We often hear questions concerning the ‘new and improved’ recommendations for Vitamin D and Calcium intake (from the Institute of Medicine) . While the Institute’s recommendations about Calcium seem to be agreed upon by most, the recommendations released for Vitamin D have caused quite a stir in groups of health care providers across the country.
The actual IOM report is quite dense and a total of 990 pages long. (If you have a free weekend, take a gander for yourself.) To be honest, I did NOT comb through all 100 of the research articles that the IOM used to make its recommendations. But here are the basic recommendations:
Raise the suggested daily intake from 400 to 600 IUs of Vitamin D. The other half of the research is focused on the suggested Calcium supplement intakes (Not taking into account food-based Calcium, how you prepare that food and what types of foods…). At the end of it all, the researchers are saying that the recommended intake is 600 IUs (800 in the elderly, 400 in wee ones), but the upper tolerable limit, where “the risk of harm increases,” is 4,000 IU per day. I feel that the intake recommendations are overly conservative, and quite limiting in light of the potential benefits that Vitamin D can offer.
The IOM is also recommending that threshold for Vitamin D testing be at the 20 ng/ml level. We generally like to see the levels around 80 ng/mls, but most people in the Northwest clock in around 20-30 on an initial screen.
Many of the studies quoted and used to formulate the new recommendations are based in toxicity studies. It looks like the toxicity studies that they used for adults all included doses of Vit D of 100,000 to 150,000 IUs of Vitamin D a day for anywhere from 3-4 weeks to several years… increasing the blood levels to anywhere from 150 to the 1000’s. This is way too high and clearly excessive supplementation!
Other studies used are based off of cases of accidental over-fortification, which is very different than the supplemental Vitamin D that our patients have come to know and love.
Another interesting article on the topic came from a Huffington Post contributor, from Dr. David Katz, whose work I generally enjoy and whose articles seem to have a natural-based-bent to them.
“Calcium and vitamin D are important nutrients. As with all nutrients, enough is good — too little or too much is bad. The IOM invokes the precautionary principle to offer recommendations that are reasonable, and willfully conservative. But a relative absence of evidence means that guidance is as much about judgment as science.”
I think at the end of it all, what I am falling back on is that checking patients’ blood levels, like any therapy we initiate, is key.
Clearly, 5,000 to 10,000 IUs of Vitamin D for extended periods of time (YEARS and YEARS) or in the presence of naturally high blood levels is likely too much (although, the data to support or negate has yet to be generated sufficiently).
However, across the upper latitudes (Oregon, Washington, Canada, Norway, Sweden, etc..) providers have found 1000 to 4000 IU daily as a maintenance dose (and, of course, using higher/lower doses when clinically indicated) does not result in unusually elevated blood levels.
The key, then is making sure that you are supplementing under the care of a provider who evaluates your Vitamin D blood levels as indicated and supports you in making informed decisions to optimize your health.
Getting your Vitamin D levels checked should be part of every person’s winter health regimen. If you haven’t been tested this year, call the clinic today at (503) 287-4970, or email firstname.lastname@example.org for an appointment.
Image courtesy: SeanMcGrath