March 26, 2003

Potato Chips Carcinogenic, Prof Suggests

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A recent discovery may give some dieters an additional reason to avoid carbohydrates. Acrylamide, a potentially carcinogenic chemical, has been found in baked or fried starch-rich foods. For others, perhaps solely health concerns will make people think twice before reaching for the next potato chip.

Last spring, three independent international groups from the U.S., England and Switzerland simultaneously announced the same discovery. While the chemical has long been identified as a possible carcinogen to humans, its high incidence level in these foods had not previously been realized. These teams realized that asparagine, a common amino acid present in cereal and grains, combines with glucose to form a N-glycoside linkage. However, the details of the chemical process that resulted in the formation of acrylamide was not previously well understood.

Prof. Bruce Ganem, chemistry and chemical biology, came up with one possible explanation.

He explained that although “everyone agreed that the N-glycoside needs to lose a molecule of carbon dioxide in order to form acrylamide, it was unclear how that might happen.”

Glycosides are known to undergo the Maillard reaction, a reaction between proteins and carbohydrates that was first described by Louis Maillard in 1912. Therefore, the British and Swiss teams suggested that the Maillard reaction was ultimately responsible for the formation of acrylamide, but they did not offer any chemical details about how this might specifically occur within fried or baked foods.

Prof. Ganem, having long-time interest in carbohydrate research, proposed an alternative to the Maillard reaction.

“What was proposed did not make good chemical sense,” said Ganem, noting that the U.S. researchers had realized “that acrylamide was also formed from a combination of asparagine and 2-deoxyglucose, which is interesting because 2-deoxyglucose lacks a key molecular feature needed for the Maillard reaction.”

Ganem drew on others’ writings and research to write an article suggesting a different pathway for the formation of acrylamide including widely-accepted analogies from closely related ideas to explain that acrylamide could be released from a natural metabolic process, known as enzymatic decarboxylation.

Prof. Ganem maintains that that his proposal was just basic organic chemistry. After he submitted his letter, he presented the same problem to his first and second year graduate students, and one graduate student came up with the same explanation that he had proposed.

Although some scientists were initially skeptical about his explanation, Prof. Ganem asserts that although the reaction pathway he described “probably would not happen under normal biological conditions, it’s important to recognize that we’re talking about temperatures well above 100 degrees Celsius, while the food is being cooked!”

No formal warnings about the dangers of acrylamide in fried and baked carbohydrate-rich foods have been issued, as this discovery is fairly new and is mainly confined within the scientific community.

Myra Berkowitz, nutritionist at Gannett: Cornell University Health Services , said that she hasn’t “received any questions about this topic yet” and that she is not “advising that they make changes based on the data at this point.”

The F.D.A., however, has formed a study group about this issue.

Alex Thompson ’04 said that “this discovery would definitely make me try really hard not to eat those types of foods.”

Prof. Ganem’s explanation will likely help scientists understand how acrylamide is formed, so that they can eventually attempt to decrease its occurrence in fried or baked foods. In the meantime, perhaps people will think a little more before they reach for their next french, or freedom, fry.

Archived article by Yonit Caplow