During exposure to sunlight 7-dehydrocholesterol in the skin absorbs UV B radiation and is converted to previtamin D3 which in turn isomerizes into vitamin D3. Previtamin D3 and vitamin D3 also absorb UV B radiation and are converted into a variety of photoproducts some of which have unique biologic properties.
The skin produces more vitamin D when in the sun during the middle of the day, the time it is at its highest point in the sky. When spending prolonged time in the hot sun, wear sunscreen, and stay hydrated. Amount of skin exposed. The more skin a person exposes, the more vitamin D the body will make.
The concurrent presence of fat in the gut enhances vitamin D absorption, but some vitamin D is absorbed even without dietary fat. Neither aging nor obesity alters vitamin D absorption from the gut [4]. Serum concentration of 25(OH)D is currently the main indicator of vitamin D status.
Abstract. To get an optimal vitamin D supplement from the sun at a minimal risk of getting cutaneous malignant melanoma (CMM), the best time of sun exposure is noon.
What About If I'm Wearing Clothes? A common misconception is that you can get vitamin D from the sun through clothing. This is not true, as the only way to trigger the chemical reaction that results in vitamin D production is for sunlight to reach your skin directly.
Sun exposure is the most important natural source of vitamin D and I would say 10-15 minutes in the early morning sun, when its UVB rays are most intense, should do the job. You could step into your balcony, terrace, garden, the neighbourhood park or any spot outdoors, with your upper and lower limbs uncovered.
Vitamin D is fat-soluble, which means it's easier for your body to absorb it if there's any kind of fat in your stomach to help it along. As a result, you'll get the biggest benefit from your vitamin D if you take it immediately after eating. You will absorb the vitamin more efficiently if your meal contains a fat.
You don't get enough exposure to sunlight. Your liver or kidneys cannot convert vitamin D to its active form in the body. You take medicines that interfere with your body's ability to convert or absorb vitamin D.
"Adequate levels of magnesium in the body are essential for the absorption and metabolism not only of vitamin D but of calcium as well," Dean states. "Magnesium converts vitamin D into its active form so that it can help calcium absorption.
According to the national Institutes of Health, between five and 30 minutes of sun exposure to your unprotected face, arms, legs or back between the hours of 10 a.m. and 3 p.m. two to three times every week is enough for your body to produce all of the D3 it needs. Sunscreen can block vitamin D production.
The best time to soak yourself in the sun to get the maximum vitamin D is between 10 am to 3 pm. At this time, the UVB rays are intense and it is also said that the body is more efficient in making vitamin D at this time.
You cannot wash vitamin D produced in the skin off!
So, no worries if you take a shower after spending some time at the beach – you'll do a good job of washing the sand off, but that vitamin D (which was produced in the deeper layers of the skin) will remain.
Magnesium assists in the activation of vitamin D, which helps regulate calcium and phosphate homeostasis to influence the growth and maintenance of bones. All of the enzymes that metabolize vitamin D seem to require magnesium, which acts as a cofactor in the enzymatic reactions in the liver and kidneys.
It can take anywhere from 1-6 months to raise vitamin D levels with supplements. How much your levels increase and how long it takes will depend on the dose and your baseline vitamin D levels.
Time of Day. The sun's rays vary in intensity throughout the day. In most places, UV rays are strongest between 10 a.m. and 4 p.m., when the sun is at its highest. If you go outside during that window, the body will produce more vitamin D in less time than if you went out in the morning or late afternoon.
In summer and spring, with 22% of uncovered skin, 1000 IU vitamin D doses are synthesized in 10-15 min of sun exposure for adults.
In general, scientists think 5 to 15 minutes -- up to 30 if you're dark-skinned -- is about right to get the most out of it without causing any health problems. You can stay out longer and get the same effect if you use sunscreen. Talk to your doctor about what's right for you.
Q. Am I still getting vitamin D when I'm outside on a gray, cloudy day? A. Just as it is possible to get a sunburn on an overcast day, it is possible to get the ultraviolet-B radiation needed for the skin to synthesize vitamin D even when skies are cloudy and gray.
Most of this UVB radiation is absorbed in the epidermis and as a result when exposed to sunlight most of the vitamin D3 that is produced in the skin is made in the living cells in the epidermis.
The question is, if not from UV exposure, how can you obtain enough vitamin D? It's pretty straightforward, actually. You can acquire vitamin D from a combination of diet and supplements. Fatty fish such as salmon, mackerel and tuna are especially good sources.