It was reported on the news today that Richard Prebble said, "not a single person has ever died from genetic
* Is Mr. Prebble not aware that genetically engineered tryptophan, produced by the Japanese chemical company Showa
Denko, killed 37 people and permanently disabled a further 1500?
* Is Mr. Prebble not aware that genetically engineered soya beans contain Brazil nut 25 albumin which is toxic to those
allergic to Brazil nuts and that the same toxicity exists in the GM soya beans?
* Is Mr. Prebble not aware that the Swiss Federal Research Station for Agroecology and Agriculture near Zürich have
proven that genetically engineered toxins increase with each insect or animal that ingests another which has initially
ingested GM toxins, and that by the time these toxins get down the food chain to humans the toxicity could be multiplied
QUESTION: How can a radio station repeat such false comments without researching the facts?
Pages two and three contain research references to the Show Denko case.
Contact details: Charles Drace TEl : 03-364-9140 days TEL: 03-365-6607 eves Fax: 03-364-9132 email:
TRYPTOPHAN SUMMARY, NOVEMBER, 1997, JOHN B. FAGAN, PH.D.
Food supplements, such as amino acids, are often manufactured by fermentative processes, in which large quantities of
bacteria are grown in vats, and the food supplement is extracted from the bacteria and purified. One amino acid,
tryptophan has been produced in this way for many years. In the late 1980's the company Showa Denko K.K. decided to use
genetic engineering to accelerate and increase the efficiency of tryptophan production. They genetically engineered
bacteria by inserting several genes that caused the bacteria to express certain enzymes at much higher levels than
normal and to express other enzymes that are not normally present in the original bacteria.
The enzymes expressed in these bacteria through genetic engineering altered cellular metabolism substantially, leading
to greatly increased production of tryptophan. These genetically engineered bacteria were immediately used in commercial
production of tryptophan, and the product placed on the market in the USA in 1988. According to US law, Showa Denko was
allowed to sell the tryptophan produced in genetically engineered bacteria without safety testing because they and other
companies had been selling tryptophan produced in non-genetically engineered bacteria for years without ill effects. It
was considered that the method of production (whether via natural or genetically engineered bacteria) was immaterial and
that, since tryptophan had already been shown to be safe, the new material needed no testing. In effect they considered
it substantially equivalent to the tryptophan that had been sold for many years.
This product was placed on the market, and within a few months it caused the deaths of 37 people and caused 1500 more
to be permanently disabled. (1). It took months to discover that the poisoning was due to toxin present in the
tryptophan produced using Showa Denko's genetically engineered bacteria (1, 2). One factor that contributed to this time
delay was the fact that the product was not labeled to distinguish it from tryptophan produced through conventional
The disease caused by this toxic product was called eosinophilia myalgia syndrome or EMS, because the initial symptoms
were elevated numbers of blood cells called eosinophils and myalgia (muscle pain). Over time many other symptoms
developed in patients that led in some cases to death and in many other cases to serious long term disability. These
symptoms included paralysis and neurological problems, painful swelling and cracking of the skin, heart problems, memory
and cognitive deficits, headaches, extremelight sensitivity, fatigue, and heart problems (3,4).
It was later shown that the tryptophan produced in genetically engineered bacteria contained one or more highly toxic
contaminants. The most prominent of these, called EBT, was identified as a dimerization product of tryptophan. It
comprised less than 0.1% of the total weight of the product, yet that was enough to kill people (1). Based on
fundamental chemical and biochemical principles, scientists have deduced that this compound was probably generated when
the concentration of tryptophan within the bacteria reached such high levels that tryptophan molecules or their
precursors began to react with each other (5). Thus, it appears that genetic manipulations led to increased tryptophan
biosynthesis, which led to increased cellular levels of tryptophan and precursors. At these high levels, these compounds
reacted with themselves, generating a deadly toxin. References
1. Mayeno, A.N. and Gleich, G.J., Eosinophilia-myalgia syndrome and tryptophan production: a cautionary tale, TIBTECH,
12, 346-352, 1994. 2. Raphals, P., Does medical mystery threaten biotech? Science, 249, 619, 1990. 3. Brenneman, D.E.,
Page, S.W., Schultzberg, M., Thomas, F.S., Zelazowski, P., Burnet, P., Avidor, R., and Sternberg, E.M., A decomposition
product of a contaminant implicated in l-tryptophan eosinophilia myalgia syndrome affects spinal cord neuronal cell
death and survival through stereospecific, maturation and partly interleukin-1-dependent mechanisms, Journal of
Pharmacology and Experimental Therapeutics, 266(2), 1029-1035, 1993. 4. Love, L.A., Rader, J.I., Crofford, L.J.,
Raybourne, R.B., Principato, M.A., Page, S.W., Trucksess, M.W., Smith, M.J., Dugan, E.M., Turner, M.L., Zelazowski, E.,
Zelazowski, P., and Sternberg, E.M., Pathological and immunological effects of ingesting l-tryptophan and 1,
1'-ethylidenebis (l-tryptophan) in Lewis rats, Journal of Clinical Investigation, Inc., 91, 804-811, March 1993. 5.
Raphals, P., EMS deaths: Is recombinant DNA technology involved?, The Medical Post, Maclean-Hunter, Toronto, 16,
November 6, 1990.