4 Mar 2011
Findings from the largest-ever study of vitamin D levels and average daily intake of supplemental vitamin D have vitamin D scientists not only suggesting higher daily vitamin D recommendations — up to 9,600 IU-per-day to get almost everyone over 40 ng/ml vitamin D blood level — but it’s produced a general guide to vitamin D recommendations.
Findings were published this month in the journal Anticancer Research.
For people severely deficient in vitamin D, each 1,000 IU/day of increased vitamin D supplementation results in a 10 ng/ml increase in vitamin D blood levels. So an individual with a vitamin D level of 20 ng/ml would need at least 3,000 IU/day of vitamin D to increase his/her levels to 50 ng/ml, according to the study. The actual amount would probably be higher, because for those with existing vitamin D levels above 30 ng/ml, each 1,000 IU/day of increased supplementation only leads to an increase of 8 ng/ml in vitamin D blood levels.
The study also concluded that daily vitamin D intake of up to 40,000 IU is unlikely to lead to vitamin D toxicity. That’s another advantage of UV-induced vitamin D — the body de-metabolizes what it doesn’t need, so UV-induced D never produces a toxic overdose.
An indoor tanning session can make up to 20,000 IU of vitamin D naturally in the skin. No food source approaches that level. An 8-ounce glass of vitamin D fortified whole milk contains only 100 IU of vitamin D.