Vitamin D has been spotlighted in the news with the release of a report by the National Academy of Sciences Institute of Medicine (IOM). This report confirms what many scientists have been saying for some time: the current recommended daily intake (RDI) for vitamin D is outdated and should be raised. The IOM has responded positively but cautiously, which is not surprising, as this non-government organization is known–and sometimes criticized–for its conservative approach to estimating nutritional needs in the general population. Nonetheless, the IOM increased the RDI to 600 IU daily for children and adults up to age 70. For those 71 and older, the new RDI is 800 IU. While encouraging, these marginal increases are a baby step.
What’s important to understand about this report is this: the new RDI is limited to what the IOM thinks we need for bone health and bone health only. Vitamin D plays a key role in keeping bones strong by regulating the absorption of calcium and its deposition into bone. This is old news and vitamin D’s best known function, about which there is no debate.
But there is clearly a lot more to vitamin D than bone health. A growing mountain of scientific evidence now indicates that vitamin D is important for many other things, including heart and cardiovascular health, immunity, brain function, the prostate, breast health, just to name a few.
The IOM did not discount this research; unfortunately however, some of the media reports make it sound as though they did. What the IOM said is that, in their judgment, the research is not conclusive enough to be factored into their new recommendations. In the eyes of conservative scientists, “conclusive evidence” would need to be rock-solid proof, a standard that could take many more years to achieve; science simply doesn’t move that fast.
Meanwhile, a growing number of experts are looking at the research that’s been done to date and concluding that, for things vitamin D does beyond keeping bones properly calcified, we almost certainly need much more than 600 to 800 IU per day. Leading experts on Vitamin D point out that we actually may need as much as 5,000 IU in order to achieve the ideal blood level of vitamin D; especially when we spend little time in the sun; in this case “we” means everybody living in the temperate zone who spends the winter indoors. Obviously a big chunk of the population.
Creighton University professor of medicine Robert Heaney, MD, who has studied the benefits of vitamin D, told the USA Today that the recommended 600 IUs of vitamin D is “way too low.” Heaney recommends people should consider taking up to 4,000 IUs a day. He added, “For me, it’s a no-brainer. There is a large body of evidence for benefit at intakes above the IOM recommendations. There is no risk, and very little cost, so why not take a chance of a benefit if there’s any possibility?”
But is it safe to take that much vitamin D? Again the media would lead you to think the IOM concluded otherwise. Not so, they merely declined to vouch for the safety of doses that exceed 10,000 IU daily and in fact acknowledged that there are no proven health risks from taking that amount. In fact, a number of studies have looked at people taking 10,000 IU and more and found no harmful effects. What’s more, the IOM doubled the “acceptable” upper daily intake limit from 2,000 to 4,000 IU, a dramatic increase.
The point is, the latest, cutting edge research strongly suggests that a lot of us need much more D than we’re getting. Secondly, taking more may do many important things to keep you healthy. And, daily consumption of as much as 5,000 units is completely safe. The problem with recommendations from ultra cautious organizations such as the IOM is they are rarely based on the cutting-edge. If we wait for them to catch up, we may miss out on the benefits of vitamin D in the meantime; indeed for some of us, by the time the final answer is in and the debate is over, it may be too late.