- ANAHEIM, Ca.- New evidence has been reported that a popular nutritional
and dietary supplement, called chromium picolinate, may be a cancer risk.
Chemists from the University of Alabama in Tuscaloosa, presented findings
here today at the national meeting of the American Chemical Society, the
world's largest scientific society, which they say show chromium(III) tris(picolinate)
causes DNA breakage. Such events are known, in some cases, to cause genetic
mutations and cancer in humans, the researchers noted.
-
- This research has been peer-reviewed
and will soon appear in the American Chemical Society journal Chemical
Research in Toxicology.
-
- Chromium picolinate is claimed to reduce
body fat and build muscle. It also has been suggested that the supplement
reduces the risk of cardiovascular disease and the symptoms of diabetes.
It often is an ingredient in products ranging from sports drinks and gum
to pills.
-
- The health claims for chromium are based
on its status as an essential human nutrient required for normal carbohydrate
and fat metabolism. The Alabama scientists believe it does this job by
making the insulin receptor work better. Still, chromium's role in these
processes is not well understood. The element is needed only in trace amounts,
but the U.S. Department of Agriculture (USDA) says that more than 90% of
American diets contain less than the minimum recommended daily allowance
of chromium and dietary sources are extremely poorly absorbed by the body.
-
- Chromium picolinate, on the other hand,
is more readily taken in during digestive processes. Furthermore, University
of Alabama chemists John B. Vincent, Ph.D., and Stephen A. Woski, Ph.D.,
say their laboratory has found the compound is remarkably stable and unaffected
by water, buffers, or blood serum proteins. "If it's stable enough
that it gets into the cells intact," says Vincent, "then it could
be a big concern."
-
- The Alabama studies advance the work
of the late Dartmouth University chemist Karen Wetterhahn, Ph.D., who died
from a widely publicized mercury-poisoning accident. In a 1995 paper she
demonstrated that chromium picolinate can get into cells, at least in a
lab dish. Her work further showed that, once inside those laboratory cells,
it appeared to induce cleavage of chromosomal DNA. Until now, though, there
was no solid explanation for just how chromium picolinate caused the damage.
-
- "Simple chromium compounds don't
do this," says Vincent. "They have to have ligands -- something
that binds to chromium -- that make the properties just right and picolinate
is one of those ligands."
-
- Vincent found that chromium picolinate
reacts with common biochemicals, like vitamin C. He says the products "can
then catalyze a reaction with oxygen to generate the potent DNA-damaging
hydroxyl radical." Indeed, when Vincent added "physiologically
relevant concentrations" of chromium picolinate to laboratory solutions
of DNA, much of the DNA was broken, he said.
-
- It is not known what actually happens
in humans, or even animals when chromium picolinate is consumed. A recent
USDA study fed rats a diet rich in the compound for 24 weeks and did not
see any ill effects. But Vincent asks, "what happens in six months,
or a year, or longer?"
-
- "I would definitely be concerned
about taking this nutritional supplement based on what we've found,"
concludes Vincent. "Careful investigation into the effects of long-term
diet supplementation with chromium picolinate are needed to evaluate its
mutagenic and carcinogenic potentials. In addition, development of other
readily absorbable sources of chromium that lack the DNA-damaging ability
of chromium picolinate seems warranted."
-
- ________________
-
- A nonprofit organization with a membership
of nearly 159,000 chemists and chemical engineers, the American Chemical
Society publishes scientific journals and databases, convenes major research
conferences, and provides educational, science policy and career programs
in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.
|
