A new study says that the popular sweetener Sucralose - known to most by its commercial name Splenda - caused cancerous tumors and leukemia in mice. The maker of the zero-calorie sweetener used in more than 4,500 foods and beverages is denying the claim.

Splenda's maker Heartland Products says the study is unreliable and doesn't conform to international standards.

Researchers from the independent Ramazzini Institute in Italy gave 457 male mice, along with 396 female mice, different levels of sucralose in their food from 12 days of gestation until they died.  Necropsies on the rodents showed an overall increased rate of malignant cancer in male mice as Splenda amounts increased in the diets.  The researchers also detected a substantially higher incidence of leukemia in the male rodents whose dose levels of sucralose reached 2,000 to 16,000 ppm.  This refutes earlier research which claimed that sucralose remained biologically inert, studies funded by the food industry.

"More studies are necessary to show the safety of sucralose, including new and more adequate carcinogenic bioassay on rats," they wrote, emphasizing the need for follow-up studies.  The Italian study was printed in the International Journal of Occupational and Environmental Health.

Splenda's website proudly declares that it is readily available in markets all over Australia.  But the US-based Center for Science in the Public Interest, which advocates safe and healthy food, has downgraded sucralose products from"caution" to "avoid" - meaning the CSPI researchers believe that people shouldn't consume it.  And using less of it isn't necessarily a defense, should the Italian research prove true:

"And even if you consume less, that doesn't mean there's no problem," said the CPSI's Lisa Lefferts.  "When something causes cancer at high doses, it generally causes cancer at lower doses, the risk is just smaller."