Since people with what looks like optimal sunlight exposure are recording "low" levels of D, my question would be:  Are the recommended levels set too high?  This has happened with other nutrients from time to time.  On what basis were these set?  Is it a theoretical basis, with some leeway added?  Who did the figures, and how was it funded?
I have a questioning mind, and so am not simply questioning the adequacy of vit D intakes, as discussed here, but looking beyond that to query on what the figures for the recommended levels are based. If they are true, why wasn't there a huge incidence of rickets in affluent families in air-polluted cities of the 19th century and first half of the 20h century, where sun exposure was the walk in the park on a good day or morning-tea in the back garden, with the sunlight filtered through air pollution?  Fish oil emulsions were widely advertised in the 1920s/'30s in Australia and recommended through into the 1940s. I believe they were on the national health in Britain during World War II and after - my brother and I were given it on a family visit to the UK.  However, I'm not so sure they were used in the 19th century or before World War I.   So why weren't the comfortably-off families suffering the deficiency diseases seen in the poor?  I think this is a very complex issue.
Virginia
in Brisbane, Queensland 

On Sun, 3 Jun 2007, cillakat  (in Atlanta) wrote:
"you guys definitely have a better shot at optimal D levels from sun,
but the few people I know in Colorado (3 specifically) who are testing
D, aren't coming out well.  And they probably have 'typical'
exposure...weekend athletes, walking the dog in am and 5/6 pm, moms
walking babies in strollers around 10 am etc."


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