Effects of agave nectar versus sucrose on weight gain, adiposity, blood glucose, insulin, and lipid responses in mice.

Agave nectar is a fructose-rich liquid sweetener derived from a plant, and is often promoted as a low glycemic alternative to refined sugar. However, little scientific research has been conducted in animals or humans to determine its metabolic and/or health effects. The aim of this study was to explore the influence of agave nectar versus sucrose on weight gain, adiposity, fasting plasma blood glucose, insulin, and lipid levels. Eighteen (n=18) male ICR mice (33.8±1.6 g) were divided into two groups (n=6 for agave nectar and n=12 for sucrose) and provided free access to one of two diets of equal energy densities differing only in a portion of the carbohydrate provided. Diets contained 20% carbohydrate (by weight of total diet) from either raw agave nectar or sucrose. Epididymal fat pads were excised, and blood was collected after 34 days. Weight gain (4.3±2.2 vs. 8.4±3.4 g), fat pad weights (0.95±0.54 vs. 1.75±0.66 g), plasma glucose (77.8±12.2 vs. 111.0±27.9 mg/dL), and insulin (0.61±0.29 vs. 1.46±0.81 ng/mL) were significantly lower (P≤.05) for agave nectar-fed mice compared to sucrose-fed mice respectively. No statistically significant differences in total cholesterol or triglycerides were detected. These results suggest that in comparison to sucrose, agave nectar may have a positive influence on weight gain and glucose control. However, more research with a larger sample of animals and/or with human subjects is warranted.

Effect of air temperature on the rectal temperature gradient at rest and during exercise.

The purpose of the current study was to determine the effect of air temperature on the rectal temperature gradient at rest and during exercise. It was hypothesized that the rectal temperature gradient would be exacerbated in cold environments and attenuated in warm environments both at rest and during exercise. Each subject completed three exercise bouts on a motor driven treadmill at approximately 55% of their previously determined maximal oxygen uptake. Three different air temperatures (10, 22, 39°C) were used for the exercise bouts. Rectal temperature was measured at rest and every 5 min during each exercise bout using 4 temperature sensors affixed at 4, 7, 10 and 13 cm past the anal sphincter. Readings obtained from the 4-cm depth were significantly (p<0.05) lower than those obtained at deeper insertion depths both at rest and during exercise for all three air temperatures. Furthermore, the results showed that the rectal temperature gradient was exacerbated in cold environments and attenuated in warm environments both at rest and during exercise.