1. Useful information you should know
Vitamin D
Useful information you should know

2. objectives What is Vitamin D and how do we get it?
How does Vit D help us?
What are the normal, low, high levels of Vit D in blood?
What are the common reasons for Vit D deficiency?
Vit D deficiency in Indians
Signs, symptoms and consequences of Vit D deficiency
Doses of Vit D
Adverse effects of excess Vit D
References

3. What is vitamin D (Vit D) and how do we get it?
Vitamin D is a fat soluble vitamin, plays an important role in several body functions
Naturally present in very few foods
Produced in our body when Ultra-Violet rays (UV rays) from Sun hit our skin that triggers Vit D synthesis in skin
Vit D obtained from food, supplements, Sun is biological inert or inactive
It undergoes two chemical reactions (first in liver, second in kidney) after which is becomes active

4. Sources of vitamin d Fish: Rawas, Tuna, Oysters, Prawns
Fish Liver oil (especially Cod liver oil)
Milk, cheese egg yolk (in small amount)
Wild Mushrooms is the only plant source of Vit D – produced when they are exposed to U-V rays
Fortified foods: In developed countries, many foods are fortified with Vit D – such as milk, orange juice, yogurt, soy milk, cereals
Endogenously produced by our skin when exposed to Sunlight
Vit D occurs in two natural forms:
Vit D2 or ergocalciferol – through plant sources and in fortified food
Vit D3 or cholecalciferol – from animal sources and from Sunlight

5. Functions of vitamin d in our body
Vit D promotes absorption of calcium from our intestines (gut)
It helps maintain adequate and balanced concentration of calcium and phosphorus in our blood
These are needed for our bone health – bone growth, remodelling and adequate mineralization required for strength
Vit D also has a possible role to play in,
Regulating our immune function
Improvement of muscle function
Lowering BP and enhancing heart health
Warding off depression
Regulating blood sugar levels, increasing evidence that Vit D may help delaying type 2 diabetes
Preventing several types of cancers

6. Vitamin d levels in our blood measured as serum 25-hydroxyvitamin D (25 (OH)D)
Nmol/L
Ng/ml
Health Status
< 30
< 12
Associated with Vit D deficiency, leading to Rickets in infants and children and osteomalacia (weak bones) in adults
30 to < 50
12 to < 20
Generally considered inadequate for bone and overall health in healthy individuals
>=50
>=20
Generally considered adequate for bone and overall health in healthy individuals
> 125
> 50
Emerging evidence links potential adverse effects (harm) to such high levels, particularly over 150 Nmol/L or 60 ng/ml
Values as recommended by committee of Institute of Medicine, USA
Carefully review the unit of measurement mentioned in your report while drawing conclusions
In India, < 20 ng/ml is considered as deficiency, 20 – 29 ng/ml as insufficiency (borderline) and > 30 ng/ml as adequate levels of Vit D in blood
Serum levels do not reflect the Vit stored/trapped in body fat

7. Common reasons for vitamin D deficiency
Vulnerable Group
Reason/s
Breast fed infants
Milk contains low Vit D, hence unless given supplement of Vit D, infants purely fed breast milk may develop deficiency
Older people
Skin becomes thinner with age, not able to efficiently produce Vit D, also less exposure to Sunlight, as mobility may decrease with age
Obesity
On one hand, increased requirement, on the other hand excess body fat traps Vit D, thus making less active Vit D available in blood for its activities
Pregnancy
Increased demand
Darker skin
Contains higher concentration of pigment melanin, which interferes with Vit D synthesis
Gastric bypass surgery
Interferes with the absorption of Vit D
Serious liver or digestive disorders
Interfere with absorption and converting Vit D to active vitamin in the body

8. Vitamin D deficiency in Indians
Vit D deficiency is widespread in India (for e.g., despite fish eating habits, many from Bengal still have it)
For those, who are pure vegetarian, there is hardly any food source to get the vitamin. High phytate content in vegetarian diet also interferes with absorption of Vit D
Overall poor nutritional status in large number of people in India
Foods are not commonly fortified with Vit D in India (Amul is one brand that offers fortified milk)
Shunning the Sun: tendency of people to avoid going out in Sun, changing lifestyle of “global” workers
Dark skin tone: Skin pigment reduces the ability of skin to make Vit D. Dark skinned people may need 20 to 30 times more exposure to Sun to make adequate Vit D compared to light skinned
Excess use of Sun screens: Sunscreen with SPF 15 can block 93% of U-V rays from Sun, thus blocking Vit D production
High level of pollution in the air, high food contamination
This Photo by Unknown Author is licensed under CC BY-SA

9. What happens when there is vit d deficiency
Without Vit D, our bones become weak, thin, brittle and may misshapen. There is loss of bone
In infants and children, Vit D deficiency may lead to rickets (pot belly and bow legs)
In adults, it may cause osteomalacia – weak bones, leading to pain
Osteoporosis leading to increased risk of fractures in older people
Several other body functions may also get affected

10. How much vitamin d we need normally?
Age/group
Vit D needed/day
0 – 12 months
400 International Units (IU)
1 to 18 years
600 IU
19 to 70 years
> 70 years
800 IU
Pregnancy, lactation
For preventing osteoporosis and fractures in older adults
400 to 1000 IU
In case of Vit D deficiency, the doctor may prescribe higher doses to treat the deficiency
Even in deficiency, the upper limit of Vit D to be prescribed is,
Adults – maximum 4000 IU/day or IU per week
Children – maximum 1000 – 3000 IU per day
This Photo by Unknown Author is licensed under CC BY-ND

11. Side effects of vitamin D
Vit D is generally safe when taken within allowable limits (both by mouth and intramuscular injection) and most people do not experience any side effects
It can, however, interact with several medications which can affect its actions:
Steroids prescribed for many illnesses such as asthma, rheumatoid arthritis etc.
Some anti-epilepsy medications such as phenobarbitone, phenytoin
Laxatives (prescribed for constipation)
Digoxin, prescribed for heart failure
Some drugs that increase urine output,
Statins prescribed for high cholesterol levels
It is, therefore, important to share with your doctor if you are taking Vit D supplements

12. Vitamin D overdose and toxicity
Vitamin D intake and levels in blood beyond defined limits do not offer any additional benefit and may cause harmful side effects
Intake of > 4000 IU/day of Vit D over a long period, increases the risk of hypervitaminosis
The signs and symptoms of Vit D toxicity include:
Loss of appetite
Nausea, vomiting
Loss of weight
Dry mouth, metallic taste in mouth
Weakness, fatigue
Headache, sleepiness
Excess urination
Irregular heart beats
Excess Vit D intake over a long period can raise calcium levels in blood, which can cause damage to heart, blood vessels and kidneys, raise the risk of kidney stone
Consult your doctor immediately if you develop any of the above

13. References: National Institute of Health (NIH), USA
Web MD and Medscape
Drugs.com
G Ritu, G Ajay. Vit D deficiency in India: Prevalence, causalities and interventions. Nutrients 2014; 6(2):729-75
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