Vitamin D deficiency in Australia

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Vitamin D deficiency in Australia has been estimated as aflicting nearly one-quarter of all adults. [1]

Contents

Background

Importance of vitamin D

Synthesis of Vitamin D 614 Synthesis of Vitamin D.jpg
Synthesis of Vitamin D

Vitamin D plays an important role in which it supports calcium absorption in the body, sustaining good bone health as well as muscle function. When calcium in the body becomes under provided for normal bodily functions, calcitriol, an active form of Vitamin D, pairs with parathyroid hormone. Together they act to assemble cells in order to increase the calcium stores taken from bone. [2] Additionally, if you consume vitamin D through your diet, or make vitamin D in your skin from UVB exposure, it is processed through two organs before it becomes activated. Vitamin D is first processed in the liver, before heading to the kidneys where it becomes activated to the form 1-25 dihydroxy vitamin D or alternatively named chemical calcitriol. [3]

Vitamin D deficiency

Vitamin D deficiency historically used to be identified through counting cases of rickets. The old theory was that if someone had enough vitamin D to prevent rickets and osteomalacia, two skeletal disorders, they were considered safe from a deficiency. Nowadays through technological advancements Vitamin D deficiencies are now identified and thus calculated through the measurement of the serum 25-OH. According to the Australian Bureau of Statistics National Health Measures Survey (NHMS), the recommend Vitamin D levels to determine deficiency are categorised as follows:

In 1997, the prevalence of deficiency, defined as <17.5 nmol/L, was 2.8%, and the prevalence of insufficiency, defined as <37.5 nmol/L, was 27.6% among Australians over the age of 15. [4] In 2011–2012, 23% of adults had a deficiency defined as below 49 nmol/L. [1]

Health effects

The health impacts commonly caused by deficiency of Vitamin D are rickets in children and osteoporosis in the elderly populations. [5]

Rickets

Rickets can be traced back to the 1600s, where a pandemic arose with children around the globe from Vitamin D deficiency. [6] The inadequate intake of UV exposure consequently lead children to numerous health problems such as, growth retardation, muscle weakness, skeletal deformities, hypocalcemia, tetany and seizures. [6] During the late 19th century autopsies conducted in the Netherlands concluded that 80–90% of children were suffering from Rickets. [6] The incidents of rickets observed within Sydney hospitals during the years of 2003–2004 have doubled. This major spike can be attributed to the growing population of migrants in Australia, many of whom are considered at high risk of vitamin D deficiency. [2]

Osteoporosis

Because of the high prevalence of vitamin D deficiency alongside the ageing of Australia's population, conditions such as osteoporosis have become widespread among Australians over 60. Osteoporosis can be defined as very fragile and brittle bones, in which serious fractures can occur with just the slightest bump or fall. [7] Osteoporosis Australia have predicted that half of all women and one third of men over the age of 60 years will suffer the debilitating effects of osteoporosis. [7]

High-risk groups

Age

Several studies conducted in Australia have revealed a deficiency ranging from 15 to 52% amongst the senior population. These deficiencies have been found to be higher amongst those who are home bound or living within institutions with less access to sun exposure. [8] Vitamin D concentration levels below 28 nmol/L are common amongst the studies conducted. Throughout Sydney nursing home studies, it has been revealed that 86% of woman and 68% of men are falling into the moderate deficiency range. [2]

In a study based in Western Australia, 63% of patients admitted with hip fractures were observed to have serum levels less than 50 nmol/L compared to 25% in the control group. [2]

Skin colour

In Australia, vitamin D deficiency has been recognised within particular subgroups such as aged, dark skinned and veiled women. [9] There is deficiencies in around 80%, particularly in dark skinned and or veiled populations. [10] The prevalence of vitamin D deficiency amongst those with dark skin, or those who cover their skin for religious reasons, can be directly attributed to extremely low sun exposure, which is the main source of vitamin D in Australia.

Veiled women or individuals with dark skin pigmentation are vulnerable to a fall of vitamin D to levels considered deficient in Australia. This is most likely because the clothing worn acts as a direct barrier to, or absorbs the UVB irradiation. [11] Dark Skin has high levels of melanin pigmentation which decreases the cutaneous production of vitamin D. Compared with those of European descent, African-Americans require six times more UVB dosage to stimulate the same production of vitamin D in the skin. [11]

Sun exposure

Despite Australia having a sunny climate, Australians are falling short of adequate levels of ultraviolet B (UVB) light from the sun. Associated factors contributing to the low vitamin D levels are seasonal variations such as winter, when there is minimal sunlight, less time spent outdoors, and people cover up due to cold weather. [2] Environmental factors that impact vitamin D production are the elevation of the sun above the horizon and amount of cloud cover.

