GENTECH archive


tryptophan: The Mayo study does not prove that GE was not the ca

I am still confused about the issue below, and I hope someone on this
list can help out. I've used the L-tryptophan argument myself, and
government scientists in the Philippines keep replying that later
studies found that the toxin was due to some non-GE contaminant,
citing other studies.

So far, this case seems to be the only case where actual deaths have
occurred from GE. (If there are others, I would be very interested in
knowing about them.) I would also appreciate an explanation in simple
terms whether the L-tryptophan case remains a strong argument against
GE and why.

Roberto Verzola

 >At 16:33 1998-12-04 +0930, Rick Roush wrote:
 >>In terms of the claims made about L-tryptophan, the following is a case in
 >>point, found on the  site
 >>recommended by BEVERLYtang, archive 476
 >>" In 1989 there was an outbreak of a new disease in the US, contracted by
 >>over 5,000 people and traced back to a batch of food supplement produced
 >>with GE bacteria. Even though it contained less than 0.1 per cent of a
 >>highly toxic compound, 37 people died and 1,500 were left with permanent
 >>disabilities. The government declared that it was not GE that was at fault
 >>but a failure in the
 >>purification process, but this new toxin had never been found in non-GE
 >>versions of the product....."
 >>The latter claim is now simply not true in view of the work cited in
 >>published in the September issue   of the journal Nature Medicine.
 >Rick's conclusion is not correct. 
 >I have carefully read the reports in question from the Mayo Clinic: 
 >First, the study in questions was not on L-tryptophan but on a related
 >compound, 5-Hydroxy-L-Tryptophan (5-OH-Trp or 5-HTP).  
 >Second, the contaminants found in the 5-HTP sample were NOT IDENTICAL with
 >those found in the EMS case. 
 >To quote exactly from the text: "peak x is, in fact, a family of nearly
 >identical compounds. Their chemical structure is similar to two
 >contaminants found in the L-tryptophan linked to EMS symptoms in 1989."
 >Third, "peak X" has not been associated with EMS.
 >The only thing that we are justified to conclude from the Mayo study is
 >that some impurities appeared in the 5 HT samples. These were not the same
 >as the causative agents of EMS. The fact that they were chemically similar
 >does not mean that they are as dangerous or dangerous at all. In some cases
 >there are very  small chemical differences between harmless molecules and
 >powerful poisons. 
 >The conclusion of Rick has thus no scientific basis. 
 >- It has not been demonstrated that the impurities causing EMS may occur in
 >L-tryptophan produced by non-GE sources.
 >Genetic engineering, which has been experimentally shown to cause metabolic
 >abnormalities, remains the most probable cause of the metabolic abnormality
 >producing the extremely potent impurity causing EMS.
 >Jaan Suurkula MD