To get more vitamin D, change your diet up and get in that sun!
The amount of vitamin D needed to correct a deficiency and lessen your risk for type 2 diabetes depends on the severity of your deficiency and your medical conditions. The time of the year also impacts your vitamin D needs.
Take vitamin D3 supplements with a meal containing fat. Studies show that when taken on an empty stomach versus with a meal vitamin D3 was not absorbed as efficiently.
There are some foods you can eat that naturally contain vitamin D. Fill your diet with fresh salmon, a teaspoon of cod liver oil once a day, eat sardines, mackerel, tuna and shiitake mushrooms. Egg yolks are great and fortified milk, or yogurt is an option as well. Try drinking fortified orange juice and eating fortified cheese.
Eating foods fortified with vitamin D3 is great, but your best bet is to get more exposure to the sun and take supplements recommended by your doctor. Have regular blood work to monitor your vitamin D levels and make an adjustment based on medical as well as seasonal changes.