Wednesday, December 1, 2010

New IOM Report Snubs Vitamin D Research

Vitamin DA new report from the U.S. Institute of Medicine (IOM) dramatically revises recommendations for adequate intake and blood levels of vitamin D in healthy persons, while raising serious questions about the veracity of research promoting benefits of the vitamin for various disorders. However, we reaffirm our position on vitamin D for ameliorating pain.

As followers of Pain Treatment Topics and this UPDATES weblog know, we have advocated for vitamin D as being of potential benefit for a range of chronic pain disorders, primarily musculoskeletal in origin [research reviews here and blogpost series here]. A preponderance of research evidence has demonstrated that persons with pain typically have deficient blood levels of vitamin D, and limited trials have generally (though not always) shown improvements in pain with vitamin D supplementation. Now, a new report might appear to contradict much of the prior evidence and challenge current recommendations.

The consensus report — Dietary Reference Intakes for Calcium and Vitamin D — was released by the Washington DC-based Institute of Medicine (IOM) on November 30, 2010, following a long period of deliberation and a review of more than 1,000 published studies [report accessible here]. The IOM had been asked by the United States and Canadian governments to assess current data on health outcomes associated with both vitamin D and calcium, as well as updating the nutrient reference values, known as Dietary Reference Intakes (DRIs). During the past decade there have been reports suggesting that higher quantities of these nutrients than previously recommended are needed for health, along with favorable studies of vitamin D in the prevention or remediation of certain autoimmune disorders, diabetes, many types of cancer, cardiovascular disease, various pain conditions, and other disorders.

While agreeing that vitamin D and calcium are essential nutrients for bone health, the 14-member expert committee assembled by the IOM concluded that there is insufficient evidence to support a role of vitamin D in benefiting any of the medical disorders studied to date. Furthermore, they note, emerging evidence indicates that too much vitamin D and/or calcium may be harmful. Here are some key recommendations of the IOM report:
  • As the “Recommended Dietary Allowance,” or RDA, most healthy North American adults (in the U.S. and Canada) need no more than 600 IU of vitamin D per day to maintain health, and those aged 71 or older may need 800 IU/day. The IOM committee believes these amounts often can be acquired via dietary intake and are not necessarily dependent on sun exposure. [While these amounts are higher than a 1997 IOM report — recommending 200 IU/day in persons up to age 50, 400 IU/day in those 50-70 years old, and 600 IU/day in those older than age 70 — Dietary Guidelines for Americans in 2005 had specified 1,000 IU/day for children and adults.]

  • Furthermore, the committee newly established that all healthy individuals get sufficient vitamin D when their blood levels of the 25(OH)D metabolite are at or above 20 ng/mL (nanograms per milliliter). [Note that 30-50 ng/mL has been traditionally considered as the range of sufficiency in research trials, with anything lower being labeled as insufficient.]

  • The committee set the Upper Level Intake for vitamin D at 4,000 IU/day, representing the high end of safe daily intake and above which risks for harm increase. [This had previously been set at 2,000 IU/day.]

  • During a press conference webcast to launch the report, IOM committee members suggested that according to their findings most persons in North America are not vitamin D deficient, laboratory testing for blood levels of the vitamin is being overused, and current lab tests for 25(OH)D lack standardization and in many cases are inaccurate.

  • As for calcium, the amount needed (RDA) ranges from 700 to 1,300 milligrams per day (mg/day), depending on age, with the higher amounts generally needed in older adults. The Upper Intake Levels for calcium range from 2,000 to 3,000 mg/day, also depending on age.

  • Most North Americans are already getting sufficient calcium in their diets, the committee notes, with the possible exception of adolescent females and elderly persons. These individuals should increase their intake of foods rich in calcium before considering supplements. [However, it should be noted that, without sufficient vitamin D, calcium will not be properly absorbed and used in the body.]
CAVEATS & CONCERNS: The need for adequate levels of the substance we now know as vitamin D for bone health, namely to prevent rickets, was first described in the 17th century. However, it was not until the early 20th century that the existence of the vitamin itself was discovered, and the biologically active metabolite of vitamin D was later acknowledged as a steroid hormone that regulates hundreds or perhaps thousands of genes in the body [historical facts here]. So, it seems biologically implausible that vitamin D would solely affect bone growth and maintenance, without influencing any other aspects of health (and/or disease) in the human body.

