Does intake of highly demineralized water damage the rat gastrointestinal tract?

Highly demineralized water (hd-water) is used frequently in laboratories and on an industrial scale. However, no systematic data seem available as to whether hd-water has a toxic potential beyond the physical risks of drinking water (drowning, water intoxication). This study investigated the impact of hd-water on function and morphology of the rat's gastrointestinal tract. One group of rats received hd-water together with the usual diet ad libitum for 14 d. A second group was exposed to hd-water after withdrawal of food and water for 24 h. Both experiments had control groups which were treated identically except that hd-water was replaced by tap water. Histology showed no signs of erosion, ulceration or inflammation in the esophagus, stomach or jejunum. Body weights and the uptake of food and water were not significantly different between the hd-water exposures and controls for 14 d. Tissue alkaline phosphatase activity was unaltered, and the mitotic rate in the epithelium of the esophagus and stomach were not different between controls and rats on hd-water. Exposure to hd-water caused no changes in the km or Vmax values for the uptake o of alpha-methyl-D-glucose from the upper jejunum. There findings indicate no impact of hd-water on the function or morphology of the rat gastrointestinal tract. There is no need for additional safety regulations when working with hd-water which go beyond those considered adequate to prevent drowning and water intoxication.