Morgan Chamberlain

mbg Supplement Editor

By Morgan Chamberlain

mbg Supplement Editor

Morgan Chamberlain is a supplement editor at mindbodygreen. She graduated from Syracuse University with a Bachelor of Science degree in magazine journalism and a minor in nutrition.

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January 19, 2023

It’s winter, which means for those of us living in cold parts of the country, days are short and access to sunshine is…unreliable, at best. This time of year, I get a lot of questions about vitamin D levels. 

Considering vitamin D deficiency and insufficiency impact a significant number of U.S. adults year-round (29% and 41%1, respectively), concerns over maintaining healthy vitamin D status are incredibly valid. 


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Whether you’re already aware of the vast health benefits of vitamin D or you’re personally feeling the mood effects of dark winter weather and wondering if your D status may play a part, you’re wise to be striving to achieve (and sustain) healthy vitamin D levels.

Why low vitamin D is so common in the winter.

While a large portion of our nation struggles with vitamin D sufficiency year-round, vitamin D status notoriously dips during the winter, especially for those in higher latitudes. 

In the 1980s, professor of medicine, physiology, and biophysics at Boston University medical center Michael Holick, M.D., Ph.D., authored foundational research on vitamin D synthesis2 that has continued to lead the evidence-based conversation on vitamin D throughout seasonal changes. 

In this research, Holick discovered the cutaneous vitamin D production (i.e., in the skin) of individuals living in Boston, Massachusetts during winter months was nonexistent. “If you are in Boston in the wintertime and you go outside for 15 minutes, you make zero vitamin D. In fact, you make no vitamin D from about November until the following March,” he previously explained to mindbodygreen

And while this logic makes sense during the wintertime, sunshine isn’t a sufficient source of vitamin D for most individuals any time of year (even during sunny summer months). Our exposure to sunshine and ability to convert it to vitamin D is impacted by numerous factors—including geographic location, season, climate, UV levels, pollution, clothing, sunscreen, age, and skin tone. 

Simply put, we can’t rely on sunlight to achieve and sustain optimal vitamin D levels, especially in the winter. (Hint: This is where vitamin D supplementation comes in.)

How to maintain healthy levels year-round.

Evidence shows that taking a quality daily vitamin D supplement is the most reliable way to ensure healthy vitamin D status, no matter where you live or what time of year it is.* 

Underscoring the importance of taking an (actually) effective dose of vitamin D in supplement form, in a 2021 study conducted in Korea, researchers found that a low-dose oral vitamin D supplement (i.e., 1,000 IU of D3 taken daily) helped modestly improve vitamin-D-deficient participants’ serum 25(OH)D levels (i.e., the blood biomarker for vitamin D status) levels, only by an average 11 ng/ml after three months. (Comparatively, participants with vitamin D deficiency that chose sunlight exposure had no significant increase in average serum 25(OH)D levels.) 

This research shows what we at mindbodygreen have known all along: Taking a daily vitamin D supplement can help you achieve and maintain healthy levels year-round.* 


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What to look for in a quality vitamin D supplement.

  • Dose: To achieve and maintain truly optimal levels of vitamin D (i.e., over 50 ng/ml), research demonstrates and experts agree that most of us need an effective high-potency daily dose of 5,000 IU.
  • Form: Choose a supplement with vitamin D3 rather than the less effective (aka inferior) vitamin D2 form.
  • Bioavailability: Because it’s a fat-soluble vitamin, vitamin D needs a little fat to ensure it absorbs optimally. Choosing a supplement that features built-in fats (e.g., organic oils) optimizes bioavailability and takes out some of the guesswork—win-win!*


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Hint: mindbodygreen’s vitamin D3 potency+ features 5,000 IU of sustainable, algae-derived organic D3 and built-in absorption technology via an organic trio of healthy oils (olive, avocado, and flaxseed) to help you achieve and sustain truly optimal levels of vitamin D through winter and beyond.*

The takeaway.

The sun isn’t a sufficient source of vitamin D for most people, most of the year. Unless you happen to live close to the equator and spend plenty of time in the sun sans sunscreen (which we don’t recommend, for the record), it’s practically impossible to get adequate sunlight to maintain optimal vitamin D levels. (And if you live in a place with freezing temperatures and snow through the winter, forget about it!)

To ensure you achieve (and maintain!) healthy vitamin D levels throughout the year, consider a premium vitamin D supplement, like mindbodygreen’s vitamin D3 potency+. With optimized dosage, form, and bioavailability, this stellar daily supplement is like sunshine in a bottle!

If you are pregnant, breastfeeding, or taking medications, consult with your doctor before starting a supplement routine. It is always optimal to consult with a health care provider when considering what supplements are right for you.