To ensure adequate vitamin D levels are reached, an average daily exposure, roughly 10% of the sunburn threshold is required on a significant area of skin, not just on the back of the hands. A burn time for a fair-skinned person could be limited to just 8 minutes in the middle of the day, during summer without sunscreens. A dark skinned person may need 45 minutes, while a covered individual might need several hours to achieve that same required exposure. The strength of the UVB changes throughout the day, so exposure time will need to change accordingly. [3]

Obesity

There is conflicting evidence to suggest whether obesity contributes to vitamin D deficiency. Obese individuals have an increased risk of being vitamin D deficient likely caused by lack of sun exposure from reduced mobility and or low levels of physical activity. [9] The serum levels of obese Australian were 8.3- 9.5 nmol/L lower in both genders comparable to those of healthy weight ranges. [9] During the AusDiab study conducted throughout Australia serum levels within obese people were shown to be 57% lower than with normal weight after receiving the same amount of UV exposure. [9]

Pregnancy

Pregnancy also poses as another high risk factor for vitamin D deficiency. The status levels of vitamin D during the last stages of pregnancy directly impact the newborns first initial months of life. [8] Babies who are exclusively breastfed with minimal exposure to sunlight or supplementation can be at greater risk of vitamin D deficiency, as human milk often has minimal vitamin D present. Recommendations for infants of the age 0–12 months are set at 5 ug/day, to assist in preventing rickets in young babies. [8] 80% of dark skinned and or veiled women in Melbourne were found to have serum levels lower than 22.5 nmol/L considering them to be within moderate ranges of vitamin D deficiency. [2]

Contributing factors

Australia's vitamin D deficiency levels in recent years[ when? ] have been on the increase, due to factors such as the long-term success of SunSmart government campaigns like Slip, Slop, Slap as well as Cancer Council Australia that have increased the general public's awareness of the risks associated with excessive sun exposure and skin cancers. [3] The 'sun smart' campaign created in 1988 had a significant impact on the public approach and behaviours towards sun exposure. [12] The success of this campaign reduced the sunburn rate by 50%, which researchers believe to have contributed to the rise in vitamin D deficiencies across Australia. [12]

In addition to the reduced sun exposure amongst the Australia populations, there have been decreases in the form of dietary intake as many people are no longer taking fatty fish oil tablets as a method of regulating vitamin D. [3]

Other factors previously mentioned are sun exposure, geographical longitude as well as season change. Greater latitudes receive sunlight that is of lesser ultra radiation strength in contrast to regions close to the equator, who receive lower variation to hours of daylight during the summer periods. [5]

Government strategies

Mandatory fortification

Vitamin D fortification in table spreads Vitamin D and Margarine.jpg
Vitamin D fortification in table spreads

In light of the increase of vitamin D deficiency throughout Australia the federal government introduced mandatory fortification of vitamins and minerals such as vitamin D in certain foods like edible oil spreads as indicated in the: Australian Standard 2.4.2. [13] It is mandatory for all food manufacturing companies producing table spreads like spreadable butter and margarine to have no less than 55 mg/kg of vitamin D, as a response to a growing public health requirements. [13]   

In response to recent advances, public policies are being reconsidered to ensure vitamin D is evidently being measured. [2] With the vitamin D deficiency resurfacing the nutrient reference value guidelines were established, in turn creating the dietary vitamin D recommendations. [2]

The dietary vitamin D guidelines are assuming limited exposure to UVB sunlight are:

Infants, Children and Adults < 50 years: 5 μg/day (200 IU/day)

Adults > 50 - < 70 years: 10 μg/day (400 IU/day)

Adults > 70 years: 15 μg/day (600 IU/day) [2]

See also

Related Research Articles

<span class="mw-page-title-main">Rickets</span> Childhood bone disorder

Rickets, scientific nomenclature: rachitis, is a condition that results in weak or soft bones in children and is caused by either dietary deficiency or genetic causes. Symptoms include bowed legs, stunted growth, bone pain, large forehead, and trouble sleeping. Complications may include bone deformities, bone pseudofractures and fractures, muscle spasms, or an abnormally curved spine. The analogous condition in adults is osteomalacia.

