Vitamin D and ultraviolet radiation. Myths and Reality

Vitamin D and ultraviolet radiation. Myths and Reality

Posted on 18 Feb 2016

By: Olga Makarova, 
PR Manager, OpenWeather

And in the dark and cold winter months, when so little of the sun and all sorts of colds and viruses diseases await around every corner, and in the hot and sunny summer, when it is so easy to burn in the scorching sun, the most important factor for the maintenance of immunity is a high level of vitamin D in the body, which depends on the amount of ultraviolet radiation received. On this subject numerous studies have been conducted, which often contradict with the data, once considered immutable fact and the resulting recommendations are often diametrically opposed to those given earlier. You've probably seen some vague guidelines, such as the recommendation to be in the sun, "a few minutes every day." But these recommendations are too general to be useful. The amount of the sunlight, which is necessary to satisfy the requirement for vitamin D varies greatly depending on your location, skin type, season, time of day, and even atmospheric conditions.

Myths about sunbathing

 1. It is best to 12am and after 3pm.

2. In order to maintain the necessary level of vitamin D in the body it is sufficient to expose to the sun hands and face 2-3 times a week for 5-15 minutes during the summer months.

3. Going to the sun, always use sunscreen.

4. Using a solarium can help to collect the missing vitamin D in the winter.

1. Sunbathing best 12am and after 3pm.

Optimum residence time in the sun to produce vitamin D is around noon, approximately between 11am and 3pm.

The fact is that the ultraviolet radiation includes a wavelength of different range that is divided into three groups:

UV-A (UVA) (315-400 nm)

UV-B (UVB) (280-315 nm)

UV-C (UVC) (100-280 nm)

UV-A and UV-B is able to pass through the ozone layer in order to reach our skin, but they are very different when it  comes to their individual characteristics.

UVB rays:

- Responsible for launching the production of vitamin D in the skin.

- Is the cause of sunburn.

- They can not penetrate the glass or clothing.

- It is only active at certain times of day and year.

UVA rays

- Do not trigger the production of vitamin D in the skin.

- Don’t cause sunburn.

- Penetrate deeper into the skin than UVB rays and are therefore the cause of premature aging, discoloration and wrinkles.

- They are able to penetrate the glass and clothing, and are active throughout the year all day long.

Between 11am and 3pm a relatively short residence time in the sun to get vitamin D because UVB rays are most intense at this time. But we must be very careful with the time of exposure to the sun. Remember that this is sufficient if the skin became slightly pink.For some people it will take just few minutes, for some it may take an hour or more. After this the chances of sunburn increase, and this is we definitely want to avoid. The fact is that the body can produce only a limited amount of vitamin D per day. Once it reaches its limit, further exposure to the sun will only bring harm and damage to the skin.

When the sun goes down to the horizon, the UVB is filtered out much more than dangerous UVA. So it is quite possible that the being in the sun at 9am or 5pm will reduce the level of vitamin D, since there is evidence that UVA destroys it. So if you want to go out in the sun to optimize the production of vitamin D and minimize the risk of malignant melanoma - the middle of the day is the best and safest time.

2. In order to maintain the necessary level of vitamin D in the body is sufficient to expose sun hands and face 2-3 times a week for 5-15 minutes during the summer months.

It is believed that for the most people it’s enough to have 15-minute exposure to UV light in order to form vitamin D in the skin in accordance with the recommendations of doctors, how much of vitamin D must be produced daily to maintain health.

However, once you get a tan, you will need to spend in the sun much more time. If you have dark skin, achieving an equilibrium point can take anywhere from two to six times more (up to an hour or two) depending on pigmentation. People with white skin quite far away from the equator (for example, in the UK or the United States to the north, central Russia) need at least three 20-minute sessions per week in the bright midday sunlight and with a minimum of clothing. The dark-skinned people, of course, need to be much longer and often in the sun, to obtain the same effect. This information is only beginning to penetrate through the media, so it is important to emphasize this point.

3. Going to the sun, always use sunscreen.

Keep in mind that the use of sunscreen is largely nullifies your effort to metabolize enough vitamin D. It is advisable to make sure that you do not have a deficiency of vitamin D, before resorting to any kind of sunscreen. But if you really need some form of protection, when you are in the sun for long periods of time, it is better to use light clothing to cover exposed areas, or look for a safer, natural products sunscreens that do not contain petroleum. It’s also important to remember that if you use the sun or safe solarium to get vitamin D, it is necessary to consider that, for vitamin D to completely pass from the skin into the bloodstream it takes about 48 hours, and you can easily wash it off with soap and water. Thus, it makes sense to limit the minimum hygiene procedures for at least 48 hours to all vitamin D was absorbed. Strange as it sounds, the washing can worsen one of the main methods of staying healthy.

4. Using a tanning bed can help to collect the missing vitamin D in the winter.

In winter, many people use bed to prepare the skin for the summer sun, to maintain the level of vitamin D, prevent winter depression, and just for the beauty. If someone does that in a commercial location, remember that it is advisable to ask the owners about what lamp they use. There’re tanning beds, which use both UVA and UVB radiation in different proportions, and in some only UVA is used. As noted above, for the production of vitamin D there must UVB radiation. In natural sunlight UVA and UVB ratio is about 2,5-5,0% of UVB, respectively, while in the sunroom with 5% UVB and 95% UVA it is about the same as if you were in the bright sunlight in the middle of the day and this is enough to get sufficient UVB radiation, and hence, vitamin D.

In recent years it has become increasingly clear that, even taking into account the recommendations of scientists and physicians are not so easy to understand what steps need to be taken to. on the one hand because of the abundance of caution not to deprive ourselves that it takes for the body to maintain good-being, and on the other, do not hurt yourself, ignoring the hazards.Accurate data, which the company OpenWeatherMap supplies in the IT-market using the most modern technologies (e.g. Big Data) can be, and in many spheres are already the basis for products that can help people get accurate forecasts and recommendations to preserve and protect their health .