Aspartame

You’ve probably seen or heard the news. According to "credible" information on www.psychotic-consciracy.com Aspartame (also known by the brand name Nutrasweet) is responsible for the deaths of tens of thousands, the increased incidence of brain tumors, Gulf War Syndrome, Multiple Sclerosis, Lupus, blindness, fibromyalgia, spousal abuse, bounced checks, higher electric bills and pretty much any other scary thing one could imagine. Sound crazy? Well, information very similar to this has been circulating around for some time in the form of web sites formed entirely on opinion and well-intentioned emails sent to you by people that care about your health. It is time we look at the available facts and concerns regarding this pervasive food additive.

Aspartame is a popular, non-nutritive, artificial sweetener that was approved by the FDA for use in 1981. Since its emergence as a food additive, it has gone on to dominate the artificial sweetener market, being approved for use in over 100 countries.^1,3The FDA has evaluated aspartame’s use in the food supply 26 times since its original approval, the results of which leave no question to its safety.¹ Aspartame is 160-200 times sweeter than sucrose and provides 4 kcal/g.² Due to its sweetening ability so little is used that it ends up being essentially calorie free. This has made it a natural for inclusion in reduced calorie foods and beverages. The FDA has established an acceptable daily intake (ADI) of 50mg/kg body weight. This does not mean that above this amount it is harmful, but that the FDA approved aspartame based upon the assumption that no one would be consuming more than 50 mg/kg of body weight in a day. How did the FDA come up with this number? If every dietary source of sugar were replaced by aspartame, intake could conceivably go this high. For the oft-used 70kg (154 pounds) person, the ADI would be 3500 mg (3.5 grams). Typical Aspartame content for popular food sources are listed below.

Food Source Aspartame (mg)

• 12 oz. Diet soft drink 170
• 8 oz. Powdered drink 100
• 8 oz. Sugar-free fruit yogurt 124
• 4 oz. Sugar-free gelatin 80
• 1 packet Nutrasweet 35
• Apex High Performance Van. 9.9
• Apex High Performance Choc. 23
• Apex High Performance Straw. 38
• Apex A Better Whey Van. 5
• Apex A Better Whey Choc. 15

For this 154 pound person to meet the FDA’s ADI, they could consume 100 packets of Nutrasweet, 20 cans of diet soda, 92 servings of Strawberry High Performance Meal Replacement or 700 servings of A Better Whey Vanilla a day. The likelihood that individuals will meet or exceed these limits is rather remote. In fact, most users of Aspartame consume less than five mg/kg of body weight a day.⁴

Chemically, Aspartame is a methyl ester of aspartic acid and phenylalanine. During Aspartame’s metabolism, it is broken up into its component pieces, two amino acids and a methyl group. The methyl group temporarily becomes methyl alcohol (methanol), which is then converted to formaldehyde, finally being oxidized to carbon dioxide.³ Methanol and formaldehyde are both toxic compounds in high doses, but are normal by-products of human metabolism. However, these normal metabolites are the target of concern for those that question aspartame’s safety. In it’s evaluation of Aspartame’s safety, the FDA determined that the level of these compounds falls well below the threshold at which they would cause harm and is less than that of many food sources, especially fresh fruits and vegetables. In fact, a 12 oz. serving of tomato juice would yield six times as much methanol as a can of diet soda.⁴ Since it is the methanol metabolite formaldehyde (formate) that has the greatest potential for toxicity, it has been looked at thoroughly. No significant rise in plasma formate from aspartame ingestion has been measured, even when abuse doses of 200 mg/kg were fed to humans. ^5,6,7,8The remaining amino acids (aspartic acid and phenylalanine) are metabolized as they would be had they been provided by conventional dietary sources.

There is a group of individuals where aspartame intake may be of greater concern. This is for individuals with a genetic metabolic error of metabolism called Phenylketonuria (PKU). Those with PKU, which is tested for and diagnosed at birth, lack an enzyme responsible for phenylalanine metabolism, allowing excessive plasma levels of this amino acid to accumulate with potential neurotoxic effects. Since aspartame contains phenylalanine, foods that contain aspartame must carry a warning label that states Warning to phenylketonurics: contains phenylalanine. Medical nutrition therapy for PKU involves a diet that controls dietary sources of phenylalanine. ² Many studies have looked at the effect of consuming normal and very high amounts of aspartame on the plasma levels of phenylalanine in persons heterozygous for PKU (those not on strict dietary control). No adverse effects were noted in this potentially susceptible group and the rise in plasma levels of phenylalanine, while significant, was small and within normal ranges.^{9,10,11,12,13} In one of the studies, researchers concluded that a fasting adult heterozygous for PKU could consume the equivalent of 24 cans of diet soda over an eight-hour period with only a mild elevation in plasma phenylalanine.⁹

