Studies performed over the last ten years have linked robust vitamin D levels with heart health, lower cancer risk, and prevention of other serious diseases, such as diabetes—and the data suggests that the current RDI (recommended daily intake) for vitamin D may be woefully inadequate. What's more, Americans' vitamin D levels appear to have declined over the past two decades. Last week, the Council for Responsible Nutrition (CRN) submitted comments to the national Institutes of Medicine calling for an increase in RDI for vitamin D. The current RDI for the "sunshine vitamin," set over a decade ago, was based on an adequate intake (AI) of 200 to 600 IU per day to prevent diseases associated with severe vitamin D deficiencies (e.g. rickets). According to the CRN press release, this recommendation is completely outdated.
Many experts suggest that the optimal range of serum 25-(OH)D is between 80 and 120 nmol/L. Data reveals that on average, Americans’ serum 25(OH)D levels are far below this, especially in the obese, the elderly and those of ethnicities with darker skin. Data suggest that the amount of vitamin D Americans need to achieve serum 25(OH)D levels between 80 and 120 nmol/L is somewhere at or above 1000 IU per day, well above the current recommendations. Furthermore, doses in this range have been shown to lower the risk of falls in the elderly, lower total cancer risk and even higher doses (> 6000 IU/day) are needed to increase vitamin D content of human breast milk.
The CRN also recommended increasing the tolerable upper level (UL) to 10,000 IU, citing evidence that it takes doses ten times that amount to reach toxicity.