Getting Vitamin D is pretty important...for you and your children. About 70% of American children are not getting enough Vitamin D.  Adults with low vitamin D are at a higher risk for diabetes, cancers, high blood pressure, and cardiovascular disease. Children with low levels of Vitamin D were at a higher risk for high blood pressure and have a lower amount of good cholesterol in their blood. They also tend to have higher levels of parathyroid hormone, meaning that their bones need more calcium to grow. There are a few ways that you can help ensure that they are at least getting more, if not enough.
Know how much Vitamin D your children should be getting. Infants, children, and teenagers should be getting about 400 IU of vitamin D every day. That's equivalent to 10 mg.
Eat foods rich in Vitamin D.
See a Vitamin D Rich Foods List for exact amounts of Vitamin D in certain foods.
Many fatty fish, such as tuna, salmon, and sardines, are rich in vitamin D.
Drink fortified milk and orange juice, and eat cereals with vitamin D supplements.
Use fortified milk instead of water in soups and oatmeal.
Feed children yogurt fortified with Vitamin D.
A teaspoon of cod liver oil has about 400 IU of Vitamin D, the recommended level for children.
Encourage outside play time. Vitamin D is a conditional vitamin, which means that it is necessary to eat only when your body does not make enough of it by itself. Your body makes it in your skin through the action of UV rays from the sun.  It only takes about 15- 20 minutes in the sun for your body to make enough. However, putting on sunscreen blocks the UV-B rays that help make Vitamin D, so slathering on sunscreen every time you go outside will not help you make more Vitamin D.
Unless you burn easily, don't put on sunscreen as soon as you go outside. Instead, wait for about 10 minutes.
People with darker skin coloring have a harder time getting enough Vitamin D naturally - that is, through exposure to the sun- because darker skin blocks UV rays.
Take vitamin supplements. Children lacking in Vitamin D can make up for it with multivitamin tablets. Make sure to purchase ones that write "Calcium + Vitamin D" for added minerals.