The media and health advocates have questioned the safety of foods and beverages containing artificial sweeteners since the1970s, when another artificial sweetener, saccharin, was linked to cancer. Diet Coke contains l-aspartyl-l-phenylalanine methyl ester -- aspartame -- an amino acid that has been loosely associated with side effects such as leg pain. However, contemporary scientific research does not support these claims. In fact, evidence suggests that aspartame has pain-relieving and anti-inflammatory properties.
Saccharin vs. Aspartame
Saccharin--the first sugar substitute--was discovered in 1879. Scientific studies of saccharin in the early 1970s linked its usage to cancerous tumors in laboratory rats. Subsequent studies showed conflicting evidence of saccharin's role as a carcinogen. The U.S. Food and Drug Administration, or FDA, attempted to ban saccharin in 1977. However, due to public outcry, the U.S. Congress passed the Saccharin Study and Labeling Act instead. This legislation mandated warning labels on all products containing saccharin to inform about lab results linking the substance to cancer in animals.
Aspartame--approved by the FDA in 1981--has been publicly accused, via the Internet, of causing all sorts of negative side effects and has been linked to systemic lupus, multiple sclerosis and other serious diseases. Yet the FDA and the American Medical Association, or AMA, have argued for the safe use of aspartame for most of the population.
Research in 1996 and 2005 linked aspartame to lymphoma, leukemia and brain cancer. These early studies prompted researchers from the National Cancer Institute, or NCI, to conduct an extensive study of about 500,000 participants who were regular consumers of diet drinks sweetened with aspartame. NCI published its research in 2006, in which it concluded that increasing consumption of aspartame did not significantly increase the incidence of the three cancers.
Diet Coke Ingredients
The ingredients listed on a Diet Coca-Cola bottle are carbonated water, caramel color, aspartame, phosphoric acid, potassium benzoate, natural flavors, citric acid and caffeine. The label also displays a warning: "PHENYLKETONURICS-CONTAINS PHENYLALANINE."
Phenylalanine
The University of Maryland Medical Center, or UMMC, describes phenylalanine as an essential amino acid that helps to build protein in the body. Phenylalanine is not produced by your body; you must ingest it. Phenylalanine is converted into a different amino acid called tyrosine, which is involved in the production of the brain chemicals that regulate your mood and memory.
Some people are born without a necessary enzyme that helps the body utilize phenylalanine. These individuals have phenylketonuria--PKU. In the United States, newborns are tested and treated for PKU to prevent severe intellectual disability. If you have PKU, you cannot eat or drink anything containing phenylalanine---hence, the strict warning on the Diet Coke label.
Phenylalanine Benefits
One form of phenylalanine, D-phenylalanine, is purported to ease chronic pain. However, research studying this effect has been unreliable or non-conclusive. Phenylalanine has been tested on animals with Parkinson's disease, so it may be beneficial to humans who have the disease. There is some evidence that phenylalanine may enhance the skin-darkening effects of ultraviolet light treatment for vitiligo, a condition that causes loss of skin pigmentation. The University of Maryland Medical Center's website points out another benefit to individuals suffering from depression: Phenylalanine is believed to increase production of dopamine and norepinephrine--two brain chemicals that elevate mood.
Aspartame and Pain
Conflicting reports have emerged linking pain to ingestion of products containing aspartame. In a November 2010 research letter to the "Journal of Pharmacology and Pharmacotherapeutics," Sapna Pradhan and associates noted that scientific issues regarding aspartame have continued to be raised, despite its FDA approval, "largely as a concern for theoretic toxicity from its metabolic components the amino acids, aspartate and phenylalanine and methanol even though dietary exposure to these components is much greater than from aspartame."
Pradhan and associates cited an earlier observational study by X-ray crystallographer Allen Edmundson, in which the researcher experienced a reduction of his own osteoarthritis pain after ingesting several Diet Cokes. Edmunson's study was published in Clinical Pharmacology and Therapeutics in 1998.
Pradhan and her colleagues conducted their own study of aspartame's effect on laboratory rats with clinically induced soft tissue inflammation and arthritis. Administration of aspartame showed anti-inflammatory potential in rats with two different experimental models of soft tissue inflammation, but failed to show a significant positive impact on rats with arthritis.
References
- "Journal of Pharmacology and Pharmacotherapeutics": "Aspartame--Sweetener with anti-inflammatory potential?"
- National Cancer Institute: Asparatame and Cancer
- University of Maryland Medical Center: Phenylalanine
- University of South Carolina: "Sugar Substitutes: Americans Opt for Sweetness and Lite"; J. Henkel; 1999
- PubMed.gov: "Treatment of osteoarthritis with aspartame"; A.B. Edmundson; 1998.
