The recommended daily amount of vitamin D is 400 IU for children up to 12 months of age, 600 IU for children ages 1 to 70 years, and 800 IU for people over the age of 70
Sources
Sunlight is the best source of Vitamin D. The vitamin is produced in the body through the effect of the sun's ultraviolet rays on chemicals that are naturally present in human skin. Fortified milk, dairy products, large fish (sardines, herring, salmon and tuna), liver and egg yolks - all are good sources of Vitamin D.