Another area of allegations has to do with the effects of Aspartame on the brain, psychological functioning, mood and seizures. It should come as no surprise that potential neurophysiologic and neuropsychologic effects of Aspartame have been studied. Studies have looked at the effect of varying doses of Aspartame on normal healthy adults and those with heterozygote PKU and have noted no effects on mood, cognitive function, EEG, 24-hr EEG, reaction time or memory, nor were there differences in measures of sedation, hunger or incidence of headache.^10,14,15,16

What about the supposed link between Aspartame consumption and seizures? Aspartame did not provoke seizures in a group of epileptic children ages five to 13 years old.¹⁷ Other studies in animals and humans concluded that there is no risk of seizure associated with Aspartame consumption in normal or vulnerable individuals.^18,19,20

Another common assertion is that Aspartame is responsible for brain tumors. The evidence for this? Reports have hypothesized that the continuous steady rise in brain tumors corresponds to the emergence of Aspartame in the food supply.²¹Analysis of data from the National Cancer Institute does not support this. Their data show a flattening of the brain cancer rate since 1985, with a slight decrease from 1991-1993.²² Also, a study on rats fed Aspartame at the level of 1-4g/kg body weight for 104 weeks found no significant difference in the incidence of brain tumors between control and test groups.²³ Let’s put this into perspective for one moment. An intake of 4g/kg body weight would be a daily intake of 273 grams of aspartame for a 150 pound person, roughly 88 times the highest expected intake and 54,545 times the normal intake. Now, consume this amount for two years straight. Studies showing an increase in brain tumors with Aspartame ingestion were not found.

How about Aspartame and its impact on attention deficit disorder? Children diagnosed with ADD were given Aspartame doses 10 times normal consumption levels and experienced no effects on cognitive or behavioral function.²⁴

About now one can see a pattern developing. For all of the sensationalistic allegations and anecdotal reports of adverse reactions made against Aspartame, none of them have been measured, observed or repeated under controlled conditions. If Aspartame was truly the public health menace that it is alleged to be, one would expect volumes upon volumes of data to support this. Well-designed studies would be able to repeatedly show adverse effects, and there would be little doubt as to its danger. However, time and time again no adverse effects are measured. Studies do not exist that show a danger to the consumption of Aspartame. The conspiracy theory web site alluded to in the opening paragraph offers no references to study results, hard data or scientific, valid proof for the allegations that Aspartame is linked to Gulf War Syndrome, Lupus or Multiple Sclerosis. In fact, the organizations that fund research, study and/or treat these conditions are not aware of any established link, theoretical or otherwise.²⁵ An email that circulates warning of the dangers of Aspartame makes mention of the several hundred studies that turn up if one searches databases with the key words "adverse effects" and "Aspartame." This is indeed true; however, if the authors of the email had taken a moment to view more than the title of the studies, they would have discovered that the conclusions of the studies did not yield any adverse effects.

Aspartame, due to its high sweetening ability and low caloric contribution to food, may enhance fat loss. When Aspartame containing foods and beverages were included as part of a low fat, hypocaloric diet, compliance was improved, weight loss was greater and weight regain was less.^26,27

It is puzzling that in the face of such overwhelming data that someone could still maintain the idea that Aspartame is harmful. It is either a case of pure denial and/or ignorance or simply a patent fear of anything that is assembled in a lab that one could maintain this fear.

Inexplicably, there are those that do not seem to tolerate Aspartame well, complaining of feeling "spacey" or development of headaches. As with any substance, natural or chemical, there are those rare individuals that would be considered "sensitive" to the substance in question. It is therefore entirely feasible that some individuals exhibit sensitivity to Aspartame. In fact, of the several hundred studies reviewed, one did show an increase in occurance of headaches following Aspartame consumption in a group that considered themselves Aspartame sensitive and had complained in the past of headaches associated with Aspartame use. ²⁸ However, duration or severity of the headaches was not increased. Also, there was a study of individuals with a history of clinical depression that showed an increase in severity of depressive symptoms at intakes of 30 mg/kg body weight a day.²⁹ There were no such reactions in the group that did not have a history of depression. For these sensitive or vulnerable individuals, a recommendation to limit or simply not consume Aspartame or products that contain it seems reasonable. In other words, if it bothers you, don’t use it. However, it is not cause to remove it from the food supply and implicate it in the demise of modern society.

