Have you got Sunshine?
I can vividly recall myself singing "Have you got a Sunshine SMILE" during my nursery rhymes classes to my heart's content. Unintentionally this rhyme has been a reminder to get enough sunshine or to be more precise the "Sunshine Vitamin".
Sunshine Vitamin aka Vitamin D is a fat-soluble vitamin that is well known for its role in the absorption of calcium and phosphorus.
Why is there a need for Vitamin D?
Vitamin D plays an important role in maintaining bone health. This is because vitamin D aids in the absorption of calcium which is an important nutrient for bone health. It reduces the risk of rickets in children and osteoporosis in adults. 
It has been found that supplementation of vitamin D to elderly people reduces the risk of hip and any nonvertebral fracture.
Apart from playing a role in bone health, studies have shown that its deficiency increases the risk for cardiovascular diseases. Therefore vitamin D also plays an important role in decreasing the risk of cardiovascular diseases.
Vitamin D possesses an antiproliferative effect that helps reduce the incidence of cancer. Clinical trials have shown that there was a reduced risk of all types of cancer in postmenopausal women with adequate vitamin D levels. 
Vitamin D is said to be an immunomodulatory hormone. Low levels of vitamin D is said to increase the risk of various immune-related diseases like tuberculosis, viral infections, rheumatoid arthritis, sepsis and respiratory infection.  The possible role of vitamin D in the prevention and management of Covid 19 has been pointed out by various scholars which need further research.
Why the name "Sunshine Vitamin"?
On exposure to the sun, our body produces vitamin D. The mechanism includes the formation of previtamin D from cholesterol on exposure to solar ultraviolet B (UVB).
It is then converted to calcidiol (storage form) in the liver and further changed to form calcitriol in the kidneys. The formation of vitamin D through adequate exposure to the sun is considered to meet around 80% of the needs.
This information should be a reason to motivate you to enjoy sunbathing for 10-30 min twice a week. While enjoying the sun, do keep in mind that prolonged exposure to UV radiation can cause skin cancer. Hence, moderate the time spent in the sun.
Best sources of vitamin D ( Apart from sunshine)
A limited number of foods naturally contain vitamin D. Vegan sources of vitamin D include mushroom and lichens. 100gm of mushroom will give you around 450 IU of vitamin D. Some of the commercially sold mushrooms are intentionally exposed to UV light to increase the vitamin D content. Including one of these in your daily diet can help you maintain your daily dose of vitamin D.
Know your Vitamin D needs
One must consume 400IU of vitamin D on daily basis.
When does the need increase?
If you think that you get enough vitamin D because you live in the tropics or consume a balanced diet then you may be wrong. In some cases, diet and exposure to sunlight may not necessarily be adequate to meet the demand of the body. In such cases, supplementation plays an important role. The various groups who are at the risk of being deficient in vitamin D levels are as follows:
Breastfed infants - Mother's milk is not enough to meet the needs of the infant. At the same time, vitamin D in breast milk depends on the vitamin D status of the mother. Therefore supplementation is necessary in such cases.
People with limited exposure to the sun - If you are a person who hardly comes out in the sun then you may need a vitamin D supplement.
People with dark skin- Melanin is responsible for our skin complexion. People with darker skin complexion have more melanin and this reduces the production of vitamin D.
People with fat malabsorption, kidney and liver damage and who have undergone bypass surgery may also need supplementation.
Aged individuals - During the process of ageing the skin loses its capacity to produce vitamin D. It is then a dietary form of the vitamin and supplementation becomes necessary. 
Increased need for vitamin D can also be observed in case of low sun intensity, usage of body coverings, magnesium deficiency and old age.
If you ever feel you come under the aforementioned category then you must surely check your vitamin D status. Apart from these, people who apply sunscreen, wear fully covered clothes and consume a vitamin D deficient diet may have low levels in the body.
Signs you are low in vitamin D
Vitamin D helps in the absorption of calcium and phosphorus therefore its deficiency can lead to disruption in bone metabolism. Check out for these signs and symptoms -
- Muscle weakness
- Difficulty in walking
- Increased swaying in elderly people
- Susceptible to fall and fracture
- Low bone mineral density
Prolonged deficiency of vitamin D can cause rickets in children and osteomalacia in adults.
- Vitamin D deficiency affects 50% of the world’s population. Even if you spend ample time in the sun, adequate vitamin D might not be produced due to multiple factors.
- Therefore in order to avoid any deficiency, one must consume mushrooms or 400 IU of vitamin D supplement from Lichens.