The North American sweetener industry has rushed to denounce a study linking aspartame with an increased risk of leukemia and lymphoma in rats, fearful that such negative publicity could dent industry growth.
A study presented at the recent Ramazzini Conference in Italy, "Framing the Future in Light of the Past: Living in a Chemical World," suggested that aspartame consumption in rats significantly increased lymphomas and leukemias in female rats.
But the food has now struck back, insisting that implications made by the Italian study are flawed.
The study, published in the European Journal of Oncology, was conducted on 1,800 rats (900 males, 900 females) over 30 years. In order to simulate daily human intake, aspartame was added to the standard rat diet in quantities of 5,000, 2,500, 100, 500, 20, 4, and 0 mg/Kg of body weight, according to the researchers.
However, the aspartame industry argues that the doses tested by the Italians were out of proportion to human consumption levels. Some of the animals, they claim, were given the amount of aspartame equivalent to that found in 2,000 cans of soft drink every day.
"With billions of man-years of safe use, consumers and health professionals can be assured that aspartame is safe for humans," said Beth Hubrich, executive director of the Calorie Control Council.
"And the rigorous scrutiny and battery of studies to which aspartame has been subjected should provide people with additional confidence in its safety."
The aspartame industry has reason to be nervous about such negative publicity. The sweeteners industry looks set to continue to grow on the back of rising health concerns over sugar-rich foods and beverages.
These concerns are driving consumers towards sugar-free products, and food makers are increasingly introducing zero-calorie or low-calorie sugar substitutes into their new product formulations. Market analyst Freedonia predicts that growth of intensity sweeteners at around 8.3 percent year on year until 2008, with sales rising from a small base of $81m in 1998 to $189m in 2008.
It is for this reason that the industry has been so vociferous in denouncing the Ramazzini study. The Calorie Control Council for example contends that the Institute's publication, the European Journal of Oncology, is not included in the MedLine (National Library of Medicine) database, the world's leading source of scientific literature.
"The researchers at Ramazzini have not followed the internationally established protocol for evaluation of animal carcinogenicity study findings," said the organization. The council also noted that the FDA's Cancer Assessment Committee said that some reported data were "unreliable" due to a "lack of critical details… and… questionable histopathological conclusions."
Health Canada has since stated that based on the limited new information available, it is not recommending any dietary changes relating to the use of aspartame.
Aspartame is composed of two amino acids, aspartic acid and phenylalanine, as the methyl ester. Amino acids are the building blocks of protein. Aspartic acid and phenylalanine are found naturally in protein containing foods, including meats, grains and dairy products.
The product is used in over 6,000 food and pharma products, with global demand currently standing at about 16,000 tons. All low-calorie sweeteners, including aspartame, have to be determined as safe by the US Food and Drug Administration.