To sum up the topic of Aspartame and safety I would like to end with an excerpt from the book Sugars and Sweeteners:

"..t is doubtful if any food additive has received more clinical study than Aspartame. As noted in this study, Aspartame has been fed under a variety of conditions to normal adults, known PKU heterozygotes, 1-yr-olds, and IDDM and NIDDM subjects. Clinical tests have focused on doses of Aspartame compatible with its use in the food supply in addition to its use under abuse situations. Administration of Aspartame to humans occurred in the fasting state, as part of a meal, or in repeated loading studies. Pharmicokinetic data developed for plasma phenylalanine concentrations indicate that a bolus dose of 34 mg/kg body weight, the 99^th percentile of projected daily intake, repeated at intervals of 2 h does not increase plasma phenylalanine concentrations above those levels experienced after ingesting a protein-containing meal. Aspartate and methanol released from Aspartame under the conditions of these clinical studies did not constitute an excessive metabolic load."³⁰

For this, I’m sure, we will be labeled a conspirator, in cahoots with the makers of Nutrasweet and getting paid handsomely for the manipulation of the facts and the purposeful, malicious harm of the American public.

I invite the opposing viewpoint to address what is written here, using peer-reviewed references to support their conclusions. If that can be done, then we have a draw. The gauntlet has been laid down.

References:

1. Position of The American Dietetic Association: Use of nutritive and non-nutritive sweeteners. J Am Diet Assn 1998; 98: 580-87.
2. Groff, JL, Gropper, SS, Hunt, SM. Advanced Nutrition and Human Metabolism. St. Paul, MN: West Publishing Company; 1995.
3. Whitney, EN, Rolfes, SR. Understanding Nutrition 7^th ed. St. Paul, MN: West Publishing Company; 1996. 756 p.
4. Butchko, HH, Kotsonis, FN. Acceptable intake vs. actual intake: The Aspartame example. J Am Coll Nutr 1991 Jun; 10(3): 258-66.
5. Stegink, LD, Filer, LJ Jr, Bell, EF, Ziegler, EE, Tephly, TR. Effect of repeated ingestion of aspartame-sweetened beverage on plasma amino acid, blood methanol, and blood formate concentrations in normal adults. Metabolism 1989 Apr; 38(4): 357-63.
6. Leon, AS, Hunninghake, DB, Bell, C, Rassin, DK, Tephly, TR. Safety of long-term large doses of aspartame. Arch Intern Med 1989 Oct; 149(10):2318-24.
7. Davoli, E, Cappellini, L, Airoldi, L, Fanelli, R. Serum methanol concentrations in rats and in men after a single dose of aspartame. Food Chem Toxicol 1986 Mar; 24(3): 187-9.
8. Stegink, LD, Brummel, MC, McMartin, K, Martin-Amat, G, Filer, LJ Jr, Baker, GL, Tephly, TR. Blood methanol concentrations in normal adult subjects administered abuse doses of aspartame. J Toxicol Environ Health 1981 Feb; 7(2): 281-90.
9. Stegink, LD, Filer, LJ Jr, Bell, EF, Ziegler, EE, Tephly, TR, Krause, WL. Repeated ingestion of aspartame-sweetened beverages: further observations in individuals heterozygous for phrnylketonuria. Metabolism 1990 Oct; 39(10): 1076-81.
10. Ttrefz, F, de Sonneville, L, Matthis, P, Benninger, C, Lanz-Englert, B, Bickel, H. Neuropsychological and biochemical investigations in heterozygotes for phenylketonuria during ingestion of high dose aspartame (a sweetener containing phenylalanine). Hum Genet 1994 Apr; 93(4): 369-74.
11. Mackey, SA, Berlin, CM Jr. Effect of dietary aspartame on plasma concentrations of phenylalanine and tyrosine in normal and homozygous phenylketonuric patients. Clin Pediatr (Phila) 1992 Jul; 31(7): 394-9.
12. Stegnik, LD, Wolf-Novak, LC, Filer, LJ Jr, Bell, EF, Ziegler, EE, Krause, WL, Brummel, MC. Aspartame-sweetened beverage: effect on plasma amino acid concentrations in normal adults and adults heterozygous for phenylketonuria. J Nutr 1987 Nov; 117(11): 1989-95.
13. Stegink, LD, Filer, LJ Jr, Baker, GL, McDonnell, JE. Effect of an abuse dose of aspartame upon plasma and erythrocyte levels of amino acids in phenylketonuric heterozygous and normal adults. J Nutr 1980 Nov; 110(11): 2216-24.
14. Spiers, PA, Sabounjian, L, Reiner, A, Myers, DK, Wurtman,J, Schomer, DL. Aspartame: neuropsychologic evaluation of acute and chronic effects. Am J Clin Nutr 1998 Sep; 68(3)¨531-7.
15. Lapierre, KA, Greenblatt, DJ, Goddard, JE, Harmatz, JS, Shader, RI. The neurophychiatric effects of aspartame in normal volunteers. J Clin Pharmacol 1990 May; 30(5): 454-60.
16. Bradstock, M, Serdula, M, Marks, J, Barnard, RJ, Crane, NT, Remington, RL, Trowbridge, FL. Evaluations to reactions to food additives: the aspartame experience. Am J Clin Nutr 1986; 43: 464-9.
17. Shaywitz, BA, Anderson, GM, Novotny, EJ, Ebersole, JS, Sullivan, CM, Gillespie, SM. Aspartame has no effect on seizures or epileptiform discharges in epileptic children. Ann Neurol 1994 Jan; 35(1): 98-103.
18. Tollefson, L, Barnard, RJ. An analysis of FDA passive surveillance reports of seizures associated with consumption of aspartame. J Am Diet Assoc 1992 May; 92(5): 598-601.
19. Dailey, JW, Lasley, SM, Burger, RL, Bettendorf, AF, Mishra, PK, Jobe, PC. Amino acids, monoamines and audiogenic seizures in genetically epilepsy-prone rats: effects of aspartame. Epilepsy Res 1991 Mar; 8(2): 122-33.
20. Rowan, AJ, Shaywitz, BA, Tuchman, L, French, JA, Luciano, D, Sullivan, CM. Aspartame and seizure susceptibility: results of a clinical study in reportedly sensitive individuals. Epilepsia 1995 Mar; 36(3): 270-5.
21. Olney, JW, Farber, NB, Spitznagel, E, Robins, LN. Increasing brain tumor rates: is there a link to aspartame? J Neuropathol Exp Neurol 1996 Nov; 55(11): 1115-23.
22. FDA statement on Aspartame.Rockville, MD: Food and Drug Administration. FDA Talk Paper. November 18, 1996.
23. Ishii, H. Incidence of brain tumors in rats fed aspartame. Toxicol Lett 1981 Mar; 7(6): 433-7.
24. Shaywitz, BA, Sullivan, CM, Anderson, GM, Gillespie, SM, Sullivan, B, Shaywitz, SE. Aspartame, behaviour, and cognitive function in children with attention deficit disorder. Pediatrics 1994 Jan; 93(1): 70-5.
25. Squillacote, D. 1999 Jan 12. The Multiple Sclerosis Foundation Website (www.msfacts.org/aspartame.htm). Aspartame(Nutrasweet): no danger.
26. Kanders, BS, Lavin, PT, Kowalchuk, MB, Greenberg, I, Blackburn, GL. An evaluation of the effect of aspartame on weight loss. Appetite 1988; 11 Suppl 1: 73-84.
27. Blackburn, GL, Kanders, BS, Lavin, PT, Keller, SD, Whatley, J. The effect of aspartame as part of a multidisciplinary weight-control program on short- and long-term control of body weight. Am J Clin Nutr 1997 Feb; 65(2): 409-18.
28. Van den Eeden, SK, Koepsell, TD, Longstreth, WT Jr, van Belle, G, Daling, JR, McKnight, B. Apartame ingestion and headaches: a randomized crossover trial. Neurology 1994 Oct; 44(10): 1787-93.
29. Walton, RG, Hudak, R, Green-Waite, RJ. Adverse reactions to aspartame: double-blind challenge in patients from a vulnerable population. Biol Psychiatry Jul 1-15; 34(1-2): 13-7.
30. Kretchmer, N, Hollenbeck, CB. Sugars and Sweeteners. Boca Raton, FL: CRC Press; 1991. 297 p.