7. Aspartic Acid Dr. Liebovitz states: "Aspartic acid is perfectly safe." While proclaimations of the "safety" of amino acids may go over well with bodybuilders reading Muscular Development - Fitness - Health, the issue of aspartic acid's "safety" as part of aspartame is not so simple as Dr. Liebovitz makes it sound. Given Dr. Liebovitz' strong beliefs in the absolute safety of all amino acid supplements (Liebovitz 1993, Liebovitz 1994), I feel that my disagreements in this section may fall on deaf ears. Nevertheless, I will endeavor to present a scientific argument showing that aspartic acid, as part of aspartame, is, at best, possibly dangerous for certain populations, and, at worst, a contributing factor in a wide variety of chronic neurological problems. In order to show how the aspartic acid taken in aspartame differs from aspartic acid which is one of the amino acids linked in protein as part of food, it is necessary to trace and compare the digestion, absorption, and metabolism of a high-protein food item and an aspartame-containing beverage. Protein Digestion & Metabolism ------------------------------ Proteins found in food are made up of building blocks called amino acids. Proteins are in the form of chains of amino acids called "peptides." (Dipeptide = a chain of two amino acids; Tripeptide = a chain of three amino acids; Polypeptide = a chain of four or more amino acids.) Amino acids are rarely found in free form -- i.e., not bound in amino acid chains known as protein molecules. As summarized by Garrison (1990), the digestion of proteins begins when a protein-containing food enters the stomach. Hydrochloric acid, pepsin, and protease enzymes break specific protein links into polypeptides (amino acid chains). When the food reaches the duodenum (part of the small intestine), the enzyme trypsin in the pancreatic juice breaks the polypeptides into dipeptides and tripeptides. As the amino acid chains progress down the small intestine, several enzymes break the amino acid chains into individual amino acids. The amino acids are then absorbed through the intestinal wall and into the bloodstream. The whole process is a long, slow process leading to a gradual absorption of amino acids into the bloodstream. In addition, because proteins from food contains many different amino acids, the ratios between the levels of amino acids in the blood does not change significantly. Aspartic Acid and Glutamic Acid Metabolism ------------------------------------------ Aspartic acid (also known as aspartate) and glutamic acid (also known as glutamate) are acidic amino acids. Glutamic acid is directly converted to alanine when it reacts with carbohydrate-derived glutamate pyruvate transaminase (GPT) in the intestinal epithelia. (Pardridge 1986, page 206-207). In the presence of glutamate oxalacetate transaminase (GOT), aspartatic acid is first converted to glutamic acid and then to alanine. However, in the absence of carbohydrate-derived pyruvic acid, the conversion of aspartic acid or glutamic acid to alanine is very slow. If protein is ingested with food, non-carbohydrate sources of pyruvic acid made in the body can convert the gradually-released glutamic acid and aspartic acid to alanine. When glutamic acid (in the form of monosodium glutamate - MSG) or aspartic acid (as part of aspartame) is ingested in free form, there is no gradual breakdown and absorption of proteins -- as there are only free amino acids (e.g., aspartic acid and glutamic acid). These amino acids are quickly absorbed. They are not converted to alanine unless they are eaten with a significant amount of pyruvic acid- forming carbohydrade such as a sugary snack. This leads to a significant spike in the blood plasma level of aspartate or glutamate. Stegink showed that glutamic acid ingested without a sugary snack spikes the plama levels of glutamate significantly (Stegink 1983b). Many other industry-sponsored experiments have shown large spikes in plasma glutamate levels after ingesting real-world amounts of MSG with water, soup, and meals. (Stegink 1979a, page 90, Stegink 1979b, pages 337-341, Stegink 1983c, Stegink 1985, Stegink 1986) The plasma glutamate increases varied from two to fourteen (14) times the increase when no glutamate was given with the meal, soup, or water (up to an average level of 60 umoles/100 ml -- the individual variation would probably put the level much higher for some people). Bessman (1948) showed a nearly five-fold increase in plasma glutamate when administering 100 mg/kg of unneutralized glutamic acid in water. Himwich (1954) showed that when given a dose of approximately 200 mg/kg (15 grams) of glutamate to adults, the plasma glutamate spiked to as much as fifteen times its fasting level. This dose can be expected in some restaurant meals (i.e., 5 grams for a 25kg child). The same type of spikes in plasma aspartate levels would be expected when ingesting aspartic acid (or aspartame). The large spikes in plasma glutamate levels after the ingestion of glutamic acid (MSG) in food, soup, or water is not unexpected. After all, a number of animal experiments with MSG showed large plasma glutamate spikes as well (Daabees 1984, Airoldi 1980, Stegink 1979a). Similarly, aspartic acid (40% of aspartame) has been shown to spike the plasma aspartate levels in animals experiments (Reynolds 1980, Applebaume 1984). This is no surprise since free aspartic acid is absorbed and metabolized in a similar way to free glutamic acid (Partridge 1986, page 206-207). It would seem obvious that plasma aspartate levels in humans would be spiked to high levels after the ingestion of aspartic acid (from aspartame), especially when ingested in liquid form, so that absorption occurs quickly. Unfortunately, what should have been a simple experiment -- measuring plasma aspartate levels after the ingestion of aspartame -- has become another embarrassment to science thanks to the involvement of Monsanto/NutraSweet-funded "scientists." In addition, the poor quality of research in this area raises additional serious questions about the honesty and accuracy of all Monsanto/NutraSweet-funded research. Two key studies which show large increases in plasma aspartate from the ingestion of aspartame were conducted by Stegink (1987a, 1987b). In the first study (Stegink 1987a), ten subjects ingested aspartame in beverage one day and one week later, the subjects ingested the same amount of aspartame in capsule form. The dosage varied from 34.9 to 60 mg/kg of aspartame. The following excerpt shows the large difference in the levels of plasma aspartate when ingesting aspartame in beverages. Plasma Aspartate Levels (umol/liter) Average Subject Solution Capsules Pre-Dose Level 1 28.5 14.5 3.2 ± 1.1 2 13.3 10.4 3.2 ± 1.1 3 46.4 14.0 3.2 ± 1.1 4 56.4 13.4 3.2 ± 1.1 5 17.0 13.9 3.2 ± 1.1 6 23.2 13.4 3.2 ± 1.1 7 30.7 14.5 3.2 ± 1.1 8 23.0 