Vitamin D deficiency is a common problem that can lead to serious health issues. To combat this, researchers are looking into fortifying foods with vitamin D. Liposomes are found to be the most effective method for fortification. Milk and cheddar cheese have been successfully fortified with vitamin D. Water sources are better for maintaining aroma depth in fortified foods compared to oil sources. Dietary 25(OH)D3 is more effective at raising vitamin D levels in the body than dietary vitamin D3. It is important to follow FDA regulations and use specific methods to determine the amount of vitamin D in fortified foods.