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 proceeded to dominate the artificial-sweetener market, being approved for use in over 100 countries. The 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. Aspartame is 160-200 times sweeter than sucrose and provides 4 kcal/g. Due to its sweetening ability, so little of it 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 amounts above this are 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. That’s 5 grams a day for a 100 kg person.
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 a 70kg (154 lbs.) person, the ADI would be 3500 mg (3.5 grams). Typical aspartame content for popular food sources are listed below.
|Food Source||Aspartame (mg)|
|340 ml. Diet soft drink||170|
|Muscle Science Perfect Protein||110|
|250 ml. Powdered drink||100|
|250 ml. Sugar-free fruit yogurt||124|
|125 ml. Sugar-free gelatin||80|
For this 70 kg (154 lb) person to meet the FDA’s ADI they could consume 100
packets of Nutrasweet, 20 cans or 3.75 2-litre bottles of diet soda, 31 servings (55 g) of Perfect Protein per day. The likelihood that individuals will meet or exceed these limits is rather remote. In fact, most users of aspartame consume less than 5 mg/kg of body weight per day.
Chemically, Aspartame is a methyl ester of aspartic acid and phenylalanine. During Aspartame’s metabolism in the gut, 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. 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 its evaluation of Aspartame’s safety, the FDA determined that the levels of these compounds fall well below the threshold at which they would cause harm and are less than that of many food sources, especially fresh fruits and vegetables. In fact, a 340 g serving of tomato juice would yield six times as much methanol as a can of diet soda. 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. The remaining amino acids (aspartic acid and phenylalanine) are metabolized as they would had they been provided by conventional dietary sources.
There is a group of individuals for whom 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 (see can of Diet Coke). Medical nutrition therapy for PKU involves a diet that controls dietary sources of phenylalanine. 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. 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.
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 neuropsychological 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-hour EEG, reaction time or memory, nor were there differences in measures of sedation, hunger or incidence of headache.
What about the supposed link between aspartame consumption and seizures? Aspartame did not provoke seizures in a group of epileptic children ages 5-13 years old. Other studies in animals and humans concluded that there is no risk of seizure associated with aspartame
consumption in normal or vulnerable individuals.
Another common assertion is that aspartame is responsible for brain tumors. Serving as evidence for this have been reports that have hypothesized that the continuous steady rise in brain tumors corresponds to the emergence of aspartame in the food supply. Analysis of data from the National Cancer Institute, however, does not support this. Data show a flattening of the brain cancer rate since 1985, with a slight decrease from 1991-1993. 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. 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 68 kg 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 that are 10 times the normal consumption levels and experienced no effects on cognitive or behavioral function. 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 or 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. An e-mail 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, upon taking a moment to view more than the title of the studies, one 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, hypo-caloric diet, compliance was improved, weight loss was greater and weight regain was less. 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 who 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 occurrence 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. Duration or severity of the headaches, however, was not increased. In addition, 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. 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. It is not, however, sufficient 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, we end with an excerpt from the book Sugars and Sweeteners "..it 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 99th 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."
Those with opposing viewpoints are invited to address what is written here, using peer-reviewed references to support their conclusions.
Below is what Wikipedia says about the Aspartame controversy….
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Main article: Aspartame
The artificial sweetener aspartame has been the subject of controversy regarding its safety since its initial approval by the U.S. Food and Drug Administration (FDA) in 1974. Some scientific studies, combined with allegations of conflicts of interest in the sweetener's FDA approval process, have been the focus of vocal activism, conspiracy theories and hoaxes regarding postulated risks of aspartame.
A 2007 safety evaluation found that the weight of existing scientific evidence indicates that aspartame is safe at current levels of consumption as a non-nutritive sweetener. Some sources of aspartame dangers and conspiracies have been the subject of critical examination. In 1987, the U.S. Government Accountability Office concluded that the food additive approval process had been followed for aspartame. Based on government research reviews and recommendations from advisory bodies such as the European Commission’s Scientific Committee on Food and the Joint FAO/WHO Expert Committee on Food Additives, aspartame has been found to be safe for human consumption by more than ninety countries worldwide. In 1999, FDA officials described the safety of aspartame as "clear cut" and stated that the product is "one of the most thoroughly tested and studied food additives the agency has ever approved."
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