Diet sodas are probably one of the last products that you'd expect to find a known carcinogen. After all, with sales of diet sodas soaring, how could such products that millions of people consume every day be known to cause cancer? The answer lies with research that has been undertaken regarding aspartame, the chemical used in artificial sweeteners such as Equal and NutraSweet, as well as in most brands of diet soda.
Aspartame: The Breakdown
It's not necessarily what's in aspartame that makes it carcinogenic, it's how the body breaks the chemicals down and the resulting byproducts that are dangerous. Aspartame produces three main byproducts when it is broken down by the body: aspartic acid, phenylalanine and methanol. The first two, aspartic acid and phenylalanine, are usually harmless and are usually broken down further into compounds that your body can easily process. Methanol, however, produces formic acid and formaldehyde, the latter of which is a known carcinogen. So, you won't see formaldehyde in the list of ingredients on your favorite diet beverage, but if you do see aspartame, be aware that your body will naturally produce formaldehyde as a result of consuming this artificial sweetener.
The Dangers of Formaldehyde
Each can of diet soda will produce approximately 20mg of methanol in the body. The methanol, in turn, will produce 6mg of formaldehyde. The EPA recommends a formaldehyde limit of 2mg per day at most. So, if you're drinking just one can, you're already in the danger zone. Research has found that formaldehyde can be dangerous even at very low levels within the body, causing irreparable damage to both the nervous system and the immune system due to prolonged exposure. Formaldehyde can also lead to irreversible genetic damage that can, over time, lead to the onset of cancer.
Since diet soda and aspartame are, in a relative sense, new products, long-term side effects due to consistent human consumption are simply not yet available. A 2007 animal study, though, published in Environmental Health Perspectives tested the long-term results on rats in the laboratory setting. The research found that those rats that were given a higher dosage of aspartame had a higher occurrence rate of lymphoma and leukemia in males and females as well as mammary carcinomas in females during the course of the study. Though these studies are animal-based, they do point to some dire possibilities with regard to long-term use of aspartame and a possible link to an increased risk of cancer.
Many detractors have also pointed out the political and monetary side of this debate as well. Many feel that the FDA, which has approved of aspartame for general use, has been hoodwinked by its manufacturers. After, aspartame was not able to become approved until Donald Rumsfeld became CEO of its manufacturer in the early 1980s. Before that, there had been many impediments to its approval. However, such allegations are only conjecture and have little bearing on the actual health effects of the product.
In the end, the decision in this case falls upon the consumer. After all, the real health effects of aspartame on the human system won't really be revealed until a generation of consumers have been exposed to the product. With all that said: Buyer beware.