The document discusses vitamin D, including its sources, functions, deficiency, and recommended intake. Some key points: - Vitamin D is important for calcium absorption and bone health. It is produced in the skin upon sun exposure and found in some foods. - It aids in calcium uptake, supporting bone formation and maintenance. Deficiency can lead to rickets in children and osteomalacia in adults. - Symptoms of deficiency include bone pain, muscle weakness, and fatigue. Risk factors include lack of sun exposure and certain medical conditions. - Recommended daily intake varies by age but getting regular sun exposure and including foods like fatty fish can help prevent deficiency.

1. Department of Nutrition
By :Arfina Aljaseer
121-i2b

2. Why do we need vitamin D ?
• Vitamin D is both a nutrient we eat and a hormone our
bodies make.
• It is a fat-soluble vitamin that has long been known to help
the body absorb and retain calcium and phosphorus,both
are critical for building bone.
• It is also produced endogenously when ultraviolet (UV) rays
from sunlight strike the skin and trigger vitamin D
synthesis.
• It is also needed for bone growth and bone remodeling by
osteoblasts and osteoclasts . Without sufficient vitamin D,
bones can become thin, brittle, or misshapen.
• Vitamin D has other roles in the body, including reduction of
inflammation as well as modulation of such processes as
cell growth, neuromuscular and immune function, and
glucose metabolism

3. Types of Vitamin D
• Ergosterol (provitamin D-2). This type is found in plants.
• Ergocalciferol (vitamin D-2). This type is also found in
plants.
• 7-dehydrocholesterol. This type is found in animals.
• Calciferol (vitamin D-3). This type is formed in the body
from exposure to sunlight.
The two major forms are vitamin D2 and vitamin D3. Vitamin D2 (ergocalciferol) is
largely human-made and added to foods, whereas vitamin D3 (cholecalciferol) is
synthesized in the skin of humans from 7-dehydrocholesterol and is also consumed
in the diet via the intake of animal-based foods.

4. Sources of vitamin D

7. Function of Vitamin D
• The major biological function of vitamin D is to
maintain normal blood levels of calcium and
phosphorus.
• Vitamin D aids in the absorption of calcium, helping
to form and maintain strong bones.
• Provide protection from and decrease an
individual’s risk of developing osteoporosis,
hypertension, cancer, and several autoimmune
diseases.
• it triggers the body’s immune cells to produce
antibodies,therefore, vitamin D promotes an overall
increase in the strength of the immune system.
• vitamin D assists in the maintenance of joint and
muscle comfort, as well as the maintenance of a
healthy mood, and supports breast, colon, and
prostate health.
• Vitamin D is also essential for the dental health. It
prevents tooth decay and loss, strengthen the
gums and reduces risk of any oral infection.

8. Action of Calcitriol on organs
Action on intestine:
• Calcitriol increases the intestinal
absorption of calcium and phosphate
• In the intestinal cells, calcitriol binds
with a cytosolic receptor to form a
calcitriol-receptor complex
• This complex interacts with a specific
DNA leading to the synthesis of a
specific calcium binding protein
• This protein increases calcium uptake
by intestine The mechanism of action
of calcitriol is similar to that of steroid
hormone
Action on bone:
• In osteoblasts of bone,
calcitriol stimulates calcium
uptake for deposition as
calcium phosphate
• Calcitriol is essential for bone
formation
• Calcitriol along with
parathyroid hormone
increases the mobilization of
calcium and phosphate from
the bone.
• Causes elevation in the
plasma calcium and
phosphate
Action on kidney:
• Calcitriol is also involved
in minimizing the
excretion of calcium and
phosphate through the
kidney by decreasing
their excretion and
enhancing reabsorption

10. Recommended Dosage

11. Deficiency
Vitamin D deficiency means you don’t have enough vitamin D in your body. It primarily causes
issues with your bones and muscles.
Signs and symptoms might
include:
• Fatigue.
• Bone pain.
• Muscle weakness, muscle aches or
muscle cramps.
• Mood changes, like depression.
However, you may have no signs or
symptoms of vitamin D deficiency.

12. Causes of vitamin D deficiency
In general, the two main causes of vitamin D
deficiency are:
• Not getting enough vitamin D in your diet and/or
through sunlight.
• Your body isn’t properly absorbing or using
vitamin D.
There are several specific causes of vitamin D
deficiency, including:
• Certain medical conditions.
• Weight loss-surgeries.
• Certain medications.
Several different biological and environmental factors
can also put you at a greater risk of developing
vitamin D deficiency, such as older age and the
amount of melanin (pigment) in your skin.

13. RICKETS
Rickets is the softening and weakening of bones in children, usually
because of an extreme and prolonged vitamin D deficiency. Rare
inherited problems also can cause rickets. Vitamin D helps your child's
body absorb calcium and phosphorus from food. Not enough vitamin D
makes it difficult to maintain proper calcium and phosphorus levels in
bones, which can cause rickets.
Signs and symptoms of rickets can include:
• Delayed growth
• Delayed motor skills
• Pain in the spine, pelvis and legs
• Muscle weakness
Because rickets softens the areas of growing tissue at the ends of a
child's bones (growth plates), it can cause skeletal deformities such as:
• Bowed legs or knock knees
• Thickened wrists and ankles
• Breastbone projection

14. OSTEOMALACIA
Osteomalacia means "soft bones." Osteomalacia is a
disease that weakens bones and can cause them to
break more easily.
It is a disorder of decreased mineralization, which
results in bone breaking down faster than it can re-form.
It is a condition that occurs in adults. In children,
inadequate concentrations of vitamin D may cause
rickets.
Causes
Osteomalacia develops most commonly due to a vitamin
D deficiency (often from not getting enough sunlight), or
less frequently, due to a digestive or kidney disorder.
Vitamin D is essential for calcium absorption and for
maintaining bone health. These disorders can interfere
with the body's ability to absorb vitamins. There are also
rare genetic conditions that can cause osteomalacia.

15. Prevention of Vitamin D Deficiency
The best way to prevent vitamin D deficiency is to ensure you’re getting enough vitamin D in your diet
and/or through sun exposure. But be careful about being in the sun for too long without sunscreen.
Excessive sun exposure puts you at an increased risk for skin cancer.
The amount of vitamin D you need each day depends on your age. The average daily recommended
amounts are listed below in micrograms (mcg) and International Units (IU).

16. References
https://www.pharmacytimes.com/view/otcfocusvitamind-0210
https://www.sciencedirect.com/science/article/abs/pii/S1879981717301262
https://my.clevelandclinic.org/health/diseases/15050-vitamin-d-vitamin-d-deficiency
https://www.msdmanuals.com/home/disorders-of-nutrition/vitamins/vitamin-d-deficiency
https://my.clevelandclinic.org/health/diseases/13017-osteomalacia
https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

17. THANK YOU!