Have enough sun exposure? The importance of Vitamin D.


I can feel such a difference in mood and energy levels when the short days of winter in the Midwest transition into the longer, sun-filled days of Spring and Summer. I go outside in my garden and soak up the sun like a little solar panel, and when I come inside my energy is recharged and seemingly endless. I apply coconut oil to my skin when I am outside for long periods–it has a natural sunscreen which does not prevent the production of Vitamin D and it contains no artificial additives that can cause other toxic reactions.

Vitamin D is a hormone that our bodies make when our skin is exposed to the sun’s ultraviolet rays. It works in the small intestine to increase calcium absorption. It is needed for bone growth and repair, and it acts on bone cells to release calcium and maintain blood calcium levels. Research has shown that most human cells have vitamin D receptors, indicating that it plays other roles in the body as well. This vitamin also helps to regulate many genes. Vitamin D insufficiency is a term that is used to describe blood levels of vitamin D that are not low enough to cause deficiency diseases, but low enough to potentially cause other health problems.

In our concern about medical research showing skin cancer to be a potential result of sunburn or extended sun exposure, our society today has perhaps become over-zealous about covering up. We wear hats, sunglasses, slather our skin with high-SPF sunscreens, and we not only block out the harmful rays, but we block what is beneficial to our bodies as well. A sunscreen with a sun protection factor (SPF) of only 15 reduces the production of vitamin D by 99 percent. While we can get some vitamin D through food sources or supplements, our greatest source is through direct exposure to sunlight. Glass windows filter out most of the ultraviolet rays that we need, so the best method is to spend some time outside in the sun.

Wearing protective hat and sunglasses


When the sun’s UV-B rays contact the skin, a reaction takes place that enables skin cells to manufacture vitamin D. If you have fair skin, experts say going outside for 10 minutes in the midday sun—in shorts and a tank top with no sunscreen—will give you enough radiation to produce about 10,000 international units of the vitamin. Darker skin is more protected against skin cancer but it is less able to absorb UV-B rays. If you are already tan or of Hispanic origin, 15 to 20 minutes in the sun will provide you with what you need. Black skin may require six times the sun exposure to make the same vitamin D levels as a very fair-skinned person.


Protecting the skin

While covering up to prevent too much sun exposure is an important step in protecting yourself from skin cancer, research has not always shown that sunscreen is the safest and most effective method.

Research has shown that sunscreen helps prevent squamous cell carcinoma, but has no effect in preventing basal cell carcinoma. For melanoma, research has been contradictory. Some research shows that sunscreen prevents melanoma, while other research shows that it increases your chance of getting melanoma.

For these reasons, the Vitamin D Council believes that covering up with clothing and/or going into the shade (after you get a little bit of sun exposure), is a safer way to protect yourself from too much sun exposure.    – Vitamin D Council



Beach unbrella and family, Sand Harbor, Lake Tahoe-Nevada State Park, Nevada. USA
Beach unbrella


Sun exposure to the skin is the human race’s natural, intended, most effective and most neglected source of vitamin D.

  • Humans make 90 percent of our vitamin D naturally from sunlight exposure to our skin – specifically, from ultraviolet B exposure to the skin, which naturally initiates the conversion of cholesterol in the skin to vitamin D3.
  • Few foods naturally contain or are fortified with supplemental vitamin D. For example, an 8-ounce glass of whole milk is fortified with 100 IU (international units) of vitamin D – just 10 percent of what the most conservative vitamin D researchers now say we need daily. In contrast, sun exposure to the skin makes thousands of units of vitamin D naturally in a relatively short period of time.
  • While vitamin D supplements are an alternative means of producing vitamin D when regular, non-burning sun exposure is not possible, oral supplementation of vitamin D is not nature’s intended means of producing this vitamin.
  • While overexposure to sunlight carries risks, the cosmetic skin care industry has misled the public into believing that any UV exposure is harmful. No research has shown that regular, non-burning exposure to UV light poses a significant risk of skin damage.
  • Humans spend less time in the sun today than at any point in human history – which is why more than 1 billion people worldwide are vitamin D deficient.

Vitamin D Comes From the Sun

Sunlight is the best and only natural source of vitamin D. Unlike dietary or supplementary vitamin D, when you get your ‘D’ from sunshine your body takes what it needs, and de-metabolizes any extra. That’s critical – as vitamin D experts and many health groups now advocate 1,000 to 2,000 IU of vitamin D daily – five to ten times the old recommendations. Because too much ‘D’ from dietary supplements may cause the body to over-process calcium, nobody really knows for sure how much supplementary vitamin D is safe. On the other hand, sunlight-induced vitamin D doesn’t have that problem – it’s the way your body is intended to make it!   –Sunshine Vitamin.org


Sunlight exposure is also important for helping to regulate the brain’s release of the hormone serotonin. When sunlight hits the retina in our eyes, it cues the brain to produce serotonin. Low levels of serotonin are associated with a higher prevalence of seasonal affective disorder (SAD), a condition in which people find themselves struggling with low (depressed) moods and have difficulties staying calm and focused. According the the Journal of Psychiatry and Neuroscience, panic attacks and other anxiety related disorders have also been linked to changing seasons and reduced sun exposure.


Light has been shown to also affect brain blood flow. Cerebral blood flow has specifically been found to improve after phototherapy in pre-term infants [30] and SAD patients [31], and has repeatedly been found to be associated with cognitive functions, such as memory. Inadequate cerebral blood flow has been found to be a likely cause or result of decreasing cognitive functions among those with cardiovascular diseases [3234], as well as correlated with age-related diseases such as Alzheimer’s [35] and non-age related diseases such as Lyme disease [36]. The relationships that serotonin, melatonin, and cerebral hemodynamics have with sunlight, depression, and cognitive function suggest that persons prone to sunlight-related mood disturbances may also be prone to sunlight-related cognitive difficulties.   – Effect of sunlight exposure on cognitive function among depressed and non-depressed participants


This doctor in this video from John Hopkins University briefly explains what happens when we get exposure to bright (artificial lights) at night, and he encourages sunlight exposure during the day:


This next video is just under 35 minutes long and covers the importance of Vitamin D and our immune systems. Data is presented by the American Academy of Environmental Medicine. Very good information. There is a huge difference between using supplementation and getting it naturally through sun exposure. (With sun exposure, the body makes what it needs and discards the rest.)




Other Sources:

Healthy Home Economist

Berkeley Wellness on Vitamin D

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