Pointing out the need for extreme caution with genetically engineered foods, the writers say such foods must be assumed guilty until lengthy tests have suggested they are, if not innocent, at worst guilty of only minor dangers. This is nowhere near the case today as large companies rush to market their GE foods.

By L R B Mann & D Straton

August 1999

By the end of the 1980s, millions of people in North America were supplementing their diet with L-tryptophan, an essential amino acid present in proteins of any normal diet. Amino acids such as tryptophan are routinely produced in micro-breweries using suitable microbial cultures. One producer, Showa Denko KK, artificially inserted genes into a bacterial species to increase its production of tryptophan.

Then in late 1989, thousands in North America fell ill with a highly unusual, if not completely novel, illness, EMS (eosinophilia-myalgia syndrome). Within months, dozens had been killed and thousands maimed. Today thousands continue to suffer permanent nasty effects, and a trickle of them continue to die early (around 75 in total by now).

We emphasise that if thalidomide had happened to cause a type of birth defect that was already common, e.g. cleft palate or severe mental retardation, we would still not know about the harm, and pregnant women would have kept on taking it for its undoubted benefits. The fractional addition to figures which were already relatively large would not have been 'statistically' significant. But as it turned out, the damage noticed was of a kind that most doctors never see in a whole career - drastic malformations of the arms and legs; so although the numbers were not huge, these cases were picked up.

Similarly, impurities in the Genetically Engineer-ed (GEd) tryptophan happened to cause an illness (EMS) which is normally extremely rare. The surge of numbers therefore stood out and got noticed. If Showa Denko's poison had caused the same numbers but of a common illness instead, say asthma, we would still not know about it. Or, if it had caused delayed harm, such as cancer, 20-30 years later, or senile dementia in some whose mothers had taken it early in pregnancy, there would have been no way to attribute the harm to the cause.

This reminds us of the need for extreme caution with GE foods. They must be assumed guilty until lengthy tests have suggested they are, if not innocent, at worst guilty of only minor dangers. This is nowhere near the case today as large companies rush to market their GE foods.

It is very disappointing to find a leading physician writing about this disaster thus: 'Rare cases of EMS were known before the introduction of the genetically engineered bacterium, which further supports the hypothesis that EMS is not due to the genetic engineering event.'

An exact analogue of that argument would run: 'Rare cases of seal-limb were known before the introduction of thalidomide, which further supports the hypothesis that seal-limb is not due to thalidomide.'

The contrast is startling with the elaborate procedure before registration of a new drug. It has taken a decade to get legal approval for supplementing humans with (a modified version of) the human hormone amylin, for treating diabetics. Yet GE foods are urged for legal distribution in great haste and with only extremely scanty testing, and the main discussion so far has been whether they should be labelled.

[The United States administration is now threatening action at the World Trade Organisation against countries introducing mandatory labelling of products containing genetically engineered or modified products.]

Labelling would not in itself be wrong, but can of course not substitute for the careful lengthy testing that would be needed before any GEd food should be approved for human consumption. Labelling of GE food would imply acceptance by authorities, as does the ingredient list of any labelled food.

The Showa Denko disaster is crucial to understanding GE food.

If a purported single chemical - the natural amino acid tryptophan, better than 98.5% pure and definitely meeting the notorious 'substantial equivalence' test - can turn out when GEd to kill dozens and cripple thousands, what will it take to check properly a potato containing a synthetic 'exact' copy of a gene for a toxin from the African clawed toad?

And most urgently, the attempt to count as 'substantially equivalent' purified sugars, oils, etc. is shown by the Showa Denko disaster to be a gamble. The assumption that soy oil from GE soybeans is exactly equivalent to ordinary soy oil requires the most careful scientific measurements to check it. Merely assuming 'substantial equivalence' will not do.

Those who search the Internet on this topic will soon discover the claim by apologists for GE that the problem was only incompetent purification of one batch of tryptophan. We disagree for several reasons - for one thing, faulty filters had been used before without apparently leading to epidemics like this.

But this question of fact is unlikely to be settled with finality, if only because Showa Denko claim the GE microbe has been exterminated so that the experiment cannot be re-run.

Whether you believe the impurities were due to incompetent purification and monitoring, or to deviant metabolism in the GE-bugs, or both, you had better believe that the fabled 'substantially equivalent' assumption flopped in that epidemic of crippling and lethal illness.

The most menacing forms of biotechnology are genetically engineered foods and other uncontained GE organisms, but some other forms of biotechnology entail serious threats to public health which are under even less control than poisons - and that's saying something.

If faulty filtering was indeed the problem, it follows that the production of amino acids and other 'health food additives' may be much more inherently hazardous than has been believed.

Perhaps the health food industry should be subject to controls on purity and safety comparable to those applied to the pharmaceutical industry.

Either way, biotechnology - which includes GE but also some other unrelated processes such as purifying lyprinol from green-shell mussels - requires much-enhanced scrutiny. - Third World Network Features

(Sources: 1. 'L-Tryptophan Puzzle Takes New Twist', Science 249, p988, 31 Aug 1990; 2. 'Does Medical Mystery Threaten Biotech?', Science 250, p619, 2 Nov 1990; 3. 'EMS and Tryptophan Production: A Cautionary Tale', TIBTECH 12, 346-352, Sep 1994)

About the writers: Dr L R B Mann, a former biochemist, served for its first dozen years on the Toxic Substances Board advising successive New Zealand ministers of health on poisons. Dr D Straton is a psychiatrist who has taken a special interest in therapeutic uses of tryptophan. The above is a revised version of their article in the Genetic Engineering issue of Soil & Health (NZ), posted on an Internet list-server.