Therefore, the IOM committee’s recognition of vitamin D as essential for bone health is “old science,” and the necessary amounts that they recommend are lower than what much of the latest research suggests. What seems most surprising is how the group so readily dismissed the hundreds of research studies during the past decade that have proposed links of some sort between vitamin D and numerous health conditions. And, while they concede that future research may indeed reveal a “compelling relationship between vitamin D and another health outcome,” their report seems like a major setback in the recent progress of vitamin D research for at least two reasons:
  1. The allegedly sufficient blood level of vitamin D recommended by the IOM committee — ie, 20 ng/mL 25(OH)D — is for healthy individuals and they concede that the recommendations are not intended for persons in therapy for acute or chronic diseases. However, the report offers no guidance for healthcare providers in meeting individual needs for vitamin D in such cases.

  2. If 20 ng/mL is accepted as a sufficiently adequate level, it means that all of the research using a higher benchmark level of sufficiency (usually 30 ng/mL or more) must now be considered invalid. In fact, rather than most Americans being deficient in vitamin D as research has established, the trend is reversed and the majority would now be considered as having adequate vitamin D levels.
As for vitamin D and pain, the IOM committee does not specifically address this one way or the other. Indeed, within the entire 1,000-page report the word “pain” is noted only 21 times and not within the context of vitamin D as affecting pain conditions. Therefore, the report neither confirms nor refutes our prior research and advocacy for vitamin D supplementation as benefitting pain relief, particularly relating to musculoskeletal disorders.

Our recommendation of 2,400 to 2,800 IU/day of vitamin D3 is well below the 4,000 IU/day safety threshold (Upper Level Intake) in the IOM report (although, we have considered our recommendation as possibly being overly conservative for some patients). Plus, we have not recommended supplemental calcium unless it is clinically determined to be necessary. Therefore, taking into account the IOM report, we do not believe it is necessary or appropriate at this time to recant our prior positions regarding vitamin D for pain.

One concern we have had lately is that 5,000 IU capsules are being marketed by major discount stores in the U.S. as “maximum strength vitamin D,” as if this is perfectly acceptable for all who believe that “more is always better” even in healthy persons. Such thinking does not appear to be widely substantiated by research evidence; however, for alternative perspectives we recommend an examination of the Vitamin D Council website [here]. This group expresses views in support of vitamin D that some have considered controversial. Yet, participants include many distinguished researchers in the field and they do present scientific evidence as validation of their positions. For example, they note that the human body does not even begin to store vitamin D as 25(OH)D until blood levels reach 50 ng/mL, and that daily intake of 5,000 IU may be needed by some persons and even 50,000 IU/day is not necessarily toxic if taken under medical supervision.

The Vitamin D Council further observes how during the 1930s there were notorious cases of vitamin D excesses leading to overdose toxicity [details here]. In reaction, by the 1950s this led to exaggerated fears among the public and healthcare providers of vitamin D poisoning. Such qualms seem to have been dispelled only in more recent years, guided by new evidence. Now, this latest IOM report appears to reflect a renewed zeal for circumspection, rejecting much of the evidence as being inadequate or inconsistent, and this may turn out not to be in the best interests of public health. Time will tell.

CONFLICT OF INTEREST / DISCLAIMER: Pain Treatment Topics and the author (SBL) do not have any financial relationships with any manufacturers or marketers of nutritional supplements containing vitamin D. These UPDATES reflect information and evidence from the sources cited and/or linked, and are not intended to provide medical advice pertaining to any health conditions. Readers should consult their healthcare providers if there are questions or concerns regarding the appropriateness of vitamin D supplementation for their individual needs.