On Jul 16, 11:37 am, Lewis Perin > wrote:
> Warren > writes:
> > DogMa wrote:
> > > Lew wrote:
> > >>> ... the fact that you don't get immediately sick from these
> > >>> things is only part of the story. There are fermentation byproducts
> > >>> that raise your chance of eventually getting cancer. Certainly not in
> > >>> all fermentation, but the potential danger is not to be dismissed
> > >>> airily.
> > > Warren wrote:
> > >> ... the esters, etc, that are produced in fermentation, when we're
> > >> talking Kombucha and other home fermented products, the levels are
> > >> so low that it's practically immaterial.
> > > I'd be fascinated to know what data support that unconcern. Fungal
> > > metabolites are, AFAIK, among the most dangerous (i.e., toxic and
> > > common) biochemicals known. Esters, most terpenes, etc. are largely
> > > OK. But delayed lethality from mere specks of things like amanita
> > > cyclic peptides is well known. The aflatoxins and kin are both
> > > severe acute toxins and proven carcinogens in microgram daily
> > > doses. I'm with Lew -
> > > not to be fearful, but neither to minimize both known and unknown risks.
> > > -DM
> > Well, honestly it's anecdotal. People have been drinking and eating
> > kefir, yoghurt, kombucha, tea, cheese, etc for millennia with no
> > adverse affects...
>
> I think it's more than anecdotal. Activities people have been engaged
> in for millennia have lots of negative (and positive) effects on their
> longevity. But Rick Chappell actually knows something about this.
> You there, Rick?
>
> /Lew
> ---
> Lew Perin /
I'm here, Lew. I'm supposed to be finishing up a bunch of slides, so
I'll just give a short version without many references.
First, the only good epidemiologic study on non-alcoholic liquids and
kidney stones showed that all such liquids except
grapefruit juice were roughly equally negatively associated with
kidney stones. (Note that I say "negatively associated with"
rather than "protective of" because this isn't a randomized study; it
could be that drinking these liquids is not causal and
is associated with something else truly protective - however, since
they have an obvious physiologic basis I find these results
believable). So drinking oxalate doesn't appear to cause oxalate
kidney stones (unless there is some kind of odd
sampling bias going on) anymore than eating cholesterol-rich eggs
causes cholesterol buildup in arteries. But oxalate in tea can still
cause harm, notably by chelating iron and preventing its absorption.
Now lots of fermentation products are bad for you. Evolutionary
biologists opine that this is why yeast, etc. developed
them - to keep us from eating the week-old carrion on which they were
growing. Aflatoxin and peanuts have already been
mentioned. But I think the issue is toxicity from _intentionally_
fermented substances. First, there is the famous link between
drinking calvados brandy and esophageal cancer in Normandy. Blaming
that on fermentation is tenuous because
calvados is distilled and fermented, while the fermented-only
substance (hard cider) doesn't seem to be dangerous. But
maybe distillation just concentrates another substance besides ethanol
which is already present in the cider. Temperature
could also have something to do with it (calvados is drunk hot, cider
cold). Temperature is also thought by some to be
the etiologic agent in the few studies in which tea was associated
with cancer (see
http://www.nature.com/bjc/journal/v8.../6600054a.html
which, seems to refer to unfermented tea ["congou"] but,
because it also calls it black tea, could also mean fermented.).
But lots of foods which are made by letting them lie around can kill
or hurt you. Read the CDC's "Morbidity and Mortality
Weekly Report" (nice beach reading, if you can get wifi at one) at
http://www.cdc.gov/mmwr/ and you can see reports
of salmonella, listeriosis, strep, and TB from cheese .
Pasteurization sure doesn't prevent them, and Mexican cheeses seem to
be the biggest culprits. Real tea doesn't appear in it, contaminated
kombucha seems to have killed one woman
and given her friend heart problems, and a whole lot of teenagers brew
a whole lot of odd plants into tisanes and end up in emergency rooms.
Regarding cancer, except with extreme cases, it's very hard to say
(smoking is such an extreme case because it is
very common and multiplies the risk of lung cancer by roughly 14).
But there is indirect evidence, e.g. the article in
http://cat.inist.fr/?aModele=afficheN&cpsidt=18548153 , in which
Queens' University researchers note that vinyl carbamate, a metabolite
of ethyl carbamate (also called urethane), causes cancer in
susceptible mice. It appears to be found
(see wikipedia article on it) in soy sauce and many alcoholic
beverages.
On an only marginally related note, I just have to report that the
bacteria which cause odor in limburger cheese have just
been found to be from the same genus as those which cause foot odor
(see Bart Knols, "On human odour, malaria mosquitoes, and Limburger
cheese," The Lancet, vol. 348, issue 9037, p. 1322, for a report on
research which won him the Ignobel prize). God's feet indeed.
Back to powerpoint.
Best,
-------------------------------------------------------------------------------
Rick Chappell, Ph.D. <> Professor, Dept. of Statistics and of
Biostatistics & Medical Informatics, University of Wisconsin Medical
School
600 Highland Avenue, K6/430 <> Madison, WI 53792 USA