HERBAL DIURETIC INDUCED DEHYDRATION AND RESTING METABOLIC RATE

Abstract

Research on factors influencing resting metabolism has focused primarily upon the effects of diet and/or exercise on resting metabolic rate (RMR). Food restriction has been shown to reduce RMR. Dieters often restrict fluid along with calories. There has been little research on the effects of fluid restriction and dehydration on metabolism. We previously reported that acute dehydration resulting from a prescription diuretic or exercise/sweating (Woodland et al. MSSE, 28:S43, 1996 and Leniszewski et al., MSSE, 32:S238, 2000) was associated with a small but negative relationship between dehydration and RMR. Since dieters often use over the counter diuretics in weight loss attempts, we decided to investigate the acute effects of two herbal diuretics and the resulting hypohydration on RMR. We compared the RMR of 14 healthy female subjects in 2 hypohydrated and 2 euhydrated conditions. The study lasted four days in which two herbal diuretic treatments were administered randomly with a 1 day washout/control day between each treatment. The two diuretics used were typical of dietary supplements containing diuretic ingredients. One contained pamabrom, and the other a dandelion/horsetail extract. Although the degree of hypohydration achieved from a one day regimen of both diuretics was small (0.36 ± 0.61% for pamabrom containing and 0.34 ± 0.82% for the dandelion/horsetail) a small but not statistically significant decrease was observed between the control RMR (1302 kcals) and treatment RMR (pamabrom 1257 kcals and dandelion/horsetail 1266 kcals). The results of this study indicate that short term usage of over the counter diuretics is associated with a small degree of hypohydration, probably too small to cause a significant reduction in RMR. The possibility remains that chronic use or higher dosage eliciting greater hypohydration might elicit a greater reduction of RMR. Supported by Suntory Water Group International