The current RDA for the vitamin is 600 IUs per day for everyone up to the age of 70 and 800 for those who are older.
But researchers from the University of California at San Diego say the amount we really need to be absorbing from all sources, including sunshine, is 7,000 IUs a day. Even this is way below the safe upper limit for teenagers and adults, which is 10,000 IUs, says lead researcher Cedric Garland.
The researchers are calling on all public health groups and agencies to urgently change the recommendation.
(Source: Nutrients, 2014; 6(10): 4472)