28.1 3.2 ± 1.1 9 8.8 17.3 3.2 ± 1.1 10 36.9 12.5 3.2 ± 1.1 Mean 28.4 15.2 "Aspartame ingested in solution significantly increased the mean plasma aspartate concentration from a baseline value of 3.2 ± 1.1 umol/L to a high mean value of 26.2 ± 16.3 umold/L at 30 minutes after dosing. ... When aspartame was ingested in capsules, the higher mean plasma aspartate concentration was significantly smaller (10.4 ± 5.0 umol/L) and occurred later (1.5 hours)." As you can see, some of the subjects had an extremely large and rapid increase in plasma aspatate when ingesting aspartame in solution. One subject (#4) spiked their plasma aspartate levels by over 18 times the pre-dose level. Regular, long-term consumption of aspartame-containing beverages which constantly spike the levels blood aspartate as shown above would be very unwise. These results were an embarrassment to Monsanto/NutraSweet. For years, NutraSweet had been trying to claim that aspartic acid from aspartame did not, for some strange reason, spike the plasma aspartate levels in humans (Stegink 1984b). The results from Stegink (1987a) show that plasma aspartate levels can be spiked to extremely high levels after the ingestion of aspartame. The Department of Clinical Research at NutraSweet conducted and funded a similar study challenging some of Stegink's results presented above (Burns 1990). This is know as "damage control." Not only did this "study" show no difference in the plasma aspartate levels when the subjects ingested aspartame in beverage as compared to aspartame in capsules, but the NutraSweet researchers had the nerve to claim that the plasma aspartate levels do not increase at all after the ingestion of aspartame in liquid. It would be interesting to see how the NutraSweet company can explain the enormous difference in the plasma aspartate levels in the two experiments. Despite the fact that Burns intended to compare his results directly to the Stegink (1987a) study, he neglected to mention the almost unbelievable difference in plasma aspartate levels between the experiments! I find it difficult to believe that a researcher would simply not notice or forget to mention this enormous difference. It makes one wonder if they were trying to avoid drawing attention to the Stegink (1987a) aspartic acid test results. One partial explaination may be that the Burns (1990) study presented the high mean values of the plasma aspartate levels as opposed to each individual's peak levels. Since individuals reach a peak aspartate level at different times, the mean level of all the participants together at a particular time will be much lower. What is important is each individual's peak aspartate level and how long they stay at dangerously high levels. Whether subject A has neurotoxic levels of plasma aspartate has nothing to do with what subject B's plasma aspartate levels are at that particular time. Yet Burns (1990) presented data as if they are related. Another possible explanation is that Burns used a lithium citrate buffer instead of a sodium citrate buffer. According to Stegink (1985), aspartate "co-elutes with reduced glutathione when lithium citrate buffers are used" giving inaccurate measurements. From the description in the published protocol, it appears this may have been done. One wonders how many times this mistake may have "inadvertantly" occurred. One final explanation is that the subjects in the Burns study may have been given a significant amount of carbohydrate (e.g., sugar) with the aspartame causing the aspartate to be converted to alanine as discussed earlier. As you will see later, secretely adding substances to the testing protocol and not mentioning that fact in the published protocol has happened quite a few times in MSG and aspartame-related "research." This possibility raises grave concerns about the formulation of the substance being testing in not only this experiment but all other NutraSweet- funded experiments and in independently-conducted experiments where the test substance was obtained from NutraSweet but not analyzed independently. In the second experiment (Stegink 1987b), 12 subjects ingested 50 mg/kg of monosodium glutamate (MSG) in soup with and then without 34 mg/kg of aspartame dissolved in a beverage. The average peak plasma aspartate level almost doubled when the aspartame was ingested with the soup. "Plasma aspartate levels were not significantly affected by ingestion of the soup/beverage meal without added MSG of aspartame. The addition of 50 mg MSG/kg body weight to the meal resulted in a significant increase (P < .05) in plasma aspartate concentration; values increased from a fasting mean of 0.83 ± 0.64 umol/dL to a high mean value of 2.69 ± 1.16 umol/dL 30 minutes after loading. Plasma aspartate concentration descreased rapidly thereafter and returned to baseline 120 minutes after loading. The addition of aspartame and MSG to the soup/beverage meal resulted in plasma aspartate concentration above values noted after ingestion of the meal providing MSG alone. The high mean (± SD) peak plasma aspartate concentration reached 5.01 ± 2.43 umol/dL at 30 minutes and returned to baseline 150 minutes after dosing." On the other hand, Stegink (1987c) purported to show no increase in plasma aspartate levels after the ingestion of 34 mg/kg of aspartame. NutraSweet researchers will have us believe that we can trust their testing procedures. Stegink (1987a) showed huge spikes in plasma aspartate levels after ingesting aspartame. Stegink (1987c) showed no increase in plasma aspartate levels from a similar amount of aspartame. Stegink (1987b) showed a large increase in plasma aspartate levels. Yet (Burns 1990) showed no increase in these levels after aspartame ingestion. In another acute-dosing study, Stegink (1977) showed that healthy volunteers ingesting aspartame caused a statistically significant increase in plasma glutamate levels with 1 hour. Remember, when aspartic acid is metabolized, some of it can get converted to glutamic acid and then 1) quickly absorbed, or 2) converted to alanine if from proteins (which are digested slowly) or ingested with sugar. One other experiment tested the milk of lactating women after the administration of 34 mg/kg of aspartame as compared to 50 mg/kg of lactose (Stegink 1979c). When ingesting the aspartame, the mean glutamate levels of the milk increased from 1.09 to 1.20 umol/100 ml and the aspartate levels increased from 2.3 to 4.8 umol/100 ml (more than doubling). The lactose "placebo" also increased the aspartate and glutamate in the milk, although not as much as the aspartame -- but who cares -- no one said that taking a dose of 50 mg/kg of lactose is healthy and it is certainly not an appropriate placebo for human studies. Baker (1976) also found a significant increase in breast milk aspartate levels, from 2.25 umoles/dL to 5.59 umoles/dL 12 hours