Re: Onions & Garlic Toxic to Dogs...

Onions are clearly worse than garlic in terms of risk of thiosulphate toxicity in dogs but garlic does contain this substance. SO rather than believe the unsupported statements I did a MedLine search at the National Library of Medicine to support them; and found the source of the worry about garlic being toxic to dogs. It was based on studies done in Japan, abstracts follow. They are a little technical. What they point out is that yes, there is a [b]potential[/b] to produce a usually fatal condition (hemolytic anemia) in dogs if they ingest quantities of thiosulphate and yes, onions and garlic both contain this substance. Onion dogs became ill, the garlic dogs in these trials did not. BUT....like everything else, just because a little might be good does not mean more is better. More may be worse. So lets not O.D. our dogs on garlic and forget about onions altogether. ?????????????????????????????????? ---------------------------------------------------------- Hematologic changes associated with the appearance of eccentrocytes after intragastric administration of garlic extract to dogs. Lee KW, Yamato O, Tajima M, Kuraoka M, Omae S, Maede Y. Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. OBJECTIVE: To determine whether dogs given garlic extract developed hemolytic anemia and to establish the hematologic characteristics induced experimentally by intragastric administration of garlic extract. ANIMALS: 8 healthy adult mixed-breed dogs. PROCEDURE: 4 dogs were given 1.25 ml of garlic extract/kg of body weight (5 g of whole garlic/kg) intragastrically once a day for 7 days. The remaining 4 control dogs received water instead of garlic extract. Complete blood counts were performed, and methemoglobin and erythrocyte-reduced glutathione concentrations, percentage of erythrocytes with Heinz bodies, and percentage of eccentrocytes were determined before and for 30 days after administration of the first dose of garlic extract. Ultrastructural analysis of eccentrocytes was performed. RESULTS: Compared with initial values, erythrocyte count, Hct, and hemoglobin concentration decreased to a minimum value on days 9 to 11 in dogs given garlic extract. Heinz body formation, an increase in erythrocyte-reduced glutathione concentration, and eccentrocytes were also detected in these dogs. [b]However, no dog developed hemolytic anemia.[/b] CONCLUSIONS AND CLINICAL RELEVANCE: The constituents of garlic have the potential to oxidize erythrocyte membranes and hemoglobin, inducing hemolysis associated with the appearance of eccentrocytes in dogs. Thus, foods containing garlic should not be fed to dogs. Eccentrocytosis appears to be a major diagnostic feature of garlic-induced hemolysis in dogs. ---------------------------------------------------------- Biochim Biophys Acta. 1999 Apr 19;1427(2):175-82. Reduced glutathione accelerates the oxidative damage produced by sodium n-propylthiosulfate, one of the causative agents of onion-induced hemolytic anemia in dogs. Yamato O, Hayashi M, Kasai E, Tajima M, Yamasaki M, Maede Y. Laboratory of Internal Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan. The oxidative effects of sodium n-propylthiosulfate, one of the causative agents of onion-induced hemolytic anemia in dogs, were investigated in vitro using three types of canine erythrocytes, which are differentiated by the concentration of reduced glutathione and the composition of intracellular cations. After incubation with sodium n-propylthiosulfate, the methemoglobin concentration and Heinz body count in all three types of erythrocytes increased and a decrease in the erythrocyte reduced glutathione concentration was then observed. The erythrocytes containing high concentrations of potassium and reduced glutathione (approximately five times the normal values) were more susceptible to oxidative damage by sodium n-propylthiosulfate than were the normal canine erythrocytes. The susceptibility of the erythrocytes containing high potassium and normal reduced glutathione concentrations was intermediate between those of erythrocytes containing high concentrations of potassium and reduced glutathione and normal canine erythrocytes. In addition, the depletion of erythrocyte reduced glutathione by 1-chloro-2, 4-dinitrobenzene resulted in a marked decrease in the oxidative injury induced by sodium n-propylthiosulfate in erythrocytes containing high concentrations of potassium and reduced glutathione. The generation of superoxide in erythrocytes containing high concentrations of potassium and reduced glutathione was 4.1 times higher than that in normal canine erythrocytes when the cells were incubated with sodium n-propylthiosulfate. These observations indicate that erythrocyte reduced glutathione, which is known as an antioxidant, accelerates the oxidative damage produced by sodium n-propylthiosulfate. Tweet