What is Vitamin D?
Vitamin D is a fat-soluble vitamin. Fat-soluble vitamins are stored in the body’s fatty tissue.
What is the Function of Vitamin D in our body?
Vitamin D helps the body absorb calcium. Calcium and phosphate are two minerals that are
essential for normal bone formation. Thus vitamin D is important for good overall health
and strong and healthy bones. It’s also an important factor in making sure muscles, heart,
lungs and brain work well and that the body can fight infection.
Our body can make its own vitamin D from sunlight. We can also get vitamin D from
supplements and a very small amount comes from a few foods you eat.
Vitamin D deficiency can lead to osteoporosis in adults or rickets in children.
Vitamin D is very important for strong bones. Calcium and phosphorus are essential for
developing the structure and strength of your bones, and we need vitamin D to absorb
these minerals. Even if we eat foods that contain a lot of calcium and phosphorus, without
enough vitamin D, we can’t absorb them into our body. Vitamin D is important for general
good health, and researchers now are discovering that vitamin D may be important for
many other reasons outside of good bone health. Some of the functions of the body that
vitamin D helps with includes:
Immune system, which helps you to fight infection
Muscle function
Cardiovascular function, for a healthy heart and circulation
Respiratory system -for healthy lungs and airways
Brain development
Anti-cancer effects
What are the sources of Vitamin D?
The body makes vitamin D when the skin is directly exposed to the sun. That is why it is
often called the “sunshine” vitamin. Most people meet at least some of their vitamin D
needs this way.
Very few foods naturally contain vitamin D. As a result, many foods are fortified with
vitamin D. Fortified means that vitamins have been added to the food.
Fatty fish (such as tuna, salmon, and mackerel) are among the best sources of vitamin D.
Beef liver, cheese, and egg yolks provide small amounts.
Mushrooms provide some vitamin D. The vitamin D content is also being boosted by
exposure to some commercially available mushrooms to ultraviolent light.
Vitamin D can be added to milk, many breakfast cereals and to some brands of orange
juice, yogurt, and margarine. Check the nutrition fact panel on the food label.
What is the daily requirement of Vitamin D?
Ten to 15 minutes of sunshine three times weekly is enough to produce the body’s
requirement of vitamin D. The sun needs to shine on the skin of your face, arms, back, or
legs (without sunscreen).
People who do not live in sunny places may not make enough vitamin D. Skin that is
exposed to sunshine indoors through a window will not produce vitamin D. Cloudy days,
shade, and having dark-coloured skin also cut down on the amount of vitamin D the skin
makes.
How common is Vitamin D deficiency in India?
One study revealed that a whopping 69 per cent of Indians suffer from vitamin D deficiency,
while a further 15 per cent were found to be vitamin D insufficient. Healthcare professionals
blame fast-paced, stressed-out lifestyles. With long working hours and little or no time for
outdoor activities, more and more people are suffering from vitamin D deficiency.
What are the types of Vitamin D?
The two major forms are vitamin D 2 or ergocalciferol, and vitamin D 3 or cholecalciferol;
vitamin D without a subscript refers to either D 2 or D 3 or both. These are known collectively
as calciferol.
What are the deficiency symptoms of Vitamin D?
A diet deficient in vitamin D in conjunction with inadequate sun exposure causes
osteomalacia (or rickets when it occurs in children), which is a softening of the bones.
Osteomalacia
Osteomalacia is a disease in adults that results from vitamin D deficiency. Characteristics of
this disease are softening of the bones, leading to bending of the spine, bowing of the legs, proximal muscle weakness, bone fragility, and increased risk for fractures. Osteomalacia reduces calcium absorption and increases calcium loss from bone, which increases the risk for bone fractures. Osteomalacia is usually present when 25-hydroxyvitamin D levels are less than about 10 ng/mL. The effects of osteomalacia are
thought to contribute to chronic musculoskeletal pain.
Rickets
Rickets, a childhood disease, is characterized by impeded growth and soft, weak,
deformed long
Bones that bend and bow under their weight as children start to walk. This condition is
characterized by bow legs, which can be caused by calcium or phosphorus deficiency, as
well as a lack of vitamin D; today, it is largely found in low-income countries in Africa, Asia,
or the Middle East and in those with genetic disorders such as pseudovitamin D deficiency
rickets.
Influence of skin pigmentation
Some research shows dark-skinned people living in temperate climates have lower vitamin
D levels.Dark-skinned people may be less efficient at making vitamin D because melanin in
the skin hinders vitamin D synthesis.
How do I know I have vitamin D deficiency?