after administration of 50 mg/kg of aspartame. Note: Only average values for each time period were presented. Also, ingesting the aspartame in cold orange juice may cause some of the aspartic acid to be converted to alanine. However, several other Monsanto/NutraSweet-funded experiments purport to show that aspartame does not spike the plasma aspartate levels after ingestion. I find that some of the studies funded by NutraSweet which show no increase in plasma aspartate levels to be extremely suspicious. The most likely flaws are mixing aspartame with a form of sugar to reduce spikes in the plasma aspartate levels and/or using a aspartate measurement procedure that is flawed as described earlier. The studies showing no change in aspartate levels are invariably the only studies cited by NutraSweet scientists when reviewing aspartame. Given what some people consider to be fraud in the pre- approval studies of aspartame and the possible fraud of aspartic acid- and glutamic acid-related studies as discussed later in this section, the results of some NutraSweet-funded studies showing no increase in plasma aspartate levels should not be accepted unless corroborated by several independent research teams. It seems clear from the Stegink (1987a), Stegink (1987b), and other studies mentioned above that aspartame (especially in liquids) can cause enormous spikes in the plasma aspartate levels under some circumstances. These experiments need to be repeated by truely independent researchers. Glutamate is readily converted to the amino acid glutamine (FASEB 1995, page 32). Other by-products of glutamate and aspartate metabolism include glucose, ornithine, proline, urea, ammonia, and fatty acids (Stegink 1984c, FASEB 1995, page 22). Vitamin B6 plays an important role in this metabolism (FASEB 1995, page 36). Other Biochemical Tests and Susceptibility ------------------------------------------ The blood plasma and erythrocyte levels of glutamate and aspartate are, of course, very important measurements. However, these are not the only places with levels of amino acids. For example, it has been shown that during migraine attacks, neuroexcitatory amino acids (glutamic acid and aspartic acid) rise significantly in the cerebrospinal fluid (CSF) and are actually lower in the plasma (Martinez 1993a). CSF levels of the amino acid taurine have also found to be significantly higher in persons suffering a migraine (Martinez 1993b). Interestingly, Plaitakis (1983) found that the oral administration of glutamic acid (MSG) increases plasma levels of taurine significantly. Is it possible that MSG and aspartame increase the levels of CSF neuroexcitatory amino acids and/or taurine in persons who experience headaches or migraine after their ingestion? Westlund (1992) has shown that glutamate can have an potent excitatory effects on spinal cord neurons. It seems important to measure CSF levels of amino acids at various times after aspartame administration. Of course, the CSF levels of amino acids or methanol metabolites may or may not be affected by aspartame or MSG administration. Or they may only be affected in a subset of individuals (i.e., migraine sufferers from aspartame). There are peripheral glutamate (and aspartate) receptors in the body which may be effected by the ingestion of aspartic acid or glutamic acid. For example, Said (1994) recently discovered excitatory amino acid (e.g., glutamic and aspartic acid) receptors in the lungs which may become overexcited and contribute to the asthmatic reaction that is sometimes experienced after MSG or aspartame administration. Measurements to determine the effects of MSG and aspartame on these receptors should be devised by independent investigators. As mentioned earlier, Plaitakis (1983) showed that the administration of glutamic acid (MSG) increases the plasma levels of taurine significantly. Bessman (1948) showed that the administration of glutamic acid decreased the plasma levels of the amino acid glutamine significantly within 15 minutes. After 30 minutes the levels of glutamine rose substantially over the fasting level. The rise in glutamine levels after its initial drop may have been due to the fact that glutamate is converted to glutamine in an attempt to keep the plasma glutamate from becoming excessive. Both Stegink 1979 and Stegink 1980 show an obvious decrease in plasma glutamine levels for at least four hours after the administration of aspartame to a group of PKU heterozygotes (persons with reduced ability to process the amino acid phenyalalnine). However, these obvious trends were not statistically significant because the groups' average glutamine levels were used at each time period. It would have been useful to look at individual measurements at each time period. The normal subjects in Stegink (1980) appeared to have an increase in the plasma levels of the amino acid, asparagine for a couple of hours after aspartame administration. But these results were not statistically significant because only six subjects were used and only the average values for each time period were presented. Plaitakis (1982) and Plaitakis (1983) found that the oral administration of glutamic acid (MSG) increased the plasma glutamate and aspartate levels substantially above controls in persons who have a deficiency of the glutamate metabolizing enzyme, glutamate dehydrogenase (GDH) such as patients with the genetic neurological disorder, olivopontocerebellar atrophy (OPCA). Such patients are good candidates for the long-term testing of real-world aspartame and MSG products by independent investigators -- if they don't mind being slowly poisoned, that is. NutraSweet researchers avoid looking at possible reasons for the suffering that their product has caused because they are simply not interested in trying to discover anything; they are trying to protect a dangerous product. If forced to do a test that might discover a problem with the product, they will simply perform the test improperly and hide those improprieties amidst a morass of half-truths. Asking such "researchers" to perform (or participate in any way in) a test on CSF amino acid levels, the effect on peripheral glutamate receptors, or anything else that might reveal a problem with the dangerous product, is an enormous waste of time and money. Before looking at exactly what the damage may be from excess aspartic acid and/or glutamic acid, it can be helpful to consider the following question: Given that physicians and researchers know so little about what causes many diseases and given that many things that researchers thought were healthy yesterday are disease-causing today, do we really want to tell people that since we cannot prove beyond any doubt whatsoever that regular aspartic acid (from aspartame) ingestion causes damage, it is okay to regularly and haphazardly wreak havoc with the amino acid levels