Aspartame's Affects On the Health of Humans - Research Paper Example

of the Aspartame: Cracking the issues The perception of taste involves a coordinated interplay of numerous processes between the taste buds and the brain. Chemical components of the substance need to stimulate a nerve impulse reaction to be interpreted in the brain as any of the flavors. Hence, artificial sweeteners were developed that mimic this effect and even provide a higher degree of “sweetness” with only a few calories compared to natural sugars. The production of artificial sweeteners in the market and replacement of natural sugars in some beverages and foodstuff are deemed to assist individuals who need to attain a considerable reduction in sugar consumption without significantly affecting their lifestyle. In spite of this, it remains necessary that the chemical components and by- products of artificial sweeteners be evaluated for possible toxicity and metabolic instability. In this paper, important information such as chemical composition, discovery, and current issues about aspartame as an artificial sweetener will be discussed. Chemical composition Aspartame is a synthetic sugar that has a very different molecular structure compared to monosaccharides. This essentially proves that the relative sweetness of a substance is not unique only to sugars. Theoretically, it is 180 to 200 times sweeter than that of sucrose, known commonly as the table sugar (Myers, 2007). Actually, aspartame occurs as a methyl ester and as an optical isomer consisting of two amino acids, L-phenylalanine and L-aspartic acid. However, only one of its enantiomers has a sweet taste, the other one tastes bitter. Some clinical trials based their assumptions on the potential toxicity of the substance upon hydrolysis. In fact, hydrolysis of aspartame with a strong acidic or basic substance yields methanol, a type of alcohol that can have toxic effects to the human body. Further hydrolysis may also break peptide bonds that generate its amino acid constituents in the solution (Myers 34). Meanwhile, commercial preparations of aspartame involve two chemical processes to prevent the build- up of the toxic by- products associated with metabolism of in a human body. The first method is aimed at joining two carboxyl groups of aspartic acid into an anhydride. Then the amino acid group is protected by another compound to prevent the destruction of chemical bonds. Specifically, phenylalanine is methylated and combined with the N- protected aspartic anhydride. Acid hydrolysis then removes the blocking group from aspartic acid. With this process however, the bitter- tasting enantiomer may be formed that would affect the total productivity yields. Some industries utilize catalytic enzymes from the bacteria Bacillus thermoproteolyticus to maximize production. Other methods of productions have been tried by industries using unmodified aspartic acid but still have lower yields compared with enzymatic catalysis (Yagasaki and Hashimoto, 2008). The relatively superior sweetness of aspartame explicitly highlights a major chemical advantage compared to carbohydrates like fructose, glucose, honey, maltose, galactose, and lactose in terms of the amount of calories provided. While aspartame provides roughly four kilocalories of energy per gram, the amount of the substance needed to attain a certain degree of sweetness when mixed with food is generally lesser than that of carbohydrates. This means that the total amount of calories provided by the metabolism of a certain amount of aspartame can be negligible. Moreover, the characteristics and duration of sweetness of aspartame is highly identical with sucrose, unlike other approved artificial sweeteners like saccharin and acesulfame potassium (US Pharmacopeia, 2011). On the other hand, aspartame may not be reliable as an additive for some food that requires a longer shelf- life. While it may have a half- life of 300 days under acidic solutions, this time frame is significantly reduced to only a few days when the pH of the solution reaches almost neutrality. Thus, aspartame may be remarkably stable when used in soft drinks. Furthermore, the instability of aspartame when subjected to elevated temperatures even at a short period makes it an undesirable ingredient in cooking. At temperatures above 150 °C, aspartame may decompose forming diketopiperazine (DKP) derivative. Currently, manufacturers continue to discover ways on increasing the stability of the substance in high temperatures by encasing it in fats and maltodextrin. It may also be mixed with other artificial sweeteners such as saccharin when used as a component of syrups and fountain beverages. Discovery Aspartame was not originally formulated to be a sugar- substitute. The discovery of the substance occurred by chance in 1965 by Mazar and Schlatter at GD Searle (Stegink, 1987). Because of its novel physical and chemical properties, the substance was thought to have a potential market value as a low- calorie sweetener to be used by individuals under carbohydrate