Vitamin D is so important that your body makes it by itself - but only after skin exposure to sufficient sunlight, hence the name 'sunshine' vitamin. Vitamin D is required for many bodily functions. Your body needs this essential vitamin to build and maintain bone and teeth health. Your skin, muscle, brain and nerves also need Vitamin D to function properly. Studies suggest that vitamin D may play an important role in the prevention of various allergic diseases. Vitamin D is a hormone, a nutrient essential for good health.

How to replenish this valuable nutrient: Keep in mind that the best way to get more vitamin D is from sunshine. Thirty minutes of sun exposure to the face, legs, or back - without sunscreen - at least twice a week should give you plenty of vitamin D. Only 20% of our vitamin D is meant to come from our diet. But it is also equally important to get vitamin D from foods or from supplements.

Foods that are high in this vitamin include fatty fishes like tuna and salmon which are a great source of vitamin D. Some dairy products like cottage cheese, soy milk, homemade sour yoghurt are rich in vitamin D. Other sources include orange juice, beef liver, egg yolks, mushroom, carrot, broccoli, avocado and sweet potatoes. Infants vitamin D storage in the first year of life relies on the mother's storage of vitamin D before birth.

Causes that can lead to vitamin D deficiency: Infants who are only breastfed, people with dark skin (which does not absorb the sunlight as well as light skin), obese people, people who have liver or kidney problems and people who use sunscreen often and people who take certain medicines, like anti-seizure drugs or steroids are at risk of vitamin D deficiency.

A long-term deficiency can lead to osteoporosis, bone and muscle aches, depression, dental changes, brittle nails, hair loss and skin sagging. Inadequate exposure to sunlight, poor choice of food, ageing process, obesity, pregnancy and lactating stages - these conditions increase the need for this vital vitamin. It can be consumed in the diet through food or supplements and by exposing yourself to the sunlight. You can have a simple blood test prescribed by your doctor to detect vitamin D deficiency.

Too much of any good thing is a bad thing. Too much vitamin D can cause an abnormally high blood calcium level, which could result in nausea, constipation, confusion, abnormal heart rhythm, and even kidney stones. But the good news is that it is nearly impossible to get too much vitamin D from sunlight or foods. Nearly all vitamin D overdoses come from supplements so be careful if you are having vitamin D supplements. Always consult your doctor before you take any supplements.

The writer is a Cosmetologist and Dermatologist.