I don’t know how many times I heard my mother say, “Why don’t you go outside and play!” on days like today when I was a kid.  The sky is blue, the sun is warm…why would you stay in if you didn’t have to?  Spring has sprung, summer will be here before we know it, and there is an almost tangible shift in how we feel.

This morning at 5:14 am the sun began it’s annual march into the Northern Hemisphere.      It is no longer dark when we wake up in the morning and there is plenty of daylight remaining when we get home from work.  The temperature is beginning to rise.  Arms and legs, in addition to hands and faces, are being exposed to the sun in all of their pasty white glory, hoping to start a summer tan.  For the first time since September we will enjoy the sun’s direct rays and the warmth they provide.  But, what else is it about that spring and summer sun that makes us feel so good, especially if we haven’t spent any significant time outside since the fall?  Sunshine = Vitamin D.  Production of this uber important nutrient takes place in the skin as the result of the UV stimulus provided by the sun.

Until recently, vitamin D was thought of as nothing more than calcium’s wingman, a secondary nutrient that helped build strong bones. But, scientists are just beginning to uncover just how essential Vitamin D is to our overall health and well being.  The fact that it is the only vitamin the human body can manufacture on its own alludes to its importance.  (Read: Vitamin D is so essential to our survival, and so rare in our environment, that we’ve evolved to fill our own Vitamin D needs).  What’s most remarkable about vitamin D is the sheer number of health issues it’s been linked to.

New research suggests that Vitamin D is essential in regulating functions like gene regulation, cell repair and turn-over, insulin production, and regulation of the immune system.  Researchers have uncovered up to 2,000 different genes—roughly one-sixth of the human genome—that are regulated by the nutrient. That means almost everything your body does relies on it.  “It affects cell death and proliferation, insulin production, and even the immune system,” says Michael F. Holick, Ph.D., M.D., director of the vitamin D, skin, and bone research laboratory at the Boston University Medical Center.

Having low vitamin D will result in your body working far below its potential. Recent studies have shown that a lack of the vitamin may be the primary culprit in depression, heart disease, pregnancy problems, birth defects, skin and other cancers, and multiple sclerosis.  And, if you rely only on sun exposure as your only source of vitamin D, you probably aren’t manufacturing nearly enough to meet your needs.  In fact, you may already be vitamin D deficient.  A number of experts, including those from the Harvard School of Public Health, have urged the government to raise its recommended daily amount of vitamin D for adults from 200 IU to at least 1,000 IU, possibly more.  “Many of my patients report a dramatic improvement in their feeling of overall well-being after they increase their vitamin D levels,” Holick says.

So, should we forsake sunscreen and burn ourselves to a crisp this summer in favor of vitamin D production?  Absolutely not – that would do more harm than good.  But here are two simple steps you can take to take to up your Vitamin D.

1. Get outside for 15 – 20 minutes every day, sans sunscreen, with as much skin exposed as possible.  This gives enough stimulus for vitamin D production without subjecting our skin to the dangers of prolonged UV exposure.
2. If getting outside is not an option, like in the winter, make sure you supplement with 1,000 – 5,000 IU of D3 (cholecalciferol – the same stuff your body makes on its own).