I just got back from Miami, where I spent seven glorious days basking in the sunlight.  When I arrived back in cold, grey New York City, I immediately felt my spirits dip.

It’s not just all in our heads: sunshine really does make us happier.  Sunlight provides us with vitamin D, in which many of us a (in fact, half the U.S. population!) are deficient. Vitamin D deficiency has been linked to depression, high blood pressure, diabetes, and bone loss. It’s so important that we all have enough of this vitamin, even if it’s just to stave off the winter blues!

What what to do?

  • Spend some time in the sun. Almost all of the vitamin D we need can come from sunlight. The problem is, most of us don’t get enough sun, especially during winter. Sun screen blocks the majority of the vitamin D-producing rays, so aim for five minutes SPF-free each day. (Make sure you cover up for the rest of the time to prevent skin damage and melanoma).
  • Eat vitamin D-rich foods. The best dietary sources of D are cod liver oil, wild salmon, sardines, and (whole) eggs. You can also find it in fortified milks or cereals, though they are heavily processed.
  • Supplement. Unfortunately, most of us won’t get enough sun or eat enough D-rich foods to keep our D levels where they should be. Therefore, it’s highly advisable that most people (especially those in northern climates) take supplements. Make sure yours contains D3, which is the most bioavailable form of the vitamin–beware, many brands contain only D2, which your body cannot easily absorb. My favorite brand is Metagenics, which can be ordered online, or Blue Bonnet, which is available in health food stores such as Whole Foods. Dr. Marc Hyman recommends that healthy individuals take 2,000 – 4,000 IU per day for optimal health.

The short of it: This is a supplement the majority of us need. I’m not one to take a bunch of supplements, but Vitamin D is a must and difficult for most of us to obtain through diet and lifestyle.