Alpha lipoic acid supplementation promotes weight loss, meta-analysis shows

Summary

This systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to determine the effect of ALA supplement on anthropometric indices among adult subjects.

The literature search included RCTs indexed in PubMed, Scopus, Web of Science, the Cochrane Library and Google Scholar databases up to September 2016. Inclusion criteria included randomized, placebo-controlled trials (either parallel or cross-over designs) involving adults and reporting mean changes in body weight and/or BMI.

Study quality was assessed using the Jadad checklist. Data were pooled by using random-effect model. All data were presented as weighted mean difference (WMD) and standard deviation (SD). To compare differences between ALA and placebo groups, the primary outcome measures were body weight and BMI and the secondary outcomes were waist circumference (WC) and adverse effects. Heterogeneity, publication bias and subgroup analyses were also performed.

A total of 12 studies published between 1997 and 2016 met the inclusion criteria and were included in the meta-analysis. The duration of study interventions varied from 8 and 48 weeks, and ALA dosages ranged from 300 to 1,800 mg/day. In most studies, it was recommended to take ALA before meals.

Results indicate that ALA supplementation significantly reduced body weight (WMD: -0.69 kg; 95% CI: -1.27, -0.10; I² = %) and BMI (WMD: -0.38 kg/m²; 95% CI: -0.53, -0.24; I² = 0%) compared to the placebo group. However, its effect on WC was not significant (WMD: -0.30 cm; 95% CI: -1.18, 0.58; I² = 17.8%). Stratification by health status indicated that ALA decreased WC in unhealthy subjects (WMD: -2.00 cm; 95% CI: -4.19, 0.19; I² = 1.3%) more than in healthy individuals (WMD: 0.03 cm; 95% CI: -0.69, 0.75; I² = 0%).

Intakes of up to 1,200 mg/day ALA were well tolerated. Skin sensation and fever were two main adverse effects reported in participants taking daily dosage of 1,800 mg/day.

Subgroup analyses indicated greater weight loss in overweight vs. obese people (WMD: -2.3 vs. -0.59 kg), in those taking ALA for less than 10 weeks vs. longer periods (WMD: -2.24 vs.-0.63 kg), when used by unhealthy vs. healthy individuals (WMD: -1.34 vs. -0.63 kg), and when used in amounts equal or less than 600 mg/day vs. higher amounts (WMD: -1.08 vs. -0.67 kg).

These findings suggest that ALA supplementation up to 1,200 mg/day is safe and well tolerated and may support weight loss efforts of overweight or obese adults, especially when taken in low-dose amounts (less than 600 mg/day) for a short period of time (e.g., less than 10 weeks).