For those unawares, aspartame has long been listed as safe to consume by WHO since 1981.
However, in recent years, the ingredient has been a cause for concern after research proved that people who consumed large amounts of products containing aspartame were at a slightly higher risk of cancer.
"There have been reports about aspartame in animals being linked to cancer, although some have criticised this work," Aston University Nutritionist Dr. Duane Mellor told The Sun.
"It has been associated with increased risk of some cancers in population studies."
"This seems to be linked to the methanol - which also exists naturally in fruits - which is released when it is broken down, as the other two products of its breakdown are amino acids naturally found in meat, dairy, and other sources of protein."
"For it to be classed as a possible carcinogen by IARC, it has to have sufficient evidence in experimental animals but not necessarily data in humans."
Some experts have criticised WHO's findings, claiming that the long-used sweetener is "safe."
"Aspartame has proven to be a safe tool to reduce calories and sugars in the diet and is one of the most extensively studied ingredients with over 40 years of high-quality science supporting its safety, Dr. John Sievenpiper, of the Department of Medicine at the University of Toronto also told The Sun.
The Secretary-General of the International Sweeteners Association, Frances-Hunt Wood echoed these sentiments.
"Aspartame is one of the most thoroughly researched ingredients in history, with over 90 food safety agencies across the globe declaring it is safe, including the European Food Safety Authority, which conducted the most comprehensive safety evaluation of aspartame to date," he said.
Despite the findings, WHO has reaffirmed that it is safe for a person to consume the previously established daily intake of aspartame per day.
"For example, with a can of diet soft drink containing 200 or 300mg of aspartame, an adult weighing 70kg would need to consume more than 9 - 14 cans per day to exceed the acceptable daily intake, assuming no other intake from other food sources," the report said.
Additional research into the potential association between aspartame exposure and higher cancer risk is expected to continue.