If you have dark skin, for example if you're of south Asian, African or African Caribbean origin, you will need longer in the sun. You need to have some skin exposed, for example, your forearms, hands and lower legs. But you can still make vitamin D even if you sit in the shade.
Vitamin D is one of the essential vitamins that the body needs, it primarily helps with the absorption of calcium. The body can get vitamin D through the sun, from food and through supplements.
So, is it possible to get vitamin D on a cloudy day? Surprisingly yes, it is still possible to get vitamin D when it's cloudy outdoors because full-spectrum sunlight still exists beyond the clouds.
Here's Why: Can you get vitamin D through a window when sunlight streams in? The answer, in general, is “no.” It might seem like glass lets all the sun's UV rays get through to you, but that's just an illusion: glass – as well as plexiglass and plastic – absorbs all UVB radiation.
In summer, exposure is best at mid morning or mid afternoon (outside peak UV times). In winter, longer exposure times are needed, preferably around midday. It is important to balance the need for sun exposure to produce adequate vitamin D, at the same time avoiding the risk of skin damage from too much exposure.
The researchers took into account the amount of clothing and the season of the year. In spring and summer, 25 percent of the body (the hands, face, neck and arms) is exposed to the sun, and in these seasons, about 8 to 10 minutes of sun exposure at noon produces the recommended amount of vitamin D.
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.
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.
Vitamin D is the sunshine vitamin that has been produced on this earth for more than 500 million years. 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.
Medical conditions that can cause vitamin D deficiency include: Cystic fibrosis, Crohn's disease and celiac disease: These conditions can prevent your intestines from adequately absorbing enough vitamin D through supplements, especially if the condition is untreated.
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. Exposure durations between erythema risk and 1000 IU vitamin D production vary between 9 and 46 min.
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.
Age – as a person ages, their skin's ability to produce vitamin D decreases. Time of day – vitamin D production is strongest mid-day between 10am and 2pm. Follow the Shadow Rule – if you are taller than your shadow is long, then your exposed skin can make vitamin D.
Although there is no scientific evidence that vitamin D can have a direct effect on the under-eye area, it is believed that puffy eyes and dark circles prevail in people deficient in vitamin D, particularly females aged 40+.
It's possible for UV rays to pass through clothing and reach the skin. In fact, a regular white cotton t-shirt may only provide a UPF rating of 5 – that means roughly 20% of UV radiation passes through the fabric and penetrates your skin.
Sunscreen prevents sunburn by blocking UVB light. Theoretically, that means sunscreen use lowers vitamin D levels. But as a practical matter, very few people put on enough sunscreen to block all UVB light, or they use sunscreen irregularly, so sunscreen's effects on vitamin D might not be that important.
According to the National Institutes of Health, vitamin D promotes calcium absorption in the gut and helps regulate the concentration of calcium and phosphorus in the blood, which supports building and maintaining healthy, strong bones and helps regulate skeletal and neuromuscular function.
Growing evidence has demonstrated that vitamin D has a role in sleep regulation [12]. Specifically, vitamin D deficiency (VDD) can increase risk of sleep disorders and is associated with sleep difficulties, shorter sleep duration, and nocturnal awakenings in children and adults [13,14,15].
Choosing the Best Vitamin D Supplement for Your Health
“Vitamin D3 is the form that is already stored in the body, so some studies have found it to be more effective,” Clifford says. “Also, take vitamin D with a healthy fat, such as sliced avocado, because it is a fat-soluble vitamin that requires fat to be absorbed.”
There are quite a few differences between vitamin D and vitamin D3, but the main difference between them is that vitamin D is a fat-soluble vitamin that regulates calcium and phosphorous levels in the body, whereas the vitamin D3 is the natural form of vitamin D produced by the body from sunlight.
Answer: No. Even though spending short periods of time in the sun can usually provide adequate amounts of vitamin D, spending longer periods of time in the sun will not increase vitamin D levels to toxic levels.