The NY Times ran an article about a study showing that most athletes had a lot vitamin D level. They raised the issue if athletic performance can be improved by correcting low vitamin D levels. There were many responses, following is mine.
The article is excellent. The recomended dose will not solve vitamin D insufficiency in most people.
I have tested 1700 people for 25-hydroxyvitamin D levels since 2005, and have treated about 1200 of them for levels less than 32 nanograms. 1000 units a day may raise some people’s level, but most people need more. I don’t know how anyone can determine how much vitamin D to take without getting a level. Some people require much higher doses, and when I’ve retested a person 3 or 6 months later, the level has never been too high.
Vitamin D toxicity hysteria is unfortunately common. The truth is that a level higher than 200 ng. is necessary to get side effects, and this would require very massive amounts of vitamin D for a long time that noone would recommend.
Some studies show higher doses, 5000 units a day, is necessary to reach a level over 32 ng. in many people. But trying to treat the insufficiency without a level is like prescribing a statin dose for cholesterol without checking a cholesterol level.
If you want to meet some people who have levels from 100 to 150 ng., go to a beach next Labor Day and talk with some of the male lifeguards who have worked full time all summer. Male llifeguards have been found to have levels in this range at the end of the summer without taking any vitamin D. Many vitamin D experts are recommending levels of 50 to 80 nanograms as ideal,.
And yes, there is evidence of Vitamin D offering resistant to viral illnesses including influenza, and much very compelling evidence regarding vitamin D and autism.
For some down to practical information on Vitamin D:
(Item #2 is an Update on Vitamin D 2009)
Both web sites are free; nothing is being sold.