Effects of carnitine supplementation on flow-mediated dilation and vascular inflammatory responses to a high-fat meal in healthy young adults.
Because carnitine has been shown to decrease oxidative stress and improve endothelial cell functioning, we examined the effects of carnitine supplementation on postprandial flow-mediated dilation (FMD) and circulating biomarkers of inflammation and oxidative stress after a high-fat meal. A randomized, double-blind, placebo-controlled, crossover study design was used. Thirty men and women (age 30 +/- 8 year, body mass 72.9 +/- 17.1 kg, body fat 13.0 +/- 6.4%) participated in 2 vascular testing days, each preceded by 3 weeks of supplementation with either 2 g/day of L-Carnitine (L-Carnitine L-Tartrate) or placebo with a 3- to 5-week washout period between trials. Brachial artery FMD in response to 5 minutes of upper arm occlusion and circulating markers of oxidative stress and inflammation were measured in the fasting state and after a standardized high-fat meal. After 3 weeks of supplementation, peak FMD in the fasting state was similar between the carnitine and placebo trials, averaging 6.6%. Peak FMD during the postprandial period decreased to 5.8% at 1.5 hours during placebo and increased to 7.7% during the carnitine trial (n = 30: p = 0.043 for supplement by time interaction effect). This improvement in postprandial vascular function was most dramatic in subjects who showed a decrease in peak FMD in response to the meal (n = 15: p = 0.003 for supplement by time interaction effect). There was a significant increase in postprandial lipemia and plasma interleukin-6 but no effect of supplementation. There were no significant postprandial changes or supplement effects for plasma tumor necrosis factor-alpha and malondialdehyde. In conclusion, consistent with other work showing a beneficial effect of carnitine on vascular function, these findings indicate that carnitine supplementation in healthy individuals improves postprandial FMD after a high-fat meal.
Volek
Jeff S
JS
Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, CT, USA. jeff.volek@uconn.edu
Judelson
Daniel A
DA
Silvestre
Ricardo
R
Yamamoto
Linda M
LM
Spiering
Barry A
BA
Hatfield
Disa L
DL
Vingren
Jakob L
JL
Quann
Erin E
EE
Anderson
Jeffrey M
JM
Maresh
Carl M
CM
Kraemer
William J
WJ
D000328:Adult; D001808:Blood Vessels / Q000276:immunology*; D002331:Carnitine / Q000008:administration & dosage*; D018592:Cross-Over Studies; D004041:Dietary Fats; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005502:Food; D006801:Humans; D007249:Inflammation; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D014664:Vasodilation; D055815:Young Adult
D004041:Dietary Fats; D015850:Interleukin-6; D002331:Carnitine