA uses Uracil (U) to align with adenine.
We can see the alignment of these bases in the screen shot of the animation which I completed to the left.
These mRNA strands (see left) then exit the cells via the pores.
http://learn.genetics.utah.edu/content/begin/dna/
They travel to organelles called ribosome which are tiny circular sacs residing on other organelles known as endoplasmic reticulum (ER). There are two types of ER, rough and smooth. Rough ER is covered in ribosome that synthesize proteins that are transported by the RER to be used elsewhere in the body. Smooth ER has more tubular sacs and is not covered by ribosome giving it a smooth appearance. It contains enzymes important for synthesizing fats, lipids, etc. scienceaid.co.uk/biology/cell/images/er.jpg
The second stage of the process of protein synthesis is translation. The mRNA sequence enters the ribosome. Around the ribosome are tRNA (transfer ribonucleic acids) which exist as triplets with an amino acid. The tRNA join onto the mRNA and the amino acids form chains. The sequence starts at AUG, then 3 nucleotides are read at a time. Each three nucleotide codon specifies a particular amino acid. The stop codons UAA, UAG and UGA tell the ribosome that the protein is complete. Small chains of amino acids are known as polypeptides, large chains are known as proteins and large chains that are coiled are known as insulin. As previously mentioned the rough ER transport the synthesised protein to be used elsewhere in the body. The mRNA return to the islets of Langerhans and the tRNA return to the ribosome, DNA cannot leave the nucleus of its cell. Protein synthesis has a start stop code but in bacteria there is no start stop code it is an ongoing process. I shall discuss this more fully later.
To evaluate whether people with diabetes type 2 should be given expensive medication I will consider what type of treatments are available.
In the past those suffering with diabetes depended on insulin sources from animals such as pigs or cows. This was unacceptable to some religious groups such as Jews, Muslims or Hindus and all vegetarians or vegans. It was also an expensive process and sometimes led to allergic reactions because of antibody tissue. The body identifies them and tries to reject them. Pork insulin differs by 1 amino acid and beef by 3 amino acids, so the body's immune system sometimes identifies them as foreign. Human synthesized insulins avoid this problem by having the correct sequence of amino acids.
In 1978 Genentech isolated the human genes which carry the code that enable the islets of Langerhans to produce insulin. They then developed a method of transferring the section of the human gene from the DNA that produces insulin to bacterial cells. This process involves removing the plasmid from the bacterial cell and cutting a section out with restriction enzymes (bacteria are used because their genes have no start stop codes and so they produce protein constantly, even when it is not needed). Meanwhile, the insulin gene is cut out from the section of DNA, also using restriction enzymes and the two are combined using ligase enzymes. The plasmid with the insulin gene is then transferred into bacteria which produce asexually so that its entire offspring are identical. This means all the offspring will have the genetic code for the production of insulin. The bacteria are placed into a fermenter which can provide an optimum environment for them to rapidly reproduce bacteria. The fermenter is filled with a solution of all the materials needed for this to happen. The insulin the cells make is released into the solution, separated, purified and packaged ready for use in daily injections to control diabetes. Genetically engineering insulin in this way is controversial. Critics claim it is unnatural and artificial and breaches the natural reproductive barriers of organisms. They fear there may be unintended side effects that may take time to become known such as alterations in the genetic make up of organisms. A benefit of genetically engineered insulin is that no animal insulin is needed. It is cheaper to produce in large amounts (if you discount the cost of all the initial research) and proponents claim it is safe to use as it is chemically the same as the insulin our bodies produce naturally so there are no allergy problems as with animal bacteria. There is also no need to kill thousands of animals to get the insulin needed. Lastly, it does not violate religious beliefs the way that animal products did. However, recent research shows that in some type I patients genetically engineered human insulin may increase chances of hypoglycemia unawareness-an abrupt, severe onset of hypoglycemia without any warning symptoms. Hypoglycemia unawareness affects an estimated 25 percent of all diabetics and 4% of all deaths in diabetic patients is directly attributable to hypoglycemia. A number of studies helped to explain why many patients report reduced awareness of hypoglycemia when transferred to genetically engineered human insulin. The first found that the blood glucose level in the brain did not go down in some patients during hypoglycemia. The brain was able to "hang on" to its sugar, even as the glucose levels fell in the rest of the body. Two other studies helped to further clarify the relationship between insulin in the brain and hypoglycemia. Because animal insulin is more lipophilic ("fat-loving"), it can cross the blood brain barrier more readily than genetically engineered human insulin, which is more hydrophilic ("water-loving"). As a result, animal insulin accumulates in the brain, thus lowering brain glucose levels during hypoglycemia. This logically allows for more hypoglycemia symptoms to be felt.