<span class="mw-page-title-main">7-Dehydrocholesterol</span> Chemical compound

7-Dehydrocholesterol (7-DHC) is a zoosterol that functions in the serum as a cholesterol precursor, and is photochemically converted to vitamin D3 in the skin, therefore functioning as provitamin-D3. The presence of this compound in human skin enables humans to manufacture vitamin D3 (cholecalciferol). Upon exposure to ultraviolet UV-B rays in the sun light, 7-DHC is converted into vitamin D3 via previtamin D3 as an intermediate isomer. It is also found in the milk of several mammalian species. Lanolin, a waxy substance that is naturally secreted by wool-bearing mammals, contains 7-DHC which is converted into vitamin D by sunlight and then ingested during grooming as a nutrient. In insects 7-dehydrocholesterol is a precursor for the hormone ecdysone, required for reaching adulthood. 7-DHC was discovered by Nobel-laureate organic chemist Adolf Windaus.

<span class="mw-page-title-main">Human nutrition</span> Nutrients supporting human health

Human nutrition deals with the provision of essential nutrients in food that are necessary to support human life and good health. Poor nutrition is a chronic problem often linked to poverty, food security, or a poor understanding of nutritional requirements. Malnutrition and its consequences are large contributors to deaths, physical deformities, and disabilities worldwide. Good nutrition is necessary for children to grow physically and mentally, and for normal human biological development.

<span class="mw-page-title-main">Cholecalciferol</span> Vitamin D3, a chemical compound

Cholecalciferol, also known as vitamin D3 or colecalciferol, is a type of vitamin D that is produced by the skin when exposed to UVB light; it is found in certain foods and can be taken as a dietary supplement.

<span class="mw-page-title-main">Ergocalciferol</span> Vitamin D2, a chemical compound

Ergocalciferol, also known as vitamin D2 and nonspecifically calciferol, is a type of vitamin D found in food and used as a dietary supplement. As a supplement it is used to prevent and treat vitamin D deficiency. This includes vitamin D deficiency due to poor absorption by the intestines or liver disease. It may also be used for low blood calcium due to hypoparathyroidism. It is taken by mouth or via injection into a muscle.

<span class="mw-page-title-main">Sun tanning</span> Darkening of skin in response to ultraviolet light

Sun tanning or tanning is the process whereby skin color is darkened or tanned. It is most often a result of exposure to ultraviolet (UV) radiation from sunlight or from artificial sources, such as a tanning lamp found in indoor tanning beds. People who deliberately tan their skin by exposure to the sun engage in a passive recreational activity of sun bathing. Some people use chemical products that can produce a tanning effect without exposure to ultraviolet radiation, known as sunless tanning.

<span class="mw-page-title-main">Osteomalacia</span> Softening of bones due to impaired bone metabolism

Osteomalacia is a disease characterized by the softening of the bones caused by impaired bone metabolism primarily due to inadequate levels of available phosphate, calcium, and vitamin D, or because of resorption of calcium. The impairment of bone metabolism causes inadequate bone mineralization.

<span class="mw-page-title-main">Hyperparathyroidism</span> Increase in parathyroid hormone levels in the blood

Hyperparathyroidism is an increase in parathyroid hormone (PTH) levels in the blood. This occurs from a disorder either within the parathyroid glands or as response to external stimuli. Symptoms of hyperparathyroidism are caused by inappropriately normal or elevated blood calcium excreted from the bones and flowing into the blood stream in response to increased production of parathyroid hormone. In healthy people, when blood calcium levels are high, parathyroid hormone levels should be low. With long-standing hyperparathyroidism, the most common symptom is kidney stones. Other symptoms may include bone pain, weakness, depression, confusion, and increased urination. Both primary and secondary may result in osteoporosis.

<span class="mw-page-title-main">Vitamin D toxicity</span> Human disease

Vitamin D toxicity, or hypervitaminosis D, is the toxic state of an excess of vitamin D. The normal range for blood concentration of 25-hydroxyvitamin D in adults is 20 to 50 nanograms per milliliter (ng/mL). Blood levels necessary to cause adverse effects in adults are thought to be greater than about 150 ng/mL, leading the Endocrine Society to suggest an upper limit for safety of 100 ng/mL.

