Sunshine vitamin and ill effects of its deficiency on health
The presence of Vitamin D in adequate quantities is nutritionally important for the body. Vitamin D is present in the form of cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2). Cholecalciferol is made in the skin in response to UVB radiation. Ergocalciferol is produced in plants and fungus, and also in response to UVB radiation.
Both forms of vitamin D are inactive and must undergo conversion in the liver and kidneys to form biologically active compounds. Ergocalciferol and cholecalciferol are hydroxylated by hepatic microsomal enzymes to 25 (OH)D, also referred to as calcifediol. Further conversion of this intermediate form in the kidneys produces the physiologically active forms, 25-dihydroxyvitamin D (calcidiol) and 1,25-dihydroxyvitamin D (calcitriol). The main circulating form is 25-dihydroxyvitamin D. Vitamin D products are primarily eliminated through excretion in the bile. The mean elimination half-life of 1,25-dihydroxyvitamin D is 5 to 8 hours in adults. The circulating vitamin D is bound to serum proteins and is widely distributed throughout the body. It is stored primarily in the liver and fat.
The body is built to get its supply of vitamin D through skin from sunlight rather than through food by mouth. Cholecalciferol and ergocalciferol can both be found in the form of a supplement. Cholecalciferol is also present in cod liver oil products. Vitamin D is scarcely found in food. Fatty fish have small quantities of cholecalciferol, while irradiated mushrooms have small quantities of ergocalciferol. Milk and yoghurt fortified with vitamin D, beef or calf liver, egg yolk and cheese also contain vitamin D.
Usefulness of vitamin D – It is useful in the following –
- Auto-immune diseases
- Chronic pain
- Heart disease
- Neuromuscular diseases
- Renal system
- Adipose tissue
- Cycle of human cells
An adequate supply of vitamin D is essential at all ages of life for the maintence of good health.
Recommended daily intake of vitamin D -
In the United States and Canada, the Institute of Medicine currently recommends the following daily intakes:
Infants, 0-12 months
Children, pregnant women and adults, 1-70 years
Seniors, more than 70 years
Children aged 4 to 8 years should not have more than 3,000 IU/day and those aged 1 to 3 years should not have more than 2,500 IU/day.
Conditions caused or affected by vitamin D deficiency -
It has been estimated that more than 1 billion people are vitamin D deficient in both the developed and developing world. Modern society has created a deficiency so high that it can be called a pandemic. Vitamin D plays a more significant role in human health than previously thought. The prevalence of vitamin D deficiency is caused by more time indoors, increased use of sunscreen, increased use of protective clothing and breastfeeding. It is also prevalent in dark skinned people.
Pregnancy – The deficiency of vitamin D during pregnancy can cause growth retardation and skeletal deformities. It may also affect birth weight. The vitamin D deficiency can put the baby at risk for rickets, abnormal bone growth, and delayed physical development. The deficiency of vitamin D in pregnancy is linked to a greater risk of preeclampsia and a greater need of c-section. The adequate levels of vitamin D during pregnancy are critical to the development of brain in the baby.
Diabetes – Vitamin D plays a vital role in the normal functioning of the immine system. Its deficiency can lead to the mal-functioning of the immune system. Type-1 diabetes develops due to the mal-functioning of the immune system, which will start attacking and killing the insulin producing cells of the pancreas, reacting as if they are the invading viruses. The insulin producing cells are unable to produce insuin, resulting in type-1 diabetes. There exists a special relationship between vitamin D deficiency and type-2 diabetes. Vitamin D directly acts on insulin producing cells in the pancreas to produce more insulin. Vitamin D reduces inflammation, which is commonly present in patients with Insulin resistance syndrome and type-2 diabetes. Vitamin D indirectly improves insulin production and it’s action by improving the level of calcium inside the cells, and it directly acts on the muscle and fat cells to improve insulin action by reducing insulin resistance.
High blood pressure – There is a growing body of evidence that suggests that vitamin D may play a role in blood pressure regulation and heart health. For example, it is known that cases of high blood pressure increase during winter and in places where a decrease in available sunlight leads to lower vitamin D production. But this role of vitamin D needs to be substantiated further.
Fatty liver disease – The inactive form of vitamin D is converted into its active form – 25 hydroxyvitamin D, which is used to perform its vital functions in the body. The activity of vitamin D is further enhanced in the kidneys, where 25-hydroxyvitamin D is converted to 1,25-dihydroxyvitamin D, the most potent form of vitamin D. When someone develops parenchymal liver disease, their liver can no longer efficiently convert vitamin D into 25-hydroxyvitamin D, leading to symptoms of vitamin D deficiency. Many factors can cause parenchymal liver disease, including alcoholism, viral hepatitis and several types of infections.
