Are All Vitamin D Supplements Are the Same?
All Vitamin D Supplements Are the Same, Right? Uhm, Not Quite.
by Greg Marshall
Dr Erin LeBlanc and her colleagues at the Kaiser Permanente Center for Health Research discovered that not only does the potency of vitamin D supplements vary from brand to brand, it varies from bottle to bottle and even from tablet to tablet from the same bottle1. Dr LeBlanc and colleagues, in collaboration with Oregon Health and Science University, conducted a clinical trial investigating the role of vitamin D in controlling menopausal symptoms such as hot flashes, mood and musculoskeletal complaints2.
The experimental design of clinical trials dictates that all subjects who are randomized to the group taking the intervention being studied should be taking the exact same dose for the duration of the study. Any results obtained from an undisciplined study would be complete gibberish. LeBlanc’s research team discovered that the potency of vitamin D varied from as little as 9 percent to as much as 149 percent of the stated dose. This was observed regardless of whether the tablets were sourced from a compounding pharmacy or purchased over the counter.
Lack of industry regulation
The dietary supplement industry in general has been enjoying a long period of freedom from any form of government regulation. While pharmaceutical companies are required to jump through one costly regulatory hoop after another, vitamin-makers answer to no one in terms of either safety or efficacy of their products. The picture worsens when compounding pharmacies get involved.
The glaring truth about compounding pharmacies was revealed in a big way in the last quarter of 2012, when it emerged that contaminated vials of steroids from a compounding center in New England were responsible for 28 deaths and more than 300 illnesses of meningitis. A gigantic flaw in the regulatory landscape came to light as a result of what grew into a major medical scandal3.
Compounding refers to the process of altering a pharmaceutical product to fit the needs of a particular patient. This can be anything from changing a solid tablet to a liquid formulation, eliminating an ingredient to which the patient is allergic or even just altering the taste to make it more palatable. When compounding is scaled up to mass production, quality and safety are sometimes compromised.
USP verification may offer some assurance
This is not to say that all vitamin manufacturers are rogues bent on deceiving the supplementing public. There is a voluntary scheme to which some manufacturers submit their products for testing of potency, purity and quality. This is run by the U.S. Pharmacopeial Convention, a non-profit, independent organization that sets standards for dietary supplements and their quality. A USP Verified Mark on the bottle means that the product has been produced in a facility that follows Good Manufacturing Practices. Such a supplement is more likely to contain the amount of vitamin D that is listed on the label.
The discovery that vitamin D tablets vary tremendously in their potency was an accident and is only a little less scandalous than the New England steroid incident. Subjecting dietary supplements to the same level of regulation as the pharmaceutical industry is likely to result in price increases that the market, long accustomed to low prices, may find unpalatable and difficult to adjust to. A middle ground needs to be identified, even if it is as simple as making potency testing compulsory. In the meantime, it would be wise for you to take a USP verified vitamin D supplement.
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References
1 LeBlanc E, et al, “Over-the-Counter and Compounded Vitamin D: Is Potency What We Expect?” JAMA Internal Medicine (2013).
2 LeBlanc E, “The Role of Vitamin D in Menopause: Relationship to Menopausal Symptoms in Body Composition (FLASH),” ClinicalTrials.gov Identifier: NCT01141972.
3 Editorial, “Meningitis scandal shows regulators failed to keep up,” Boston Globe, 2012.
