More than three fourths of all Americans are vitamin D-deficient.

It now appears most of us need about 5,000 units a day if we avoid the sun. The government was off by a factor of ten; an ,i>“order-of-magnitude error.”,/i> Mistakes of this scale are rare in medicine.

50,000-63,000 individuals in the United States and 19,000-25,000 in the UK die prematurely from cancer annually due to insufficient vitamin D.