Acesulfame Potassium vs Potassium Sorbate: which is worse?

What is Acesulfame Potassium?

Acesulfame potassium (Ace-K) is a calorie-free synthetic sweetener approximately 200 times sweeter than sucrose. It contains a potassium atom bonded to an oxathiazinone dioxide ring structure. It is heat-stable and non-metabolized, passing through the body unchanged. Often blended with sucralose or aspartame to mask bitter aftertaste.

What is Potassium Sorbate?

Potassium sorbate is the potassium salt of sorbic acid, a naturally occurring short-chain fatty acid originally derived from the mountain ash berry (Sorbus aucuparia). Commercial potassium sorbate is synthetically produced by reacting sorbic acid with potassium hydroxide. It is the most widely used food preservative globally.

Documented risks

Acesulfame Potassium: The safety database for Ace-K is considered less comprehensive than that for other sweeteners. Critics have argued that the original FDA approval studies from the 1970s-1980s were insufficient in quality and length to definitively establish long-term safety. The Center for Science in the Public Interest (CSPI) has petitioned for additional testing. Two rat studies found statistically significant increases in lung tumors (in male rats) and mammary tumors at high doses. Regulatory agencies have argued these doses far exceeded typical human exposure and attributed the tumor findings to other factors. However, the question of whether Ace-K's approval studies meet modern standards has been raised by independent researchers. A 2021 study in Cell found that Ace-K and other non-nutritive sweeteners altered gut microbiome composition and affected glucose tolerance in some human participants. Ace-K specifically was associated with changes in gut bacteria that correlated with glycemic effects. Neurological concerns: some animal studies suggest Ace-K may affect brain neurotransmitter systems. A 2013 study in PLoS ONE found that Ace-K consumption in pregnant mice altered offspring postnatal taste preference and increased weight gain, suggesting potential transgenerational effects. These findings were at doses exceeding typical human intake. Endocrine disruption potential has been raised in some in vitro studies, but comprehensive human data are lacking.

Potassium Sorbate: Potassium sorbate has a generally good safety profile compared to other synthetic preservatives. EFSA's 2015 re-evaluation maintained the ADI at 3 mg/kg body weight, finding no significant carcinogenicity or genotoxicity. However, some human and in vitro studies have documented concerns. A 2010 study in Toxicology in Vitro found potassium sorbate was genotoxic (caused DNA strand breaks) in human blood cells at concentrations achievable in food. The study found it damaged peripheral blood lymphocytes. A 2014 study in Food and Chemical Toxicology found potassium sorbate caused DNA damage in human lymphocytes at food use concentrations. Contact dermatitis and allergic reactions from topical use are documented. At very high doses in animal studies, liver and kidney effects have been observed. The general regulatory consensus is that potassium sorbate is one of the safer food preservatives, but the in vitro genotoxicity findings deserve attention.