Vitamin D or Sunscreen use?
Before we get in this discussion let's try understand some concepts first:
1) "What is solar radiation"?
Indeed there are a lot of previous studies about it, but the first and one most important was in the half of the nineteenth century when Joseph von Fraunhofer detailed, in 1814, a spectroscopic observations of the solar spectrum showing 574 dark spectral lines. And his explanation was based on the absorption in the Sun's atmosphere, which was given by G. R. Kirchhoff around 45 years later.
Excuse-me but I like a little bit of history!
After these works some others came over, but based on mathematical equations to try define some process such as scattering, polarization and absorption of the light could affect and reach the Earth.
In simply words, solar radiation could be defined as the light or energy which come from the sun in different ways. And as a results of those studies mentioned before, these "ways" were rearranged in the electromagnetic spectrum, that explains the different types of light waves.
Light waves are vibrations of electromagnetic fields which shows low or high frequencies. The former has a low energy waves with long wavelength and the second shows the opposite, high energy and short wavelength. All of them are presented in our lives somehow, as shown the picture below.
As you can see at this picture the frequency is related to the energy somehow. Electromagnetic waves with longer wavelengths and lower frequency, have less energy than ones with shorter wavelengths and higher frequency. And here is the point! This is the reason why ultraviolet radiation could be dangerous. The energy is so high that may damage the cells DNA.
2) "But, don't we need the solar radiation to produce Vitamin D and avoid diseases"?
Yes! Indeed we really need the solar radiation to keep us alive and warm in the Earth. It's essential for our biochemistry and for a nice feeling (mainly after a long winter!).
As I wrote some years ago, Vitamin D plays an important role to regulate calcium taken it by our food, that helps to build strong bones, teeth, send messages along your nerves and participate muscles contraction, as your heart beats, for example.
The ultraviolet light from the sun makes a type of cholesterol, found just under our skin, turn into something called vitamin D3 or cholecalciferol. This Vitamin D3 it's carried to liver changing into more active form called 25-hydrovitamin D3. This molecule goes to kidneys and becomes more reactive form than before called 1,25-hydrovitamin D3.
Vitamin D is found in some foods as beef liver, egg yolks, milk, salmon, sardines and shrimp. However, it´s presented as Vitamin D2 or ergocalciferol. In supplements we can found cholecalciferol or ergocalciferol. It means that we this radiation to take the vitamin D in an appropriate form.
The deficiency of Vitamin D affects bones, muscle, brain, prostate, breast, colon and immune cells health. The 1,25-dihydroxyvitamin D controls more than 200 genes, including genes responsible for the regulation of cellular proliferation, differentiation, apoptosis, and angiogenesis. The orders disorders are: schizophrenia, depression, lung function and wheezing illnesses.
3) "Sounds good, but if it's needed to the biochemistry balance in our body, why do the people use sunscreen"?
The purpose of the sunscreen is protect our skin from the ultraviolet energy shown above, that supposed to be high enough to cause cells damages.
The two types of ultraviolet radiation are: UVA and UVB. The UVA has a longer wavelength than UVB.
The UVA rays are up to 95 percent of the total UV radiation being more prevalent and then, they penetrate in the skin deeper than UVB.
Recent studies showed that although UVB causes skin aging and wrinkling, the UVA rays affect skin cells called keratinocytes in the basal layer of the epidermis, where the most skin cancers occur. This is the reason that the people advise you use the sunscreen, to avoid these damages.
However, the point is the quality of the chemicals inside the sunscreen lotions, already discussed in this fun page. Some of them instead of protect you could cause health problems like unbalanced hormone or irritate the skin. And lately, most of people are believing that if you use these protective lotions you could avoid the Vitamin D absorption and develop diseases.
Sunscreen use X Vitamin D
I open now the debate. Based on the last posts and what do you know, what do you think about it?
I believe that everything should be balanced. It's possible to get your irradiation needed to develop the Vitamin D before 10 am and after 4 pm. Between this time the energy by the ultraviolet waves is too high and really cause damages.
Related to the sunscreen, choose one with physical blocks, as titanium oxide, and more natural as possible. Choose one that not only protects you from UVB but also from UVA, called broad-spectrum. Don't let you and your kids get the sun of the noon time, when it is the maximum irradiation.
Yes, I believe that you may balance everything. The Vitamin D absorption, the quality of the sunscreen and your moment to enjoy the sun. Get the pleasure with the responsibility.
Have a great summer everyone!
Barbara F.
References:
Coulson, Kinsell L, solar and terrestrial radiation, 1975
http://www.skincancer.org/