in various parts of the body? It is reminiscent of telling people that smoking cigarettes is safe. There are two main health concerns with ingesting significant quantities of aspartic acid from aspartame. The first is acute reactions. The second is long term damage also known as excitatory amino acid damage. In order to discuss the effects of aspartic acid on health it will be necessary to discuss the well-studied effects of glutamic acid (MSG) on health. Most neuroscientists and health professionals agree that these two amino acids have similar effects in many cases as they both stimulate the same types of cells in the same way. In addition, many people who are sensitive to MSG experience similar acute reactions from aspartame. Excitotoxins (Summary) ---------------------- Excitotoxins are defined as amino acids such as aspartic acid and glutamic acid which, when applied to certain types of neurons (brain cells) at certain concentrations will cause them to become overstimulated and die (Blaylock 1994, Glossary). What follows is a summary of how excitotoxins cause cell death or overstimulation from Blaylock (1994), Lipton (1994), and Nicholls (1990). Aspartate and glutamate are important neurotransmitters, a chemical which allows neurons (brain cells) in the brain to communicate between each other. Normally, excess aspartate and glutamate is pumped back in the the glial cells surrounding the neurons. However, when particular types of neurons are exposed to excessive amount of aspartate and glutamate, these neural cells are overstimulated and, at a certain level of aspartate and/or glutamate, the cells die. Aspartate and glutamate can open the calcium channel in the neurons so that calcium can move into the cell. A number of chemical reactions occur within the cell which eventually leads to the release of chemicals which stimulate connected neurons. One of the products of this chemical reaction in the neuron is arachidonic acid. Arachidonic acid then reacts with two different enzymes causing the production of free radicals such as the hydroxyl radical. The hydroxyl radical, left unchecked can kill brain cells. Fortunately, the potentially destructive free radicals are absorbed by antioxidant vitamins such as C, E, and beta carotene. Magnesium, chromium, zinc and selinium are all very important protectors of neural cells. Magnesium normally blocks the calcium channel from opening. Aspartate and glutamate can remove this block and open the calcium channel -- a normal reaction. However, when the glutamate or aspartate levels become excessive, the calcium channels in some neural cells can get stuck open, leading to the overstimulation or destruction of those cells and adjacent cells. Not every nearby brain cell is affected -- only the cells with glutamate receptors. The pumping action to remove excess glutamate back into the glial cells takes an enormous amount of energy in the form of the chemical ATP (adenosine triphosphate). In addition, it is important that there is adequate magnesium, and vitamins C, E, and beta carotene in order to prevent cell damage. If brain energy or any of the proper vitamins or minerals are lacking, neural cell death can occur. In severe cases of lack of brain energy or vitamins or minerals, a normal glutamate level can lead to cell death. Normally, there is a blood brain barrier to prevent excessive glutamate levels from entering the brain. The blood-brain barrier is a system in the walls of the capillaries within the brain that is used to keep toxic substances from entering the brain. However, there are areas of the brain which are not protected by this barrier including the hypothalamus (a part of the brain which controls the release of hormones from the pituitary gland), the circumventricular organs (a part of the brain stem), and the pineal gland (a gland which controls the production of the hormone melatonin and stops the release of the luteinizing hormone (LH) which plays a part in sex hormone control -- estrogen (females) and testosterone (males)). It has been shown experimentally in animals that prolonged high levels of glutamate in the blood plasma cause glutamate to seep through the blood brain barrier (Toth 1981). This might occur if a person were ingesting amounts of glutamic acid and aspartic acid that are not normally found in a healthy diet -- say from MSG and aspartame. In addition, the blood brain barrier appears not to be fully developed during infancy and childhood possibly allowing excess glutamate to be delivered to the brain (Wakai 1978, Olney 1988, Risau 1991). Finally, there are a number of conditions which can damage the bloodbrain barrier to some extent and allow excess glutamate to seepl into the brain: - head injuries (Tanno 1992, Shapira 1993) - certain diseases (e.g., diabetes, alzheimer's, MS, ALS, etc.) (Alafuzoff 1987, Scheibel 1988, Chambron 1994, Bennett 1995) - hypertension (Alafuzoff 1987) - exposure to certain chemicals (Stewart 1988, Velaj 1985) - exposure to radiation (Krueck 1994) - infections (Chaturvedi 1991, Mathur 1992) - brain tumors (Lohle 1992) - strokes or mini-strokes which happen frequently in the elderly (Banks 1988, Alafuzoff 1983) - aging may cause a partial breakdown especially if there is poor health (Pardridge 1988b, Banks 1988, Alafuzoff 1987) Excitotoxins (Rodent Studies) ----------------------------- There is no question that glutamate and aspartate administered subcutaneously or orally to mice or rats cause cell death to neural cells in certain areas of the brain. Both independent scientists and industry scientists agree on this point (Olney 1969b, 1969c, 1980, MSG 1994, Burde 1971, Okaniwa 1979). At first, the food industry challenged these findings and even claimed that the destruction of the arcuate nucleas in the hypothalamus was of no importance (Olney 1988). The destruction of circumventricular organ neurons in infant mice have been shown to occur at low doses of glutamate and aspartate. Independent researchers such as Okaniwa (1979) and Olney (1970) have shown the cell death to begin at a dose of 0.5 g/kg body weight. Other researchers found the minimum dosage to be between 0.5 and 0.7 g/kg body weight (Takasaki 1979, Applebaum 1984, Daabees (1985). Both Applebaum (1984) and Daabees (1985) showed that the effect of glutamate and aspartate is cumulative such that 0.25 g/kg aspartate + 0.25 g/kg glutamate caused brain lesions. The dosage in the rodent experiments above may, at first glance, seem rather high -- 0.5 g/kg = 500 mg/kg. However, humans concentrate glutamate (and probably aspartate) in the plasma at five (5) times that of rodents (Olney 1988, Stegink 1979a, page 90). This translates to a dose of 100 mg/kg for human infants. Since it is not uncommon to find as much as 5,000 mg of MSG added to restaurant dishes (Olney 1984) and many soups and broths contain as much as 