L-tryptophan: The Urban Myth and the True Facts
RALPH BLANCHFIELD
IUFoST Representative

In the account "IUFoST champions science in the GM fray", reference is made to the refutation of the L-tryptophan myth by IUFoST representative Ralph Blanchfield.

The following what he wrote in AgBioView in response to Dr McHughen’s message.

"On 4 February 1999, at the height of the skilfully-planned and executed campaign targeting UK consumers and intimidating UK manufacturers and retailers, I took part in a short UK radio debate in which Joan Walley MP was also a participant. Two days earlier, preceding UK Prime Minister’s Question Time, Joan had instigated and opened a Parliamentary debate attacking GM (a brief part of which was shown on TV) in which she reflected the propaganda and (inadvertently, I’m sure) made a false statement to Parliament, about the alleged linking to GM food of the disease that caused 1500 illnesses and 37 deaths in USA in 1989. On the radio programme I gave a summary of the actual science (see below) and suggested that she owed a duty to the House to make a statement, setting the record straight and apologising for having inadvertently misled it, as, if I were in her shoes, I would have felt obliged to do. The presenter invited her to respond to that, but instead she adopted the politicians’ technique of making some remarks which, however, completely ignored the subject on which she had been asked to respond. Of course she did not apologise to the House.

The story refers to the so-called Eosinophilia-Myalgia Syndrome (EMS syndrome) associated with some dietary supplements containing the amino acid L-tryptophan, The story as Joan Walley quoted it in the House, and which was faithfully reported in the media, is just one of a number of carefully-fostered myths, which have been peddled for years. As far as I can trace it, it was originated from the self-styled Maharishi University of Management, a pseudo-religious organisation ideologically opposed to GM and to any other application of science and technology to food. (its political arm is the Natural Law Party).

Yes, the illnesses and death occurred, but the rest of the story is moonshine. In reality, extensive investigation traced the cause to an impurity in L-tryptophan made by just one of its several chemical manufacturers, all in Japan. The culprit was Showa Denko KK of Tokyo (the fourth largest chemical manufacturer in Japan, but which had some 80% of the market for L-tryptophan).

There has been litigation by plaintiffs against SD KK. The genetic modification red herring came up early, and plaintiffs' attorneys thought they could use it. However, the evidence proved that GM had nothing to do with the case, however inflammatory the suggestion might be. There have been three trials, and the issue was not raised seriously by the plaintiffs because there was such overwhelming evidence against it being a factor.

The manufacture of L-tryptophan is by a fermentation which also results in the formation of a number of secondary substances. To produce L-tryptophan of a purity necessary for human ingestion, the fermentation product mixture has to go through purification processes to remove the impurities, by-products and cellular debris, including treatment with activated carbon and reverse osmosis.

Investigation of the records of Showa Denko KK showed that in the critical period (December 1988 to June 1989) they made a number of simultaneous changes to the manufacturing protocols. One of these was the use of the fermentation organism Bacillus amyloliquefaciens that had been genetically altered to increase the production of L-tryptophan. But this was accompanied by the partial bypassing of the reverse osmosis purification procedure, and a halving of the amount of activated carbon used thus failing to carry out the purification effectively. Subsequent research showed that in consequence the procedure left behind some sixty impurities; and also found significant correlation between the development of EMS and the reduction of the activated charcoal.

There have been several attempts to explain the precise mechanism by which the syndrome occurred. One involves a residual impurity 1,1 '- ethylidenebis-[tryptophan] (EBT), which then broke down to give 1-methyl-l,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA), a substance that was thought to have been involved in the EMS syndrome. Another suggests that it was the result of a reaction between two (or more) impurities. Like so many food poisoning outbreaks investigated after the event, the exact mechanism is unlikely now to be conclusively proved, but certainly it was nothing to do with GM. Thus the "tryptophan" story was not a consequence of genetic modification, nor of tryptophan itself, but of short-cutting by a particular chemical manufacturer. And the cause of the illness was not tryptophan, but an impurity or impurities left in as a result of that short-cutting.

I did not have time in the Conference to give all the above details, but I gave enough of a summary to refute the myth. I also did not have time to mention another important consideration. Apart from this incident, which involved a large number of cases, there have been scattered occurrences of EMS syndrome associated with tryptophan both before and since, in which the fermentation organism had not been genetically altered, and presumably resulting from accidental processing failures.

There is a vast array of literature relating to EMS, in all its aspects -- medical, epidemiological, toxicological, relating to the source material, and reviews. My own knowledge of the subject comes partly from the literature, and partly from private information from a well-respected fellow food scientist who for the last 8 years served as an independent expert looking into the manufacturing of L-tryptophan by Showa Denko KK, and who has participated in three trials.

There is an easy way to access a much wider literature on the subject. You can access the Medline database direct, or you can do so from the home page of the IFST Web site www.ifst.org. If you scroll past the search engine to search our Web site, you come to the Awards that we have been accorded. The third of these, the Citeline "Valuable Resource Award" contains a search engine. Enter (without the inverted commas) "EMS and tryptophan". You will get a screen with the results of a Web search, but near the top there will be a link " MEDLINE - Full Result". Click on that and you will get the "vast array" to which I referred. Most of them provide abstracts (by clicking on the author's name), and there is a facility for ordering full texts. There is also a useful facility -- listed against each title the is a link 'Related papers'."