> Bottom line: If you're Vit D deficient then it may be a good idea to supplement a little Vit D which is cheap, easy and extremely low risk (Note: nothing is ever zero risk across a large enough population but supplementing a small amount of Vit D is about as safe as these things ever get).
Too much vitamin D can cause pretty serious symptoms, including neurological symptoms. This condition has been getting more common since so many people are supplementing.
Very true. That said, I've been taking 5000IU daily for the last couple years after a blood test showed my levels were a bit low. As of last week, my 25-Hydroxy D level is 76, near the middle of the 30-100 normal range.
Everyone's different: what's right for me isn't right for you. I just mean that to demonstrate that it's possible for some healthy adults to take a pretty significant amount every single day and have perfectly reasonable blood levels.
Vitamin D has a very long half-life in the body once stored. On the order of a month or two.
This leads a lot of people into slowly overdosing over several years. They start with low levels, get up to mid-range on their next blood test, and think they're on the right track. Continuing the same dose for years can easily put you over the top if you're not careful.
I read somewhere that additionally supplied vitamin K decreases these side effects. However I'd like to see a scientific paper instead of an article