winter sunshine, vitamin D, seasonal affective disorder, SAD, fatigue, winter blues, winter depression, light nutrient

Vitamin D: Support in the Dark Days of Winter

My story of vitamin D resuscitation.

I used to struggle with winter. And thought it was just how it was. The short days, long nights, unforgiving cold. Just awful! I felt sluggish and tired and blah about everything.

Each year I met the descent into winter with dread, and pined for the release of spring.

When I learned that the light nutrient, vitamin D, helped others with seasonal affective disorder, I was excited to try it. There were no large studies at the time, but lots of interesting anecdotal support that it worked.

But there was a culture of fear about vitamin D toxicity that I learned in my medical training and still seems to be lingering… This made many of us squeamish about using it in significant doses.

Turns out, there was no basis for that fear—vitamin D toxicity is extremely rare and near impossible for the average person to achieve, even with extraordinary doses over long periods of time.

In short, it was nothing short of a miracle for me. Just 5000 IU per day—10,000 IU later as I tracked my blood levels.

My energy rose, my mood improved, my outlook became more positive. Like I had been flooded with the most profound and beautiful light.

Many of my clients experienced the same thing. Incredible. Who knew that the nutrient of light—impossible to synthesize within the skin when the energy of the sun is low in the winter months—could make such a difference!

Don’t forget about vitamin D this winter.

From the Archives

Karyn Shanks, MD. Vitamin D: Boost Your Winter Mojo. 2016.


Karyn Shanks MD


Karyn Shanks, MD, is a physician who lives and practices in Iowa City. Her work is inspired by the revolutionary science of Functional Medicine, body-mind wisdom, and the transformational journeys of thousands of clients over her twenty-eight year career. She believes that the bones of healing are in what we do for ourselves.

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