Vitamin D3 is a fat soluble vitamin having the potential of getting synthesized in the process of sufficient sun exposure. It bears the nick name of ‘’ Sunshine Vitamin” due to possibility of such synthesis.
Vitamin D3 is not grouped under essential dietary vitamin since to a great extent its synthesis takes place on daily basis. Its classification in vitamins is due to the fact that by its composition it is an organic compound and performs the role of nutrition in small amounts. In case the Vitamin D3 synthesis falls short of the daily requirement it needs to be sourced through diet or supplement options available.
Quite similar to other vitamins, the Vitamin D3 discovery came to light by studies focused on finding out a food substance deficiency of which was responsible for the disease of Rickets found in children suffering from Osteomalacia. The naturally occurring Vitamin D is included in staple foods like milk responsible in avoidance of Vitamin D deficiency.
The measurement of serum levels of Vitamin D3 determined by blood test is the indication about its synthesis occurred as a consequence of sunlight exposure as well as absorption through dietary sources. The belief is that the Vitamin D3 synthesis is responsible to maintain sufficiently its required serum level.
There is evidence indicating synthesis of Vitamin D caused by Sun exposure functioning with feedback loop mechanism, responsible for prevention of toxicity. Considering the potential of cancer occurrence there are no official recommendations suggesting the time period required for the synthesis to take place sufficient to fulfill the Vitamin D3 needs.
The data related to Vitamin D3 requirement in respect of dietary intake, it is based on the assumption that no synthesis takes place, which is quite unrealistic to assume, because occurrence of normal Vitamin D synthesis cannot be prevented.
Existence of Vitamin D in its Various Forms:
Vitamin D1 is a molecular compound Ergo-calciferol with Lumisterol having the ratio of 1:1 of each of these constituents.
Vitamin D2 is derived from Ergocalciferol.
Vitamin D3 is derived from Cholecalciferol produced from 7-dehydrocholesterol present in the skin.Vitamin D4 is represented by 22-Di-hydroergocalciferol.Vitamin D5 is Sito-calciferol produced from 7-de-hydrositosterol.In reality there are large numbers of forms of vitamin D existing referred as Vitamers out of which the two major kind of forms are vitamin D2 or Ergocalciferol and Vitamin D3 or Cholecalciferol. If there is no subscript numeral attached to vitamin D it has reference to Vitamin D2 or Vitamin D3 or both of them collectively termed as calciferol.
During the year 1936, Vitamin D3’s chemical structure got established and it was proved to be formed when the ultraviolet irradiation took place of its precursor i.e. 7-dehydrocholesterol.
As per the chemical classification the different forms of vitamin D are put under secosteroids explained as steroids with one of the bonds observed broken in its steroid rings. The difference in the structure of vitamin D2 and vitamin D3 is related to the individual side chains. The D2 side chain has a double bond existing between carbons 22 and 23, and presence of methyl group on carbon 24.
The Vitamin D undergoes conversion to calcidiol in the liver, which in turn partly gets converted to calcitriol by the kidneys being the biologically active Vitamin D found in the blood circulation performing a hormone related role, responsible for regulation of Calcium and Phosphate concentrations in the circulating blood. It promotes healthy bone growth and its remodeling activities.
The remaining calcidiol conversion is affected outside kidneys to calcitriol responsible for performance of cell activities like:
Calcitriol is affecting the neuromuscular function and inflammation process.
The primary role of Vitamin D is in bone health and no other health improvement has been reported by administration of Vitamin D supplements. Moreover there are evidences suggesting that use of Vitamin D supplements can achieve higher levels potentially harmful to the persons taking its supplements.
Reduction in Mortality Rates of Elderly Women:
The elderly women availing dependent care experience reduction of their mortality with Vitamin supplements intake. When vitamin D deficiency increases it becomes the cause of abnormal body functioning and premature aging sets in.
The harmful effects of vitamin D deficiency are suffered more by black color population in contrast to the white color population.
The vitamin D deficiency is marked with presence of osteomalacia, the condition in children is known as Rickets. There are increased incidences of falls as a result of low Vitamin D serum levels cause of lowered bone mineral density. The supplementation with vitamin D3 and calcium affects improvement in the bone mineral density to a limited extent, thereby causing reduction in risk of falling and bone fracture in specific group of persons living in institutions.
The Cardiovascular Diseases:
There is no strong evidence in favor of Vitamin D supplementation required for cardiovascular health. Although moderate to high doses of Vitamin D supplementation is likely to reduce risks associated with cardiovascular disease. Its clinical significance is disputed. However the suggestion is there explaining association of vitamin D deficiency causing heart palpitations possibly its role in regulation of magnesium and calcium.
Vitamin D Deficiency & Asthma Attacks:
Presence of lower serum levels of vitamin D in association with use of corticosteroids and effect of worsened airflow limitation was observed in a study involving asthmatic patients. The supplementation of Vitamin D was responsible for enhancing the gluco-corticoid action in the immune markers known as peripheral blood mononuclear cells (PBMCs) of the asthmatic patients and enhancing the immune-suppressive action exerted by Dexa-methasone, the steroid in vitro testing.