Erythorbic acid

Erythorbic acid, also known as isoascorbic acid, is a stereoisomer of ascorbic acid (vitamin C). Although structurally similar to vitamin C, it has minimal vitamin C activity in the body. It is used as an antioxidant in processed meats, canned fish, frozen vegetables, and fruit-based products to prevent discolouration and oxidative degradation — largely the same functional role as vitamin C but at lower cost.

JECFA's ADI for erythorbic acid is "not specified," last reviewed in 1990. The compound is metabolised similarly to ascorbic acid and excreted renally when present in excess. No adverse effects have been identified at any realistic dietary intake level, and there is no evidence of toxicity in human studies. Its safety profile closely mirrors that of vitamin C, despite lacking its vitamin activity.

Erythorbic acid is permitted in the EU, US (GRAS), UK, and most global markets. It is widely used in the cured meat industry and is common in processed ham, hot dogs, sausages, and canned goods. Consumers tracking vitamin C intake should note that erythorbic acid does not contribute to vitamin C status, despite being structurally related. For the general population, it is a safe and well-established antioxidant with no known adverse effects at normal exposure levels.