No – 10 minutes per day of sun-UVB is NOT enough

Many people and doctors believe that 10 minutes a day in the sun a few days a week provides enough vitamin D

WRONG most of the time 

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VitaminDWiki video Does Less Sun mean More Disease

Time in the sun to get 4000 IU

Vitamin D Workshop for Seniors contains the following summary chart

Assumes

• 2X more minutes going to Seattle, which is at a higher latitude (47 instead of 32)
• 3X more for seniors instead of youth
• 2X more for standing than lying down
• All items multiply

Incorrectly assumed that all skin produces the same amount of vitamin D
This is wrong - the table needs to be recomputed
Does not include

• Obese (2X more minutes)
• Black Skin (5X more minutes)
• Early morning or late afternoon sun (2X more minutes)
• Sun during Spring or Fall ( shoulder season >2X more minutes)
• Urban haze - perhaps 2X or 4x more minutes
• Light clouds

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Vitamin D lasts in your body for about a month
There are ways to increase the amount of vitamin d you get from the sun
If you can't sunbathe all year, consider taking supplements, using a sunbed, or getting your own UVB lamp

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A study was published in May 2011 on the amount of sun needed to get 20 ng/ml of vitamin D

Mote: many recommend much more: 30, 40, and even 50 ng/ml

• • Air pollution reduces UV and thus vitamin D - Aug 2010
• Got sun/UV 3 times per week for 6 weeks
  • The danger of skin cancer if all tanning is done just once per week instead of spread over three times
• Assumed 30% of skin exposed (shorts and T-shirt)
• Assumed summer sun intensity
  • There is such a thing as a vitamin D winter
  • Very little vitamin D when your shadow is longer than you are

For white, thin youth living more than 30 degrees away from the equator

• 20–40 minutes if STANDING
• 10-20 minutes if LYING DOWN

But 20 ng/ml only prevents Rickets

If want to achieve, say 36ng/ml, then about 2X longer is needed
Standing – but be aware that any time over 30 minutes may cause skin cancer

• 1 hour of white, young, and thin
• 3 hours if white, elderly, and thin
• 5 hours if dark, young, and thin
• 30 hours if dark, elderly, and obese
  • totally impossible - longer than a day
  • Perhaps the factors do not multiply - we have no data

Tables from the paper - which assumes 3 times per week

• Vertical = standing
• Horizontal = lying down
• Better still would be on a slant board - to place the body perpendicular to the rays of the sun.

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The vitamin D debate: translating controlled experiments into reality for human sun exposure times.

Photochem Photobiol. 2011 May;87(3):741-5. doi: 10.1111/j.1751-1097.2011.00898.x. Epub 2011 Feb 14.
Webb AR, Kift R, Berry JL, Rhodes LE.
School of Earth Atmospheric and Environmental Sciences, University of Manchester, Manchester, UK Vitamin D Research Laboratory, School of Biomedical Sciences, University of Manchester, Manchester Royal Infirmary, Manchester, UK Photobiology Unit, Dermatological Sciences, School of Translational Medicine, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester, UK.

Exposure to sunlight, specifically ultraviolet radiation, has both positive and negative health effects. Maximizing the benefits (vitamin D synthesis) while minimizing the damage is a multifaceted problem in which many of the elements are poorly quantified. Here we show how rigorously conducted large sample-size laboratory studies of the effect of ultraviolet radiation dose on vitamin D status can be applied to real-life situations. This was achieved by modeling the radiation incident on different surfaces for different solar locations and equating it with the controlled exposures in laboratory studies.

Results from both model and experimental data show that relatively short exposures of a modest amount of unprotected skin to summer sunlight in northern climes, on a regular basis during lunchtime hours, increases vitamin D to sufficiency status (?20?ng?mL(-1) ) in the white Caucasian population. While both sun exposure conditions and human skin responses are variable in real life, these quantitative findings provide a guide for authorities devising sunlight exposure recommendations.

Registered readers can CLICK HERE to see the PDF file

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Vitamin D sun time suggestions condensed from Translated German website

Time vs. skin type (on each side of the body – in Southern Europe/US, June-August, 11 – 2 PM)

• Type 1 may get 5 minutes per day.
• Type 2 can get 10 minutes per day.
• Type 3 may get 15 minutes per day.
• Type 4 should get 20 minutes per day.
• Type 5 should get 25 minutes per day.
• Type 6 should get 30 minutes per day.

Add 5 minutes if in Northern Europe/US

2X times in shoulder seasons = March-May, September

2X times in non-noon = 10-11 AM or 3-5 PM

3X times if both shoulder season and non-noon (not 4X)

Tips:

• When first tanning, reduce the following times by half.
• Lie down so that you get into a shadow at the time allocated.
• Always take a short time with the sun.
• Do not exceed these times; it will redden your skin and cause skin damage and sunburn

Added by VitaminDWiki

• Increase times 3X if elderly
• Increase times 2X if overweight
• Increase times 3X if cloudy or you are in the shade
• Increase times 2X if hazy
• Increase times 2X if standing
• Add 10 minutes? if very far from the equator: Alaska/Finland
• Decrease times ( 1/2 ?) if near equator
• The times above assume
  • % of body exposed to the sun - we guess 30% = shorts and T-shirt
  • Daily? Rather than 3 days a week

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McKenzie - 2009.pdf has the following graph