Whatever insulin a diabetes sufferer is given, it will only ever provide a treatment and never a cure. However, it is possible that a cure for the condition is just around the corner. Stem cells provide some hope for diabetes sufferers. Stem Cells are non-specific undifferentiated cells which have the potential to develop into specialized cell types in the body during early life and growth. When a stem cell divides each new cell has the ability to remain as a stem cell or become another type of cell with a specific job such as a blood or brain cell. Stem cells can also perform the function of an internal repair system, dividing without limit to replenish or replace other cells. Cells die and need replacing, or more are needed for growth or healing, so cells split to facilitate this. This is known as cell division. There are two types of cell division, mitosis and meiosis. In human cells mitosis is responsible for repair and growth. In 1962 Leonard Hayflick discovered that there was a limit to how many times a cell could go through the mitosis cycle and that when the limit was reached (52 times) a cell would be unable to replicate again. Prior to this people thought that normal cells had an unlimited potential to replicate. Stem cells do not conform to the Hayflick limit and this is why scientists are so interested in them. They could be placed into the body to repair or replace diseased cells and so cure currently incurable diseases such as Diabetes. In Brazil stem cell treatment has meant that some diabetes 1 sufferers have not had to inject themselves with insulin for years. The treatment prevents the immune systems of patients with diabetes 1 from mistakenly destroying the cells in the islets of Langerhans which produce insulin. Tests on the patients show that they had elevated blood concentrations of C-peptide, a breakdown product of insulin production, a sign that the patients were making insulin themselves. The treatment relies on extracting and storing CD34 stem cells from the blood of patients which can grow into all white blood cells of the immune system. The patients then receive drugs that destroy what remains of their immune systems, including those aspects that attack the islets. Finally the stored stem cells are returned to the patient so that they can regenerate afresh an immune system that will no longer attack islet cells. Twelve of the original 20 patients who benefited from the treatment are still free of insulin, 8 relapsed but are on lower doses of insulin than before and still have higher levels of C-peptide, suggesting that their islets have gained some benefit from the treatment. However, the treatment failed in three patients and nine of the men suffered low sperm counts later. Some critics have questioned the validity of the results claiming the outcomes may have been due to the effects of the immunosuppressive drugs used in the treatment regime, or simply due to better care the patients received because they were in a clinical trial. The treatment will also not benefit type 2 diabetes sufferers as they make insulin anyway, their diabetes is the result of their bodies not responding to insulin the way it should.
Journal reference: Journal of the American Medical Association, vol 301, p1573
In the above research the stem cells were collected from the patients’ own bone marrow. This is less controversial than using embryonic stem cells. For Catholics and other religious groups with absolute values about the sanctity of life, human life begins at conception and the deliberate destruction of that life is equivalent to murder. Other people who do not have those kinds of absolute beliefs have argued that life begins much later than at conception and that whilst the embryo has the potential for life; it is not equivalent to a human life. It has no brain or heart, has none of the qualities that make a human being human, is not a sentient being and cannot survive outside the womb. Scientists, look at blatocysts neutrally and argue that they are nothing but a cluster of cells that have not even differentiated into any kind of distinct tissue, never mind the structures of a human body. The UK government says that life begins when the infant can be born alive and survives outside the womb. This is currently 24 weeks though it changes as science advances.
Supporters of stem cell research argue that the destruction of a single embryo is justified if it provides a cure for otherwise incurable diseases in large numbers of patients. Even some pro-lifers claim that morally and religiously it is right to save existing life through embryonic stem cell therapy. However, others with more extreme moral or religious views say it is immoral to destroy a human embryo, even to save or reduce suffering in thousands of existing human lives. They believe that a soul comes into being from the moment of conception and, as such, even a zygote is one of God’s creations and therefore sacred. To argue that experimenting on one life to save others is right, is to argue that the ends justify the means, which would also be condoning the experimentation on Jews by the Nazis which led to progressive outcomes for science and medicine. Opponents of stem cell research particularly those with strong religious views about God’s will argue that disease is God’s will in action in the world. If you contract a terminal incurable illness it is because it is your time to die. If embryonic stem cells are used in the treatment of diabetes 2 this is likely to fuel controversy even further as many people feel that diabetes 2 results from obesity, which in the popular imagination results from the life style choices of the sufferer.
Genomics-what is it?
What can it potentially do?
How could it cure diabetes?
What are the benefits and risks of this scientific advance?
Are there any ethical issues?
Having explained and discusse
d all this go back to the original question of whether people with type 2 diabetes should receive expensive medical treatment. Implications and ethical thoughts on this, your opinion, sustained by what you have learned.
