Ascorbic Acid vs Citric Acid: which is worse?

What is Ascorbic Acid?

Ascorbic acid is the chemical name for vitamin C, an essential water-soluble vitamin found abundantly in fruits and vegetables. As a food additive (E300), it functions as an antioxidant preservative, preventing oxidative browning and rancidity. Commercial ascorbic acid is produced by fermentation of glucose, most commonly from corn.

What is Citric Acid?

Citric acid is a weak organic acid naturally occurring in citrus fruits. Commercial citric acid is produced almost entirely by fermentation of sugar substrates (typically molasses or corn syrup) using the mold Aspergillus niger. It is the most widely used food acidulant and preservative globally, also functioning as a chelating agent and flavor enhancer.

Documented risks

Ascorbic Acid: Generally recognized as safe. Note: when ascorbic acid is combined with sodium benzoate or benzoic acid in acidic beverages, benzene can form — a Class 1 carcinogen. This combination should be avoided in formulations. As a standalone additive, ascorbic acid is not only safe but nutritionally beneficial. Very high supplemental doses (>2 g/day) can cause diarrhea and kidney stone risk in predisposed individuals.

Citric Acid: Generally recognized as safe. Excessive consumption can erode tooth enamel due to its acidic nature — dentists recommend rinsing with water after consuming highly citric drinks. A 2018 report in the journal BMJ Case Reports described a cluster of inflammatory reactions (joint pain, muscle weakness) in individuals who reported reactions specifically to industrially produced citric acid, hypothesizing residual Aspergillus proteins from the fermentation process as a potential cause. This remains a hypothesis without controlled clinical evidence, and regulatory agencies maintain its safety status.