Kava
The FDA recently advised the public about the potential risk of
severe liver injury, including cirrhosis and liver failure, associated with use of kava-containing dietary supplements.
At least 4 affected patients have required liver transplants. According to the FDA, 21 different names are used for kava on
the labels of dietary supplements.
Canada and some European c
ountries have removed kava from
the market. PC Spes
A February 2002 letter from BotanicLab warned their customers
that the California Department of Health Services had found that PC Spes, an herbal dietary supplement
with estrogen-like effects sold for
“prostate health,” appeared to be contaminated with the anticoagulant warfarin (Coumadin, and others).
A second letter in March told cust
omers that alprazolam (Xanax,
and others) had also been found in PC Spes.
A recent laboratory analysis of PC Spes manufactured between
1996 and mid-1999 found that the concentrations of listed ingredients thought to be active varied from lot to lot, and some lots also contained indomethacin (Indoc
in, and others) and the estrogen
diethylstilbestrol. Echinacea
Echinacea is a dietary supplement widely used for prevention
and treatment of colds.
In vitro or in vivo pharmacologic activity has been reported for
various constituents of these plants.
The amounts of these constituents vary in any particular
formulation, depending not only on the species and plant part, but also on the season of harvesting.
In one study of 12 products marketed in the US, the percentage
of phenolic compounds such as cichoric acid (which may or may not be an active ingredient) varied from brand to brand and within different lots of a single brand.
Echinacea products, like other herbal dietary supplements, may
contain a wide range of organochlorine pesticides, including some that are banned in the US. Melatonin
In a published study, mass spectrometry identified 7
contaminants in 3 different commerc
ial preparations of melatonin,
including some contaminants pr
eviously found in L-tryptophan
associated with an epidemic of
eosinophiliamyalgia syndrome that
occurred in the US in 1989.
An evaluation of the physical qualities of 9 commercial
melatonin tablet products found excessive friability, failure to disintegrate and excessive variation in hardness. Glucosamine
Investigators in a National Institutes of Health study of
glucosamine and chondroitin for treatme
nt of arthritis could not find
a satisfactory source that containe
d consistent amounts from batch to
batch and had to manufacture the drugs themselves.
Conclusion
The main problems with dietary supplements, even if questions
about their effectiveness and adverse effects were answered satisfactorily, are that their potency may vary and their purity is suspect.
Physicians should tell their patient
s that we really don’t know
what’s in them.
Nutrition for Sports, Essentials of 151
