Vitamin D is a fat-soluble vitamin, meaning it does not mix with water. This vitamin can be found in various foods, but it can also be produced inside the body with a little help from the sun. When UV rays hit the skin, the process to create Vitamin D begins. Once converted to its active form, vitamin D has many roles. A few of those roles include promoting calcium absorption in the gut, maintaining adequate calcium and phosphate concentrations, reducing inflammation, aiding in cell growth, aiding in neuromuscular and immune function, glucose metabolism, and bone growth and remodeling. Without vitamin D, bones would be brittle and thin leading to rickets in children and osteoporosis in adults. The top 5 sources of vitamin D include cod liver oil, trout, salmon, mushrooms, and fortified milk. Other sources include sardines and eggs. Supplements are an easy way to avoid nutrient deficiencies, however, it is important to talk with your doctor before taking single nutrients in high doses.