Alpha lipoic acid benefits people with metabolic diseases, meta-analysis shows
Highlights
- Meta-analysis of 24 randomized, controlled trials with patients with metabolic diseases
- ALA supplementation ranges from 200 to 1,800 mg/day
- Study duration ranges from 2 to 51 weeks
- ALA supplementation significantly improves glycemic control and lipid profiles
- No detrimental effect on HDL cholesterol levels
Summary
This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to explore the effect of alpha-lipoic acid (ALA) supplementation on glycemic control and lipid profiles in patients with metabolic diseases.
The literature search included RCTs indexed in MEDLINE, EMBASE, Web of Science and Cochrane Library databases up to October 2017. Inclusion criteria included original RCTs involving patients with metabolic diseases with intervention groups receiving ALA supplements or ALA plus other nutrients and control groups receiving placebo. Measurements of the mean changes of glycemic control and/or lipid profiles with standard deviations (SD) for the intervention and control groups were also required.
Study quality was assessed using the Cochrane risk of bias tool. Data were pooled using the inverse variance method and expressed as standardized mean difference (SMD) with 95% confidence intervals (95% CI). Heterogeneity was assessed with I-squared (I2) and Cochrane’s Q tests. Publication bias and subgroup analyses were also performed.
A total of 24 studies published between 2007 and 2015 met the inclusion criteria (16 studies using ALA alone; 8 studies using ALA plus other nutrients) and were included in the meta-analysis. The duration of study interventions varied from 2 to 51 weeks, and ALA dosages ranged from 200 to 1,800 mg/day.
Results indicate that ALA supplementation significantly improved glycemic control and lipid profiles with no detrimental effect on HDL cholesterol levels (see Table 1).
| Table 1. Effect of ALA on Glycemic/Lipid Parameters | |||
| Parameter | SMD | 95% CI | P-value |
| Fasting Glucose | -0.54 | (-0.89, -0.19) | P=.003 |
| Insulin | -1.01 | (-1.70, -0.31) | P=.006 |
| HOMA-IR | -0.76 | (-1.15, -0.36) | P<.001 |
| HbA1c | -1.22 | (-2.01, -0.44) | P=.002 |
| Triglycerides | -0.58 | (-1.00, -0.16) | P=.006 |
| Total Cholesterol | -0.64 | (-1.01, -0.27) | P=.001 |
| LDL Cholesterol | -0.44 | (-0.76, -0.11) | P=.008 |
| HDL Cholesterol | 0.57 | -0.14, 1.29 | P=.11 |
| SMD indicates standardized mean difference; CI, confidence interval; HOMA-IR, homeostasis model assessment of insulin resistance; HbA1c, hemoglobin 1c. | |||
These findings indicate that ALA supplementation may offer clinical value for patients with metabolic diseases to improve glycemic control and blood lipid profiles without adversely affecting HDL-cholesterol levels.
