Effects of Alpha-Lipoic Acid Supplementation in Peripheral Arterial Disease: A Pilot Study
Objective: To examine whether 3 months of lipoic acid (LA) supplementation improved walking tolerance and delayed claudication pain onset in peripheral arterial disease (PAD).
Design: Randomized, double-blind, controlled study.
Setting: General Clinical Research Center.
Subjects: Twenty-eight (28) participants (15 men, 13 women) with PAD (ankle brachial index range 0.9–0.4, mean age 73.2 ± 1.6 years).
Intervention: LA (600 mg/day) or placebo for 3 months.
Outcome measures: Walking tolerance was assessed by 6-minute walk test distance, 4-meter walk time, initial claudication pain time (ICT) and distance (ICD), and peak claudication pain. Serum was assessed for inflammation (C-reactive protein [CRP]) and oxidative stress (lipid hydroperoxides) as potential mechanisms for changes in walking tolerance.
Results: ICT increased 34.4% and 15%, ICD was reduced by 40.5% and 18%, and peak claudication pain ratings were reduced by 93% and 7% in LA and placebo groups, respectively. Although the improvements in peak pain and ICT achieved significance within the LA group (both p < 0.05), the interactions of group by time were not found to be significant (p > 0.05). Oxidative stress and CRP measures were not different between groups by month 3 (p > 0.05). There were no serious side-effects associated with the LA.