I think it’s fair to say most of us know we need vitamin D. After all, we don’t call spending some time in the sun “getting a healthy dose of vitamin D” for nothing. Vitamin D (sometimes affectionately known as the “sunshine vitamin”) is one of the essential vitamins—meaning your body needs it in order to work properly.
But how does sunlight actually turn into vitamin D? And why do we need it, exactly?
Cue the Experts
Knowing very little beyond the above information (even though I once had a vitamin D deficiency, myself), I reached out to four medical experts to help better explain this vitamin, its functions and some of the risks associated with not getting enough of it. Read on for advice from board-certified dermatologist Alan M. Dattner, MD; Annie Grochocinski, RD, LDN, CNSC at the University of Chicago Medicine; June Hatfield MS, RD, CNSC, LD at Children’s Hospital Los Angeles; and Kathleen Meehan MS, RD, LDN, a registered dietitian nutritionist. (You can read more about each of them at the bottom of this post.)
What does vitamin D do for the body?
While many of its functions are internal, vitamin D also plays a role in skin health and wellness—especially when it comes to aging skin. “Vitamin D helps protect against oxidative damage of the skin,” says Dr. Dattner. It does this by protecting the skin from premature aging—especially in relation to sun exposure. This is why you might see vitamin D used in the topical treatment of psoriasis, says Hatfield. “[It] also regulates the activity of cathelicidin, an antimicrobial protein that promotes wound healing and tissue repair and may modulate the inflammatory responses in the skin.”
Vitamin D plays a vital role in helping the body absorb and maintain a healthy amount of calcium and phosphorus—in order to keep our teeth and bones healthy and strong. Without enough vitamin D, says Hatfield, your body would only be able to absorb and utilize somewhere between 10–15% of dietary calcium and around 60% of phosphorus.
Meehan adds, “Vitamin D helps control cell growth and may reduce inflammation. Preliminary studies in mice have determined that vitamin D may help protect skin against UV rays, but it’s still too early to know whether that applies to humans as well. It’s exciting, but right now more research is needed to determine exactly what role vitamin D plays in skin health.”