Sunshine & Supplementation: Vitamin D Sources

The relationship between humans and the sun is downright remarkable. To start with, our bright, white star (technically it’s a rainbow of colors) keeps us warm, provides energy for our food to grow, and light for our days. But beyond that, the sun’s impact on the human health and longevity is fascinating when you consider its direct relationship with our skin.

It all starts with a steroid called 7-dehydrocholesterol. Your skin makes large quantities of this steroid in its sebaceous glands, which are microscopic glands responsible for secreting oil to lubricate and waterproof your skin. 7-dehydrocholesterol is then secreted onto your skin’s surface. During sunlight exposure, ultraviolet B (UVB) rays penetrate the external skin layers. Some of the 7-dehydrocholesterol absorbs the photons from the sun’s rays whereby converting it to previtamin D3. Then, through an amazing process called thermal isomerization, the chemical structure of previtamin D3 changes to vitamin D3 or cholecalciferol over a period of a few days.

The coolest part? Your body has mechanisms to prevent it from synthesizing too much vitamin D from the sun. As you get more exposure to the sun, the pigment in your skin (melanin) accumulates. This is the process of tanning. And as the melanin accumulates, it reduces the rate of vitamin D synthesis. The darker your skin, the harder it is for your body to get enough vitamin D from the sun. Eventually the skin exposed to the sun reaches a level of equilibrium where it can’t synthesize vitamin D any more during that thermal isomerization period.

Getting the right amount of sun exposure for adequate vitamin D synthesis really depends on a number of factors, including your age, the color of your skin, your longitudinal location, the time of day and, most importantly, the amount of skin you expose.

Here’s the rule of thumb from the Vitamin D Council: “Your body can produce adequate vitamin D in just under HALF the time it takes for your skin to turn pink.” Of course keep in mind you will get flushed when it’s hot out. While this rule of thumb is a bit challenging because I can’t give you an exact time requirement, it’s very helpful because it takes into account all of the factors that reduce synthesis rates.

For example, I’m an olive-skinned woman in her late thirties living in Boston. In June at around 1pm on a sunny day, it takes about 30 minutes for my skin to turn pink. Can you estimate your time requirement for adequate vitamin D synthesis? Click here for more tips.

When all else fails, however, supplement with vitamin D.

The sun is our best source of vitamin D, but for many of us living in the North it doesn’t cut it during the winter months. Plus, if you have a history of skin cancer, I’m sure your stress level would be through the roof while sitting in the sun. Instead, opt for a high-quality vitamin D3 supplement.

Remember, not all supplements are created the same. Skip the radio and digital advertisements, and instead opt for high-quality supplements that are recommended by a health care practitioner you trust. If you aren’t comfortable doing your homework on researching the quality and purity of brands available in your local supermarket, Costco, Target, etc., take the safe route and choose brands created by Emerson Ecologics Quality Partner program. Without a health care professional, you may not be able to purchase them from the website but you can certainly feel safe you are buying a brand that’s top quality and professional grade.

Scientific understanding of the functions and benefits of vitamin D to our health is still in its infancy. To date, we’re pretty darn certain this vitamin (or hormone-like vitamin) is important to lowering our risk of many chronic diseases. Heck, vitamin D has the power to communicate with our genes and have them (de)activate when necessary. That’s powerful!

Unfortunately, many conventional doctors aren’t paying enough attention to vitamin D levels because frankly they haven’t been adequately trained on its functions and importance. Remember, scientific findings on vitamin D functions in the body are still being discovered! Plus, the Institute for Medicine, the main organization that provides advice on health policy, didn’t increase the vitamin D recommendations to 600 IU daily (up to 800 IU for those 71 and older) until 2010, a level that continues to be highly criticized and contested for being too low for optimal health.

So take your health into your own hands! How can you start getting enough vitamin D today? Below are some steps to help you get there. And always keep any eye out for a vitamin D challenge on hubbub!

  • Estimate your personal exposure time requirement
  • Schedule your vitamin D dose throughout your day
  • Plan your clothing accordingly. You could even wear a vitamin D (or "tan through") shirt to work!
  • Choose a vitamin D3 supplement brand that you like and order it
  • Start taking a daily supplement. Plan to up your dosage in the winter months when sun isn’t an option if you live in the North


  1. Challem, Jack. (2011, December). The Vitamin D Debate. Retrieved on May 28, 2015 from
  2. Gropper, S. S., & Smith, J. L. (2012). Advanced Nutrition and Human Metabolism (6 edition). Belmont, OH: Cengage Learning.
  3. Masterjohn, Christopher. (2006, December 17). From Seafood to Sunshine: A New Understanding of Vitamin D Safety. Retrieved April 7, 2015, from
  4. Vitamin D Council. (n.d.) How do I get the vitamin D my body needs? Retrieved June 11, 2015, from