HERB - research, the skin, and my lack of knowledge (long)

[Gaylin Walli]

Suzanna kindly stated:

>First off, let me point out that there is no problem with using comfrey
>*externally*.  The problems come from taking it internally (and that for
>longer periods of time).  It is an excellent healing agent and contains
>significant amounts of allantion, which promotes growth and healing of
>the skin.

Although in general I tend to agree with Suzanna about external use
of comfrey, I believe an argument can be made for caution and
consideration. I admit, however, that the same argument can be
made for any number of herbs, so let me give my layman's take
on the situation and issues that led me to posting the comfrey
information in the bruise ointment recipe (I've posted the comfrey
information before, btw).

Transdermal absorption (absorption through skin) has been studied
extensively for a variety of chemicals. Despite the fact that the
skin is arguably the most effective waste elimination organ in the
body, some researchers believe that repeated applications of some
substances over long periods of time can result in dermal toxicity
that will eventually effect other organs in the body.

Some researchers will argue that already damaged skin is *more*
susceptible to toxic levels of chemicals than otherwise healthy skin.
Thus, even though the skin may normally be effective at quickly
eliminating toxins from the body, damaged skin may be unable to
react similarly or, if able to react, unable to do it as quickly.

Now, to my knowledge, there have been absolutely no studies on
the transdermal figures related to topical comfrey application.
And even more importantly, few studies of chemical toxicity
and dermally applied essential oils ON HUMANS. There's an
absolutely HUGE body of literature, however, on the effects
of transdermally applied essential oils on animals. But there are
equally huge problems with the studies that I have read on
the subject. First, the researchers freely admitted that the
absorption of chemical through animal skin is generally believe
to be significantly higher than through human skin. Second,
the studies that I've read on systemic toxicity have all been
done on already damaged skin of animals, thus compounding
the original absorption problem. Third, of the studies that I've
read, animals were treated with very high doses of chemicals
over long periods of time, not matching in the slightest the
possible use by humans.

So that leaves us with the general feeling that the basic studies
of transdermal absorption of chemicals is fundamentally flawed
and perhaps we have little to worry about, right?

I don't believe so. And mostly because I think I simply don't
know enough about anything in herbal research to give answers
beyond "well, it appears in period that they did it this way" or
"the research I've read suggests this" or even "I've only tried
this on myself but it works for me." Weasly answers, but the
only safe answers I can give.

Because we are researchers in a topic that people find compellingly
easy to use on their own with little research, we will always be
bombarded with questions and requests for "something this treats
or deals with this problem I have." How many of us *haven't* had
this question when aquaintances and friends have found out we do
period herbal research? I am bombarded with these questions daily.
"Iasmin, do you know anything about XYZ plant?" or "Iasmin, do
have any period treatments for ABC condition?" Very common
questions for me.

My point in posting the research on the comfrey toxicity in the
article on bruise creams was not so much in an effort to warn
people of the potential toxicity of internally taken plant material.
It was more an effort to get people to start doing some research
on their own and also cover my behind should research prove at
some point in the future that transdermally applied comfrey really
is a bad thing. I don't believe it is at this point, but I'm always
expecting to be proven wrong where herbs are concerned. With the
speed with which e-mail and website information gets posted, I
fully expect to have my e-mail appear somewhere that I can't
control it.

Thus, I try *very* hard to let people know when there is  a
question about herbal safety that I believe warrants pointing out
beyond the standard "I'm not a doctor" disclaimer. Somewhere
down the line if someone comes to me and says "Did you know
we're trying to hold you responsible" I can easily point to the
disclaimer as part of my defense (legal wranglings aside). So that's
the crux of it. I'm covering my behind and trying to cover there's
at the same time.

If I'm being too careful, I'd appreciate being yanked back to the
reality plane. :)

Always in service,

Iasmin de Cordoba, gwalli at infoengine.com
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