• 1300 publications mentioning McKenzie and Vitamin D 2016-2020 Google Scholar
• Vitamin D produced by UVB – June 2013
• Even small amounts of UVB result in increased vitamin D levels – March 2012

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See also VitaminDWiki

Minutes in the sun

• How many minutes of sun do I need – age, skin color, UV index – Nov 2014
• Doctor survey: 64 % incorrectly think 10 minutes of sun is enough,
  33 % say use sunscreen in the winter – May 2012]
• Minutes in the Sun for 1000 IU default 30 degrees North
  • Face 3.5%, neck 2%, trunk 26%, hands 6%, arms 14%, legs 14%, thighs 18%
• Polish children need 45 minutes of noon sun to get 800 IU of Vitamin D – July 2020
• 9 minutes of full noon sun daily is all you need (if have white skin and believe that 10 ng is enough) – Aug 2018
• 25 minutes of daily sun provided less than half of the response as 500 IU of vitamin D (Korea) – RCT March 2019
• Only 1000 IU of vitamin D in 10 minutes at 36 degrees, nude, summer, noon – April 2013
• 60 minutes of sunlight needed to decrease vitamin D deficiency in sunny climate – Dec 2012
• Vitamin D from safe sun: only 500 IU in 10 minutes when include windchill – Jan 2018
• 1400 IU of Vitamin D from Summer noonday German sun from a 10 minute walk – Feb 2018
• Time in sun (in Spain) to get 4,000 IU of vitamin D: half hour in July , 2 hours in October – Sept 2016
• Canadians have a hard time getting 1,000 IU of vitamin D from the sun – July 2015 mid-latitude
  • 

- - - - - -

• Increase your vitamin D from the sun by wearing a tan-through instead of standard shirt
• Little variation in vitamin D levels with skin color in Brazil – July 2014
• Equation of IU vs time in the sun - Jan 2012
• 1,000 IU of vitamin D from the sun not available in the winter (Switzerland too) – April 2019
• Complex relationship between UVB and vitamin D – April 2012
  This article may result in a rewrite of this web page. It questions many of the assumptions made here about:
  Amount of skin area, color of skin, obesity, etc. There are several reasons why the study may be wrong, however.
• Seniors, like everyone else, need vitamin D but should avoid sunburns – 2011
• All items in Noontime Sun331 items
• 4X more suburban UV than urban UV – Nov 2010
• all items in category Deficiency of D468 items
• Melanoma risk with sunburns - 2010.PDF
• UVB causes sunburn - UVA causes melanoma - 2011.PDF
• Poor knowledge by office workers of vitamin D and sunscreen - July 2010
• Scared Out of the Sun for Fifty Years – Jan 2011
• Overview Suntans and melanoma
• Increased UVB intensity did not increase vitamin D generated – Nov 2010
  • Is there a limit as to how much vitamin D the body will produce over a several-day time period? Replenish cholesterol?
• For small amounts of sunshine the amount of skin exposed may not matter – Jan 2011
• Sun increases but tanning bed decreases longevity - April 2011 PDF file
• UV calculators on the web
• Many reasons why vitamin D deficiency has become epidemic in past 30-40 years
• Weekly UV almost doubled elderly Vitamin D levels to 20 ng – Dec 2010
• When you get enough vitamin D, be sure to get cofactors too
• Ways to increase the amount of vitamin D you get from the sun
• Tanning while getting little vitamin D
• Whites were 2X more likely to be vitamin D deficient if wear long sleeves – Jan 2012
  No decrease, however, in the reported use of sunscreen
• Vitamin D from psoriasis lamps, tanning beds, and the sun – Jan 2012
• Shade Provision For Uv Minimisation: A Review Jan 2014 PDF is attached at the bottom of this page
  Long article is about Australia seeking shade. They even have ''shade audits.'
• Vitamin D from the sun vs time of day which has the following graphic

Map of annual solar radiation

Accounts for latitude and clouds, but not altitude (e.g. Colorado) link dead Oct 2015

SED = “standard erythema dose” = approximately the UV Index.

Erythemal dose = amount of sun to create a slight reddening of the skin

For light skin, 1.5 SED ==> slight reddening
The darker the skin, the more SED needed (black skin needs 5X more)

UV index for a light-skinned person

1.5 = 1 hour
3.0 = 1/2 hour
6.0 = 1/3 hour

UV index for a person with black skin

1.5 = 5 hour
3.0 = 2.5 hour
6.0 = 5/6 hour

Note: SED is defined for UVA (tanning), not UVB (vitamin D), so it overestimates the amount of vitamin D at high latitudes or non-noon.

alternate term: MED =“minimal erythemal dose” – varies with darkness of skin

UV Index scale

UV Index Minnesota

UV Index Hawaii

Sunshine Prescription June 2012

A half hour or more sun a day is a human right and should become a lifestyle habit like tooth brushing

Comment on an article in Mercola in July 2012

Experiment with getting 20 minutes of mid-day sun every weekday in Korea ( same latitude as Washington DC)

Exposure on hands, forearms, and face every weekday for four weeks. Facial sunblock and sunglasses were permitted.
Vitamin D levels DECREASED. But it was October/November
The experiment reported in Vitamin D Council Jan 2013

Pick Your Poison – Sunscreens vs. Sunburns Green Med Info June 2013

UVB varies a lot with time of year and latitude - copyright protected

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Items in both VitaminDWiki categories, Seniors and Sun, are listed here:

Short URL = http://www.is.gd/timeinsun