Evaluating the Lipid-Lowering Effects of α-lipoic Acid Supplementation: A Systematic Review

Abstract

Dietary supplementation of α-lipoic acid, an 8-carbon organosulfur compound, has been widely reported to lower blood glucose concentration and/or improve insulin sensitivity in previous randomized controlled trials. Although animal model studies further report fairly consistent lipid lowering in both blood and tissue pools in response to α-lipoic acid supplementation, results from human studies are mixed. According to PRISMA guidelines, we conducted a systematic review of published randomized controlled studies (RCTs) to assess the efficacy of α-lipoic acid supplementation as a strategy to improve dyslipidemia, with a focus on serum lipid endpoints including TC, low density lipoprotein cholesterol (LDL-C), HDL-C, and TG. PubMed, EMBASE, Cochrane Evidence-Based Medicine Reviews, Proquest, Web of Science, and Scopus were searched to identify RCTs that reported the effects of α-lipoic acid on blood lipid concentrations from 1970 to 2017. We included RCTs reporting blood lipid responses in adults supplemented with oral α-lipoic acid versus a placebo or control for at least one month. Studies were reviewed and data were extracted by two independent study authors. Seventeen studies were deemed eligible for inclusion. Overall, mean percent changes in blood lipid endpoints in response to α-lipoic acid varied considerably between studies for total cholesterol (–10.5 to +13.9), low-density lipoprotein cholesterol (–19.67 to +9.06), high-density lipoprotein cholesterol (–12.5 to +29.20), and triglycerides (–38.57 to +17.0). Results of this systematic review suggest little consistent benefit on serum lipids in response to α-lipoic acid supplementation. Further well-controlled studies designed and powered to detect improvements in blood lipids in hypercholesterolemic individuals are warranted (PROSPERO registration number: CRD42018105933).

Keywords:

• α-lipoic acid
• blood lipids
• dietary supplementation
• nutraceuticals
• systematic review

Declaration of interest

The authors declare no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Additional information

Funding

This research was supported by a KO1 grant (1K01AT007826-01A1) from the National Center for Complementary and Integrative Health (NCCIH) (to TCR).

Notes on contributors

Nicole Erickson

Nicole Erickson, MS, RD, Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA 14214. Research interests: dietetics, nutrition.

Michelle Zafron

Michelle Zafron, MS, University Libraries, University at Buffalo, Buffalo, NY, USA 14214. Research interests: information literacy and evidence-based practice, social media, and academic libraries.

Scott V. Harding

Scott V. Harding, PhD, Department of Biochemistry, Faculty of Science, Memorial University of Newfoundland, St. John’s, NL A1C 5S7. Research interests: functional foods, fructose and cardiometabolic disease, sleep and activity.

Christopher P.F. Marinangeli

Christopher P. Marinangeli, PhD, Pulse Canada, Winnipeg, MB R3M 0A5, Canada. Research interests: dietary patterns and chronic disease risk, environmentally sustainable dietary patterns.

Todd C. Rideout

Todd C. Rideout, PhD, Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA 14214. Research interests: dietary supplements, lipid metabolism, cardiovascular disease.