A double-blind, randomized controlled trial (RCT) of L-carnitine and conjugated linoleic acid-based health food with health claims

In the present study, we investigated the physical effect of health food (supplement) which contains L-carnitine (200mg) and conjugated linoleic acid (700mg) for 8 weeks with a double-blind, randomized controlled non-crossover design. Overweight individuals (17 males and 18 females; age: 48.3±6.6yrs; BMI: 25.5±2.6) were assigned to either Study Group (n=18) or Control Group (n=17). A small increase in serum levels of HbAlc (3.3%) and CRP (35.3%) was noted in the Study Group (p<0.05), and a significant increase in urinary isoprostane production rate (38.9%) and its creatinine -adjusted value (isoprostane/CRE) (44.4%), which is a marker for damage of fatty acids by free radicals. No effect was observed for indicators related to body composition and lipid metabolism. The results showed a significant improvement for the following subjective symptoms: “Easily break into a sweat”, “Irritability”, “Easily angered”, “Sense of tension”, however, “Early satiety” exacerbated. The sole parameter we found a significant intergroup difference in rate of change was in urinary isoprostane production rate and its creatinine-corrected value, and the score obtained in the questionnaire for “Easily angered”. In conclusion, these findings suggest that the consumption of the test compounds with L-carnitine and conjugated linoleic acid can reduce some mental symptoms; however, the efficacy on QOL was equivocal. As unfavorable phenomenon, elevation of HbAlc, CRP and urinary isoprostane were observed during the study.