Can Vit. D deficiency be caused by wearing sunscreen while outdoors? A generation ago, prior to widespread sunscreen use, one didn’t hear about Vit D deficiency.
Can Vit. D deficiency be caused by wearing sunscreen while outdoors?
You just beat me to that exact question. Does use of sunscreen block Vitamin D from being absorbed into the body?
It would have to be extensive use of a broad spectrum sunscreen that filters UVA and UVB tp drastically reduce D synthesis.
UVA is the DNA damaging ultraviolet— the melanoma causing wavelength. So most screens focus on that, and the UVB which is the wavelength that activates subdermal conversion reaction, can still get through generally. UVB causes the sunburn (based on intensity and skin type)— and it is also UVB that causes the photochemical reaction making D3 from the cholesterol in the skin, ironically.
Need to correct something think i said— “overdosing on Vit D from too much sun”.... should have added, when drinking a lot of milk (which is Federal law required to have D enrichment in the milk), and getting a lot of sun— then the milk D3 adds to the already sufficient D from the sun— and voila headache city. Can’t “overdose” on the sun caused vit. D— there is a natural feedback reaction that degrades excess D3 created in the skin— at that location. Drinking in excess D on top of the steady state— that’s what can cause overdose. Didn’t make that clear.
Darker the skin/complexion the more time of exposure to sunlight (and the strength of that sunlight) is needed to provide enough reaction/creation of vit. D. Have read that 4-5 minutes on the face (unscreened am guessing) is enough for normal daily. The D vitamin addition to milk is from way back in blackened overcast skies like in Pittsburgh of old and coal/steel towns. Really don’t need it if get enough sun.
Many sunscreens do not block UVA radiation well at all—and are of little use in shielding against the DNA damage. Need to have a good UVA shield at least or a spectrum UVA/UVB type screen). Personally more worried about the melanoma of too much UVA... so, lather up with a top end one. Work keeps away from outdoor fun the last few years.