Is sunshine really the best way to get vitamin D? This is a great time of year to ask that, since school is on summer break for most people. We just recently vacationed in Florida, like so many do this time of year. I noticed the great amount of sunscreen being lathered or sprayed on to avoid sunburn, as well as those hiding beneath tents and umbrellas. What should we really be doing to get this vital nutrient naturally?
How does sunshine make vitamin D?
When sunshine touches our skin, it creates vitamin D from cholesterol. The ultraviolet B (UVB) rays from the sun use that cholesterol in our skin cells to provide the energy for vitamin D production. When we have adequate amounts, vitamin D helps with calcium absorption in the gut and balances it with phosphorous to mineralize and grow healthy bones. It also controls cell growth and immunity and reduces inflammation.
Why most of us are deficient in vitamin D
If our primary source of vitamin D is sunshine, then one obvious reason that we are deficient is that we don’t go outside enough. Even if we go outside, it is just to drive to work and back home again. We need to spend no less than ten minutes in the sun at least three times per week, up to thirty minutes every day if your skin is darker. Darker skin is a protection from too much sun, so it takes more time in the sun to manufacture enough vitamin D.
Skin type, time of day, age, season, and location
Skin type is not the only factor in determining how much vitamin D is made in our skin by the sun. The time of day is very important as well. Midday, between 11:00 AM and 1:00 PM is the best time, since the wavelength of UVB rays is between 290 and 320 nm. This range is essential for our skin to create vitamin D (1).
As we age, our skin loses some of its ability to create vitamin D from sunshine. Obviously, the summer is the best season and the equator is the best geographic location to receive peak sun exposure. Using the FastRT simulation tool, investigators calculated the length of daily exposure needed to get 1,000 International Units (IU) of vitamin D. If someone with darker white skin were in Miami at noon, he would need six minutes in the summer and fifteen minutes in the winter. If the same person were in Boston at noon, he would still need six minutes in the summer, but that time would increase to one hour in the winter. Someone with brown skin would need two hours in the winter (2).
Do not use sunscreen during these minimal times. It blocks the production of vitamin D. Once you get your dose of sunshine, feel free to apply sunscreen or move to the shade. Please do not use the standard sunscreen, though. It is full of toxic chemicals that absorb into the skin and then are baked further by the sun. Sunscreen and an unhealthy diet are likely the true causes of skin cancer. Find a natural sunscreen that uses zinc as its primary ingredient or make your own. We have a recipe if you want to mix up your own.
Cortisol, the stress hormone
Vitamin D is actually a hormone and when stress releases cortisol, another hormone, it can have a negative impact on our ability to create and absorb vitamin D. When we are highly stressed, cortisol turns off our vitamin D receptors. This causes our body to excrete vitamin D, instead of absorbing it (3).
Dietary sources of vitamin D
Animal-based foods that naturally contain vitamin D are fatty fish, beef liver, cheese, and egg yolks. There are many foods that have been fortified with vitamin D as well, such as cereal, orange juice, yogurt, cow’s milk, and nut milk. The only vegan food that naturally contains vitamin D is mushrooms, especially Portobello and Maitake. A cup and a half of these mushrooms will easily get you to 1,000 IU. Exposing them to UVB rays further increases their vitamin D content, so set them in the sunshine before eating.
Also, a diet high in sugar makes our skin less healthy, not to mention weakening our immune system. A healthy diet, especially if it contains green plants with chlorophyll, gives our skin the strength it needs to synthesize vitamin D from the sun.
Best supplemental form of vitamin D
Vitamin D3 is the most natural supplemental form and needs a little help from vitamin K2 to direct it to our bones. Most of us need massive doses of D3, so I take 5,000 IU per day in addition to what’s contained in my multivitamin. Since Joann tans easily, she takes double that. It is fat soluble, so it’s possible to get too much, but usually from taking excessive doses of a supplement, not from the sun or diet. Doses up to 10,000 IU have been shown to be safe for healthy adults (4).
Certainly, don’t overdo the sun. Try not to get beyond a little pink. In fact, if you don’t care about tanning, just get what you need to create some vitamin D. Add this healthy activity to your day, along with eating nutritious food, exercising, drinking purified water, breathing clean air, and getting some negative ions by grounding. Be sure and subscribe to our newsletter to get the latest news and posts. Enjoy the sunshine!
- Umesh Isalkar. The Times of India. “Low on vitamin D? Just soak in the sun between 11am & 1pm.” 2015 December 19.
- Craig A. Elmets, MD. NEJM Journal Watch Dermatology. “How Much Sunlight Is Equivalent to Vitamin D Supplementation?” 2010 June 4.
- Sam Schartz. Energize Organics. “Cortisol the Master Hormone.” 2018 November 26.
- JN Hathcock, et al. PubMed. “Risk assessment for vitamin D.” 2007 January.
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