Healthy Sun Exposure

By Tracy Tranchitella, ND

I am almost certain that I’m raising some eyebrows with a mere mention of healthy sun exposure, but let’s talk it out. Humans have existed with that great ball of fire since the dawn of man. To be fair, we were quite a bit harrier in our early days which, though not so pretty, offered some protection against the sun. Modern humans have much less body hair, so we need clothing for protection against the elements–and it’s generally more socially acceptable–unless you live in a nudist colony in South Florida!

We create vitamin D through sun exposure on our skin. You could say that we make our own vitamin D, which we do, but we need a little help from ultraviolet rays (UVB) to make that happen. If we are always covered head to toe in clothing or slathered in sunscreen, we block the rays needed to create that vitamin D. I am not suggesting that your patients go out and cook themselves in the summer sun, just recommending some unfiltered sun exposure on your arms and legs for 10-20 minutes between 10 am and 4 pm, 2-4 times per week. Vitamin D production through sun exposure tends to max out around 30 minutes. Vitamin D acquired through sun exposure is the active form of vitamin D meaning that it is available for the body to use without any further biochemical conversions.

We can also acquire vitamin D from foods and supplements and for those who live far north or south of the equator, this is likely their main source of vitamin D. Interestingly, those who are indigenous to environments closer the poles tend to have fairer skin and need less sun exposure to make vitamin D. People who live closer to the equator and have darker skin need more time in the sun to make adequate vitamin D. Regardless of skin tone, a large part of the traditional diet of those who live far north of the equator tends to include lots of fatty fish to meet vitamin D needs. Vitamin D from food requires a few biochemical conversions before it becomes the active form of vitamin D. Food sources of vitamin D include egg yolks, fatty fish, beef liver, fortified dairy products, mushrooms, and fish liver oils.

We can assess vitamin D status in a simple blood test by measuring 25-OH-Vitamin D. The normal range for 25-OH-Vitamin D is 30-100 ng/mL (Lab Corp) with the optimal range being somewhere between 50-70 ng/mL. If you are at the lower end of the range, moderate sun exposure and supplementation may be needed. Typical daily dosing for vitamin D ranges between 2000-5000 IU/day and should be in the form of vitamin D3 (cholecalciferol) along with some vitamin K2 (menaquinone-7) to support absorption and utilization. Do keep in mind that testing is important not only to determine deficiency but to also prevent over-supplementation. Once the 25-OH-Vitamin D level is optimized, a lower supplement dose may be necessary especially if you enjoy the sun in the warmer months.

Vitamin D is necessary for bone support and calcium metabolism, healthy immune function, hormone and neurotransmitter production, insulin sensitivity, muscle strength and integrity, cardiovascular health, and cancer prevention. For more information about the benefits of vitamin D, please visit The National Institutes of Health website here. The benefits of adequate vitamin D are foundational to many aspects of good health.

In addition to promoting vitamin D production, healthy sun exposure also has the benefits of enhancing the circadian rhythm that allows us to respond to the cycles of light and dark, supports mood through enhancing the release of serotonin, improves sleep, reduces blood pressure, reduces stress, and supports immune health through various pathways. Healthy sun exposure is supportive of good health and like many things, too much of good thing can be bad, so don’t hide from the sun but don’t get overexposed and allow your skin to burn.

Enjoy your summer and a little sunshine too!