2,600 mg of MSG per 12 ounces (Consumer Reports 1978), humans are already being dosed with large amounts of free glutamate. Even for a 50 kg (110 lbs.) person, 5000 mg of glutamate works out to a dose of 100 mg/kg (or 250 mg/kg for a 20kg child!). Both Daabees (1985) and Olney (1988) are in agreement that the plasma glutamate of infant rodents must reach approximately 75 umoles/100 ml to cause excitotoxic cell death. This value is several times less than the value of 200 umoles/100 ml used by Pardridge (1986) to discount the danger of aspartate. The 75 umole/100 ml plasma glutamate levels can easily be obtained in infants and children by eating canned soup (or broth) with MSG or restaurant meals. Now that aspartame is on the market, humans have an additional source of significant amounts of exicitotoxins, which as described above, have a cumulative effect with MSG (Olney 1988, Applebaum 1984). While MSG can raise the glutamate level significantly more than aspartame raises the aspartate (and glutamate) levels, the combination of the two could easily raise the level of plasma glutamate plus aspartate in infants to a level that has been shown in animals experiments to cause brain lesions. Excitotoxins (Primate Studies) ------------------------------ For many years, the food industry has been arguing that high levels of plasma glutamate or aspartate do not cause excitotoxic damage in primates (e.g., monkeys, humans), but only in rodents. In order to see the lengths to which the food industry is willing to go to counter the findings of independent scientists that glutamate (MSG) and aspartate (from aspartame) can cause brain lesions in primates, here is an excerpt from Dr. John W. Olney's statement before the 1993 Federation of American Societies for Experimental Biology (FASEB) LSRO Committee Proceedings looking into the MSG issue (Olney 1993): Argument #5: Glutamate is a rat poison, but not a human poison. The paramount argument which has been the all-time favorite with the food industry and FDA is that glutamate is toxic only for subprimate species (e.g. rodents), but not for primates. In other words, glutamate is a rat poison but not a human poison. This issue has a long and sordid history. 1. When I reported in 1969-70 that glutamate destroys neurons in the hypothalamus when administered either subcutaneously or orally to immature mice (Olney 1969b, 1969c, 1970, 1971), a U.S. Senate Nutrition Committee was investigating infant nutrition and asked me to comment on the fact that glutamate was being added to baby foods (a fact that I was not aware of until they brought it to my attention). I asked how much was being added. At first, FDA and industry officials both claimed that only trace amounts were being added to foods. However, when pressed to provide details, they revealed that they were adding > 600 mg per 4-1/2 Oz jar (which translates into > 100 mg/kg body wt for the unwitting human baby, and is clearly in the same general dose range that destroys neurons in the infant animal brain). Under pressure from the Senate Committee, FDA arranged for a special "blue ribbon" committee to evaluate the safety of glutamate for babies. The committee investigated the matter and concluded that glutamate was safe, but the committee was then investigated (at my instigation) and most of its members were found to have close financial ties with the food industry (this was corroborated by U.S. Senators and written up in a news article that appeared in Science in 1972) (Gillette 1972). Of particular note, the Committee Chairman, Lloyd J. Filer, was found to be receiving monies from both the baby food industry and the glutamate industry while he chaired this committee. 2. When the Filer committee met in 1969-70, I was asked to present my findings to them. Inter alia, I advised the committee that I had demonstrated glutamate-induced brain damage in infant monkeys as well as rodents; the monkey findings were not yet published, but I presented them to the Filer committee. Carefully thereafter, over a period of two years, I completed my monkey study and published the data in the world's leading neuropathology journal (Olney 1972). Hastily, on behalf of the glutamate and food industries, Filer assembled a group of non- neuroscientists (Reynolds, Filer et al) to study the issue. They hurriedly reported in Science in 1971 that infant monkeys are not susceptible to glutamate neurotoxicity (Reynolds 1971) and recommended that my findings be dismissed as fixation artefact. At this time, the glutamate and food industries had also hired several other non-neuroscience groups to study this brain damage issue. At first, they claimed that my findings could not be confirmed in any species, not even rodents (e.g., see Oser 1971), but later the industry consortium changed their story with respect to rodents and other subprimate species when numerous legitimate neuroscientists began reporting confirmation of my findings in these inexpensive species. However, the accuracy and authenticity of the industry findings in monkeys were never challenged, except by me, for a simple reason: no one outside the food/glutamate industry circle had either the motivation or funding to study monkeys. 3. In the 1970 era, I became alarmed at some apparent flaws in the findings of Reynolds et al. and began to challenge these authors. For example, they tube-fed very large doses (2-4 g/kg) of glutamate to infant monkeys, which led me to suspect that their infant monkeys probably vomited. This raised a crucial issue; if their infant monkeys vomited, they obviously lost dose control and this would render their data unreliable for establishing the safety of glutamate. I questioned Dr. Reynolds on this in public at a scientific meeting a few months before their Science paper appeared in print. In front of a large audience, she admitted that their monkeys vomited. However, a few months later when their Science paper appeared in print (Reynolds 1971), I was surprised to read the following description: "Each infant was maintained in an incubator with handling and cuddling at intervals for a 6 hour period. No unusual behavior was exhibited by the infants." No mention was made at all of vomiting. Therefore, I wrote a letter to Science pointing out that by the author's own acknowledgement at a public meeting, these infants had vomited. The letter was accepted for publication in Science and was sent to Dr. Reynolds for her response. To my astonishment, in a letter signed by W.A. Reynolds which I have in my files, she responded with a denial that they had encountered problems with vomiting or with dose control. Therefore, I withdrew my letter and this exchange was never published. 