restrictions. Initial clinical trials were performed on animals until 1973 when the product was finally petitioned for use in the United States. The presentation was accompanied with a large amount of data indicating the safety of the substance including its possible toxicity and instability (General Accounting Office, 1986). Eventually, aspartame penetrated the US market in 1974 under the trade name NutraSweet. However, it was later withdrawn after the publication of experimental results of Dr. John Olney of Washington University Medical School in St. Louis that indicated carcinogenic effects of the substance to test animals (Whitmore, 1996). Olney and Turner of Turner and Label Company formally filed an objection to the FDA decision on the approval and regulation of the substance for public use (General Accounting Office, 1986). The conflicting arguments were based on the end- products of aspartame metabolism which include a toxic alcohol and two other amino acids upon hydrolysis. Phenylalanine is usually avoided by people with an inborn condition called phenylketonuria (PKU). As a consequence of opposing clinical evidences, a formal evidentiary hearing was formed to specifically convene for the issue of product safety (Whitmore, 1996). A Public Board of Inquiry (PBOI) was composed of three scientists outside of the FDA to confirm or negate the evidences presented by the conflicting parties. It was not until 1980 when the PBOI officially convened for three days to address the issue utilizing a new set of data provided by the Iowa research group. Results of the investigation confirmed that aspartame is generally safe to use only under the circumstances specified in the original petition filed by Searle in the FDA. While declaring this, they inexplicably agreed with Olney on the potential tumor- forming properties of the end- products of aspartame metabolism. Thus, the PBOI finally withdrew their approval of the petition but the issue remained unsettled. The involved parties demanded for succinct explanations of the decision by the PBOI. After a thorough review of the decision, aspartame was finally approved as an artificial sweetener in food and beverages. Until now, several studies continue to look for clinical evidences that either approve or negate the use of aspartame even if the substance has already been made widely available as a component of sugarless beverages and artificially sweetened food known even in the international market (Stegink, 1987). Health risks and benefits Since its approval to be used in the market as an artificial sweetener, aspartame has been tagged with tremendously negative reviews by the public (Lean & Hankey, 2004). The situation pressed even the European Scientific Committee on Food to rediscover the chemical components of the substance including its potential health risks and benefits to consumers. In particular, the phenylalanine subunit of aspartame can be hazardous to individuals with the genetic disease known as phenylketonuria (PKU). The condition results from an inborn deficiency of phenylalanine hydroxylase to metabolize phenylalanine as an amino acid. This results to the build- up of the specific amino acid in the blood which causes metabolic disturbance and electrolyte imbalance. The clinical symptoms of the condition include behavioral disturbances as well as mental and emotional instability. Generally, people with PKU are aware of their health condition as well as their food restrictions. In addition, people who particularly need the nutritional advantages derived from natural sugars are specifically cautioned with the consumption of artificial sweeteners. These people include those who need to attain their daily caloric requirements. Aspartame can provide a very little amount of calories which can be insufficient to fulfill caloric requirements of a highly active adults and malnourished children. Hypoglycemia, or lower- than- normal level of blood sugar, may result as a consequence of using artificial sweeteners which have no caloric values. Thus, public awareness of products containing aspartame remains the responsibility of authorized agencies such as the Food and Drug Administration (FDA), European Food Standards Authority (EFSA), Food Standards Agency (FSA), and other national agencies. Subsequent nutritional studies concluded that aspartame consumption is safe up to 40 mg/ kg body weight/ day (Lean & Hankey, 2004). Since consumers are not expected to calculate consumption on a daily basis, this value is simply translated as having consumed up to ten cans of artificially sweetened drinks, which is nearly impossible even for an adult consumer. The review of 500 studies in 2002 further concluded that consumption of food and drinks with artificial sweeteners has no direct influence with depression, hair loss, and dementia. While cancer and tumor- formation in the brains of test animals have been shown in some studies, its occurrence was not appreciated in humans (Soffritti, 2005). This is probably due to the dosage of aspartame administered