Vitamin D can be obtained from sunlight through ultra violet rays as well as from foods but sunlight is one of the best sources to obtain vitamin D. There are very less variety of foods that contain vitamin D.
One can obtain vitamin D very easily by spending very less time in the sun. It is important for infants as well. Infants or babies under one year should be exposed to direct sun to obtain vitamin D.10 to 15 minutes exposure is safe but not too much exposure because it leads to skin diseases like skin cancer. It is found that dark skinned people require more exposure to sunlight to require the same amount of vitamin D compared to light skinned people.
Vitamin D is very important for the body to absorb calcium and to build strong bones. It also plays an important role in immune function, blood clotting, muscle health, to control blood pressure, helps prevent infections and certain diseases like osteoporosis, which is caused due to the deficiency of vitamin D.
Symptoms of vitamin D deficiency are joint or bone pains, muscle pains, severe asthma, fatigue, depression, frequent bone fractures, lowered immunity and lowered energy levels which indicate that the body requires vitamin D.
The sources through which vitamin D can be obtained other than sunlight are fatty fish such as salmon, mushrooms, sardines, milk, yogurt, mackerel, fortified orange juice etc.
If you are unable to get vitamin D through diet, simply expose yourself to sunlight 10-15 minutes twice or thrice a week. Sunlight is the best source to obtain vitamin D. Another way to get vitamin D is through supplements which should be used according to the advice by a doctor.