A bottle of Coca-Cola is pictured as people have lunch at a shopping mall in Arlington, Virginia, on February 15, 2011 (AFP)

The World Health Organization published an unsettling study in May, revealing that commonly used non-sugar sweeteners such as aspartame are likely useless for weight loss, and warned that long-term use may raise the risk of diabetes, cardiovascular disease, and death.

The WHO subsequently declared in a second report that aspartame, a main ingredient in Diet Coke, was a "possible carcinogen" in July.

Afterward, the organization issued a third report that contradicts its earlier findings in which it alleged that safe consumption was possible at levels deemed safe decades ago.

A recent investigation by the public health advocacy group US Right-To-Know believes this stems from beverage industry manipulation of the review process by consultants connected to an alleged Coca-Cola front group.

Eight WHO panelists discovered to be involved in determining safe levels of aspartame use are beverage industry consultants who presently or previously worked with the suspected Coke front organization, International Life Sciences Institute (Ilsi).

An obvious conflict of interest

Gary Ruskin, executive director of US Right-To-Know, called their role "an obvious conflict of interest," detailing that their conclusions about aspartame safety are therefore not credible or reliable.

Aspartame is authorized for global use, and major food and beverage firms have defended using it for decades.

Even though the WHO rated aspartame a "possible carcinogenic", its Joint Expert Committee on Food Additives (Jecfa), which establishes consumption guidelines, confirmed the permissible daily intake of 40 mg/kg body weight the same day.

Ilsi advertises itself as a charity that does "science for the public good," yet it was created in 1978 by a Coca-Cola executive who worked for the business until 2021, according to US Right-To-Know. Other Coca-Cola officials have collaborated with the organization, and US Right-To-Know revealed that tax records indicate millions of dollars in donations from Coca-Cola and other beverage industry companies.

Six of the 13 Jefca panel members with links to the industry organization were discovered by US Right-To-Know. Following the publication of its report, the WHO recognized two more of its members as having industry links.

A WHO spokesperson responded to The Guardian and defended the use of industry consultants in the assessment process.

Spokesperson Fadéla Chaib stated that experts were selected by Jefca to "likely to make the best contributions," alleging that conflicts of interest need only be declared within 4 years, according to the WHO's guideline.

“To our knowledge, the experts you listed by name have not participated in any Ilsi activities for at least 10 years,” she retorted.

However, this largely contradicts a statement made by WHO to the French news agency Le Parisien just weeks previously, in which it confirmed that two employees now working with Ilsi were involved in the process. The WHO at the time expressed "regret that this interest was not declared by these two experts, either in the written statement or orally at the opening of the meeting."

The involvement of Ilsi-tied consultants in WHO's assessment process is especially concerning, according to Ruskin, because WHO has "much higher standards" in place to guarantee no conflicts of interest in its operations like using public and peer-reviewed science.

He divulges that many media outlets had covered the WHO's decision regarding aspartame as a split one, without mentioning Ilsi's "fingerprints on the safety assessment,“ a lack of information he believes has so "poorly served the public."

Beverage makers such as Coca-Cola and PepsiCo have in the past modified their ingredient composition several times to comply with evolving food regulations.