4. Four years after the Science report, Reynolds and Filer together with Stegink, came out with another paper (Stegink 1975) which clearly pertained to the same experiment on the same group of monkeys. This time they admitted in print that their monkeys had vomited, which raises serious questions concerning: 1) Their failure to mention this obviously important point in their initial report, and 2) The signed letter denying vomiting. There were a number of other discrepancies between the first and second report which reflect poorly upon the reliability and credibility of these authors. For example, they identified individual monkeys as being of a certain species and receiving a certain dose of glutamate in the first report, then identified the same monkeys in the second report as being of another species and/or receiving a different dose of glutamate. 5. In addition, the 2nd report by Reynolds, Filer and colleagues (Stegink 1975), admitted for the first time that their monkeys were maintained under Sernylan (phencyclidine) anesthesia throughout the 6 hr experiment. Failure to divulge in their 1st report that their animals were anesthetized with phencyclidine is a particularly critical omission, since the use of phencyclidine thoroughly invalidates the entire study in the eyes of any knowledgable neuroscientist. Phencyclidine is one of the most potent antagonists of glutamate receptors known (Wang 1990, Olney 1990a, Olney 1986). Administration of phencyclidine or its various analogs, such as MK-801, totally prevents glutamate (even very high doses of glutamate) from damaging the hypothalamus (Wang 1990). Not only does the use of phencyclidine totally invalidate the primate non-susceptibility claims of Reynolds et al., their deliberate representation that "No unusual behavior was exhibited by the infants" when they clearly were aware that their infant monkeys had actually been drugged and anesthetized, raises additional grave questions. 6. I also criticized Reynolds et al for presenting nothing but spurious illustrations; while my findings showed that oral glutamate destroys neurons only in a very specific region of the hypothalamus, in their 1st paper they published illustrations of a different and irrelevant hypothalamic region in support of their claim that glutamate is non toxic. In the following year, I invited Reynolds et al to send a member of their group to my laboratory to learn how to find glutamate damage in monkey brain. In May 1972, a member of their group (Dr. N. Lemkey-Johnston) did visit my laboratory and reviewed microscopic slides with me and she told me she was convinced that glutamate neuropathology was present in the hypothalamus of my monkeys. She also thanked me for pointing out specifically where to look in the hypothalamus to find these lesions. Although I do not know the details, it is my understanding that Dr. N. Lemkey-Johnston became ill shortly thereafter and ceased functioning as a scientist. Two years later, when Reynolds et al published their second paper (Stegink 1975), they stated that they had treated a few additional monkeys with glutamate and had serially sectioned the hypothalamus to provide definitive evidence of no damage. To my amazement, the illustration they showed was once again from the wrong region of the brain. In that same year (1975), I met with Dr. Reynolds and made it very clear to her that I considered it unethical for researchers to persistently make claims regarding non-susceptibility of monkeys to glutamate neurotoxicity, if they repeatedly presented nothing but spurious documentation of those claims. She apologized and promised to provide me with illustrations from the correct brain region, but no such illustrations were ever provided. Instead, as described in the next paragraph, she subsequently made additional claims in the medical literature and documented them even more spuriously. 7. In 1976, Reynolds et al attempted to convince the world definitively that glutamate is non- toxic for the infant primate by publishing a 3rd report (Reynolds 1976) in which new evidence is presented on an additional specie of monkey (fascicularis, a specie not documented in their first 2 reports). This report is illustrated with a brain section from a 7 day old fascicularis monkey that ingested glutamate 5 hrs earlier (Appendix, Exhibit # 2). Incredibly, the brain section used to illustrate the new finding is the same brain section used in their second report (Stegink 1975) to illustrate lack of brain damage in a 1 day old rhesus monkey dosed with glutamate 6 hrs earlier (Appendix, Exhibit #2). These illustrations are obviously spurious for two reasons: 1) They cannot possibly constitute evidence from two separate monkeys or two separate species because they are one and the same photograph which has merely been cropped differently during photographic printer; 2) Regardless how this photograph is cropped, it does not authentically document lack of glutamate toxicity because it is selected from the caudal level of the hypothalamus which lies outside the zone that is subject to damage by orally administered glutamate. When Dr. Reynolds published this spurious photograph in her 3rd paper (Reynolds 1976), she had very good reason to know that it was from the wrong region of the brain, because not only had I instructed her colleague and co-author on this matter in 1972, but I met with Dr. Reynolds herself in 1975 and briefed her very carefully and pointedly on both the science and the ethics of this matter. This briefing was one year prior to the publication of her 3rd spuriously documented report. 8. Industry representatives will likely respond to this information by claiming that several other laboratories also studied this issue and reported that glutamate does not damage infant monkey brain. If this position is taken, some pointed questions should be asked: 1) Were all such studies funded by the glutamate or food industries, despite failure of the authors to disclose industry support in some of the published reports? 2) Was undisclosed vomiting and loss of dose control a problem in these studies, as it was in the Reynolds et al study? 3) Was phencyclidine anesthesia used, but not disclosed, as was the case in the Reynolds et al. study? 4) How can FDA or the scientific community know whether vomiting occurred, or phencyclidine anesthesia was used, if the authors of industry-funded studies do not disclose this kind of crucial information in their published reports? 5) Are records available from these laboratories for FDA inspection to obtain an objective answer to questions 1 through 4? 6) Did any of the authors of these studies have any demonstrated expertise in neuropathology research? 7) Were any of these studies published in a refereed neuropathology journal? 8) Did these groups report their findings in obscure journals editorially controlled either by themselves or their very close associates who have financial ties with the food industry? 