Food fortification is the addition of micronutrients to food products. Food enrichment specifically means adding back nutrients lost during food processing, while fortification includes adding nutrients not naturally present. Food manufacturers and governments have used these practices since the 1920s to help prevent nutrient deficiencies in populations. Common nutrient deficiencies in a region often result from local soil conditions or limitations of staple foods. The addition of micronutrients to staples and condiments can prevent large-scale deficiency diseases in these cases.

<span class="mw-page-title-main">Calcifediol</span> Chemical compound

Calcifediol, also known as calcidiol, 25-hydroxycholecalciferol, or 25-hydroxyvitamin D3 (abbreviated 25(OH)D3), is a form of vitamin D produced in the liver by hydroxylation of vitamin D3 (cholecalciferol) by the enzyme vitamin D 25-hydroxylase. Calcifediol can be further hydroxylated by the enzyme 25(OH)D-1α-hydroxylase, primarily in the kidney, to form calcitriol (1,25-(OH)2D3), which is the active hormonal form of vitamin D.

Vitamin B<sub>12</sub> deficiency Disorder resulting from low blood levels of vitamin B12

Vitamin B12 deficiency, also known as cobalamin deficiency, is the medical condition in which the blood and tissue have a lower than normal level of vitamin B12. Symptoms can vary from none to severe. Mild deficiency may have few or absent symptoms. In moderate deficiency, feeling tired, headaches, soreness of the tongue, mouth ulcers, breathlessness, feeling faint, rapid heartbeat, low blood pressure, pallor, hair loss, decreased ability to think and severe joint pain and the beginning of neurological symptoms, including abnormal sensations such as pins and needles, numbness and tinnitus may occur. Severe deficiency may include symptoms of reduced heart function as well as more severe neurological symptoms, including changes in reflexes, poor muscle function, memory problems, blurred vision, irritability, ataxia, decreased smell and taste, decreased level of consciousness, depression, anxiety, guilt and psychosis. If left untreated, some of these changes can become permanent. Temporary infertility, reversible with treatment, may occur. A late finding type of anemia known as megaloblastic anemia is often but not always present. In exclusively breastfed infants of vegan mothers, undetected and untreated deficiency can lead to poor growth, poor development, and difficulties with movement.

<span class="mw-page-title-main">Vitamin D deficiency</span> Human disorder

Vitamin D deficiency or hypovitaminosis D is a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate exposure to sunlight, particularly sunlight with adequate ultraviolet B rays (UVB). Vitamin D deficiency can also be caused by inadequate nutritional intake of vitamin D; disorders that limit vitamin D absorption; and disorders that impair the conversion of vitamin D to active metabolites, including certain liver, kidney, and hereditary disorders. Deficiency impairs bone mineralization, leading to bone-softening diseases, such as rickets in children. It can also worsen osteomalacia and osteoporosis in adults, increasing the risk of bone fractures. Muscle weakness is also a common symptom of vitamin D deficiency, further increasing the risk of fall and bone fractures in adults. Vitamin D deficiency is associated with the development of schizophrenia.

<span class="mw-page-title-main">Vitamin D</span> Group of fat-soluble secosteroids

Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, along with numerous other biological functions. In humans, the most significant compounds within this group are vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol).

<span class="mw-page-title-main">Health effects of sunlight exposure</span>

Exposure of skin to ultraviolet radiation from sunlight presents both positive and negative health effects. On the positive side, UV exposure enables the synthesis of vitamin D3, which is essential for bone health and potentially plays a role in inhibiting certain cancers. While vitamin D can also be obtained through dietary supplements, UV exposure offers benefits such as enhanced subdermal nitric oxide production and improved endorphin levels, which are not achievable through supplementation alone. Additionally, exposure to visible light supports melatonin synthesis, maintains circadian rhythms, and reduces the risk of seasonal affective disorder.

<span class="mw-page-title-main">Michael F. Holick</span> American physician–scientist

Michael F. Holick is an American adult endocrinologist, specializing in vitamin D, such as the identification of both calcidiol, the major circulating form of vitamin D, and calcitriol, the active form of vitamin D. His work has been the basis for diagnostic tests and therapies for vitamin D-related diseases. He is a professor of medicine at the Boston University Medical Center and editor-in-chief of the journal Clinical Laboratory.

