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About the Quality of
Chondroitin in Dietary Supplements
Chondroitin is a widely used ingredient that occurs naturally in the
body of warm-blooded animals, and forms an important building block
of joint cartilage. Dozens of scientific studies have clearly
demonstrated that dietary supplementation of chondroitin in
combination with Glucosamine, another building block of cartilage,
benefits joints.
The chondroitin sulfate offered to manufacturers of dietary
supplements varies widely in quality, species of origin, and country
of origin. Only through reliable testing by a qualified analytical
laboratory can the manufacturer of chondroitin-containing products
be certain of its potency. Unfortunately, this expensive ingredient
is widely available in adulterated form, and may vary in potency
more than perhaps any other ingredient in the largely unregulated
health food industry, ranging from less than 10% to greater than 90%
purity. Below we discuss this problem and what is being done to
correct it.
Origin
Chondroitin sulfate is typically produced from cartilage obtained
from cattle, pig, or poultry slaughterhouses, or as a byproduct of
the shark fisheries industry. Shark cartilage is most widely used in
Europe and Japan, while bovine chondroitin is more popular in the
US. The worldwide availability of shark cartilage is rather limited,
and much of the presumable marketed shark chondroitin on the market
today is actually derived from bovine trachea. This true origin of
the chondroitin can only be detected by rather expensive and
detailed chemical analyses. Bovine trachea are widely available, and
produce chondroitin molecules of smaller size, which can be more
easily absorbed by the body. A disadvantage of bovine chondroitin is
the common misconception that BSE, the source of mad cow disease,
may be present. However, this fear is unfounded, as BSE prions can
only occur in proteins, which are absent in good quality chondroitin,
due to the complicated extraction processes.
Certificates do not tell the whole
story...
Chondroitin sulfate varies widely in price. Cheap chondroitin,
commonly referred to as “food grade” chondroitin, is commonly
used for animal supplements, as well as in some low cost human
supplements. This chondroitin consists mostly of molecules which
have similar chemical characteristics to true chondroitin molecules,
but are in fact different and not biologically active. While a
product may claim, for example, to contain 200 mg per tablet, the
actual beneficial chondroitin content could be less than 20 mg.
Pharmaceutical grade chondroitin is typically five to ten times as
expensive as food grade chondroitin, but should contain 90 - 98%
pure chondroitin. Pharmaceutical grade chondroitin will also be free
of any source proteins. Manufacturers of dietary supplements often rely on
the “certificate of analysis” (CofA) of specific lots, and it is
uncommon to verify the CofA concentration by an independent
analytical laboratory. Even when manufacturers do have the source
material tested, there may be no guarantee that the results will be
accurate. The problem is that the analytical method currently
accepted by the US Pharmacopeia (USP), the CPC titration method, is
faulty, and can be easily tricked to give false positive results.
This procedure treats molecules which are chemically related to
chondroitin but are quite useless as true chondroitin. While a more
reliable method is already available, it is optional, as it is not
yet the “official” USP method.
It is quite possible that a CofA which states that the chondroitin
concentration is >90% by USP, may in fact contain little, if any,
real chondroitin. According to Dr. Ron Peterson of Shuster
Laboratories, a renowned US testing lab, dozens of samples are
received every week, mostly of Chinese origin. Shuster Labs is
usually requested to analyze these samples for chondroitin following
USP, i.e. the faulty CPC titration method. It is quite easy to
understand how many producers can still legally claim high quality,
i.e. >90% chondroitin, on their certificates for food-grade
material.
Enzymatic HPLC
To put a halt to this practice, Dr. David Ji of Analytical
Laboratory in Anaheim developed a new analytical method which takes
advantage of the ability of certain specialized enzymes to break
down chondroitin molecules into smaller parts, which can then be
analyzed. Since only true chondroitin molecules are attacked by
these enzymes, it is highly specific, and unaffected by the presence
of chondroitin-like molecules. An added advantage is that the
concentrations of the breakdown products, so-called Type A and Type
C molecules, can yield an indication of the origin of the
chondroitin, land-based or marine, and based on the known A/C ratio.
 
Figure 1: Typical chromatograph of chondroitin from bovine trachea
(A) and from shark (B)
In response to a growing concern about the quality of chondroitin in
today’s supplement products, the enzymatic HPLC method has been
proposed to replace the CPC titration method as the official USP
method of testing. The method is currently being tested by multiple
analytical laboratories, and following the expected positive outcome
of this study, it is expected to become the new method of choice in
circa 2008. Until that time the manufacturer of chondroitin
containing supplements has no choice but to submit samples of the
raw material to a qualified laboratory for analysis by enzymatic
HPLC. To avoid being misled, consumers should put their trust in
brand names (e.g., ChondroPure® and only purchase chondroitin-containing pet health
supplements from reputable, high quality manufacturers.
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