1.20—High Doses of Tryptophan Cause EM

Tryptophan used as a food supplement causes health problems.

See Genetic Roulette’s False Claims at Bottom of Page

Analysis of Peer-Reviewed Research:

The claim that a GM microbe was at fault was made without any evidence.  It is a sort of urban legend created by those who oppose GM crops in order to try to discredit them.  No cause and effect between a GM microbe and the EMS disease has ever been established nor is there a need to find such a link, because another cause of the illness has been discovered. EMS is a dreadful and distressing illness which has caused a number of deaths. It is very important for people considering unusual diets or dietary supplements to get accurate information where there are real hazards. For some years now, an explanation for the illness has been known to medical scientists. EMS is triggered by consumption of large amounts of the dietary supplement L-tryptophan.  We can prove that Jeff Smith is aware of this discovery and that he refuses to tell the truth about L-tryptophan. This could actually endanger people.  The FDA has posted a warning on its webpage that consumption of L-tryptophan is potentially harmful.  People need to know about this, but instead Genetic Roulette continues to propagate unfounded myths about GM technology.

1.  It is known that large doses tryptophan itself cause EMS. Since a report by Smith and Garrett in 2005, medical science has known that genetic modification is irrelevant to EMS, and that the supplement itself—that is to say consuming large amounts of L-tryptophan, whether or not it was made using genetic manipulation, causes health problems. This has been suspected for many years. Smith avoids quoting FDA reports that contradict his story.

2.  EMS is not exclusively associated with GM tryptophan.  There are at least two reports in the medical literature of EMS disease caused by L-tryptophan in 1986, well before genetic engineered microbes were used in its manufacture.  Tryptophan produced by different companies has also caused EMS.

3.  Contaminants in L-tryptophan do not cause EMS.  The search for evidence that contaminants in L-tryptophan produced by genetic engineering are toxic has proved fruitless, and there is no actual evidence that these contaminants are harmful.

4.  A mechanism by which L-tryptophan could cause EMS has been identified.  Metabolites formed from L-tryptophan itself inside the body are implicated in causing the condition known as EMS.

5.  Smith refuses to tell the whole story. Jeffrey Smith has been made aware of these facts about L-tryptophan not being the cause of EMS since early 2006 but has chosen not to make any correction to misleading commentary about tryptophan in his book.


Smith MJ, and Garrett RH (2005). Review. A heretofore undisclosed crux of Eosinophilia-Myalgia Syndrome: compromised histamine degradation. Inflammation Research 54: 435–450.

FDA, U. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition Office of Nutritional Products, Labeling, and Dietary Supplements, (February 2001) Information Paper on L-tryptophan and 5-hydroxy-L-tryptophan www.cfsan.fda.gov/~dms/ds-tryp1.html accessed Dec 7 2008.

Genetic Roulette Falsely Claims:

A GM food supplement killed about 100 people

1. One brand of the supplement L-tryptophan caused a deadly US epidemic in the 1980s.

2. The company genetically engineered bacteria to produce the supplement more economically.

3. The product contained many contaminants five or six of which were suspected as the cause of the disease.

4. Discovering the epidemic required multiple coincidences, suggesting that adverse reactions to GM foods may be hard to identify.

Genetic Roulette asserts that a food supplement using genetically manipulated bacteria killed people, and implies that genetic modification of bacteria used to make the dietary supplement was responsible for the illness called EMS.