If you spend the bulk of your time indoors, you should probably add this supplement to your stack. Experts share exactly how ...

Rachael Link is a registered dietitian and health writer based in San Francisco. She completed her undergraduate degree at the University of Central Missouri and holds a master’s degree from New York ...

Like other vitamins, vitamin D is a substance needed for health but only in tiny amounts. Unlike other vitamins, it doesn't occur naturally in many foods (except seafood, mushrooms, and egg yolks), ...

Scientists discovered that vitamin D2 supplements can lower levels of vitamin D3, the form the body uses most effectively. Unlike D2, vitamin D3 enhances the immune system’s first line of defense ...

Vitamin D2 and D3 are the two main forms of vitamin D. Vitamin D2 is present in plants and yeast, while D3 comes from animal sources. Vitamin D is essential for a range of bodily functions, such as ...