This article is more than 5 years old. Information may no longer be current.
USPSTF: Insufficient evidence on vitamin D, calcium supplementation
The current evidence on the beneficial balance of vitamin D and calcium supplementation for fracture prevention in adults is lacking, according to a new US Preventive Services Task Force recommendation statement.
On behalf of the US Preventive Services Task Force (USPSTF), Virginia A. Moyer, MD, MPH, of Baylor College of Medicine, wrote that 56% of women aged at least 60 years currently take vitamin D, and 60% take a calcium supplement.
However, the USPSTF concludes that the current evidence is insufficient to assess the balance of the benefits or harms of daily supplementation with vitamin D3 >400 IU and calcium >1,000 mg for the primary prevention of fractures in noninstitutionalized, community-dwelling postmenopausal women.
Moreover, the USPSTF recommends against daily supplementation with ≤400 IU of vitamin D3 and ≤1,000 mg of calcium for the primary prevention of fractures in noninstitutionalized, community-dwelling postmenopausal women.
“Research is needed to determine whether daily supplementation with greater than 400 IU vitamin D3 and greater than 1,000 mg calcium reduces fracture incidence in postmenopausal women or older men,” Moyer wrote.
These recommendations exclude treatment of patients with osteoporosis or vitamin D deficiencies.
In an accompanying editorial, Marion Nestle, MPH, PhD, of New York University, and Malden C. Nesheim, PhD, of Cornell University, wrote that vitamin D is not a typical vitamin because it is produced in response to the action of sunlight on skin.
“Like other hormones, vitamin D has multiple roles in the body, not all of them well-understood. Vitamin D supplementation, therefore, must be considered a form of hormone replacement therapy. As such, it raises all of the questions about efficacy, dose, and side effects currently asked of such therapies,” Nestle and Nesheim wrote.
In addition, the USPSTF uses the same precautionary approach that the Institute of Medicine once did, and further recommendations on vitamin D supplementation are highly anticipated, they wrote.
“While we wait for the results of further research, the USPSTF’s cautious, evidence-based advice should encourage clinicians to think carefully before advising calcium and vitamin D supplementation for healthy individuals,” Nestle and Nesheim wrote.
For more information:
Moyer VA. Ann Intern Med. 2013;doi:10.7326/0003-4819-158-9-201305070-00605.
Nesheim MC. Ann Intern Med. 2013; In press.
Disclosure: Nesheim reports receiving royalties associated with her book from the University of California. Nestle reports receiving payment for lectures, including service on speakers’ bureaus from the Steven Barclay Agency; royalties from published works by the University of California; and travel expenses paid for by various entities.
Perspective
Back to Top
The problem with the studies on which these recommendations are based is they were not properly designed or conducted. Most were done in subjects who were already getting enough calcium and/or vitamin D (or not stated) or the dose given was not sufficient to provide a benefit.
Calcium is the raw material for bone. It is hard to imagine being able to preserve or build bone without enough calcium. Vitamin D is important for the absorption and assimilation of calcium. I stand by the American Association of Clinical Endocrinologists guidelines that, for patients with osteoporosis or who are concerned about bone health, recommend a calcium intake of 1,200 mg daily (diet may be sufficient) and a 25-hydroxyvitamin D levels of at least 30 ng/mL, which usually requires a vitamin D supplement of 1,000 IU to 2,000 IU daily.
Perspective
Back to Top
The new USPSTF recommendations are not very helpful and might confuse patients and lead some people to not take supplements that could potentially help them. There’s a heavy reliance in the report on two large systematic reviews, both of which were severely flawed.
Also, there’s a problem in my view with the basic approach to the question in the first place. If you start with looking at what was the ancestral intake of these nutrients (i.e., the intake that prehistoric humans were exposed to and therefore to which human physiology is fine-tuned) you will find that the vitamin D intake would be several times what we currently have—at least 2.5 to 3 times the current levels. The same is true for calcium.
The ancestral intake of vitamin D, for example produces, a blood level of about 50 ng/mL; people living in Kenya today and following ancestral lifestyles have been shown to have exactly those kinds of levels. In addition, outdoor summer workers here in the temperate latitudes have levels even higher. Therefore, these are entirely safe levels. They’re what healthy people have under non-industrialized, non-urban conditions. That’s what is “normal.” The burden of proof should not be on those who propose an intake that is “normal” but on those who say a lower intake is safe.
I believe the USPSTF usually produces good recommendations, particularly for procedures such as screening for prostate cancer. However, when it comes to nutrients, a different approach is needed. The USPSTF approach is simply not well suited to nutrients. Fundamentally, they asked the wrong question and not surprisingly they got the wrong answer.