Vitamin D and cancer risk:
Vitamin D is important for reducing the risk of many cancers. A report by the Institute of Medicine (IOM) and the Endocrine Society’s Clinical Practice Guidelines tripled the amount of vitamin D required for most children and adults. The Endocrine Society’s Clinical Guidelines for vitamin D concluded that vitamin D deficiency be defined as a 25(OH)D < 20 ng/ml, insufficiency as a 25(OH)D of 21–29 ng/ml and sufficiency as a 25(OH)D of 30–100 ng/ml. For preventing and treating vitamin D deficiency the Guidelines recommended vitamin D intake should be: children < 1 y 400-1,000 IU/d, children 1-18 y 600-1,000 IU/d and adults 1,500-2,000 IU/d to maintain 25(OH)D concentrations of 40–60 ng/ml. Upper limits of vitamin D intake were also set as follows: 2000 IU/day for children up to age 1 year; 4000 IU/day for children aged 1 – 18 years, and up to 10,000 IU/day for adults aged 19 years and older. The IOM report concluded that dietary and supplemental vitamin D intake is adequate to satisfy both children and adult, but their study suffered from serious flaws. A study (Moore et al) suggests that neither children nor adults in the US are obtaining the new RDA for vitamin D. Among women vitamin D intake from food was 156–208 IU/d and with supplements 244–324 IU/d. For men, corresponding values were 208–320 IU/d and 308–392 IU/d. There is no evidence that there is a downside to increasing vitamin D intake in children and adults, with the exception of those with chronic granuloma forming disorder or lymphoma in which high vitamin D levels may occur resulting in high calcium levels. (23)