Occurrence of dermatitis in rats fed a cholesterol diet containing field horsetail (Equisetum arvense L.).

The effects of dietary field horsetail (Equisetum arvense L.) powder on lipid components were studied in rats fed a 20% casein diet with or without cholesterol (0.5% cholesterol and 0.15% sodium cholate) for 14 days. The ingestion of 0.4% or 4% Equisetum arvense L. powder did not influence food intake or growth. However, a cholesterol diet with Equisetum arvense L. at 4% caused dermatitis at the neck, head and back in about 20-65% of the rats. This dermatitis was reversed when the diet was changed to commercial pellets. There were no apparent effects on serum or liver lipids in the rats fed Equisetum arvense L. irrespective of dietary cholesterol. Serum IgE levels measured by enzyme-linked immunoassay revealed that the induction of IgE may not necessarily be involved in the dermatitis caused by the intake of Equisetum arvense L. These results suggest that the ingestion of large amounts of Equisetum arvense L. as cooking material is not recommended for those with a cholesterol-rich diet.