Monosodium L(+) tartrate toxicity in two year dietary feeding to rats

Re-evaluation of l(+)-tartaric acid (E 334), sodium tartrates (E 335), potassium tartrates (E 336), potassium sodium tartrate (E 337) and calcium tartrate (E 354) as food additives

The EFSA Panel on Food Additives and Flavourings (FAF) provides a scientific opinion on tartaric acid-tartrates (E 334-337, 354) when used as food additives. The Scientific Committee for Food (SCF) in 1990 established an acceptable daily intake (ADI) of 30 mg/kg body weight (bw) per day, for l(+)-tartaric acid and its potassium and sodium salts. The metabolism of l(+)-tartaric acid and its potassium sodium salt was shown to be species dependent, with a greater absorption in rats than in humans. No toxic effects, including nephrotoxicity, were observed in toxicological studies in which the l(+)-form was tested. There was no indication for a genotoxic potential of tartaric acid and its sodium and potassium salts. In a chronic study in rats, no indication for carcinogenicity of monosodium l(+)-tartrate was reported at the highest dose tested (3,100 mg/kg bw per day). The available studies for maternal or developmental toxicity did not report any relevant effects; no studies for reproductive toxicity were available; however, no effects on reproductive organs were observed in the chronic toxicity study. The Panel concluded that the data on systemic availability were robust enough to derive a chemical-specific uncertainty factor instead of the usual default uncertainty factor of 100. A total uncertainty factor of 10 was derived by applying a total interspecies uncertainty factor of 1 instead of 10, based on data showing lower internal exposure in humans compared to rats. The Panel established a group ADI for l(+)-tartaric acid-tartrates (E 334-337 and E 354) of 240 mg/kg bw per day, expressed as tartaric acid, by applying the total uncertainty factor of 10 to the reference point of 3,100 mg sodium tartrate/kg bw per day, approximately to 2,440 mg tartaric acid/kg bw per day. The exposure estimates for the different population groups for the refined non-brand-loyal exposure scenario did not exceed the group ADI of 240 mg/kg bw per day, expressed as tartaric acid. Some recommendations were made by the Panel.

Renal and bone uptake of tartaric acid in rats: comparison of L(+) and DL-Forms

Plasma concentrations of radioactivity declined biphasically with half-lives of about 15 and 58 h respectively in rats dosed with monosodium DL-[14C]tartrate for 7 days at a dose level of 2.73 g/kg/day. Uptake and retention of radioactivity occurred in blood cells, kidneys and bones where it was detected for at least 12 days after dosing. Renal retention (11202 +/- 4469 ppm at 6 h, n = 7) was probably due to precipitation of the poorly soluble calcium DL-tartrate in the tubules leading to increased kidney weight, nephrotoxicity and even death. The more soluble, naturally-occurring L(+)-[14C] tartrate was not retained in the kidneys (1287 +/- 118 ppm at 6 h, n = 8) when administered to rats under the same conditions, and the initial decline of plasma concentrations of radioactivity was more rapid (t 0.5 approx. 3 h). For this reason, monosodium L(+)-tartrate was non-toxic at 2.73 g/kg/day whereas monosodium DL-tartrate was toxic at this dosage.