Aspartame is an artificial sweetener that was approved for use in the united states in 1981 by the US Food and Drug Administration (FDA). Aspartame is around 200 times sweeter than sugar and is currently the second most widely used artificial sweetener behind sucralose (Splenda).
Aspartame critics claim that the sweetener causes everything from brain tumors and seizures to leukemia. Fortunately aspartame has been the subject of numerous studies of both humans and animals and has been shown to be safe at levels far beyond the acceptable daily intake (ADI).
The ADI for a product is determined by dividing the highest daily intake of aspartame that has no observable toxicological effects. This amount is determined through animal toxicology studies and is then divided by 100 to determine the ADI.
The ADI for aspartame is 50mg per kg of body weight. This amount of aspartame represents about 15 cans of diet soft drink a day for a 120 pound individual or about 70 table-top packets of sweetener. Studies have found that the average daily consumption of aspartame is just 3-5 percent of the ADI with around 9 in 10 individuals consuming less than ten percent of the ADI.
A few studies have shown a link between aspartame and certain cancers, however this is at aspartame levels equivalent of over 1000 cans of diet soft drink a day. One such study, which is often cited by aspartame critics as evidence of aspartame’s carcinogenic effects is called “First Experimental Demonstration of the Multipotential Carcinogenic Effects of Aspartame Administered in the Feed to Sprague-Dawley Rats.” and is published in the journal Environmental Health Perspectives.
This study involved adding aspartame to the daily feed of mice from the age of 8 weeks for the remainder of the rats lifetimes. The rats received either 4, 20, 100, 500, 2500 or 5,000mg of aspartame per kg of body weight.
Interestingly the control group, which consisted of rats which received no aspartame actually died earlier than most of the groups receiving aspartame. In fact, in the female rats, the control group had the shortest survival time and the group of rats that received the 5,000mg per kg dose of aspartame (equivalent to 1,500 cans of diet soda a day) actually lived the longest of all the groups. At the age of 120 weeks around 29 percent of the rats on the highest aspartame diet were still alive compared to just 16 percent for the control group.
As each rat died, an autopsy was performed to determine the presence of tumors. While at high levels of aspartame, the rats did display a slightly greater likelihood of developing tumors, the researchers failed to take into account the fact that these rats lived significantly longer than the control group of rats and therefore naturally would expect to have a slightly greater rate of tumor development.
The researchers concluded that “Our research shows that [aspartame] is a multi-potential carcinogenic compound whose carcinogenic effects are evident even at a daily dose of 20mg/kg bw, much less than the current ADI for humans in Europe (40mg/kg bw) and in the United States (50mg/kg bw).” This however was not shown in the results, at lower levels of aspartame there was virtually no effect on tumor rates. For example amongst male rats, the number of rats that developed tumors was lower in the 4mg, 20mg and 500mg groups compared to the control group. The control group had a tumor rate of 35.3% compared to 29.3%, 32% and 34% in the 4mg, 20mg and 500mg groups respectively.
The largest study on humans to date was conducted by the National Cancer Institute and was published in April 2006. The study found absolutely no correlation between aspartame use and the rate of leukemias, lymphomas and brain tumors.
With no studies showing adverse effects from aspartame at levels relevant to humans and over 100 studies attesting to the safety of aspartame, even at levels far beyond what could possibly be consumed by humans, people should not be concerned by consuming some aspartame in their diet.