Re: Vitamin D and sunlight.
Cletus Declared Vit D Not-A-Slide so here goes.
(Move along if you think Cletus is loopy)
You have the right on the sunscreen issue with Vit D deficiency but I have not read about computer screens and would like to find that info.
Sunscreen has been used more and more due to the correlation with sun exposure and skin cancer. But the use of sunscreens have the effect you describe inhibiting Vit D synthesis. A common sense application is needed for people. Get some sun, but don’t fry your skin.
Other Vitamin D points that to be considered:
The further north or south you live from the tropics the less likely you will be able to absorb sunlight to synthesize the minumum D needed. IIRC, for northern hemisphere, in winter one needs to be below the 35N parallel. In summer as the earth tilts the sun reaches well north with enough UVB to synthesize D but I don’t recall the time and parallel progression. I recommend all our kids and grandkids in Maine take supplemental D year-round.
The next point also relevant is that when exposing your skin to the sun’s rays for D production energy, one must “greatly expose themselves.” You need your bare skin exposed as much as you can. If not comfortable in some skimpy tops and shorts, and you lack outdoor privacy to be comfortable scantily clad, take a supplement.
Skin color also relates to absorption, darker complected people absorb slower, light complected absorb more quickly. (Almost like God placed people correctly centuries ago for best Vit D production.)
Another claimed hindrance to UVB absorption is obesity. I am not clear on how or why with that so tend to take it with a grain of salt.
My take away from this is that most people in North America would do well with a “D” supplement. The exceptions are people who either work outdoors or spend their off-work time outdoors.
Mrs. Toddler and I take a D supplement every day even though I'm outside a lot. I recommend you get the D+K2. There are several good videos on youtube about the benefits of K2 with your D.
We also supplement with Lugol's iodine. Again youtube is a good source of info.
Public service announcement :)