Vitamin D from sun - minutes for 1000 IU (wrong in many ways)

Estimation of exposure durations for vitamin D production and sunburn risk in Switzerland

Journal of Exposure Science & Environmental Epidemiology (2019)

A. Religi, C. Backes, A. Chatelan, J.-L. Bulliard, L. Vuilleumier, L. Moccozet, M. Bochud & D. Vernez

1. Ignored 3X less Vitamin D from the sun if dark skin genes(250 IU) 4X variation between individuals from the same amount of sun (500- 2000 IU) 4X difference in the amount of skin exposed to the sun (500- 2000 IU) 2X? less burn if start with a good level of vitamin D 4X more vitamin D if wear a UV transparent shirt 1. Incorrect 3X less Vitamin D from the sun if elderly (250 IU)         text claimed 2X more time for elderly, but chart appears to say less time 4X more vitamin D is actually needed (4,000 IU) --- Yes, too much sun can result in sunburn, especially if you have a low level of vitamin D * Increase your vitamin D from the sun by wearing a tan-through instead of standard shirt * allows getting more vitamin D per minute by getting UV to more skin at the same time * 25 minutes of daily sun provided less than half of the response as 500 IU of vitamin D (Korea) – RCT March 2019 * Vitamin D from safe sun: only 500 IU in 10 minutes when include windchill – Jan 2018 * 2 cents of vitamin D far better than sunbathing for 30 minutes daily – Nov 2017 * Take much less time and has no chance of damaging skin * 4,000 IU of Vitamin D is OK - 19 organizations agree - 2018 * Many organizations believe that 1,000 IU is not enough --- 1. No – 10 minutes per day of sun-UVB is NOT enough contains {include} and, from 2009 Note: The body is aded in repairing skin damage by Vitamin D It is not know how long the repair takes - minutes, hours, days... It might be that the damage is repaired in 2 hours ---

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Following images are for Locrano, 46 degrees latitude and low elevation

Note: This seems to indicate that seniors need far less time in the sun to get 1,000 IU that younger adults,
but their study and others say the opposite

Although overexposure to solar ultraviolet radiation (UVR) is responsible for cutaneous melanoma and epithelial skin cancer and can cause negative health effects such as sunburn, a “little and often” exposure regime is often suggested to produce naturally recommended vitamin D levels, being essential for skeletal health. This study aimed to quantify solar UV doses needed to trigger 1000 International Units (IU) vitamin D doses and, at the same time, producing sunburn in Switzerland. Solar UV erythema irradiance (in mW/m2) measured at four meteorological stations in Switzerland for the period 2005–2017 were used to evaluate effective solar UV radiation producing 1000 IU vitamin D doses in skin phototype II and III individuals. Daily solar UV exposure durations (in minutes) needed to produce vitamin D with limited sunburn risk were estimated while considering mean vitamin D food intake of the Swiss population and seasonal skin coverage. 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. In winter and autumn, the recommended vitamin D production without sunburn risks often unachievable, since up to 6.5 h of sun exposure might be necessary considering 8–10% of uncovered skin surface. The vitamin D food intake only represented 10% of the recommended vitamin D production and remained unchanged throughout the year. These findings might clarify why vitamin D deficiency is common in Switzerland. Moreover, exposure durations between recommended vitamin D and increased sunburn risk might only differ by few minutes. Without additional oral vitamin D supplementation, daily doses of vitamin D (1000 IU) are not reachable in autumn and winter months in Switzerland.