The lead study author from Brigham and Women's Hospital in Boston explained her findings in an interview with NBC's Robert Bazell.
"We found an increased risk of non-Hodgkin lymphomas and multiple myeloma," says Dr. Eva Schernhammer.
But her study, published in the American Journal of Clinical Nutrition, fell flat with outside experts.
"The study itself is not done well, the findings are not reliable," says the Cleveland Clinic's Dr. Steven Nissen.
Aspartame is found in diet sodas and thousands of other products.
The genesis for the new study was an earlier one in rats fed aspartame.
That study linked the rats' artificially sweetened diet to leukemia.
The current study combined data from two large observational studies of humans.
Although a release to the media called out aspartame in diet sodas, the association was also found with regular soda.
Brigham and Women's Hospital released a statement calling the study "weak" after a further review.
"We are in the position of promoting public health and so we put out bad science, we're actually harming the public's understanding of what they need to know and that's not a responsible thing to do," Dr. Nissen says.
Aspartame has been in diet sodas since the 1980s and was approved as a general purpose sweetener in 1996.
The Food and Drug Administration says its approval was based on more than 100 studies.
A statement from the FDA reads, "Although this study raises issues that need to be further investigated, FDA finds no reason to alter its previous conclusion about the safety of aspartame."
The American Beverage Association also weighed in on the study, pointing out that aspartame has been proven as a safe alternative to sugar.
FULL STATEMENT FROM THE FOOD AND DRUG ADMINISTRATION:
"FDA approved the use of aspartame for limited food uses in 1981 and as a general-purpose sweetener in 1996. FDA's conclusions about the safety of aspartame are based on a detailed review of a large body of evidence, including more than 100 toxicological and clinical studies. We continue to monitor research findings that concern the safe use of additives in food and evaluate new reports to interpret any findings that bear on the safe use of an additive. Although this study raises issues that need to be further investigated, FDA finds no reason to alter its previous conclusion about the safety of aspartame as a general purpose sweetener in food."
FULL STATEMENT FROM BRIGHAM AND WOMEN'S HOSPITAL'S SENIOR VP OF COMMUNICATION AND PUBLIC AFFAIRS:
"It has come to our attention that the scientific leaders at Brigham and Women's Hospital did not have an opportunity, prior to today, to review the findings of the paper entitled "Consumption of Artificial Sweetener and Sugar Containing Soda and the Risk of Lymphoma and Leukemia in Men and Women," to be published in today's Journal of Clinical Nutrition. Upon review of the findings, the consensus of our scientific leaders is that the data is weak, and that BWH Media Relations was premature in the promotion of this work. We apologize for the time you have invested in this story."
FULL STATEMENT FROM THE AMERICAN BEVERAGE ASSOCIATION:
In response to "Consumption of Artificial Sweetener and Sugar Containing Soda and the Risk of Lymphoma and Leukemia in Men and Women," a study published today in the American Journal of Clinical Nutrition, the American Beverage Association issued the following statement:
"The authors said it best: their study has 'limited application' and their findings may be 'due entirely to chance.' We agree.
The fact is: Aspartame, which is an ingredient found in many beverages as well as thousands of foods, has been deemed safe for decades by the world's leading toxicologists, as well as the National Cancer Institute and other regulatory agencies and public health experts around the world. Let's stick to the facts."
Additional Background Information:
The bottom line is that consumers should have complete confidence in aspartame based on the findings of the vast body of available studies, conducted by some of the world's leading toxicologists.
Aspartame is one of the most thoroughly tested ingredients of all time with more than 200 scientific studies confirming its safety.
It has been repeatedly reviewed and approved by regulatory agencies around the globe, including the U.S. Food and Drug Administration, the British Food Standards Agency, the European Union Scientific Committee on Food, and the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives.
Quite simply, aspartame is a safe ingredient for human consumption that provides an effective way to reduce caloric intake without sacrificing taste and helps consumers maintain a healthy weight, a position supported by the American Dietetic Association. The only exception is that people born with phenylketonuria (PKU) cannot metabolize phenylalanine and therefore should avoid aspartame from any source.
There is no credible evidence linking aspartame consumption in beverages to cancers of any kind.
In 2006, the National Cancer Institute published a long-term study of almost 500,000 people that showed no link between aspartame consumption in beverages and cancer.
In 2007, an expert panel of some of the world's leading toxicologists looked at more than 500 studies, articles and reports on aspartame's health effects spanning the last 25 years. The renowned experts found "no credible evidence" that aspartame is carcinogenic, neurotoxic or has any adverse health effect, even when consumed in amounts greater than the established average daily intake (ADI).
The authors note that there are limitations to their paper, including self-reporting and imperfect assessment of aspartame intake.
Importantly, the authors also reference previous work by the European Ramazzini Foundation, whose findings are controversial and not based in sound science. In fact, the laboratory practices, animal health conditions, methods and conclusions of previous studies from this same group of researchers have been questioned by respected scientific and regulatory organizations, including the United Kingdom's Food Standards Agency, the European Food Safety Authority and the U.S. Food and Drug Administration. Furthermore, they have consistently failed to provide all of their data on their previous studies to the U.S. Food and Drug Administration or other independent bodies for review.
It is important to note that the author's own conclusions that, because of the differences observed in the study outcomes, the findings might be due entirely to chance and not real associations.
According to the Mayo Clinic, "scientists don't understand the exact causes of leukemia." In fact, the Mayo Clinic website notes that it "seems to develop from a combination of genetic and environmental factors."
Nowhere is consumption of sweeteners listed as a risk factor.
The National Cancer Institute does not list consumption of sweeteners among the risk factors.
However, according to the Mayo Clinic, a factor that may increase risk is older age. Importantly, the study participants were tracked over 22 years.
The body of available science has not shown that sugar intake causes adverse health effects in humans.
Glucose, a simple sugar and part of the ingredient sugar (sucrose), is the essential fuel source for every cell in the human body. Without an adequate supply of glucose, whether taken directly from the diet or produced by one's body, life is not possible."