Reviewed individually, inappropriate handling of subjects, methodology, and/or statistical analysis in any one study might be attributed to shoddy science or sloppy scholarship. However, there is sameness in these studies which lies in the fact that methodology virtually guarantees that no statistically significant difference between subjects treated with monosodium glutamate and subjects treated another way will be found; and/or no significant relationship will be found between two or more variables being investigated. Researchers, then, can legitimately conclude that subjects who were given monosodium glutamate did not have more reactions than subjects given a placebo; or subjects consuming greater quantities of monosodium glutamate did not become taller, shorter, fatter, or thinner, and did not have more adverse reactions or higher blood pressure than others. It is these studies that industry points to when claiming that monosodium glutamate is safe, or when claiming that the safety (never toxicity) of monosodium glutamate is controversial. We submit, however, that since industry bases its claim for the safety of monosodium glutamate on these studies, industry itself has demonstrated that ingestion of monosodium glutamate places consumers at risk. There really is no controversy.
Following are details of methodology used by industry. Not every method is used in every study.
A) Offer several hundred dollars to persons who agree to participate in the study and claim to be sensitive to the product without checking the validity of their claims.
B) Require that subjects qualify as “well subjects:” people who claim to have no pre-existing medical conditions such as asthma, allergies, seizures, or headaches, for example, and therefore have no history of adverse reactions.
C) Require that people who would participate in a study first demonstrate that they will not react to "screening placebos” that will contain toxic or allergenic material similar to the test material. Only people who were not sensitive to the test material would then be serving as subjects in these studies.
D) Meet the requirements for obtaining informed consent. Requiring informed consent biases these studies (2,3).
Drawing conclusions based on failure to find a difference (i.e., on failure to reject the null hypothesis) is grossly inappropriate (4-6). Failure to find a statistically significant difference between groups may provide useful information for planning one's next experiment, but it proves nothing.
Beyond research design…
In addition to issues of research design and methodology, investigators have been known to:
A) Draw conclusions that do not follow from the results of the study;
B) Minimize discussion of embarrassing data;
C) Direct readers' attention to things deemed to be of value to industry; not necessarily reporting all data or results of statistical tests;
D) Include discussion of ideas that have little or nothing to do with the results of the study;
E) In discussion, include material that industry wants presented to the public, whether or not it is relevant to the stated intent of the research;
F) Fail to publish, or even talk about, the results of studies that don't come out as planned.
The issue of placebo integrity…
The test material used in these studies was the flavor enhancer monosodium glutamate, supplied directly or indirectly by Ajinomoto, Co., Inc.
Processed free glutamic acid is, by definition, an inevitable component of monosodium glutamate. Processed free glutamic acid is a known neurotoxin and endocrine disruptor (7) alleged to cause adverse reactions ranging from mild and transitory to debilitating and life threatening (8,9). Processed free glutamic acid will be found in ingredients other than monosodium glutamate -- in an escalating number of ingredients used in a wide range of processed foods.
Processed free glutamic acid made by any method will cause the same brain lesions, neuroendocrine disorders, retinal degeneration, and adverse reactions as the processed free glutamic acid found in monosodium glutamate (10,11). In the United States, consumers who understand that they react adversely to processed free glutamic acid, no matter how it is manufactured, and regardless of the ingredient in which it is found, often refer to all processed free glutamic acid as “MSG.” Those who manufacture, sell, and promote the use of monosodium glutamate routinely restrict their use of the acronym “MSG” to refer to monosodium glutamate; and “MSG” is often used as shorthand for monosodium glutamate in the scientific literature. When researchers report that no subject had been given access to MSG, it does not preclude the possibility that there may have been access to processed free glutamic acid delivered in a form other than monosodium glutamate. Ingredients that contain processed free glutamic acid include, but are not limited to, monosodium glutamate, monopotassium glutamate, L-glutamic acid, L-glutamate, all hydrolyzed protein products, autolyzed yeast, yeast extract, calcium caseinate, sodium caseinate, gelatin, pectin, citric acid made from corn, maltodextrin, textured vegetable protein, most natural flavors and natural flavoring, soy protein isolate, and whey protein concentrate. Reactions to processed free glutamic acid will occur regardless of the names of the ingredients in which it is hidden (11).
Aspartame is known to cause the same brain damage and endocrine disorders as are caused by processed free glutamic acid (7).
Aspartame contains aspartic acid, a neurotoxic endocrine disruptor that causes virtually identical brain lesions and neuroendocrine disorders as those caused by the glutamic acid component of monosodium glutamate and the other ingredients that contain processed free glutamic acid (7,12); and those two neurotoxic amino acids are known to work in an additive fashion (7). Aspartame also contains phenylalanine and a methyl ester. According to records no longer kept by the Adverse Reactions Monitoring System of the FDA, ingestion of aspartame produces, with rare exception, the same adverse reactions as those produced by ingestion of monosodium glutamate; and monosodium glutamate and aspartame reactions occur with the same relative frequency (8,13).
Beginning in 1978, before aspartame was approved by the FDA for use in food, glutamate-industry researchers used aspartame in placebos (14). Over and above the fact that use of aspartame in placebos is grossly inappropriate, the fact that aspartame-containing products are supposed to carry a warning on their labels did not deter industry from using the substance, or the FDA from allowing its use.
REFERENCES
1. Samuels A. The toxicity/safety of processed free glutamic acid (MSG): a study in suppression of information. Account Res. 1999;6:259-310.
2. Mitchell AM, Kline JA. Systematic bias introduced by the informed consent process in a diagnostic research study. Acad Emerg. Med 2008;15:225-30.
3. Bjarnason NH, Kampmann JP. Selection bias introduced by the informed consent process. Lancet. 2003;361:1990.
4. Ferguson GA. Statistical Analysis in Psychology and Education. New York: McGraw-Hill; 1959.
5. Weinberg GH, Schumaker JA. Statistics: An Intuitive Approach. Belmont: Wadsworth; 1962.
6. McNemar Q. Psychological Statistics. New York: Wiley; 1949.
7. Olney JW, Ho O. Brain damage in infant mice following oral intake of glutamate, aspartate or cysteine. Nature. 1970;227:609-10.
8. FDA Technical Information Specialist (HFS-728). Memorandum to Health Hazard Evaluation Board. Re: Summary of Adverse Reactions Attributed to MSG. June 26, 1997.
9. Federation of American Societies for Experimental Biology (FASEB). Analysis of adverse reactions to monosodium glutamate (MSG). Raiten DJ, Talbot, JM, Fisher, KD, eds. Bethesda, MD: Life Sciences Research Office, FASEB; 1995:77-79.
10. Olney JW, Ho OL, Rhee V. Brain-damaging potential of protein hydrolysates. N Engl J Med. 1973; 289:391-93.
11. FDA Bureau of Foods. Letter to a consumer from S.I. Delgado. March 3, 1981. “...if you wish to avoid the so-called 'Chinese restaurant syndrome,' you should also avoid foods which contain hydrolized vegetable protein.”
12. Price MT, Olney JW, Lowry OH, Buchsbaum S. Uptake of exogenous glutamate and aspartate by circumventricular organs but not other regions of brain. Neurochem. 1981;36:1774-80.
13. FDA Technical Information Specialist (HFS-728). Memorandum to Health Hazard Evaluation Board. Re: Summary of Adverse Reactions Attributed to Aspartame. June 26, 1997.
14. Ebert AG. Letter to Sue Ann Anderson, R.D., Ph.D., Senior Staff Scientist, FASEB. March 22, 1991.