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Unwanted
Supplements
By Christian Basi
MU researcher warns supplements could
contain lead at levels unsafe for children and pregnant women
Currently, over-the-counter dietary supplements, such as ginkgo
biloba and St. John’s wort, are not subjected to Food
and Drug Administration (FDA) approval. Therefore, many
scientists have tested the supplements to determine their effectiveness
and safety. In a study that included more than 86 dietary supplement
products purchased in 2000 and 2001, a University of Missouri-Columbia
researcher has found that some of the products contain lead
at levels that are dangerous to children and pregnant women.
“There are two ways that lead and other potentially toxic
trace metals may be seeping into the supplements,” said
Dave Robertson, a professor of chemistry and researcher at the
MU Research Reactor.
“Plants may draw and accumulate heavy metals from the
ground as they grow. In addition, there is the possibility of
metal contamination being introduced along with the binders
or during the manufacturing process of these products.”
Robertson oversaw the research that was conducted by Ethan Balkin,
a senior biology major at MU. Using a technique called X-ray
fluorescence, the team tested more than 20 types of dietary
supplements in 86 products. The researchers ground several samples
of each product into powder, shaped it into a large pellet and
subjected it to X-rays. During this process, the elements emitted
a distinct spectroscopic signature, which is a unique method
of X-ray identification. By identifying and measuring the signature
the researchers were able to determine what elements were present
and in what quantity.
The researchers scanned for 72 elements, including lead, nickel,
copper and arsenic. Lead was the only element that exceeded
the federal safety standard for consumption. In the products
they tested, 58 contained levels of lead that exceeded safety
standards for children under 6 years old, 39 exceeded safety
standards for children age 7 or older, and 18 supplements contained
lead levels that exceeded safety standards for pregnant women.
However, more recent tests of the same products purchased in
2003 indicate that the quality of the supplements may be improving.
“There is clearly the potential for toxic materials to
slip in to these supplements and we should make sure that there
is good quality control in the manufacture of these materials,”
Robertson said. “However, preliminary results from our
most recent survey indicate less lead contamination than we
observed in our original study.”
The study was funded in part by the National
Science Foundation and was presented at the 2002 summer
conference of the Federation
of American Societies for Experimental Biology.
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Last Update:
November 15, 2007
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