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1. PRESENTER : YASH SUNILKUMAR LODHA.
TOPIC : ALL ABOUT VITAMIN D

2. OBJECTIVES :
What is vitamin D
Types.
Biology.
Roles.
SYNTHESIS OF VITAMIN D
Vitamin D Deficiency
Symptoms and Health Risks of Vitamin D Deficiency
Causes of Vitamin D Deficiency:
Tests for Vitamin D Deficiency:
VITAMINE D AND COVID 19 :

4. Cholecalciferol

5. 5/4/2021

6. Several forms (vitamers) of vitamin D exist. The two major forms are vitamin
D2 or ergocalciferol, and vitamin D3 or cholecalciferol; vitamin D without a
subscript refers to either D2 or D3 or both. These are known collectively as
calciferol. Vitamin D2 was chemically characterized in 1931. In 1935,
the chemical structure of vitamin D3 was established and proven to result
from the ultraviolet irradiation of 7-dehydrocholesterol.
Chemically, the various forms of vitamin D are secosteroids, i.e., steroids in
which one of the bonds in the steroid rings is broken.The structural
difference between vitamin D2 and vitamin D3 is the side chain of D2 that
contains a double bond between carbons 22 and 23, and a methyl
group on carbon 24.

7. • BIOLOGY:
• The active vitamin D metabolite calcitriol mediates its biological effects by
binding to the vitamin D receptor (VDR), which is principally located in
the nuclei of target cells.
• The binding of calcitriol to the VDR allows the VDR to act as a transcription
factor that modulates the gene expression of transport proteins (such
as TRPV6 and calbindin), which are involved in calcium absorption in the
intestine.
• The vitamin D receptor belongs to the nuclear receptor superfamily
of steroid/thyroid hormone receptors, and VDRs are expressed by cells in
most organs, including the brain, heart, skin, gonads, prostate, and breast.
• VDR activation in the intestine, bone, kidney, and parathyroid gland cells
leads to the maintenance of calcium and phosphorus levels in the blood
(with the assistance of parathyroid hormone and calcitonin) and to the
maintenance of bone content.

8. • ROLES:
• One of the most important roles of vitamin D is to maintain skeletal calcium
balance by promoting calcium absorption in the intestines, promoting bone
resorption by increasing osteoclast number, maintaining calcium and
phosphate levels for bone formation, and allowing proper functioning of
parathyroid hormone to maintain serum calcium levels.
• Vitamin D deficiency can result in lower bone mineral density and an
increased risk of reduced bone density (osteoporosis) or bone
fracture because a lack of vitamin D alters mineral metabolism in the body.
• [20] Thus, vitamin D is also critical for bone remodeling through its role as a
potent stimulator of bone resorption.
• The VDR regulates cell proliferation and differentiation.
• Vitamin D also affects the immune system, and VDRs are expressed in
several white blood cells, including monocytes and activated T and B cells. In
vitro, vitamin D increases expression of the tyrosine hydroxylase gene
in adrenal medullary cells, and affects the synthesis of neurotrophic
factors, nitric oxide synthase, and glutathione.
• Vitamin D receptor expression decreases with age and findings suggest that
vitamin D is directly related to muscle strength, mass and function, all being
important factors to an athlete's performance

9. SYNTHESIS OF VITAMIN D :

10. Vitamin D Deficiency
If you shun the sun, suffer from milk allergies, or adhere to a
strict vegan diet, you may be at risk for vitamin D deficiency. Known
as the sunshine vitamin, vitamin D is produced by the body in
response to skin being exposed to sunlight. It is also occurs naturally
in a few foods -- including some fish, fish liver oils, and egg yolks --
and in fortified dairy and grain products.
Vitamin D is essential for strong bones, because it helps the body
use calcium from the diet. Traditionally, vitamin D deficiency has
been associated with rickets, a disease in which the bone tissue
doesn't properly mineralize, leading to soft bones and skeletal
deformities. But increasingly, research is revealing the importance of
vitamin D in protecting against a host of health problems