to animals that resulted in chromosomal mutations and malignancies (National Cancer Institute, 2009). The dosage consumption of aspartame is largely different in test animals and humans due to the variations in the body size and capacity to withstand fluctuations in chemical levels attributed to any intake of food and beverage (Stegink, 1987). In terms of preventing nutritional problems, clinical reviews prove that aspartame can facilitate a significant reduction in caloric consumptions of individuals, both male and female. In a study by Tordoff and Alleva (1990), the calories consumed in carbohydrates can be sufficiently vanquished with the use of non- nutritive and synthetic sweeteners. Meanwhile, cutting down sugar consumption also generate further advantages in terms of risk reduction from diabetes mellitus, obesity, heart problems, and other cardiovascular and metabolic disorders. Thus, the health conditions that result from too much consumption sugar can be prevented with the replacement of sugar with artificial sweeteners especially aspartame. For instance, high concentration of fructose in sucrose increases the triglycerides in the body responsible for the development of heart problems. Specifically, diabetes mellitus results from the gradual reduction in insulin produced by the pancreas to promote utilization of glucose by body cells. The decreased functionality of the pancreas results from the overwhelming levels of blood glucose that occurs in a long- term basis (Lean & Hankey, 2004). Therefore, the uncontrollable increases in blood glucose levels may be prevented by regulating sugar consumption with the use of artificial sweeteners, in addition to proper diet and weight control. Similarly, obesity may also be prevented with the replacement of sugar with artificial sweeteners. While this may not be exclusively valid for adult population, the use of “diet” drinks remains to be inversely proportional to weight gain among children (BMJ). Along with this, aspartame prevents the development of dental caries because it does not contain sugar which forms as a substrate for bacterial proliferation in the mouth. Conclusions Advancements in chemistry have led to the development of several food additives in the market. With the increased concern on the potential risks of food additives to health, aspartame easily acquired a good share of negative comments from the public. In fact, the first appearance of aspartame in the market triggered numerous objections and even conflicting evidences from researches and experiments. This is very reasonable for a concerned public. In fact, the premises of counter arguments based on the end- products of aspartame metabolism demand a considerable time and effort for government agencies to verify so as not to put the public safety in peril. On the other hand, the safety of aspartame has now been confirmed by international agencies including the FDA, EFSA, and FSA. Thus, the benefits of the substance deserve to be emphasized in public information systems so as to maximize acceptance of the product. Generally, the major benefits derived from artificial sweeteners can be attributed to the reduction of sugar consumption among individuals specifically at high risk of developing metabolic conditions. While the product has been accepted by the authority, continuous regulation of aspartame remains a vital component when public safety is of utmost concern. Works cited General Accounting Office. Six Former HHS Employees’ Involvement in Aspartame’s Approval. [Federal Accounting Office], July 1986. Print. Lean, Michael and Hankey, Catherine. Aspartame and its effects on health: The sweetener has been demonised unfairly in sections of the press and several websites. British Medical Journal. Vol. 329, pp. 755- 56. 2 Oct. 2004. Print. Myers, Richard L. The 100 most important chemical compounds: a reference guide. Westport City: Greenwood Publishing Group, 2007. Print. National Cancer Institute. Artificial Sweeteners and Cancer. National Institute of Health. 5 Aug. 2009. Web. 30 Nov. 2011. Soffritti, M, Belpoggi, F, Esposti, D, Lambertini, L. Aspartame induces lymphomas and leukaemias in rats. European Journal of Oncology. Vol. 10(2), pp. 107–116. 2005. Print. Stegink, Lewis D. The aspartame story: a model for the clinical testing of a food additive. American Journal of Clinical Nutrition. Vol. 46, pp. 204-15. 1987. Print. Tordoff, Michael G. and Alleva, Annette M. Effect of drinking soda sweetened with aspartame or high-fructose corn syrup on food intake and body weight. American Journal of Clinical Nutrition. Vol. 51, pp. 963- 9. 1990. Print. US Pharmacopeia. Food Ingredient Reference Standards. Washington D.C.: Government Printing office, 2011. Print. Whitmore, Arthur. FDA Statement on Aspartame. Rockville, MD: U.S. Department of Health and Human Services, 1996. Print. Yagasaki, Makoto & Hashimoto, Shin-ichi. Synthesis and application of dipeptides; current status and perspectives. Applied Microbiology and Biotechnology. Vol. 81 (1), pp. 13–22. 2008. Print. Read More