Diet Sodas usually contain aspartame which produces formaldehyde as you digest it--more than the legal limit.

Aspartame—just the amount in one can of diet soda—produces an excessive amount of the carcinogen formaldehyde in your body. Aspartame is the chemical in Equal® and NutraSweet® and is the sweetener in most diet sodas. Formaldehyde isn’t listed in the ingredients; your body produces it as you digest the soda.

When you drink a diet soda, your body breaks down the aspartame into aspartic acid, phenylalanine, and methanol, one molecule of each.

• aspartic acid is harmless; it’s broken down into alanine, an amino acid, and oxaloacetate, an organic compound
• phenylalanine, an allergen to some people, is broken down into mostly tyrosine, an amino acid, and to a lesser extent into phenylethylamine, an alkaloid, and phenylpyruvate.
• methanol (wood alcohol) is broken down into formic acid (the toxin in ant bites) and formaldehyde which is a carcinogen.

Each diet soda with aspartame produces about 20 mg of methanol. The methanol breaks down further into 6 mg of formaldehyde which is three times the daily EPA limit. It’s 30 times the limit in New Jersey, 100 times the limit in California, and 300 times the limit in Maryland.

The formaldehyde from each can of diet soda is more than the legal limit of this dangerous chemical.

Dr. Devra Davis, the director of the Center for Environmental Oncology at the University of Pittsburgh Cancer Institute, says that all scientific evidence about aspartame has been negative for human health, and it wasn’t until Donald Rumsfeld left government and became the CEO of G.D. Searle, the manufacturer, that the government approved aspartame for use in human food and drinks.

Interviewed by the Pittsburgh Post Gazette, when asked about Donald Rumsfeld’s connection to the aspartame approval, Dr. Davis stated:

“I don't know what his precise role was. I only know that prior to his becoming CEO of Searle, aspartame had been turned down by every scientific group reviewing its safety and that the General Counsel of the FDA asked the U.S. Attorney's office to convene a grand jury to decide whether to indict the producer for knowingly misrepresenting findings... The grand jury never acted. Those working on this for the government went to work for Searle. The day after Reagan's inauguration, the company resubmitted a request for approval. Within five months of Reagan's presidency, aspartame was approved.”

In her new book, The Secret History of the War on Cancer, Dr. Davis describes the manipulation of the US government by the chemical industry—not only with respect to aspartame but many other chemicals that touch the daily lives of the citizens.

Formaldehyde isn’t the only nasty chemical in diet soda. Don’t drink your diet soda if it has been warmed by the sun for a while. According to a 2006 article in the Albuquerque Journal, the heat and light cause the ascorbic acid and the benzoate preservatives in soda to form benzene, another carcinogen that produces leukemia and other blood diseases.

For more information on preventing cancer, see The Center for Environmental Oncology or the Environmental Working Group.

Resources:

1. Jadrnak, J., “Group Challenges Soft Drink Contents,” Albuquerque Journal, April 11, 2006.
2. “Dr. Devra Davis chat transcript” downloaded Oct. 13, 2007 from http://www.post-gazette.com/pg/07284/824678-114.stm, Pittsburgh Post-Gazette, October 11, 2007.