This opinion concerns the only GRAS use of nickel, that as a catalyst in the hydrogenation of edible oils and fats. According to industry, a residue of 0.1 to 1.5 ppm nickel may be present in the hydrogenated oils. There are few data on the amount of nickel actually consumed by humans from this sources, but at the average level of 0.55ppm reported by industry in 1975 it can be estimated that the per capita intake from the residual in hydrogenated oils was about 30 mg. This amount is about an order of magnitude lower than that ingested in the diet from natural sources, which is estimated at 300 to 600mg per day.
Most of the nickel ingested is excreted in the feces; a small proportion is absorbed and excreted in urine and sweat. Nickel and nickel salts when administered orally to various species of animals have relatively low toxicities. Granulocytic hyperplasia of the bone marrow was observed in dogs fed high levels (60mg per kg body weight) of nickel as the sulfate but carcinogenicity has not been reported for nickel and nickel salts administered orally to experimental animals; however, tumors have resulted following parenteral administration. Adverse effects on reproductive performance have been reported in mice fed nickel acetate; daily intake was estimated to be 335mg per kg body weight. Daily ingestion of 9.4 mg nickel as nickel sulfate per kg body weight, has caused infertility in rats. However, no effect on the reproductive performance of rats resulted from feeding up to 100mg per kg body weight of catalytic nickel power. The existence of nickel dermatitis from occupational contract with nickel or nickel salts as well as in the general population is recognized. No data are available indicating the occurence of allergic reactions to the oral ingestion of nickel and nickel salts.
Based on these considerations, the Select Committee concludes that: There is no evidence in the available information on elemental nickel that demonstrates, or suggests reasonable grounds to suspect, a hazard to the public when it is used at levels that are now current and in the manner now practiced or that might reasonably be expected in the future.