When the sky is gray: The importance of Vitamin D


It’s that time of year again, when the holiday season has passed and Spring seems too far away. You start to notice the sky is more cloudy and gray. With the sun being less frequent, we need to be mindful of our Vitamin D intake. About 50% of the population gets an insufficient amount of vitamin D.1The benefits of getting adequate vitamin D include maintaining bone strength by aiding in the absorption of the important minerals calcium and phosphorus (without vitamin D, we would only absorb about 15% of calcium and 60% of phosphorus we ingest), helping muscle function and supporting the overall health of your immune, brain and nervous systems.2 

Several studies have found that vitamin D can even be a better preventative measure against the flu than the actual flu vaccine! Researchers have found that when individuals are low or deficient in vitamin D, they report more cold and flu cases. Antimicrobial peptides have an increased presence in your lungs with greater vitamin D intake, offering protection from respiratory infections. The theory that scientists have come to believe is that the reason we see most flu and cold cases in the winter is because there is less sun, therefore we intake less vitamin D.3 The sun is a great provider of this vitamin, but on dreary days, where can you seek solace?


Honestly, sun is the best and most natural way to get vitamin D is by exposing your bare skin to sunlight (ultraviolet B rays). This can happen very quickly, particularly in the summer. You don’t need to tan or burn your skin to get vitamin D. You only need to expose your skin for around half the time it takes for your skin to begin to burn. In the winter, UV levels are much lower making it almost impossible to make vitamin D in our skin. The other way to get vitamin D is through what we eat, though there are not many foods that are good sources of vitamin D. Options include:

  • Fish - the most common sources are salmon, tuna, cod liver oil and wild-caught fatty fish
  • Beef liver, cheese or eggs have smaller amounts
  • Fortified milk and cereals, as well as yogurts, soy beverages or orange juice however these food tend to be processed and aren't generally a recommended way to get your vitamin D
  • Supplementation - Most people benefit from some form of supplementation, especially in the winter. Recent research found that vitamin D3 is twice as effective as vitamin D2 at raising blood levels, which is important because a lot of prescriptions for vitamin D are in the D2 form. 

The recommended intake of Vitamin D according to the Institutes of Medicine are4:

  • Infants 0-12 months - 400 IU (10 mcg).
  • Children 1-18 years - 600 IU (15 mcg)
  • Adults to age 70 - 600 IU (15 mcg).
  • Adults over 70 - 800 IU (20 mcg).
  • Pregnant or lactating women - 600 IU (15 mcg).


Current recommended intakes for vitamin D is to achieve a serum level status of 20 ng/mL. That level has been hotly debated as not nearly being high enough. Multiple studies support the need for vitamin D levels above 20 ng/ml for optimal health, finding that levels below 40 ng/ml are linked to chronic diseases like lung, colon, prostate and breast cancers, depression, autoimmune diseases and reproductive disorders like PCOS. The published journal article: The Big Vitamin D Mistake calls for new vitamin D recommendations as follows: 1000 IU for children <1 year on enriched formula and 1500 IU for breastfed children older than 6 months, 3000 IU for children >1 year of age, and around 8000 IU for young adults and thereafter. That's a big difference from current RDA guidelines!

Research has shown that lifeguards, farmers near the equator and sun dwelling hunter gatherers maintain blood levels between 40-80 ng/ml on sun exposure alone. As Dr. Cannell once said, “Humans make thousands of units of vitamin D within minutes of whole body exposure to sunlight. From what we know of nature, it is unlikely such a system evolved by chance.”

Because vitamin D is not overly common in our food, supplementation may be a solution for you. Those at risk of having deficiencies are older adults, those with chronic conditions, infants, those with darker skin, immune compromised patients, those living in northern climates (Hello Minnesotans!) and obese individuals. However, at Thrive Nutrition we see that most healthy adults not supplementing are deficient as well, which makes sense because adults rarely go outside during the week due to 9 am to 5 pm jobs. When we recommend vitamin D supplementation, we also either tie in vitamin K supplementationeither in with Vitamin D, in a multivitamin or through your diet with fermented foods. Because vitamin D increases calcium absorption, we need to make sure vitamin K is there to tell the calcium to get out of your arteries and into your bones, where you want it! *Consult your health care practitioner before starting supplements. 

We partner with Fullscript for supplements, and through it we offer a discount of 15% off on pharmaceutical-grade, pure and potent supplements. Even non-members get  the discount, so start getting cheaper supplements today, sign up is easy!

Posted on February 6, 2018 .