Vitamin D is essential for your bones (your body needs it to absorb calcium), and it might play a role in muscular health, cardiovascular health, immunity, preventing diabetes, preventing cancer, and preventing the inescapable sadness of human existence. Only one of those is made up!
The problem is that almost 40% of healthy young adults are deficient in vitamin D, and it’s not that easy to get it from food, with mushrooms, fatty fish, and egg yolks being some of the only dietary sources of D. Fortunately, your body makes vitamin D when you’re exposed to ultraviolet rays (i.e. sunlight), but it can be difficult to get outside if it’s winter and you have a job (and/or access to a streaming video service).
Since people with different skin colors make different amounts, integrative physician and cardiologist Dr. Dennis Goodman recommends knowing your individual level. “Ask your doctor to check your 25-hydroxyvitamin D -- that’s a blood test, very easy to get.” This is definitely one where some people are advised to take supplements, since you can only have so much D-fortified milk and cereal. “I’d rather see someone getting it from a supplement than not getting it at all,” Dr. Goodman says.