Interactive effects of caffeine, carnitine, choline and exercise on body fat in rats

We have shown that supplementary choline (Ch) promotes carnitine (Cn) conservation by healthy adults and guinea pig skeletal muscle (J Nutr 125: 1938, 1995; Am J Clin Nutr 63: 904, 1996), which suggests promotion of fat oxidation. A body of equivocal data indicates that supplementary Ch and caffeine (Cf) also promote fat oxidation, but interactive effects of these supplements have not been studied Our objective was to determine effects of a combination of Ch, Cn, and Cf supplementation with (E) or without (NE) exercise on body fat and energy substrate utilization. 20 male S.D. rats (200g bw) were fed for 4 wks, Purina chow nonsupplemented (NS) or supplemented (S) with Ch, Cn and Cf at the rate of 11.5, 0.5 and 0.1 g/ kg chow, respectively. The E groups (one half of each dietary group) were trained on a treadmill (6 days/ wk) reaching a running speed of 18 m/min for 25 min at 15% grade. The VO₂ max was determined on 18th day in a respirometer equipped with treadmill. Blood, 24 h urine and tissues were collected after 21 days of execise. The results show that compared to the NS group the S group had higher VO₂ max, however, the RER and endurance was not significantly different. The body weights of the NSE and SE groups were significantly lower than NE groups. The epididymal, inguinal and perirenal fat pads were significantly smaller in the SE group. The urinary and serum short-chain acylcarnitines were significantly higher in the SE than NSE group. The combination of supplements increased aerobic exercise capacity and reduced body fat by enhanced fatty acid oxidation.