Hypothesis - 40 ng is enough vitamin D if high latitude or dark skin
Recommendations of amount of vitamin D to have generally vary between 30ng/ml and 60 ng/ml
The Institute of Medicine proposed 20 ng/ml in Nov 2010]
Dr. Veith presented an interesting hypothesis in May 2011
Some people (Caucasians?) living in high latitudes (which have a large variation in UV during the year)
get adverse reactions to high (50 ng+) levels of vitamin D for the entire year
It MIGHT be OK to have higher levels during the summer.
The data only hints that having > 50NG/ml all year long might be a problem
CICK HERE to get to reference - PDF and soon audio and video
Humans evolved to have a constant amount of vitamin D
U shaped risk curve only where UV varies a lot with season - Veith
Pancreatic Cancer increases with high levels of vitamin D only where UV varies a lot with season
Prostate Cancer U-shaped curve from Lappe May 2011
Note: this shows having 24 ng/ml all year long increases prostate cancer
Concerning people with dark skins
There have been various reports in 2009, 2010, and 2011 which seem to indicate that dark skinned people do not need as much as those with light skins
Unknown so far
- Does this apply only to dark skinned people living far from the equator
See in Vitamin D Life
Meta-analysis vitamin D not change with latitude unless caucasian - 2009
Blacks may not need as much Vitamin D - many articles
Blacks and whites may need different levels of vitamin D etc – Sept 2010
Vitamin D blood levels vary with estimated amount of African Ancestry – Sept 2010
Improved blood flow in blacks with just 2000 IU of vitamin D – Feb 2011
Dark skinned Caribbean seniors have enough vitamin D – April 2011
Vitamin D blood levels vary with estimated amount of African Ancestry – Sept 2010
Meta-analysis vitamin D not change with latitude unless caucasian - 2009 PDF file