Clinical trials to evaluate the anti-inflammatory effects of ALA have, in the past, produced mixed results
Chronic inflammation is associated with metabolic disorders. More specifically, increased levels of C-reactive protein (CRP), interleukin-6 (IL-6), and tumour necrosis factor (TNF) are correlated with an increased risk for cardiovascular disease and diabetes.
Alpha-lipoic acid (ALA) is an antioxidant nutrient that may reduce inflammation by scavenging free radicals or down-regulating pro-inflammatory signalling cascades.
To summarise the currently available data on the effects of ALA on inflammatory markers in patients with metabolic disorders, researchers conducted a systematic review and meta-analysis.
Eighteen studies were included in the meta-analysis. All of the studies were placebo-controlled randomised trials involving adults with metabolic syndrome, cardiovascular disease, chronic kidney disease, diabetes, or related metabolic disorders.
Studies reported on mean changes between pre- and post-intervention CRP, IL-6, or TNF-alpha following ALA supplementation.
The included studies ranged in duration from two weeks to 12 months. The dosage of oral ALA supplementation ranged from 300–600 mg per day.
The results showed that ALA supplementation significantly decreased CRP by a standard mean difference (SMD) of -1.52 mg/L (95% CI, -2.25 to -0.80; p <0.001). ALA decreased IL-6 by a mean of -1.96 pg/mL (95% CI, -2.60 to -1.32; p <0.001) and decreased TNF-alpha by a mean of -2.62 pg/mL (95% CI, -3.70 to -1.55; p <0.001).
There was significant heterogeneity among the studies and the authors were not able to evaluate the effect of dosage or duration of ALA supplementation on inflammatory markers.
More extensive studies are needed, but the current evidence suggests that ALA has a beneficial effect on inflammatory markers in patients with metabolic syndrome and other related disorders.