Health advocate Gary Null has provided an unintentional educational lesson for those of us using dietary supplements. Taking one of his own products, he developed vitamin D toxicity. As there have been only a few cases of vitamin D toxicity ever reported, there is an inevitably interesting story behind this announcement.

The story is that his supplement contained 1,000 TIMES the amount of vitamin D it was supposed to. Instead of taking 2,000 iu a day, he was taking 2,000,000 iu day after day for a month. Wow!


Also, a recent independent analysis of St John’s Wort products found that fully one half of those tested were either contaminated with heavy metals (lead, cadmium) or deficient in the active marker compounds essential to the herb’s effects. 12 years ago a similar study found that the majority of products sold as St John’s Wort at health food stores was not actually St John’s Wort.

Please use these as a reminder to make sure that you purchase good supplements that have been analyzed for purity and content. As you can see on my MVM bottles, look for USP certification on vitamins. Purchase the best quality herbs, processed by manufacturers who comply with Good Manufacturing Practices, tested for marker compounds as noted on the label and ideally confirmed by independent testing.


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Michael Carlston, MD is an internationally recognized authority in the integration of conventional and complementary medicine in clinical practice, as well as medical education, research and organizational consulting. Practicing in Santa Rosa, California, Dr. Carlston was voted “Best General Physician In Sonoma County, California” by readers of the Sonoma County Independent newspaper and also named one of the outstanding physicians in the Bay Area by San Francisco Focus Magazine. With 30+ years in private practice, his expertise is in nutrition, homeopathy and sports medicine.