Biology Sample Assignment Part 2

Instructions: Following statement justifying the position that you take.

'Vitamin D Deficiency is an emerging health problem in Australia. Dietary intakes are inadequate and it is too risky to expose ourselves to the sun. Supplementation with vitamin D is essential to prevent vitamin D deficiency in Australia.'

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  1. The introduction should be change and focus on vitamin D not the different types of vitamin D.
  2. You still don't show the position you take are you agree with taking vitamin supplement or disagree and why?
  3. Try don't use another website except Australian website because we want to address this is a problematic issue in Australia and we want to address that
  4. You don't use any of transition signals which is very important look at on this website please http://www.lc.unsw.edu.au/onlib/trans1.html
  5. This is an Australian website show the need for individual to consume of this vitamins daily http://www.nrv.gov.au/nutrients/index.htm

These past few decades have a dramatic change in the demographic composition of Australian society. One of the most marked changes is the aging of the population. The number of elderly individuals is predicted to grow ten fold in the next half century. Aging is exemplified by the reduced ability to deal with stress and a higher incidence of disease and immobility, finally ending in death (Weinart & Timiras, 2003, 1706). This presents significant challenges for the community and particularly for the healthcare sector. There are a variety of challenges which need to be overcome. However, the onus is still on the individual to ensure that they take appropriate care of their health. Since major changes occur with age a viable strategy is needed to ensure that the transition to older age is as smooth as possible. Hence, in this essay, the changes that occur in the person as they get older will be examined. Moreover, the possible lifestyle choices which can enhance healthy aging will be evaluated.

Vitamin D is group of prohormones, which do not have hormone activity by itself but by a complex mechanism become active hormones. They are soluble in fat. There are five forms of vitamin D ranging from vitamin D1 to Vitamin D5, but the most important ones are vitamin D2 also known as 'Ergocalciferol' and vitamin D3 or 'Cholecalciferol'. Collectively they are known as 'Calciferol'. Invertebrates, fungus and plants produce Vitamin D2 for their protection from the harmful UV radiation. Vertebrates cannot produce Vitamin D2. However, vertebrates can produce Vitamin D3. 7-dehydrocholesterol reacts with UVB radiation in human skin and produces Vitamin D3. UV B radiation has a wavelength of 270-300nm and is present in natural sunlight when the UV index is greater than three. If UVB is exposed to the body for a long time, equilibrium is achieved between generation and degradation of vitamin D3. According to the Institute of Medicine, vitamin D3 is more effective than vitamin D2 in human beings.

The main cause for vitamin D deficiency is the reduced intake or synthesis of cholecalciferol which might be due to reduced exposure to sunlight, reduced synthesis of vitamin D from given UVB exposure, low consumption of foods with high content of vitamin D. Disorders like small bowl disorder, pancreatic insufficiency and biliary obstruction are also important causes of Vitamin D deficiency. The other reason is the reduced synthesis or enhanced degradation of 25OHD, which mainly, occurs in people who are suffering from chronic disorders like hepatitis and cirrhosis. Other reasons are the limited absorption of vitamin D due to impaired gastrointestinal tract. Liver or kidney disorders results in impaired conversion of vitamin D into active metabolites necessary for important biochemical reactions. Skin color and body fat is also a major determinant for the deficiency of vitamin D in the body as dark skinned people have difficulty to synthesize vitamin D through the exposure of UVB rays. Hereditary is rarely responsible for vitamin D deficiency. According to Grant & Holick, vitamin D deficiency results in bone softening diseases because of impaired mineralization of bones. Following are the main medical conditions resulting due to the deficiency of vitamin D.

Rickets is a medical condition-affecting child, in this, the bones are deformed and long bones have impeded growth. Osteomalacia is medical condition affecting the adults. In this disorder thinning of bones, occur along with the weakness of proximal muscles resulting in bone fragility making the bones susceptible to fracture. Osteoporpsis is the condition in which the bone mineral density is reduced due to lack of vitamin D. This results in fragile bone, which is susceptible to fracture. It has been found that vitamin D deficiency also results in increased susceptibility of several chronic diseases like high blood pressure, cancer, chronic pain, tuberculosis and seasonal affective disorder. Some researchers have also found that lack of vitamin D results in peripheral artery disease and cognitive impairment resulting in memory loss. Some studies had led to the conclusion that vitamin D deficiency also causes type 1 diabetes.

The easy to notice symptoms for the deficiency of vitamin D are muscle aches, bone pain and weakness. For infants the bones will get soft due to low calcium level. Increased susceptibility to fracture of bones for example slight jarring or minor fall is enough to fracture the bone.

The main source of Vitamin D is exposure to the direct sunlight. The season of year, geographic latitude of the region, time of the day, weather of the region like cloudy day or not and use of sunscreen affect the amount of UV ray exposure and hence the synthesis of vitamin D in the body. The other source of vitamin D is the vitamin D rich food. It is essential for people who are not able to go out in the sun and synthesize vitamin D. The vitamin D rich diet is also recommended to old and dark skinned people. Nowson C & Margerison C has found out that many countries are fortifying foods such as milk products, bread, breakfast cereals and pastries with vitamin D2 and/or vitamin D3, to minimize the risk of vitamin D deficiency among the local inhabitants.

Table, shows the natural food sources for vitamin D.

Food Amount taken Vitamin D provided
Fish Liver oil ( Cod oil) 15 mL 1,360 IU
Herring 85 g 1383 IU
Catfish 85g 425 IU
Salmon 100g 360 IU
Mackerel 100g 345 IU
Sardines 50 g 250 IU
Tuna 85 g 200IU
Eel 100g 200IU
Egg One whole 20IU
Beef Liver 100g 15IU
Swiss Cheese 28g 12IU

Note: 1 IU=25ng

Table, shows the fortified food sources for vitamin D.

