But the Food and Drug Administration has said repeatedly, and as recently as last Friday, that aspartame is safe.
On The Early Show Tuesday, medical contributor Dr. Mallika Marshall explained to co-anchor Julie Chen that, "These were researchers in Italy who have believed for some time that aspartame poses an increased risk of cancer."
Marshall said the researchers gave aspartame to pregnant rats, and to the baby rats beginning five weeks after birth.
"After the dose was adjusted for the smaller body weights of the rats," Marshall continued, "(the researchers) say there was a slightly increased risk of cancer among those rats who were given about 40 percent of what the FDA has deemed a maximum accepted daily dose of aspartame. Among those rats who got twice that dose, they say the risk of cancer was significantly higher."
That's a possible source of concern, Marshall pointed out, because aspartame is "all over the place. It's estimated there are 6,000 products worldwide that contain it … from diet sodas to reduced calorie foods, to gum and sugar-free candy. It can even be found in some medications to sweeten the taste to 'help the medicine go down.' so to speak. It's so all around us."
So, how concerned should consumers be?
"There are a couple of things to keep in mind," Marshall responded. "First of all, for the past 25 to 26 years, aspartame has generally been regarded as safe in the United States, based on previous studies that haven't shown a significant link with cancer or any other serious health problems. Also, this study wasn't particularly large, and the data hasn't even been published yet. I think it's going to take some time to tease out this information and try to figure out whether there is a health risk and how that should change how we handle aspartame in our food supply.
"That said, however, parents of children should keep one thing in mind. And that is, if there is a toxic effect of aspartame, and I'm not saying there is, the jury is still out, but if there is, the effects are probably going to be greater, the smaller your body weight, so children would be more susceptible than adults.
"I know we have this growing problem of childhood obesity in this country, and parents are looking for any way to reduce the caloric intake of their kids. But I think we should probably be a little less cavalier about giving our children tons of foods with artificial sweeteners and probably should go back to the basics of milk and water and fruits and vegetables instead of diet soda and reduced calorie foods."
The researchers cautioned that pregnant moms that consumed aspartame appeared to pass on the cancer risk to fetuses, with the vulnerability of fetuses being such that exposure in womb seemed to add to cancer risk later in life. The researchers noted that that parallels the human experience.
Just last Friday, the FDA shot down the conclusion of the same researchers, based on a 2005 study they did, that aspartame raises cancer risks. Previously, the European Food Safety Authority had done the same when it looked at that 2005 study.