Health threat? Isn't that an exaggeration? Well, it depends.
For the average consumer, it probably ain't a problem. With the ever-increasing
number of studies that show that berberine could be used instead of metformin
and/or on top of medical treatments for high blood glucose and/or lipids, some
consumers may end with lower/higher levels of glucose or lipids in the blood
when they (a) switch from one 500mg product to the other or (b) simply start a
new bottle that was produced by the same manufacturer, but contains more/less
of the active ingredient (note: I personally was afraid that the deviations
from the label may be much larger and am relatively happy with the results, but
I guess that's my personal disillusionment).
The last-mentioned possibility that the potency varies not
just between products, but also from batch to batch, is also why I wouldn't
rely too much on the data from the study at hand. The next batch of supplement #9, the
"best" supplement in this study, of which the authors rightly point
out that it was limited "[p]rimarily" by the fact that they
"analyzed the berberine content of one individual bottle from each
manufacturer" (Funk 2017), may well contain significantly lower amounts of
berberine than the one that was tested by Funk et al. for the study at hand. As
previously hinted at, this is a general problem with dietary supplements. It's
a problem you should know about, and one that disqualifies them as 1:1
replacement for medications, but not one that should make you shy away from
supplements altogether, in my humble opinion.
References:
- Funk, R.S. et al. "Variability in Potency Among Commercial Preparations of Berberine." J Diet Suppl. 2017 Aug 9:1-9. doi: 10.1080/19390211.2017.1347227. [Epub ahead of print]
- Brown, Paula N., and Mark C. Roman. "Determination of hydrastine and berberine in goldenseal raw materials, extracts, and dietary supplements by high-performance liquid chromatography with UV: Collaborative study." Journal of AOAC International 91.4 (2008): 694-701.
- Dong, Hui, et al. "Berberine in the treatment of type 2 diabetes mellitus: a systemic review and meta-analysis." Evidence-Based Complementary and Alternative Medicine 2012 (2012).
- Dong, Hui, et al. "The effects of berberine on blood lipids: a systemic review and meta-analysis of randomized controlled trials." Planta medica 79.06 (2013): 437-446.
- Edwards, David J., and Emily J. Draper. "Variations in alkaloid content of herbal products containing goldenseal." Journal of the American Pharmacists Association 43.3 (2003): 419-423.
- Gershwin, M. Eric, et al. "Public safety and dietary supplementation." Annals of the New York Academy of Sciences 1190.1 (2010): 104-117.
- Sarma, Nandakumara, Gabriel Giancaspro, and Jaap Venema. "Dietary supplements quality analysis tools from the United States Pharmacopeia." Drug testing and analysis 8.3-4 (2016): 418-423.
- Sun, Yiyi, et al. "A systematic review of the anticancer properties of berberine, a natural product from Chinese herbs." Anti-cancer drugs 20.9 (2009): 757-769.
- Ye, Minzhong, et al. "Neuropharmacological and pharmacokinetic properties of berberine: a review of recent research." Journal of Pharmacy and Pharmacology 61.7 (2009): 831-837.
