Effect of L-carnitine Supplementation on Nutritional Status and Physical Performance Under Calorie Restriction

Abstract

L-carnitine is popular as a potential ergogenic aid because of its role in the conversion of fat into energy. The present study was undertaken to investigate the effect of short term supplementation of L-carnitine on metabolic markers and physical efficiency tests under short term calorie restriction. Male albino rats were divided into four groups (n = 12 in each)-control, calorie restricted (CR for 5 days, 25 % of basal food intake), L-carnitine supplemented (CAR, given orally for 5 days at a dose of 100 mg/kg), CR with L-carnitine supplementation (CR ? CAR). Food intake and body weight of the rats were measured along with biochemical variables like blood glucose, tissue glycogen, plasma and muscle protein and enzymatic activities of CPT-1 (carnitine palmitoyl transferase-1) and AMP kinase. Results demonstrated that Lcarnitine caused marked increase in muscle glycogen, plasma protein, CPT-1 activity and swim time of rats (P \ 0.05) on short term supplementation. In addition to the substantive effects caused by CR alone, L-carnitine under CR significantly affected muscle glycogen, plasma protein, CPT-1 activity and AMP kinase (P \ 0.05). Short term CR along with L-carnitine also resulted in increased swim time of rats than control, CR and L-carnitine treated rats (P \ 0.05). The present study was an attempt towards developing an approach for better adherence to dietary restriction regimen, with the use of L-carnitine.

Effect of L-carnitine and Hoodia gordonii Supplementation on Metabolic Markers and Physical Performance under Short Term Calorie Restriction in Rats

“…The significantly reduced AMPK activity of the treated group vscontrol (p<0.05) could be due to these reasons. Calorie restriction is known to increase the levels of plasma proteins 43 , an effect which was not observed here 14,19 (Table 2).…”

“…Previous studies from our laboratory have already shown that supplementation with L-carnitine and H. gordonii increases CPT-1 activity under CR 14,19 . The activity of CPT-1 in treated rats was significantly (p<0.05) higher than that of control rats (Table 2), thus emphasizing the role of L-carnitine and dietary energy restriction in fatty acid oxidation.…”

“…The role of L-carnitine in glucose oxidation remains controversial. However, our previous studies show that both L-carnitine 19 and H. gordonii 14 lower the blood glucose levels when supplemented during CR. Besides, experimental evidence suggests that there are specific neuronal cell types in the arcuate nucleus that sense the availability of peripheral nutrients, fatty acids and in turn suppress endogenous glucose production 34,35 .…”

“…Previous studies have shown that calorie restriction does not deteriorate work efficiency [63][64][65] and modest energy restriction (upto 20 per cent of intake) for a period of 2 weeks has shown not to impair performance 66 . L-carnitine under short term CR improves swim time of rats 19 . Tulp 9 , et al has reported the use of H. gordonii in improving endurance by the San people of South Africa.…”

“…The crude extract of H. gordonii was administered at a dose of 100 mg/kg body weight (minimum dose effective for causing a reduction in food intake was selected after a dose response study) 13 . L-carnitine was administered 2 h after H. gordonii was given to the rats at a dose of 100 mg/kg body weight 19 . The control rats were given equal amount of water using feeding needle along with food and water that was available ad libitum for 6 hours and left over food was weighed.…”