James:
I love the blog and a lot of the articles. I am a dermatologist and wanted to comment on the Vitamin D article posted on July 21, 2011. Despite what you might read on the Internet, you cannot get a significant amount of Vitamin D from sunlight. This is a huge misconception. Even if you tanned for 8 hours, you would only get about 3% of your daily Vitamin D. You would also cause a lot of sun damage which increases your risk of skin cancer. I realize a lot of information says otherwise, but if you check with the American Academy of Dermatology, you will read data from experts.
Also, although Vitamin D is important, science doesn’t support a lot of claims in the article about fighting the flu, etc. It is true that is you have a deficiency of Vitamin D, you can weaken your immune system, but taking extra Vitamin D does not “boost” your immune system. I realize a lot of holistic medicine people want to believe this, but it isn’t backed up by any science.
Again, not trying to be negative, but just wanting to let people know that tanning is not a good way to try to get Vitamin D. Tanning also has some bad effects (skin cancer). – Dr. C.S.
Hey Jim,
Living in the Eastern mountains with the associated cloudy days and longish winters our clinic has never tested anyone with enough Vitamin D3 in their system.
The accepted norms for Vitamin D3 in adults is 30 ng/mL to 100 ng/mL. Being more interested in finding the optimal level instead of the statistical normal range we aim for most adults to be in 70 ng/mL – 89 ng/mL range and for those with cancer the optimal range seems to be 90ng/mL to100 ng/mL.
We have also found that 50,000 IU per day for only three days to be a good weapon in fighting winter colds, flus, etc.
For the 25-hydroxyvitamin D test, we get the most consistency from Labcorp which is available nationwide. – S.D. in West Virginia