I'll add my anecdata. I'm dark skinned and an engineer, so sunlight and me are strangers at best.
I've taken 5000 IU/day (with vitamin K2) and have my blood levels tested every year. I don't remember what my serum levels are but they were on the high end of healthy individuals. Last I checked, my levels matched what a person reaches who spends the day in the sunlight, perhaps like a outdoor worker.
Whatever you try, if you have an annual check up, you should get you blood levels tested to verify you reach sane levels. I think most studies and articles fail to mention how dark the subjects are.
Agreed... also anecdotal, I have a autoimmune condition (psoriasis which includes on my face) that taking more Vitamin D helps with (so long as stress doesn't increase). I started taking 50,000 IU's to keep it under control. [I also take the K2 supplement] I also took a DNA test, and it indicated I had problems with Vitamin D absorption. A year later, my blood levels were tested and I was square in the normal range (taking 50,000 IU a day). But the two data points (from DNA and blood test) I think are important considerations.
Am in Canada, my doctor is Nigerian. He mentioned that for most of his patients, esp. the darker skinned ones, if they come in presenting symptoms of things that could be fixed by Vit D he doesn't even bother ordering blood work anymore -- he just sends em to go buy a bottle of Vit D, and call me if that doesn't work or things get worse.
I've taken 5000 IU/day (with vitamin K2) and have my blood levels tested every year. I don't remember what my serum levels are but they were on the high end of healthy individuals. Last I checked, my levels matched what a person reaches who spends the day in the sunlight, perhaps like a outdoor worker.
Whatever you try, if you have an annual check up, you should get you blood levels tested to verify you reach sane levels. I think most studies and articles fail to mention how dark the subjects are.