How much of sunlight is sufficient for vitamin D generation? More than commonly believed.According to recent studies, at least 50% of the world population has deficit in vitamin D. People who live in areas with a small number of sunny days per year and / or a high degree of air pollution are at increased risk of getting vitamin D deficiency and its related diseases. A growing number of studies indicates that vitamin D plays an important role in the prevention of many diseases.
Its main task - calcium absorption and utilization of its salts for the formation of bones and teeth. Vitamin D gives strength to our skeleton and regulates calcium metabolism in the body. The lack of vitamin D develops diseases such as, for example, osteoporosis. According to many large-scale studies, the optimal level of vitamin D may help prevent at least 16 different types of cancer, including pancreatic, lung, ovarian, prostate and skin cancer. There is evidence that adequate levels of vitamin D may reduce the risk of preterm birth. It can also help to protect a newborn baby from many health problems.
Who is most at risk of vitamin D deficiency?
- those who are a little in the sun;
- the elderly people are more at risk due to lack of mobility and the skin is less sensitive to UV, and after 65 the skin loses the ability to synthesize vitamin D;
- those who are on a non-nutrition diet;
- who suffer from alcoholism - alcohol impairs the absorption of nutrients;
- diabetics and cancer patients;
- people with dark skin - a high rate of vitamin D deficiency among blacks is widely documented;
- nursing mothers - breastfeeding will lead to a vitamin D deficiency for the child if the mother is not able to keep her own level high enough to meet the needs of the child;
- obesity - a fat-soluble vitamin D gets trapped in fat tissue, preventing its metabolism and its use by the body.
How to produce vitamin D?
Regular sun exposure, without sunscreen, under the action of ultraviolet radiation causes the skin to produce vitamin D naturally. But how much UV should be sufficient for its generation? The skin's ability to create the necessary amount of vitamin D when exposed to UV radiation depends on many factors. The mechanism of formation of vitamin D rests on the accumulation of "base" for its production (provitamin D) in the skin and subsequent synthesis of vitamin by kidneys in amounts necessary for the organism.
Another argument for the ultraviolet radiation is that an excessive amount of vitamin D simply can not be formed - the body itself stops its synthesis. If you take vitamin D inside - in the form of food, beverages, supplements and drugs, the risk of overdose is real, that is very dangerous for the body, in particular the excess of vitamin D adversely affect the kidneys.So getting vitamin D naturally eliminates its negative impact on the human overdose and is the best way to optimize the level of vitamin D. But there are several factors that influence its production, which is important to take into account.
Factors influencing the production of vitamin D in the skin.
Production of previtamin D3 in the skin is very individual and will vary depending on several factors, including:
- weather conditions, such as cloud cover and pollution, the ozone layer, the surface reflection;
- the breadth and height;
- season;
- time of the day;
- use of sunscreen;
- clothing.
Weather
The more clouds, the less ultraviolet radiation reaches the earth's surface. However, the UV can, to some extent penetrate cloud cover, so that it is possible to get a sunburn on a cloudy day. This is especially true when there’re light clouds in the sky that can block infrared light but not UV, whereby sunlight appears deceptively weak. Similarly, some kind of surface reflect UV radiation, increasing its intensity even in the shaded areas. These surfaces include sand, snow and water.
Air pollution, on the other hand, can block ultraviolet radiation very efficiently. If the contaminated air contains a large amount of ozone O3, penetration of ultraviolet radiation can be reduced sometimes to dangerously low levels for at-risk groups. This is especially true in urban areas, surrounded by hills and mountains, which become a trap for air pollution.
The breadth and height
UV radiation is more intense at higher altitudes because there is less of absorption by the atmosphere. Radiation increases by about 10 percent for each additional mile above sea level. Thus, at higher altitudes you can get burn much faster and it is often difficult to remember because it’s generally cooler.
Season
It makes sense to start "training" the skin in the early spring, when the sun is still soft. In many parts of the world even possible, and perhaps advisable to sunbathe in the afternoon in winter with minimum clothes, if the weather conditions allow (find a place closed to the wind, which can significantly reduce the cold). This is time of year, when the level of vitamin D may fall to 50 per cent in comparison with the summer months.
Thus, the more we know about what surrounds us, and how affects us, the more significant we can influence their own health, the duration and quality of life, so that the importance of accurate data about the environment is difficult to overestimate. You can use the older system of calculating the amount of UV for a certain altitude, latitude, time of day and year, to determine the level of contamination of the color of air and smell, but in the modern world, there are technologies to obtain accurate data on weather conditions, UV radiation (UV index) data on air pollution in large volumes and virtually in real time, which allows to improve the standard of living.
OpenWeatherMap actively uses the latest technology to provide actual data making them available and, most importantly, comfortable to use.