9) Did they report their findings in obscure journals without even providing histological illustrations of the brain to document their claims? 10) Did these other studies pertain to only a small number of monkeys distributed over several laboratories, thereby providing multicenter evidence for the food industry and FDA to cite as justification for keeping on the GRAS [generally recognized as safe] list for two additional decades after Olney et al (Olney 1972) published bona fide evidence for primate susceptibility to glutamate-induced brain damage in a highly reputable, rigorously refereed neuropathology journal? In summary, the record shows that FDA for two decades has been assuring the public that glutamate is safe, based largely on certain industry-generated monkey data which appear upon close scrutiny to be seriously flawed and spurious. However, even if these data were not flawed and spurious, it is obvious from industry's own findings, shown in Fig. 1 above, that the pharmacokinetics of gluatmate absorption and/or metabolism are so disparate between monkeys and man that monkeys, despite their phylogenetic closeness to humans, must be regarded as a singularly inappropriate animal model for evaluating oral gluatmate safety. Oral doses of glutamate that cause dramatic increases in blood glutamate concentrations in humans, cause no increase at all in monkeys. There are a couple of points that need to be made in regards to Dr. Olney's statement: 1. When Dr. Olney was referring to "the pharmacokinetics of gluatmate absorption and/or metabolism are so disparate between monkeys and man that monkeys, despite thier phylogenetic closeness to humans," he referenced a graph showing that humans concentrate glutamate 20 times more than monkeys when administered orally (Olney 1988, Stegink 1979a, page 90). This means that the dosage given to monkeys cannot be extrapolated to that of humans on a one-to-one basis. It also means that rodents may be a better animal model for testing glutamate than monkeys. 2. The Reynolds (1976) experiment (discussed by Dr. Olney above) was funded by G.D. Searle and tested both aspartame and MSG on neonatal primates. Therefore, the NutraSweet industry was involved in this fiasco as well. After learning about the sordid history behind both the NutraSweet industry's research and the Glutamate Association's-sponsored research and how key information was left out of published reports, I find it difficult to imagine how anyone could trust any of the "science" which is supported by those industries. As Dr. Olney mentions, there were a number of other studies which are used by the glutamate and aspartame industries to support their contention that glutamate and aspartate adversely affect only rodents despite the finding of an independent, experienced neuropathologist (Olney 1969a, Olney 1972). Reynolds (1980) administered aspartame at 2g/kg to eight monkeys and aspartame (2 g/kg) plus MSG (1 g/kg) to six other monkeys. She did not find any brain lesions in the monkeys. Phencyclidine was given to the monkeys before the administration of aspartame and MSG. As Dr. Olney pointed out, this totally invalidates the experiment because phencyclidine is a powerful drug which prevents glutmate and aspartate from damaging brain cells. In addition, considering that humans concentrate glutamate in the plasma at least 20 times more than monkeys, the dose given was too small. Oser (1974) claimed to find no brain lesions in monkeys given MSG. This study can be discounted for the simple reason that he was unable to find brain lesion in infant mice and rats given a high dosage of MSG in the same experiment. He was unable to find brain lesions in rodents in an earlier experiment (Oser 1971). Since it is widely known that infant rodents develop brain lesions at the dosage used in his experiments, he must have had one or more major flaws in the protocols which did not allow him to find lesions. Therefore, the results in the monkeys should be discounted as should the results in the dogs from both the 1971 and 1974 publications. The study by Wen (1973) can be discounted by the same reason. In the same study as his monkey study, despite giving extremely large doses of MSG to rodents, he was unable to find any brain lesions. The lack of effects on rodents given such large doses of MSG would point to one or more flaws in his protocols. One major flaw in the protocol is that animals must be sacrificed within 8 hours of the MSG dose in order to find the brain lesions. If they are sacrificed any later, the massive influx of glial cells will obscure the lesions (Burde 1971, MSG 1994). The monkeys in this experiment were kept alive for days following the MSG dosing. The study by Newman (1973) can be discounted for the simple reason that it appears that the monkeys did not get even close to the stated dose of MSG (if they got any at all). Table I shows the plasma glutamate levels within 4 hours after MSG dosing. The levels are not significantly higher than the control animals. However, in Olney (1972) the plasma glutamate levels at 4 hours are four to five times the base level (for a similar dose). Reynolds (1980) shows similar increases in plasma glutamate levels at 4 hours. Therefore, there was likely a major flaw that caused the monkeys in the Newman experiment to have no rise in plasma glutamate. There are a number of possible reasons. It is possible that the monkeys did not get much MSG. Newman states that "the test solution was readily consumed voluntarily by all animals on all occasions throughout the study." However, the term "readily" is not very specific. The MSG was supplied by Ajinomoto Company of Japan, the company that makes it and a member of the Glutamate Association. It appears that the purity of the MSG was not tested by the investigators. Whatever the reason, it is obvious that something was done incorrectly to cause no rise in plasma glutamate. In addition, Newman used older, less susceptible monkeys in the higher dose part of the experiment. Formalin was used for the brain tissue fixation. Burde (1971) points out that: "Infant rat brains perfused with formalin were extremely fragile. Tissue preservation was not satisfactory for photography, but the affected areas could not be identified and were in the periventricular arcuate area." Newman did not show any photos to back up his claim that there were no lesions. Finally, Newman did not list his funding source. In 1979, R. Heywood conducted an experiment on a single rhesus monkey (Heywood 1979). Heywood had been the coinvestigator on the Newman study mentioned above. In this study, Heywood admits that a dose of 4 g/kg of MSG caused vomitting at 43, 81 and 90 minutes after dosing. Heywood also states that the plasma glutamate level rose from 138 ug/ml to 333 ug/ml (unlike what happened in the Newman study). Among the more glaring problems with this report are: 1) the monkey