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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