Despite its effect on glucose metabolism and lipid oxidation, acetyl-L-carnitine supplementation used to treat individuals with type 2 diabetes, hypertension, and dyslipidemia did not lower systolic blood pressure when maintained on stable statin therapy, according to a study published in the Journal of Endocrine Society.
The prospective, double-blind, placebo-controlled trial included 229 participants over 40 who were diagnosed with type 2 diabetes, presented hypertension and dyslipidemia, and were on stabilizing therapies (antihypertensive, hypoglycemic, and lipid-lowering). Participants were stratified according to baseline demographic characteristics and previous statin therapy, and were randomly assigned to an acetyl-L-carnitine group (n=116) or a placebo group (n=113).
Blood pressure was measured prior to each treatment, and blood samples were taken after overnight fasting. The glucose disposal rate was calculated by testing the rate of glucose infusion during a hyperinsulinemic-euglycemic clamp and was used to assess insulin sensitivity. Additional tests for albuminuria and glomerular filtration rates were used to evaluate renal function.
The results did now show significant change in blood pressure outcomes for the acetyl-L-carnitine group, however the blood pressure of participants in the placebo group dropped significantly (from 138.1 ± 18.3 mm Hg to 134.5 ± 15.1 mm HG; P=.0187). Lipid and metabolic profiles did not differ significantly between groups, and renal parameters remained largely unchanged throughout treatment. Though some signs of improved insulin sensitivity were observed in study groups with short-term statin use, the overall findings challenge the association between improved insulin sensitivity and decreased blood pressure.
Limitations of the study included a study population of all participants with type 2 diabetes on hypoglycemic treatment; there was no study group composed of participants without diabetes. Also, an older study group population (mean age was 64.7 ± 7.6) could suggest an increased resistance to antihypertensive drugs and greater vascular stiffness. A number of current and former smokers were included in this trial, which could have contributed to increased vascular stiffness as well.
Researchers conclude that a stable statin therapy may blunt the possible hypotensive effect of acetyl-L-carnitine supplementation in individuals with type 2 diabetes and recommend further exploration on the effect of acetyl-L-carnitine in both persons with and without diabetes who have hypertension but do not require treatment with statins.
Parvanova A, Trillini M, Podestà MA, et al. Blood pressure and metabolic effects of acetyl-l-carnitine in type 2 diabetes: DIABASI randomized controlled trial. J Endocr Soc. 2018; 2(5): 420–436.