Food Amount taken Vitamin D provided
Nonfat, reduced fat and whole milk with vitamin D fortified 1 cup 98IU
Fortified Margarine 1 Tablespoon 60IU
Pudding made from fortified milk ½ cup 50IU
Ready-to-eat cereals fortified with 10% of the daily value for vitamin D ¾ cup-1 cup 40IU

According to Legacy Health System, Blood calcidol (25-hydroxy-vitamin D) level is used for the determination of vitamin D. If the content is 0-14.9 ng/mL, it is considered highly deficient. 15.0-31.9 ng/ mL is classified as mildly deficient. Optimal range is 32-100 ng/mL, while grater than 100.0 ng/mL is considered to be toxic.

Adequate Intake levels of vitamin D suggested by the Institute of Medicine of the National Academy of Science is 200 IU/day for ages ranging from infant to 50 years old, 400IU/day for ages 51-70 years old and 600IU/day over 70 years old people.

As mentioned earlier if people are exposed to sunlight for a longer time, there would be an equilibrium achieved between the generation and degradation of vitamin D, but it is not the case with vitamin D supplements. Excess intake of vitamin D can cause toxicity and high calcium level in blood (Hypercalcemia).

The early symptoms to be noticed for excess of vitamin D are loss of appetite, nausea, high blood pressure, weakness and vomiting. Due to high calcium levels, there are increased chances of calcium deposit in kidneys, heart, lungs and blood vessels. These deposits can result in the malfunctioning of kidney and kidney failure.

Most common and effective source of vitamin D is natural sunlight as the skin synthesizes vitamin D in presence of UV B rays. Holick suggests that 5-30 minutes of sun exposure between 10AM to 3 PM, twice a week is enough to synthesize appropriate amount of Vitamin D. The expose body parts could be legs, arms, face or back.

Complete cloud, shades or pollution can result in 50-60% blockage of UV energy. In addition, UVB radiation is not able to penetrate through glass and hence it is not recommended to sit inside glass room. Sunscreen with SPF (sunscreen protection factor) above 8 blocks the UVB; hence, one should be careful about the sunscreen application and vitamin D consumption.

However, there is equilibrium for the synthesis of vitamin D, but excess exposure to sunlight can result in other problems. Wolpowitz & Gilchrest have found out that UV radiation is carcinogen and causes skin cancer among individuals. The prolonged exposure also results in the dryness of skin demanding cosmetic surgery for cure.

High usage of vitamin D fortified food will result in vitamin D toxicity and excess of deposits of calcium in liver resulting in fatal disorders. Hence, it is recommended that people should strike a balance between the consumption of food and exposure to sunlight regarding the intake of vitamin D. For example, dark skinned people and people who use veiled clothes should increase their vitamin intake though natural food and fortified food, as they are unable to synthesize vitamin D with the help of UVB present in natural sunlight. For other people it is suggested that they should be aware with the time of day and intensity of UVB and then only should shed their clothes and bask in the sun.

There is increasing consideration in Australia about the diseases arising due to deficiency in vitamin D. It has been estimated that certain community of people might be more affected with the deficiency. According to Nowson et al, dark skinned women who are veiled have 80% chances of having the deficiency. In addition, elder people have higher chances of having the deficiency. People who have skin condition are advised to be away from the sunlight also have higher chances of having the deficiency.

Another report showed the vitamin D deficiency in the refugees living in Australia. Among the refugees, vitamin D deficiency has been found in immigrants from the Mediterranean, Middle East, southern Asia and Africa as early as in 1960s but recently it has been observed in refugees from Africa and Middle East. The dark skinned refugees mostly showed the symptoms. Also new born infants do not have exposure to direct sunlight and mother's milk is poor source of vitamin D to them, also their mother keep them in veils most of the time.

In Australia, there is a need to balance the skin cancer risk and sun exposure due to its geographical location. It is safe to bask in sun when UV level is below 3, but higher values can pose a health risk. September through end of April, generally have UV level above 3, in Australia. During May and August, extra care is to be taken as UV level peaks during middle of the day. Damaging level of UV is related to the time of year and there is no clear relation between the temperature and UV levels, making it difficult to predict the threat of exposure. UV levels can be extreme on 21*C and as well as on 40*C depending on the time of the year. Hence, body has to be protected with sunscreens and proper clothing.

In conclusion, we found out the importance of vitamin D and the causes of vitamin D deficiency. Though vitamin D is produced in the body with the help of UVB rays, excess exposure to skin also threatens the human beings of skin cancer. There are many natural food sources of vitamin D like fish oil & fatty fishes but they are not particularly effective as the content is low for the required and recommended consumption. People could take fortified food containing vitamin D but again there is risk of toxication due to excess consumption. Unlike the natural sunlight where the generation and degradation of vitamin D is in equilibrium, excess consumption of vitamin D leads to deposit of calcium in liver, heart and lungs posing serious threat to human lives. Hence, proper balance has to be maintained for the vitamin D intake through the channels of food and sunlight.

Australia has seen a rise in the influx of immigrants from Middle East, south Asia and Africa. Due to the tradition of these people who prefer to be veiled, there have been increased occurrences of Vitamin D deficiency. Also refugees who are dark skinned show low amount of vitamin D levels in the body. Australia by its geographic location has ample amount of sunlight but one has to be careful with the time, season and year in Australia, as they are the major determinant for UVB exposure. Exposure beyond suggested levels causes skin cancer. Hence, people living in Australia must be careful with their diet and exposure to sun, so that they can prevent the disorders arising due to vitamin D deficiency.

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