Effect of Water Hardness on Acetate Absorption

Purpose: Drinking water plays an important role for health. Several investigators have demonstrated a relation between risk for cardiovascular disease and drinking water hardness. Hard water primarily consists of Ca2+ and Mg2+ metal cations and might affect intestinal absorption of some nutrients. The aim of this study is to compare the solvent effect of hard water on absorption and metabolism of acetate using breath test in rats. Methods: Twenty female rats of the F344 strain aged 12 weeks were used. After 24-hr fasting, rats are orally administrated 1 cc of water containing sodium 13C-acetate (100 mg/kg) and housed in an animal chamber. Five kinds of water with hardness of 8, 20, 50, 300, and 1550 mg/L, were used as solvent of 13C-acetate. The expired air in the chamber is collected in a breath-sampling bag using a tube and aspiration pump. The 13CO2 concentration is measured using an infrared spectrometer at 10-min interval for 120 min and expressed as delta per mil. Results: The differences between 13C-acetate dissolved in each water were shown in Figure. The vertical line represents the 13CO2 value after ingestion of 13C-acetate dissolved water. In general, hard water with hardness more than 300 mg/L reduced 13CO2 excretion in the first 50 min, compared to soft water with hardness less than 100 mg/L. The peak time of 13CO2 excretion (Tmax) is 30 min and shorter in water with hardness of 8 and 20. The peak value of 13CO2 excretion (Cmax) reached a maximum of 1603 ± 48‰ using soft water with hardness of 8, followed by using water with hardness of 50, 20, 1555, and 300. This suggests that absorption and metabolism of acetate may be influenced by water hardness. Conclusion: Although it is known that dietary restriction and increased physical activity can lead to weight loss and prevent the risk for metabolic syndrome, such lifestyle changes may be difficult to implement and maintain. Hard water that effect absorption and metabolism of acetate may be helpful adjuncts to a dietary approach to body weight control.