Allergies – The past research has shown that vitamin D is important for normal immune system and its deficiency is common in obese individuals. Obese persons have lower levels of adiponectine and vitamin D; they also have increased levels of IgE, IL-6 and IL-13. The adipokines and markers of allergic disease seem to depend on the vitamin D deficiency seen more obese patients. This leads to conclude that the increased risk for allergy in obesity may be mediated by vitamin D to some extent.
Crohn’s disease – According to a recent research, the supplements of vitamin D may help those with Crohn’s disease overcome the fatigue and decreased muscle strenghth that are so common in the disease. Vitamin D is getting a lot of attention in inflammatory bowel disease treatments.
Depression – Exactly how vitamin D and depression may be linked is unclear. Vitamin D deficiency may result in depression, or depression may increase risk for low vitamin D levels. It has been found that women with moderate to severe depression had substantial improvement in their symptoms of depression after they received treatment for their vitamin D deficiency.
Dental caries – Just as vitamin D is needed for healthy bones, it is also necessary for baby’s oral health. Teeth start to form in utero, so dental problems can start before they even erupt. It's long been known that calcium helps strengthen a fetus' teeth during the development process, but now scientists have discovered a link between prenatal vitamin D and tooth decay. So, it means that expectant mothers need to increase their vitamin D intake so as to prevent childhood dental problems.
Multiple sclerosis – A new study suggests that vitamin D can slow the progression of multiple sclerosis (MS) and also reduce harmful brain activity. There is no scientific consensus on a treatment protocol. But it has been found that persons having multiple sclerosis with lower vitamin D levels -- below 50 nanomoles per liter (nmol/L) -- are more likely to develop new brain lesions and have a worse prognosis than those with higher levels.
Osteopenia and osteoporosis – Vitamin D is key to calcium absorption. All people begin losing bone mass after they reach peak bone density at about 30 years of age. The thicker the bones are at about age 30, the longer it takes to develop osteopenia or osteoporosis. Women are far more likely to develop osteopenia and osteoporosis than men because the loss of bone mass speeds up at the time of menopause due to hormonal changes. Osteopenia refers to a bone density that is lower than normal but not low enough to be classified as osteopororsis.
Cancer – A recent study found an association between low vitamin D levels and death from cancer among study partcipants with a history of the disease. However, no such association was found among participants without a history of cancer. This indicates that vitamin D may be important in cancer prognosis.
Celiac disease - Vitamin D deficiency occurs in 64% of men and 71% of women with celiac disease, making it an extremely common problem in celiacs due to malabsorption. Vitamin D deficiency also leads to calcium deficiency because an individual needs adequate levels of vitamin D to absorb calcium in foods. Many celiacs avoid diary products due to lactose intolerance. So, they may be further at risk for calcium deficiency.
Cystic fibrosis – One of the major nuritional factors that results in poor skeletal health in the patients of cystic fibrosis is deficiency of vitamin D. Vitamin D deficiency increases the risk for osteoporosis and subsequently vertebral fractures. The prevalence of occult vertebral fractures has been reported to be as high as 51% in persons with cystic fibrosis. Vertebral fractures result in chronic pain and kyphosis, which further result in worsening of respiratory health.
Obesity - Observational studies have consistently reported an increased risk of vitamin D deficiency in those who are obese. As obesity increases worldwide, so does Vitamin D deficiency, which can pose a serious range of health issues.
Erectile dysfunction - Vitamin D deficiency is one of several factors that associates with increased cardiovascular risk, and, therefore, there is strong possibilty that it may affect the penile vasculature adversely. A research indicates that vitamin D associates with reduced risk of several nonvascular contributing factors for erectile dysfunction. Therefore, it concludes that vitamin D deficiency contributes to erectile dysfunction.
Asthma – The researchers have found that vitamin D deficiency is linked to increased airway reactivity, lower lung function and worse asthma control. Vitamin D supplementation may improve asthma control by blocking the cascade of inflammation-causing proteins in the lung, as well as increasing production of the protein interleukin-10, which has anti-inflammatory effects.
We have seen that adequate blood levels of vitamin D are essentially required by the body to function optimally. It is a new “IT” vitamin. Let us not ignore its value. Let us bring sunshine in our life!