太陽への露出によるダメージは、ビタミンDを摂取することによる利益を上回りますか?


3

いくつかの記事を読んだところ、直射日光を20〜30分程度直接当てることを推奨している記事や、10〜15分、5分で十分という記事もあります。これは地域によって異なると思いますが、季節やその他の条件。

しかし、1日未満の日光に当たると、皮膚が(Sun Protection and Vitamin D - The Skin Cancer Foundation)の損傷を受け始めると述べている記事を見つけました。this otherでは、ビタミンDを得るために日光浴をする必要があるという考えは神話であると述べられています。イエール医学のThis oneも同様の主張をしている。一般的に、これらの記事はすべて、ビタミンD欠乏症を補うためにサプリメントを摂取するほうが、太陽にさらすよりも良いことを示唆しています。

3

I like your curiosity and logical thinking - you're just missing a few pieces of the puzzle.

The sun emits ultraviolet light radiation which is the component of sunlight that is able to damage skin.

Ultraviolet (UV) is a form of electromagnetic radiation with wavelengths between 10 to 400 nanometers, shorter than that of visible light but longer than X-rays. To put nanometers into perspective - A human hair is around 75,000 nanometers in diameter. There are sub-types of UV which define the wavelength size:

  1. Ultraviolet A - UVA - 400–315 nanometers
  2. Ultraviolet B - UVB - 315–280 nanometers
  3. Ultraviolet C - UVC - 280–100 nanometers

Interestingly UVB is essential synthesize Vitamin D.

UV light is able to damage DNA. This results with humans cells (typically skin cells) to attempt to repair themselves. As a result sometimes genetic mutations arise - some of which give the cell the ability to divide more frequently (cancer). The process of UV damage is shown in the image below.

UV damaging DNA

Although advertises I'm sure would love you to believe that Vitamin D should always be gained from their supplement, the world health organisation states the following "...5 to 15 minutes of casual sun exposure of hands, face and arms two to three times a week during the summer months is sufficient to keep your vitamin D levels high.". Yes I understand - supplements avoid aforementioned damage to DNA - but you will be safe if you follow the above directive (it's free) and learn more information on other methods to prevent damage when in situations of long-term exposure.

In terms of further scientific reading I would like to direct you toward higher quality literature. This web-page explains the difference between and the best information resource out of: News articles, Journal articles and, Peer-reviewed scientific articles. In saying this, I also think Wikipedia in the 21st century has gained a highly respected and excellent reputation for free high quality information.

Attached is a Chloropleth map displaying the total average daily ambient ultraviolet radiation (UVR) level across the world.