Vitamin D
(for general health)
Even the healthiest of men, who also happen to work indoors from 9 to 5 and hit the gym right after work, are almost assuredly deficient in vitamin D. No sunlight may work for vampires, but it will deprive humans of this essential vitamin. The RDA is 600 IU but can increase to around 2000 IU if there is a serious deficiency, and for higher doses you’ll need it in supplement form. For best results, try to catch some actual rays from the sun. Spending 10-15 minutes outdoors without sunscreen every day is ideal. If you’re exposed to the sun often, and are not deficient, your recommended daily amount can be met by ingesting fish, dairy, yogurt, or cod liver oil. Yum!