Lactic Acid vs Benzoic 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 Benzoic Acid?

Benzoic acid is a naturally occurring aromatic carboxylic acid found in cranberries, prunes, cinnamon, and many berries. It is used as a preservative against bacteria, yeast, and fungi at pH below 4.5. In the body, benzoic acid is conjugated with glycine to form hippuric acid, which is excreted in urine.

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.

Benzoic Acid: When benzoic acid (or sodium benzoate) is combined with ascorbic acid (vitamin C) in beverages, it can form benzene, a known carcinogen classified as Group 1 by IARC. This reaction is promoted by heat and light. The FDA and EFSA monitor benzene levels in beverages and have set informal guidance limits. A 1999 Lancet publication and the subsequent 2007 'Southampton study' did not directly involve benzoic acid, but sodium benzoate was included in the tested mixture. Some individuals with aspirin sensitivity may react to benzoic acid. The ADI is 5 mg/kg body weight/day.