11. 5/4/2021
• Causes of Vitamin D Deficiency:
• Vitamin D deficiency can occur for a number of reasons:
• You don't consume the recommended levels of the vitamin over time.
• This is likely if you follow a strict vegan diet, because most of the natural
sources are animal-based, including fish and fish oils, egg yolks, fortified milk,
and beef liver.
• Your exposure to sunlight is limited. Because the body makes vitamin D when
your skin is exposed to sunlight, you may be at risk of deficiency if you are
homebound, live in northern latitudes, wear long robes or head coverings for
religious reasons, or have an occupation that prevents sun exposure.
• You have dark skin. The pigment melanin reduces the skin's ability to make
vitamin D in response to sunlight exposure. Some studies show that older adults
with darker skin are at high risk of vitamin D deficiency.
• Your kidneys cannot convert vitamin D to its active form. As people age,
their kidneys are less able to convert vitamin D to its active form, thus
increasing their risk of vitamin D deficiency.

12. • Your digestive tract cannot adequately absorb vitamin D. Certain
medical problems, including Crohn's disease, cystic fibrosis, and celiac
disease, can affect your intestine's ability to absorb vitamin D from the
food you eat.
• You are obese. Vitamin D is extracted from the blood by fat cells,
altering its release into the circulation. People with a body mass index of
30 or greater often have low blood levels of vitamin D.

13. Symptoms and Health Risks of Vitamin D Deficiency:
Symptoms of bone pain and muscle weakness can mean you have
a vitamin D deficiency. However, for many people, the symptoms
are subtle. Yet, even without symptoms, too little vitamin D can
pose health risks. Low blood levels of the vitamin have been
associated with the following:
Increased risk of death from cardiovascular disease
Cognitive impairment in older adults
Severe asthma in children
Cancer
Research suggests that vitamin D could play a role in the
prevention and treatment of a number of different conditions,
including type1 and type 2 diabetes, hypertension, glucose
intolerance, and multiple sclerosis

14. Tests for Vitamin D Deficiency:
• Treatment for vitamin D deficiency involves getting more vitamin D -- through
diet and supplements.
• Although there is no consensus on vitamin D levels required for optimal health
-- and it likely differs depending on age and health conditions -- a
concentration of less than 20 nanograms per milliliter is generally considered
inadequate, requiring treatment.
• Guidelines from the Institute of Medicine increased the recommended dietary
allowance (RDA) of vitamin D to 600 international units (IU) for everyone ages
1-70, and raised it to 800 IU for adults older than age 70 to optimize bone
health.
• The safe upper limit was also raised to 4,000 IU. Doctors may prescribe more
than 4,000 IU to correct a vitamin D deficiency.
• If you don't spend much time in the sun or always are careful to cover your
skin (sunscreen inhibits vitamin D production), you should speak to your doctor
about taking a vitamin D supplement, particularly if you have risk factors for
vitamin D deficiency.

15. VITAMINE D AND COVID 19 :
Vitamin D deficiency has been shown to potentially increase the risk of severe
respiratory infections.
This has caused a renewed interest of this potential in 2020 during the COVID-19
pandemic.
A systematic review and meta-analysis of 27 publications found that vitamin D
deficiency was not associated with a higher probability of becoming infected
with COVID-19, but found positive correlations between vitamin D deficiency
and the severity of the disease, including increases in hospitalization and
mortality rates.
In June 2020, the US National Institutes of Health found insufficient evidence to
recommend for or against using vitamin D supplementation specifically to
prevent or treat COVID-19.
In the same month UK NICE found no evidence for or against taking vitamin D
supplements specifically to prevent or treat COVID-19.
Both organizations included recommendations to continue the previous
established recommendations on vitamin D supplementation for other reasons,
such as bone and muscle health, as applicable.

16. Both organizations noted that more people may require supplementation due to
lower amounts of sun exposure during the pandemic,and the NHS has provided
free daily vitamin D supplements for people at high risk from COVID-19.
The major complication of COVID-19 is acute respiratory distress syndrome (ARDS),
which may be aggravated by vitamin D deficiency, an association that is not
specific to coronavirus infections.
A number of trials in different countries are being carried out in 2020 to address
the potential for the use of vitamin D for the prevention and treatment of SARS-
CoV-2 infections.

17. Thank you !!!