Vitamin D is a vitamin that we mainly get from sunlight; however, it is widely obtained as a nutritional supplement. Vitamin D helps with the following:Immune system, which helps you to fight infectionMuscle functionCardiovascular function, for a healthy heart and circulationRespiratory system, for healthy lungs and airwaysBrain developmentAnti-cancer effectsHow much can I supplement?There are many factors with Vitamin D supplementation that should be considered but knowing your current Vitamin D level is important.Normal levels of Vitamin D are still widely debated but levels below 30ng/dL are generally considered low while some experts consider between 50-70ng/dL normal.Supplementation should be based on several factors including weight, skin type, sun exposure, and other co-morbities but generally 5000 IU or greater for a short period of time has shown to positively improve Vitamin D levels, while 2000 IU has be shown to maintain levels. Supplementation of less than 1000 IU has not demonstrated any effect.What is your Vitamin D level?