NARINGIN DOES NOT ALTER CAFFEINE PHARMACOKINETICS, ENERGY EXPENDITURE, OR CARDIOVASCULAR HAEMODYNAMICS IN HUMANS FOLLOWING CAFFEINE CONSUMPTION
Article first published online: 16 MAR 2006
Clinical and Experimental Pharmacology and Physiology
Volume 33, Issue 4, pages 310–314, April 2006
How to Cite
Ballard, T. L., Halaweish, F. T., Stevermer, C. L., Agrawal, P. and Vukovich, M. D. (2006), NARINGIN DOES NOT ALTER CAFFEINE PHARMACOKINETICS, ENERGY EXPENDITURE, OR CARDIOVASCULAR HAEMODYNAMICS IN HUMANS FOLLOWING CAFFEINE CONSUMPTION. Clinical and Experimental Pharmacology and Physiology, 33: 310–314. doi: 10.1111/j.1440-1681.2006.04367.x
- Issue published online: 16 MAR 2006
- Article first published online: 16 MAR 2006
- Received 27 June 2005; revision 7 September 2005; accepted 6 November 2005.
- energy expenditure;
- food–drug interaction;
- grapefruit juice;
- 1Naringin, a grapefruit constituent interacts with many medications including caffeine, a popular weight loss supplement. The purpose of the current study was to identify changes in caffeine pharmacokinetics, resting energy expenditure (REE), oxygen consumption (VO2) and respiratory exchange ratio (RER) after an acute dosage of caffeine and naringin.
- 2Using a double-blinded, counterbalanced design, REE, VO2, and RER were measured before and systematically for 8 h after a single dosage of caffeine (CAF, 200 mg) with and without naringin (100 mg (CN100) or 200 mg (CN200)) in 10 apparently healthy individuals. A standardized meal was provided following 240-minute measurements (400 kcals; 35 g carbohydrate; 27 g protein; 7 g fat).
- 3Caffeine, CN100, CN200 did not alter VO2 or VO2 area under the curve (137 301 ± 8318, 139 729 ± 9300, 134 297 ± 8318, mL/480 min). Resting energy expenditure (k/cals) was 10.0 ± 1.4% higher with CAF versus CN200 (6.0 ± 1.4%) and CN100 (6 ± 1.5%) at 240 min (P = 0.07) which was then negated following a standardized meal. Percent change in RER from pre to 240 min and pre to 480 min was not different between the CAF, CN100, or CN200 (–0.2 ± 1.7%, 1.7 ± 1.7%, –2.8 ± 1.9%).
- 4Although caffeine alone suggests a trend of increased REE, the results of the present study indicate that concurrent consumption of caffeine with naringin in acute dosages does not affect RER, VO2, and prevents the increase of REE in adult humans. The results suggest that the interaction of grapefruit juice and caffeine may be due to constituents of grapefruit juice other than naringin or in addition to naringin.