<span class="mw-page-title-main">Vegan nutrition</span> Nutritional and human health aspects of vegan diets

Vegan nutrition refers to the nutritional and human health aspects of vegan diets. A well-planned vegan diet is suitable to meet all recommendations for nutrients in every stage of human life. Vegan diets tend to be higher in dietary fiber, magnesium, folic acid, vitamin C, vitamin E, and phytochemicals; and lower in calories, saturated fat, iron, cholesterol, long-chain omega-3 fatty acids, vitamin D, calcium, zinc, and vitamin B12.

<span class="mw-page-title-main">Dark skin</span> Human skin color

Dark skin is a type of human skin color that is rich in melanin pigments. People with dark skin are often referred to as black people, although this usage can be ambiguous in some countries where it is also used to specifically refer to different ethnic groups or populations.

Nutrition is the intake of food, considered in relation to the body's dietary needs. Well-maintained nutrition includes a balanced diet as well as a regular exercise routine. Nutrition is an essential aspect of everyday life as it aids in supporting mental as well as physical body functioning. The National Health and Medical Research Council determines the Dietary Guidelines within Australia and it requires children to consume an adequate amount of food from each of the five food groups, which includes fruit, vegetables, meat and poultry, whole grains as well as dairy products. Nutrition is especially important for developing children as it influences every aspect of their growth and development. Nutrition allows children to maintain a stable BMI, reduces the risks of developing obesity, anemia and diabetes as well as minimises child susceptibility to mineral and vitamin deficiencies.

References

  1. 1 2 "Australian Health Survey: Biomedical Results for Nutrients, 2011–12 | Australian Bureau of Statistics". 12 November 2013.
  2. 1 2 3 4 5 6 7 8 9 Shrapnel, William; Truswell, Stewart (1 December 2006). "Vitamin D deficiency in Australia and New Zealand: What are the dietary options?". Nutrition & Dietetics. 63 (4): 206–212. doi:10.1111/j.1747-0080.2006.00080.x. ISSN   1747-0080.
  3. 1 2 3 4 "Vitamin D". Radio National. 31 October 1999. Retrieved 2 September 2015.
  4. ↑ "Vitamin D". 17 March 2014.
  5. 1 2 Quaggiotto, P; Tran, H; Bhanugopan, M (1 January 2014). "Vitamin D deficiency remains prevalent despite increased laboratory testing in New South Wales, Australia". Singapore Medical Journal. 55 (5): 271–280. doi:10.11622/smedj.2014071. PMC   4291993 . PMID   24862752. Archived from the original on 22 December 2015. Retrieved 3 September 2015.
  6. 1 2 3 Holick, M. F. (1 January 2006). "Resurrection of vitamin D deficiency and rickets". Journal of Clinical Investigation. 116 (8): 2062–2072. doi:10.1172/jci29449. PMC   1523417 . PMID   16886050.
  7. 1 2 "Calcium, Vitamin D and Osteoporosis" (PDF). Archived from the original (PDF) on 21 March 2016. Retrieved 31 August 2015.
  8. 1 2 3 "Vitamin D | Nutrient Reference Values". www.nrv.gov.au. 17 March 2014. Retrieved 2 September 2015.
  9. 1 2 3 4 Daly, Robin M.; Gagnon, Claudia; Lu, Zhong X.; Magliano, Dianna J.; Dunstan, David W.; Sikaris, Ken A.; Zimmet, Paul Z.; Ebeling, Peter R.; Shaw, Jonathan E. (1 July 2012). "Prevalence of vitamin D deficiency and its determinants in Australian adults aged 25 years and older: a national, population-based study". Clinical Endocrinology. 77 (1): 26–35. doi:10.1111/j.1365-2265.2011.04320.x. ISSN   1365-2265. PMID   22168576. S2CID   22371996.
  10. ↑ "Vitamin D in Australia" (PDF). Archived from the original (PDF) on 4 March 2016. Retrieved 3 September 2015.
  11. 1 2 "Vitamin D deficiency and multicultural Australia". The Medical Journal of Australia. 2001.[ permanent dead link ]
  12. 1 2 Timms, Brad (2002). ""Slip, Slop, Slap" campaign may need rethink". Oncology. 3 (10): 588. doi:10.1016/S1470-2045(02)00892-6.
  13. 1 2 "Vitamins and minerals added to food". www.foodstandards.gov.au. Archived from the original on 24 September 2015. Retrieved 3 September 2015.
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