Lactic Acid vs Citric Acid: which is worse?

What is Lactic Acid?

Lactic acid is an organic acid naturally produced during fermentation of carbohydrates by lactic acid bacteria. It gives fermented foods such as yogurt, cheese, and sauerkraut their characteristic tangy flavor. Commercial lactic acid used in food is produced by bacterial fermentation of glucose or lactose, or in some cases by chemical synthesis.

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

Lactic Acid: Lactic acid is a normal byproduct of human metabolism (produced during anaerobic exercise). It is generally recognized as safe at food additive levels. Excessive consumption of foods acidified with lactic acid could theoretically contribute to dental erosion, as with all acidulants. For individuals with rare inborn errors of lactate metabolism, dietary lactic acid may require monitoring.

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.