Vitamins are organic compounds essential for the normal growth, development, and maintenance
of the body functions. These micronutrients?? are obtained from different sources. Some vitamins are
absorbed in small quantities from the diet, while others are produced in the body when exposed to
sunlight, or by indigenous bacteria present in our body. Vitamins are essential for many physiological
functions. Deficiency of these micronutrients is more common in pregnant women and children under
the age of five years. Vitamin deficiency is detrimental to growth and development, intellectual growth,
and perinatal sustenance. Serious cases of low vitamin levels are associated with mortality and morbidity.
There are two major classes of vitamins depending on their solubility in fat or water.
Classification of Vitamins
The classification of vitamins is based on their solubility in fat or water. Vitamin B complex and
Vitamin C are water-soluble vitamins, whereas Vitamin A, D, E and K are fat soluble vitamins.
Fat-Soluble Vitamins
Fat soluble vitamins will not dissolve in water. Instead, fat-soluble vitamins are absorbed best when
taken with higher-fatty foods, Fats carry these vitamins through the intestine into the bloodstream.
Once absorbed into the body, fat-soluble vitamins are stored in fatty tissues and liver. The body can
use these stores for future use. Vitamin A, D, E and K are fat-soluble vitamins.
Vitamin A
Vitamin A includes a group of fat-soluble retinoids. This group contains retinol, retinal, and retinyl esters.
Human diet is composed of two forms of vitamin A. First form is preformed vitamin A (retinol and its
esterified form, retinyl ester) and second form is the provitamin A carotenoids. Most of the body's
vitamin A is stored in the liver in the form of retinyl esters. It is transported to the required body part
bound to a protein.
Vitamin A is critical for vision as an essential component of rhodopsin, a protein that absorbs light
in the retinal receptors, and because it supports the normal differentiation and functioning of the
conjunctival membranes and cornea. Other roles of vitamin A include assisting in cell growth and
cell differentiation. It also plays a critical role in the
Endogenous synthesis of vitamin D happens when ultraviolet rays from sunlight strike the skin.
This striking activates Vitamin D synthesis. Vitamin D helps to maintain adequate serum calcium
and phosphate concentrations in blood. This balance facilitates normal mineralization of bone.
It also prevents hypocalcemic tetany. Insufficient levels of vitamin D can cause the bones to
become thin and brittle.
Biology of Sunshine Vitamin
Vitamin D that is sourced from the diet or obtained from skin is biologically inactive or inert.
In order to get activated, this inert form must undergo hydroxylation in the liver and kidneys.
The first hydroxylation that takes place in the liver converts vitamin D to 25hydroxyvitamin D
[25(OH)D], also known as calcidiol. The second hydroxylation occurs in the kidney and forms
the physiologically active 1, 25-dihydroxy vitamin D [1,25(OH),D], also known as calcitriol.
Calcitriol is the biologically active form of vitamin D.
Groups at Risk of Vitamin D Inadequacy
Natural food sources are insufficient resources for vitamin D. A large number of people require
both regular consumption of vitamin D-fortified foods and exposure to sunlight for maintenance
of healthy vitamin D status.
Elderly people
Ageing is the reason that puts the elderly people at higher risk of developing vitamin D insufficiency.
The skin of older people cannot efficiently synthesize vitamin D. The other two causes could be
the inadequate intake of vitamins and limited sun exposure due to prolonged stay indoors.
Limited sun exposure
Individuals who are homebound eg. housewives, those who completely cover their bodies under
clothing, working in office (occupation that demands indoor stay) possess higher risk of low
vitamin D in the body.
Dark skin color
People with dark skin have high amount of pigment melanin that absorbs UV-B rays and decrease
the production of vitamin D through skin.
Fat malabsorption
Vitamin D is fat-soluble vitamin that requires the presence of fats in the gut for absorption. Those
people who have issues in fat absorption/reduced fat absorption from dietary source need vitamin
D supplements to fulfill body requirement.
Obesity
Overweight individuals are at greater risk of having low vitamin D, as the higher BMI value is
related to lower serum 25(OH)D levels. These individuals need higher intake of vitamin D to meet
the requirement compared to the non-obese people. Moreover, high amount of fats in the body
captures more vitamins and alters its release in the blood circulation,
Gastric Bypass Surgery
Gastric bypass surgery is also one of the reasons for low vitamin D levels in the body. In this surgical
procedure, the stomach is divided and bypassed with small intestine. As the upper small part of the
intestine absorbs vitamin D thus leading to low absorption of vitamin D.
Evaluation of Vitamin D and other fat-soluble Vitamins
Vitamin D evaluation is requisite to check whether an individual has sufficient levels of vitamin
D in the body. Levels of vitamin D in the body are estimated by measuring the concentration of
circulating 25(OH)D in the bloodstream. There are many commercial techniques which are been
used by various diagnostic laboratories for evaluation of the vitamin D. Some of them are
Radioimmunoassay (RIA), High-Performance Liquid Chromatography (HPLC), Chemiluminescence
Immunoassay (CLIA), etc.
Thyrocare offers tests to estimate the levels of vitamin D in the body. It has various tests like
25-OH vitamin D (total), vitamin profile that measures the vitamin level with the use of
instrumentation/technology like CLIA, ELISA, LCMS, etc. These tests are available at highly
affordable rates.
Other fat-soluble vitamins like A,K, and E are also been tested using technology like LCMS.
These tests help to track the vitamin levels and also warns about the risk associated with it.
FSV-LCMS
It is a superior analytical technique that has a combination of liquid chromatography and
mass spectrometry. The liquid chromatography provides physical separation and mass
spectrometry gives mass analysis. With the use of this technology, biomolecules like
amino acids, vitamins and drugs, etc are analyzed. Thyrocare technologies use LCMS for
screening the fat-soluble vitamins like A, K and E. This efficient method provide results
with precision and specificity at molecular levels.
D Total-CLIA
CLIA is a highly sophisticated technique that functions on the principle of emission of light by
the chemical labels attached to the antigen-antibody reaction. It is used for detection of various
components present in the blood. It is a highly sensitive technique used for estimation of vitamin D.
25-OH-ELISA
Enzyme-linked immunosorbent assay (ELISA) is a sensitive biochemistry technique that analyses
antigenantibody complexes with the use of enzyme-labeled antibodies. It is a plate-based technique
for detection and quantification of peptides, proteins, vitamins, antibodies and hormones. It is also
used for analysis of vitamin D levels in the body.
D Total with D2, D3-LCMS
A unique combination of two techniques - liquid chromatography and mass spectrometry is a high
quality and high output technology that is used for estimation of Vitamin D total. The physical separation
and mass analysis, both are taken care of in this combination. It is a highly LCMS specific and precise analysis,
thus giving you accurate results.
Thyrocare, with the state-of-the-art technology and instrumentation help to gain insight into the
health status by screening vitamin deficiencies that could possess risk/potential for diseases.
Therefore, to maintain optimum well-being get a preventive health checkup at affordable rate @ Thyrocare.
