As a Finn, I have found that the natives really don't want to hear that most of the country is on the same latitudes as Alaska.
As for your question, well... <snark value="11">I did.</snark> Wonderful ice breaker in pubs, btw. "I moved to London for the weather."
The medical community also seems to think that 20 ng/ml is when the deficiency starts, when in reality it's more like 40. Some studies have shown that you can see benefits upwards of 60 ng/ml. Other research has shown that Vitamin D helps with sleep in the 60-80 ng/ml range.
I've seen many people on Reddit say that their blood tests level came out at 5-10. That's crazy. Get your 25(OH)D level checked.
Some of the studies that have shown "no improvement" from Vitamin D saw that result mainly because they were still prescribing far too little Vitamin D (yet still higher than the RDA).
10,000 IU may be necessary just to maintain your level. However, you also have to keep in mind that you won't be getting D only from the supplement, so throughout the year you should actually increase your Vitamin D level as you get more sun exposure. Meanwhile the 10,000 IU (which by the way is "only" 250 micrograms) will maintain those high levels. Then, in the second year, you may further increase your Vitamin D level as you once again get more exposure in the sunny days. So you should check your Vitamin D at least after a year, to ensure your levels aren't too high. After you're stabilized you should need around 5,000-7000 IU, but it's really dependent on each person's needs, so you'll have to figure out on your own through trial and error.
However, you also need to keep in mind that not everyone uses Vitamin D as efficiently. You may have undiscovered gallbladder issues for instance, or your gut bacteria is not well balanced, or your stomach doesn't have enough acid, or you're not taking Vitamin D with enough fat, and all of these factors which could impact how easily you're absorbing Vitamin D.
This is part of the reason why the FDA can't just recommend "everyone should take 10,000 IU". Plus, people of color need much more Vitamin D, so if the FDA recommends everyone 2,000 IU as a higher minimum, that may still not be enough for them.
https://www.youtube.com/watch?v=v3pK0dccQ38&feature=youtu.be...
https://www.youtube.com/watch?v=xF24xmJQK1k
https://www.foundmyfitness.com/vitamin-d
https://www.vitamindcouncil.org/i-tested-my-vitamin-d-level-...
I don't think so.
'The body needs sunlight to produce the vitamin' okay. But now i say: '15 Minutes of sunlight a day is enough for your body'.
What now?
Where is your study saying how much sunlight is relevant? And if it makes sense to supplement? And what are the dangners of too much?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2873840/
After reviewing over 1300 article titles and evaluating 270 articles in detail, we pooled ORs from 51 independent study populations for “ever” sunburned and risk of cutaneous melanoma. Among these, 26 studies reported results from dose-response analyses. Dose-response analyses were examined using both fixed-effects models and Bayesian random-effects models.
Results:
An increased risk of melanoma was seen with increasing number of sunburns for all time-periods (childhood, adolescence, adulthood and lifetime). In an attempt to understand how risk between life-periods compares, we also report these same linear models on a scale of 5 sunburns per decade for each life-period. The magnitude of risk for 5 sunburns per decade is highest for adult and lifetime sunburns.
Conclusions:
Overall, these results show an increased risk of melanoma with increasing number of sunburns during all life-periods, not just childhood. Prevention efforts should focus on reducing sunburns during all life-periods.