- One researcher found that many vitamin D supplements do not have the amount claimed
- A national testing lab disagreed
- There are many indications that the 400 IU claimed in many one-a-day supplements is not very bio-available
- It appears that most (but not all) gelcap and liquid forms of vitamin D have the amount claimed
- Sometimes the solid forms of vitamin D do not appear to be very bio-available
It is apparently difficult to get consistent measurements of vitamin D when it is in a supplement mix.
Consumer Labs, with years of experience, still initially can get inconsistent results when trying to determine the amount of vitamin D in a supplement.
Dr. Christopher P. Eckstein (below) will provide us with more information after he gets results from other testing labs.
There is still a concern, as shown by The Heart Scan Blog, below, that some the blood serum level does not increase until a person switches off of some brands of vitamin D.
This is a strong indication that some vitamin D supplement do not have the amount they claim
By Richard Robinson, Contributing Writer, MedPage Today
Published: June 07, 2010
Reviewed by Ari Green, MD; Assistant Professor, University of California, San Francisco and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner Earn CME/CE credit
- Explain to interested patients that in one small but carefully done study, the actual dose of OTC vitamin D was below the listed dose in all brands tested.
- Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
SAN ANTONIO — Multiple sclerosis (MS) patients taking over-the-counter vitamin D aren't getting what they're paying for, or what their neurologists recommend, according to a study presented here.
The mean vitamin D content from 10 OTC brands was only 33% of what the label claimed, with the actual content ranging from less than 1% to 82% of the advertised level. The study was presented at the meeting of the Joint Consortium of Multiple Sclerosis Centers and America's Committee on Treatment and Research in Multiple Sclerosis.
Vitamin D supplements are increasingly being recommended to MS patients, both for osteoporosis, which is common in the disease, and for presumed immunomodulatory actions as well, according to senior author Peter Calabresi, MD, of the Department of Neurology at Johns Hopkins University in Baltimore. "As the role of vitamin D in immune regulation in MS gains increasing focus, oral supplementation is growing," he said.
The level of recommended supplementation depends on the patient's individual deficiency, although 4000 IU daily is a common dose.
However, given the wide variety of vitamin D3 (cholecalciferol) supplements available and "limited regulation within the nutritional supplement industry, the true vitamin D3 content of over-the-counter supplements is a concern," Calabresi said.
To test levels in commonly purchased supplements, his group collected 10 bottles of OTC supplements from local and on-line retail pharmacies.
Vitamin D3 was extracted by standard techniques and samples were analyzed by liquid chromatography and mass spectrometry.
The labeled doses ranged from 400 IU to 10,000 IU, but the mean actual dose was only 33.5% of the labeled dose, with a range from 0.24% to 81.7%
none with 100%?
Lower-dose products tended to be closer to their labeled dose than higher-dose products, with the
- three 400-IU products averaging 51.5%, the
- two 1000-IU products averaging 34%, and the
- three 10,000-IU products averaging 29.9%.
On the other hand, the single worst sample — the one with only 0.24% of what it claimed — was a 400-IU sample.
Neither national in-store retail brands nor online brands were more true to their labels.
The discrepancy between the advertised and actual vitamin D content "may contribute to the difficulty for some patients to reach adequate serum vitamin D levels despite supplementation," Calabresi said.
"This reflects the need for increased regulation of the vitamin industry."
Because their lab is not certified to do drug testing, Calabresi declined to name the products tested in this study.
Patients taking vitamin D supplements should have serum measurements made after starting therapy to determine whether they are reaching target levels, he said.
The authors reported no disclosures.
Primary source: Consortium of Multiple Sclerosis Centers
Eckstein C, et al "Vitamin D3 content in commercially available oral supplements" CMSC-ACTRIMS 2010; P. 33-34. http://main.nationalmssociety.org/site/PageNavigator/HOM_ACTRIMS_2010_Posters
Christopher P. Eckstein, MD Johns Hopkins University Baltimore, Maryland USA
Suspect: Nature Made gelcaps appear very low, Healthy Origins
Probably OK from comments on the forum: NOW, Country Life, 8000iu of Walgreen's "Finest Natural" D3 gelcaps , Bio-Tech capsules, Vitamin Shoppe, Sam's Club Members Mark, Nature's Life,
Also: concern about lack of oil (non gel cap or meal) when in a powder or dry
Here is a a tiny portion of their report
Here is our graph of their Jan 2010 vitamin D report showing the huge variation
When a person say - I have vitamin D in my multi-vitamin - it does not mean much