Why You May Want to Consider a Vitamin D Supplement—Especially During this Covid Winter

Here we are, almost through this crazy year, embarking upon the cold season.  And not just temperature cold, but cold colds, compounded this year by the ever-present Miss Rona, who unfortunately is impervious to the chilly temps.  One thing we may not think enough about during this viral season is Vitamin D, which isn’t just the sunshine vitamin—Vitamin D is essential for our immune system. 

Vitamin D acts like a hormone in our bodies, and every cell in our body has a Vitamin D receptor, making it no surprise that Vitamin D is involved in myriad important bodily functions, including bone remodeling, calcium absorption, and cellular functioning, in addition to improved immunity.  A 2010 study examining the incidence of children contracting the flu found a greater than 40% reduction in contraction for those children taking a Vitamin D3 supplement during flu season.  Seems really relevant in 2020!

Unfortunately, though many of us in sunny California are at less of a risk of Vitamin D deficiency, there is an overall deficiency in the populace.  A 2011 study indicates an overall prevalence rate of Vitamin D deficiency of 41.6% in the United States, with that number skyrocketing to over 80% for African Americans.  And in general, the signs of a Vitamin D deficiency are either subtle or hard to attribute to the deficiency—symptoms like fatigue, a tendency to get sick more often, lower back pain, depression, or hair loss.  It’s likely that many of us have suffered with one or more of these symptoms and not even given Vitamin D a passing thought.  Maybe we should start.

So how can we get Vitamin D? Our body naturally makes Vitamin D from cholesterol when exposed to sunlight, which is a very effective way to raise our Vitamin D levels, with the caveat that it requires sun exposure without sunscreen and should be done in moderation, and the further caveat that sufficient sunlight isn’t always available during winter months.  We can also get Vitamin D from food sources, though rarely is that sufficient to ensure robust enough levels of Vitamin D in our bodies.  So, especially in this less sunny season, supplements may be the answer.  And this is where I got confused when I decided to add Vitamin D to my arsenal—what kind do I take? Vitamin D3? Vitamin D2?

Vitamin D3 versus Vitamin D2 Supplementation

Both Vitamin D2 and D3 are essential for our bodies.  They get converted by our livers and kidneys into the active form of Vitamin D that circulates in our bodies.  But there are a couple significant differences.

First, Vitamin D3 is the form of Vitamin D our body makes when exposed to the sun, which is why it is the form of Vitamin D considered the sunshine vitamin.  Second, studies show that Vitamin D3 appears to more effectively raise levels of active Vitamin D in our bodies than Vitamin D2, which is why we generally see and are advised to take Vitamin D3 supplements as opposed to D2.  However, one potential issue with Vitamin D3 is that it comes overwhelmingly from animal sources, and so supplementation with Vitamin D3 may be hard to swallow (pun intended!) for vegans and vegetarians.  By contrast, Vitamin D2 comes solely from plant sources and yeast.  Though I lean vegan (yes, that’s a thing, I swear), I still currently take Vitamin D3, but for some this is a definite consideration.  And ultimately, though Vitamin D2 is less effective at raising active Vitamin D levels in our bodies, it still does, and once Vitamin D3 and D2 are converted into active Vitamin D, their benefits and effect on the body are the same. So if Vitamin D2 fits more within your dietary regimen, that’s a fine way to go.

One other thing to consider is the amount of Vitamin D to take.  General guidelines say to cap it at 4,000 IU daily to avoid any side effects (like kidney stones or constipation resulting from too much calcium absorption).  Unlike water-soluble vitamins, Vitamin D, along with Vitamins A, K, and E, is a fat-soluble vitamin that gets stored in the body, not secreted.  It’s therefore possible to overdose on this class of fat-soluble vitamins.  So, more is not necessarily better when it comes to Vitamin D supplementation.  

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There is an overwhelming amount to be concerned about these days, right?  Too much.  So anything we can do to fortify our bodies and minds is something to consider.  Vitamin D and its central role in immune function might be one of them.  And as schools are opening (particularly given the study involving children I mentioned above), it’s something we should also probably think about for our kiddos.  Also, if you’re experiencing symptoms consistent with Vitamin D deficiency, you can ask your doctor to check your Vitamin D level—a level of 20 ng/mL or lower is considered deficient.

So go outside sans sunscreen for a little bit (not too long, no thanks skin cancer), soak up some rays (just 10 minutes of midday sunlight can be sufficient), and think about consulting with your doctor and/or researching whether a Vitamin D supplement is appropriate for you.