Select Committee on GRAS Substances (SCOGS) Opinion: Erythorbic acid (D-isoascorbic acid)
The GRAS Substances (SCOGS) Database allows access to opinions and conclusions from 115 SCOGS reports published between 1972-1980 on the safety of over 370 Generally Recognized As Safe (GRAS) food substances. The GRAS ingredient reviews were conducted by the Select Committee in response to a 1969 White House directive by President Richard M. Nixon.
Erythorbic acid (D-isoascorbic acid)
- SCOGS-Report Number: 59*
- Type Of Conclusion: 1
- ID Code: 89-65-6
- Year: 1979
- 21 CFR Section: 182.3041
L-ascorbic acid, vitamin C, occurs in nutritionally significant amounts as a natural constituent of many fruits, vegetables, berries, and melons. As a vitamin it is needed in the diet of all age groups. L-ascorbic acid and its sodium salt are antioxidants and they are extensively used as preservatives, color stabilizers and for related functions in various foods and beverages. Calcium ascorbate and ascorbyl palmitate, a derivative of ascorbic acid having greater fat solubility, also are anti-oxidants, but appear not to have significant use in processed foods.
In addition to their use in foods as antioxidants, L-ascorbic acid and its salts are added to some foods as a source of vitamin C. These sources constitute a significant proportion of the total ascorbate intake of the general population.
Erythorbic acid (D-isoascorbic acid), a stereoisomer of L-ascorbic acid, and its sodium salt, also are effective antioxidants and are used for this purpose in a number of food products. The quantities used in 1970 were substantially less than for the ascorbates. The vitamin activity of erythorbates is only one -twentieth that of ascorbic acid, and their anti-oxidant effectiveness is not greater than for the ascorbates. For this reason, it would seem desirable, where possible, to use L-ascorbic acid rather than erythorbic acid as an antioxidant.
From studies in guinea pigs and man it can be concluded that although erythorbic acid shares the same absorption and tissue uptake system as ascorbic acid it has little antiscorbutic activity. Although competition between ascorbic acid and erythorbic acid has been demonstrated at a biochemical level, there is no firm evidence that such competition will produce a scorbutic state. Whether this biochemical interaction could result in a clinically significant depletion of ascorbic acid remains to be established.
Both short- and long-term toxicity studies have demonstrated tolerance without adverse effects for large amounts of orally administered L-ascorbic acid, sodium L-ascorbate, and erythorbic acid in several species including mice, rats, guinea pigs, rabbits, and dogs.
A substantial number of short-term experiments with human subjects ingesting 1 to 4 g of ascorbate daily have generally not revealed any harmful effects. Some subjects have received higher amounts, up to at least 8 to 10 g per day. In most instances no untoward results have been noted. But there is marked paucity of such studies that were well controlled and in which inquiring attention was given to possible harmful effects. In due course, such studies would be desirable.
In the various studies on the effect of ingesting excessive amounts of ascorbates, attention has been focused on questions including oxalate excretion and renal tract stones, effects on the utilization of copper, iron, and other metals, need for vitamin B12, blood coagulation, and reproductive performance. The findings indicate that the tolerance to excessive amounts of ascorbic acid and its sodium salt is high. Several investigators have reported the development of dependency in animals and human after ingestion of large amounts of ascorbates for extended time periods; however, the levels of ascorbates added to foods by 1 to 3 orders of magnitude.
It is notable that no data have been found concerning the possible effects of ascorbyl palmitate and calcium ascorbate in humans, and there is practically no information regarding the latter in animals. Information concerning ascorbyl palmitate in animals is almost as limited. The few meaningful experiments suggest that ascorbyl palmitate is tolerated about the same as ascorbic acid and sodium ascorbate. This should be expected. It is reasonable to assume that the tolerance to calcium ascorbate is approximately the same as for sodium ascorbate and this is a high level.
In view of the foregoing, The Select Committee concludes that:
There is no evidence in the available information on L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, ascorbyl palmitate (palmitoyl L-ascorbic), erythorbic acid (D-isoascorbic acid), and sodium erythorbate (sodium D-isoascorbate) that demonstrates, or suggests reasonable grounds to suspect, a hazard to the public when they are used as food ingredients at levels that are now current or that might reasonably be expected in the future.
*Complete reports containing details of the safety studies that formed the basis of the opinions and conclusions and are available from the National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 22161 (703) 605-6000.