The effect of oral alpha-lipoic acid in overweight/obese individuals on brachial-ankle pulse wave velocity and supine blood pressure: a randomized, crossover, double-blind, placebo-controlled trial

Abstract

To investigate the effect of oral alpha-lipoic acid (ALA) supplement on brachial-ankle pulse wave velocity (baPWV), supine systolic blood pressure (SBP) and diastolic blood pressure (DBP) in overweight/obese individuals. An 8-week double-blind, randomized, placebo-controlled and cross-over trial with a 4-week washout between cross-over periods. Sixty-three males and 40 females aged 22 - 57 years old who met the inclusion criteria as (1) Han ethnicity; (2) 20 - 60 years old; (3) BMI ≥ 25 kg/m(2) and having at least one of the following risk factors: borderline hypertension (130 mm Hg ≤ SBP < 140 mm Hg and/or 85 mm Hg ≤ supine DBP< 90 mm Hg), dyslipidemia (fasting total cholesterol ≥ 5.2 mmol/L or HDL-C < 1.04 mmol/L), or impaired fasting glucose (6.1 mmol/L ≤ fasting glucose < 7.0 mmol/L); (4) Not on any antioxidant vitamin supplement. They were randomly assigned to Group 1 or Group 2 in a 1:1 ratio balanced for gender. Group 1 received 8 weeks ALA (1200 mg/day) followed by 4-week washout period and followed by another 8 weeks placebo; while Group 2 received 8 weeks placebo (1200 mg/day) followed by 4-week washout period, and followed by ALA treatment for 8 weeks. BaPWV and supine blood pressure were measured at the beginning of 1(st) phase and 2(nd) phase and at the endpoint of the whole trial. Mixed effect linear regression model was performed to compare the change of baPWV and supine blood pressure between ALA group and placebo group. BaPWV decreased -33.03 cm/s ± 130.70 cm/s for ALA group and increased 5.66 cm/s ± 139.89 cm/s for placebo group, supine systolic blood pressure decreased -4.09 mm Hg ± 9.18 mm Hg for ALA group and -2.32 mm Hg ± 8.16 mm Hg for placebo group. Supine diastolic blood pressure decreased -1.29 mm Hg ± 6.55 mm Hg for ALA group and -0.48 mm Hg ± 6.63 mm Hg for placebo group. These three mix-effect models did not show significant effect of ALA treatment after adjustment on baseline values, sex, age, treatment sequence or period. The current trial did not provide evidence that oral intake of ALA for 8 weeks had significant effects on lowering baPWV, supine systolic blood pressure or supine diastolic blood pressure.