Susan Burger has done a very nice job of elucidating the vitamin
A/beta-carotene question.  When Dee's doctor decided not to pursue a
putative case of hypervitaminosis-carotene with further testing of both his
patient and the supplement she had taken, we lost the chance to find out
what was in the pill that actually caused the symptoms.  We cannot assume it
was the carotene without testing the hypothesis, because
hypervitaminosis-carotene has never been seen before.  Was hers the first
case?  Or was there retinol in the pill?  Was there another component or
contaminant in the formulation which caused her symptoms? (In two recent
studies of imported supplements, for example, contamination levels were
dangerously high.) So, there is still as yet no known toxicity for beta
carotene.

I always add "as yet," because as long as people are willing to do these
experiments on themselves, we stand to gain more information.  That is how
we found out the toxicity level for vitamin B-6 (pyridoxine).  When
individuals at high levels of supplementation developed irreversible nerve
damage, then we had the information.  Good for medical science, not good for
the individuals who took the pills.

Finally, there are many reasons that taking megadoses (pharmaceutical doses)
of molecules such as vitamins and minerals may be dangerous which are
unrelated to simple toxicity.  The lung cancer study is a perfect example,
as Lara points out.  In this case there was no toxicity, and yet through
some mechanism, the subjects in the supplement group actually had worse
outcomes from their preexisting cancers.

Another example of an uncontrolled field trial is the case of infant
formula.  It isn't just the DHA and ARA.  It's every formulation they've
ever come up with, including the time they took out the sodium chloride to
make a "low salt" formulation, but forgot that chloride is an absolute
necessity.  Babies are at a much higher risk from these trials, partly
because unlike adults, they have no diversity in their food intake.  But as
long as people are willing to volunteer their babies for these experiments,
medical science stands to gain more information....

Arly Helm, MS, IBCLC

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