3 ms·

Does the wearing of sunscreen inhibit the creation/uptake of vitamin D?

WalterSear 5y ago
The sun isn't actually a good source for vitamin D: even hawaiian surfers and people with tropical outdoor jobs can develop a deficiency: https://pubmed.ncbi.nlm.nih.gov/17426097/ https://pubmed.ncbi.nlm.nih.gov/17426097/ I suspect that at least part of the reason that it's not as effective as expected is that the current US RDA is over an order of magnitude too low, due ancient arithmetic error we discovered in 2014: https://pubmed.ncbi.nlm.nih.gov/25333201/ https://pubmed.ncbi.nlm.nih.gov/25333201/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5541280/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5541280/ 9k is what the science suggests, if you correct for this error, though, given that vitamin D absorption is highly variable, it's best to have your levels tested repeatedly until you know how much you need to take. (I am currently taking 15k daily, and only recently got my levels to stop bouncing around the bottom end of normal.) IMHO, this huge discrepancy between our previous understanding and the actually needed amount is also likely why so much vitamin D science is often conflicted: the differences between supplementing 2k iu (a number I've seen a bunch of times in the literature) and not supplementing aren't all that great if you needed 9k to begin with. I should also mention that concerns about vitamin d overdose are also misguided: while serious, it takes heroic doses on a daily basis - for years: The evidence is clear that vitamin D toxicity is one of the rarest medical conditions and is typically due to intentional or inadvertent intake of extremely high doses of vitamin D (usually in the range of 50,000-100,000 IU/d for months to years) https://www.mayoclinicproceedings.org/article/S0025-6196(15)00244-X/fulltext https://www.mayoclinicproceedings.org/article/S0025-6196(15)... Addtionaly, one may want to be conscious of one's magnesium intake as well: it is consumed during vitamin d metabolism, and our widespread misunderstanding of vitamin D requirements means that research into appropriate magnesium intake concurrent to increased (ie appropriate) vitamin D has not been done.

The sun isn't actually a good source for vitamin D: even hawaiian surfers and people with tropical outdoor jobs can develop a deficiency: https://pubmed.ncbi.nlm.nih.gov/17426097/ https://pubmed.ncbi.nlm.nih.gov/17426097/ I suspect that at least part of the reason that it's not as effective as expected is that the current US RDA is over an order of magnitude too low, due ancient arithmetic error we discovered in 2014: https://pubmed.ncbi.nlm.nih.gov/25333201/ https://pubmed.ncbi.nlm.nih.gov/25333201/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5541280/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5541280/ 9k is what the science suggests, if you correct for this error, though, given that vitamin D absorption is highly variable, it's best to have your levels tested repeatedly until you know how much you need to take. (I am currently taking 15k daily, and only recently got my levels to stop bouncing around the bottom end of normal.) IMHO, this huge discrepancy between our previous understanding and the actually needed amount is also likely why so much vitamin D science is often conflicted: the differences between supplementing 2k iu (a number I've seen a bunch of times in the literature) and not supplementing aren't all that great if you needed 9k to begin with. I should also mention that concerns about vitamin d overdose are also misguided: while serious, it takes heroic doses on a daily basis - for years: The evidence is clear that vitamin D toxicity is one of the rarest medical conditions and is typically due to intentional or inadvertent intake of extremely high doses of vitamin D (usually in the range of 50,000-100,000 IU/d for months to years) https://www.mayoclinicproceedings.org/article/S0025-6196(15)00244-X/fulltext https://www.mayoclinicproceedings.org/article/S0025-6196(15)... Addtionaly, one may want to be conscious of one's magnesium intake as well: it is consumed during vitamin d metabolism, and our widespread misunderstanding of vitamin D requirements means that research into appropriate magnesium intake concurrent to increased (ie appropriate) vitamin D has not been done.