Because vitamin D can come from sun, food, and supplements, the best measure of one’s
vitamin D status is blood levels of a form known as 25-hydroxyvitamin D. Blood levels are
described either as nanograms per milliliter (ng/mL) or nanomoles per liter (nmol/L), where
0.4 ng/mL = 1 nmol/L.
Levels below 30 nmol/L (12 ng/mL) are too low for bone or overall health, and levels above
125 nmol/L (50 ng/mL) are probably too high. Levels of 50 nmol/L or above (20 ng/mL or
above) are sufficient for most individuals.
The Recommended Dietary Allowance (RDA) for vitamins reflects how much of each vitamin
most people should get on a daily basis.
The RDA for vitamins may be used as goals for each person.
How much of each vitamin you need depends on your age and gender. Other factors,
such as pregnancy and your health, are also important.
Infants (adequate intake of vitamin D) – 400 IU (10 micrograms (mcg) per day)
Children – 1 – 8 years: 600 IU (15 mcg/day)
Older children and adults – 9 – 70 years: 600 IU (15 mcg/day)
Elderly Adults over 70 years: 800 IU (20 mcg/day)
In general, people over age 50 need higher amounts of vitamin D than younger people.
Vitamin D toxicity almost always occurs from using too many supplements rather than more
sunshine.
The safe upper limit for vitamin D is:
1,000 to 1,500 IU/day for infants
2,500 to 3,000 IU/day for children 1 – 8 years
4,000 IU/day for children 9 years and older, adults, and pregnant and breast-feeding teens and women
One microgram of cholecalciferol (D 3 ) is the same as 40 IU of vitamin D.
What is the treatment of Vitamin D deficiency?
BY MOUTH:
* For preventing osteoporosis and fractures: 400-1000 IU per day has been used for
older adults. Some experts recommended higher doses of 1000-2000 IU daily.
* For preventing falls: 800-1000 IU/day has been used in combination with calcium 1000-
1200 mg/day.
* For preventing multiple sclerosis (MS): long-term consumption of at least 400 IU per
day, mainly in the form of a multivitamin supplement, has been used.
* For preventing all cancer types: calcium 1400-1500 mg/day plus vitamin D3
(cholecalciferol) 1100 IU/day in postmenopausal women has been used.
* For muscle pain caused by medications called “statins”: vitamin D2 (ergocalciferol) or
vitamin D3 (cholecalciferol) 50,000 units once a week or 400 IU daily.
* For preventing the flu: vitamin D (cholecalciferol) 1200 IU daily.
* Most vitamin supplements contain only 400 IU (10 mcg) vitamin D.
Fortified Foods in India
A nice article on this subject “Fortification of Foods with Vitamin D in India” by Ritu G and
Ajay Gupta can be found in Nutrients 2014, 6, 3601-3623; www.mdpi.com/journal/nutrients
Foods are rarely fortified with vitamin D in India. Limitations pertaining to vitamin D fortified
milk, AmulTM (Anand, Gujarat, India) and Kellogg’s breakfast cereals. Some studies support
the strategy of the fortification of foods in India for redressing malnutrition problems in
India. They also suggest that to reach sufficiency, a daily intake of more than 1000 IU may be
required to attain vitamin D sufficiency.
The authors suggest that the epidemic of vitamin D deficiency in India and its health
consequences call for a population-based approach, such as food fortification rather than
prescribing vitamin D supplements. Fortification doses in India would need to be adjusted to
suit the vitamin D status and dietary patterns of Indians. Considering the diversity of foods
and cultures, a large variety of foods will need to be fortified. We propose the addition of
vitamin D to wheat flour, maida, rice and rice flour in India, to increase mean daily dietary
intakes of vitamin D.
Do it yourself strategy
Two examples of fortification at home are as follows: (a) The average wheat flour
consumption per person per day is about 200 gm. Mix contents of 1 sachet to 2.1 kg of
wheat flour thoroughly and store in a cool, dark and dry place. This premix will be sufficient
for four persons for 15 days. Add one cup (1 cup = 140 g) to flour before kneading the dough
once every day for a family of four. This will provide about 1000 IU of vitamin D per person
per day. (b) Add the contents of one sachet of vitamin D in 300 mL of condensed milk, mix
thoroughly and store in an amber glass jar in the refrigerator. Consume 5 mL or one
teaspoon every day after a meal or add once per day to milk, brewed tea or coffee. This will
provide about 1000 IU of vitamin D every day.
Are there any risks of Vitamin D overdose?
Too much vitamin D can make the intestines absorb too much calcium. This may cause high
levels of calcium in the blood. High blood calcium can lead to:
Calcium deposits in soft tissues such as the heart and lungs
Confusion and disorientation
Kidney stones & damage to the kidneys
Nausea, vomiting, constipation, poor appetite, weakness, and weight loss
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