vomitted and therefore did not get the full dose of MSG, 2) the investigators did not say what part of the hypothalamus was examined (as not all parts are vulnerable), 3) no photos were shown to back up the claim of no lesions, 4) the brain tissue was not examined with the electron microscope, and 5) formalin was used for brain tissue fixation. Several years after more detailed studies were conducted on infant monkeys, there seems to have been no reason to conduct such a small, sloppy, and poorly documented experiment. After discounting the above-mentioned industry-connected monkey studies for obvious mistakes and inconsistencies, we are left with: a) two studies showing brain lesions in monkeys from oral intake of MSG which were conducted by the reknowned neuropathologist, Dr. John W. Olney, who originally discovered brain lesions from excitatory amino acids such as glutamate (Olney 1969a, Olney 1972); and b) two studies by R. Abraham (Abraham 1971, Abraham 1975) showing no brain lesions in monkeys from oral intake of MSG. Abraham (1971) tested four monkeys with a dose of 4 g/kg of MSG. However, two of these monkeys were not sacrificed until 24 hours after the dose. This would cause the influx of glial cells to obscure the lesions as described earlier. In addition, damaged cells are removed from the area within 24 hours of glutmate or aspartate administration (Olney 1972). Therefore, these two particular monkeys can be discarded. One of the two remaining monkeys was given the MSG orally and one by subcutaneous injection. However, an oral dose of 4 g/kg of MSG often causes vomitting as discussed above and admitted to by Stegink and Reynolds (Stegink 1975). This leaves us with one test monkey and one monkey strongly suspected to have vomitted in the Abraham (1971) study. In this experiment, Abraham found that only 60% of the infant mice he treated with a dose of 4 g/kg developed lesions. However, other laboratories have found that such extremely high doses of MSG in mice cause lesions in 100% of the mice (Olney 1970, Burde 1971, Daabees 1985, Lemkey-Johnston 1974). Even at a dose of 1 g/kg, Takasaki (1979) found that 75% of the mice develop lesions. Abraham (1971) claimed that only 60% of the mice which received 4 g/kg developed brain lesion and 43% of the mice receiving 1 g/kg developed lesions. This sugessts that Abraham had a major defect somewhere in his experiment which would prevent brain lesions from either a) developing and/or b) being discovered. This puts the results of his remaining monkey from this experiment (or "monkeys" if one included the monkey that likely vomitted up the MSG) into serious doubt. It is of note that Abraham (1971) supported his findings with only a single picture from the hypothlalmus of a monkey that was sacrificed after 24 hours after MSG administration and did not include pictures from the monkeys who were sacrified after 3 hours. At best, this study is highly suspect and probably should be discounted due to the inadequate sacrifice schedules, likely vomitting, and poor results in the mice part of the experiment. Like the earlier Abraham study, the Abraham (1975) study had only two monkeys which were given MSG and sacrificed before 24 hours had elapsed. It seems rather odd that Abraham would continue testing monkeys by sacrificing them after 24 hours after MSG administration since it had already been published in the scientific journals that the glial cells would obscure the brain damage and that the damaged cells would be removed when an inappropriate sacrifice schedule was used (Burde 1971, Olney 1972). In fact, Olney (1972), three years prior to this study (when critiquing the Abraham (1971) study), stated the following: However, beause of the remarkable efficiency with which degenerate elements are removed from the scene of an MSG-induced lesion (minimal lesions are cleared from the mouse brain within 12 to 18 hours), it is essential to examine the brain earlier than 24 hours. This is particularly true if, due to vomiting, the infant retained very little MSG and, therefore, sustained only a minimal lesion. One monkey was give 4 g/kg of MSG orally, the other was given the same dose subcutaneously. Once again, the monkey given an oral dose of 4 g/kg is likely to have vomitted. Abraham. It is also important to note that, as discussed earlier, plasma glutamate levels in monkeys after glutamate administration stay extremely high until at least 4 hours. Yet Abraham sacrificed these two monkeys after only three (3) hours. According to researchers at Dr. Olney's laboratory, a 3-hour sacrifice schedule is the minimum needed to find any brain lesions (Samuels 1995a). If the earlier sacrifice schedule is combined with other minor or major experimental errors, no lesions would likely be found. Abraham (1975) stated that "The present investigation was undertaken in an attempt to resolve some aspects of this controversy." It appears that Abraham merely repeated most of the same flaws in his 1971 experiment and did not address Olney's direct criticisms. This study, therefore, should be discounted as well. Excitotoxins (Humans) --------------------- Several discoveries have proven that ingested excitotoxins can cause adverse effects in human beings. In 1987, 150 Canadians got sick (4 died and 12 suffered permanent memory loss) after ingesting mussels whifch had high levels of domoic acid, a potent glutamate analog (Perl 1990). In parts of Asia and Africa, the chickling pea plant was eaten by some people during times of famine. It contains a naturally-occurring excitotoxin, §-N-oxalylamino-L-alanine (BOAA), which has been shown to kill motor neurons (Spencer 1986). One of the more likely causes of the form of the ALS-like illness in the Chamorro population in Guam is the ingestion of improperly processed cycad flour which contains the excitotoxin, §-N-methylamino-L-alanine (BMAA) (Spencer 1987, Choi 1992). The Chamorros ate a large amount of this seed during the famine following World War II. In the 1950s, the rate of the Guam ALS-Parkinson's-dementia complex was 50 to 100 times higher than in developed countries (Kurland 1988). The Chamorros no longer ingest much cycad flour (Chamuit, 1994). It was found that many people who ate the flour didn't come down with the disease until many years later, suggesting that the excitotoxic exposure plus age-related cell loss set the stage for the disease. As Choi (1992) states: "Such a model raises the possibility that nerve cell damage resulting from exposure to environmental excitotoxins could pave the way for other neurodegenerative diseases, such as Alzheimer's Parkinson's, or ALS, whose symptoms would become apparent only decades later. Garruto (1980) found that immigrants to the U.S. from high-risk areas in Guam had a high incidence of ALS even though they had not ingested cycad flour for over 30 years.