Taurine supplementation shows promise in reducing metabolic syndrome risk factors, study finds

By Pooja Toshniwal PahariaReviewed by Susha Cheriyedath, M.Sc.May 20 2024

In a recent study published in the journal Nutrition & Diabetes, researchers meta-analyzed randomized clinical trials (RCTs) to assess the impact of taurine supplementation on metabolic syndrome (MetS)-related variables.

MetS is an international health problem defined by abdominal obesity, hypertension, hyperglycemia, hypertriglyceridemia, and low high-density lipoprotein (HDL) values. The condition raises the risk of cardiovascular disorders, diabetes mellitus type 2, and stroke. Studies identify taurine as a probable MetS treatment agent due to taurine's involvement in mitochondrial function, osmoregulation, cell membrane integrity, antioxidative defense, and cation balance regulation. However, the conflicting results make it difficult to evaluate whether taurine lowers MetS risk.

Study: Taurine reduces the risk for metabolic syndrome: a systematic review and meta-analysis of randomized controlled trials. Image Credit: M.Photografer / Shutterstock

About the study

In the present meta-analysis, researchers performed meta-regressions on taurine's impact on MetS parameters, indicating its efficacy in reducing risk factors in the general population.

The researchers examined the PubMed, Embase, Cochrane CENTRAL, ClinicalTrials.gov, and Web of Science databases for records published until 1 December 2023. The study focused on known metabolic syndrome diagnostic criteria, such as diastolic blood pressure (DBP), systolic blood pressure (SBP), fasting blood glucose (FBG), HDL, and triglycerides.

The researchers used meta-regressions to investigate dose-dependent associations depending on the total dose of taurine throughout treatment. Secondary outcomes included body composition parameters [weight and body mass index (BMI)], glycemic control [glycated hemoglobin (HbA1c), fasting insulin, and homeostatic model assessment (HOMA)], lipid profile [total cholesterol (TC) and low-density lipoprotein (LDL)], and side effects.

The researchers compared taurine supplementation to other therapies and evaluated parameters related to MetS diagnosis in human subjects, providing before and after intervention data on MetS outcomes. They excluded non-RCTs, short follow-ups, herbal remedies with unknown active components, studies without data for pre- and post-intervention endpoints, studies not studying interest outcomes, and those testing the immediate impacts of energizing beverages.

Two researchers first evaluated the titles and abstracts of the identified records to establish their eligibility, then conducted a full-text review. They manually searched other databases and reviewed the reference lists for pertinent meta-analyses. They used the Cochrane risk of bias tool (RoB 2) for RCTs to assess the methodological quality of the included studies and examined intervention adherence using the per-protocol methodology.

For continuous outcomes, the researchers estimated the weighted mean difference (WMD), while for categorical outcomes, they used odds ratios (OR). The study used I2 statistics to assess heterogeneity between studies, performed a one-study removal sensitivity analysis to see if excluding a trial significantly changed the effect size, and visually examined the distribution of effect sizes in a funnel plot to evaluate publication bias.

Results and discussion

Initially, the researchers identified 2,517 records, excluding 2,476 after the title and abstract screening and 13 records after the full-text screening. After applying eligibility criteria, they analyzed 1,024 individuals included in 25 trials. Among the records, 18 were at risk of bias due to a lack of allocation concealment information, seven were low-risk, and none were high-risk. The investigation of funnel plots for all outcomes found no indication of publication bias, and the distribution effect sizes were symmetric, as validated by Egger's regression test.

Taurine dosages in the trials varied from 0.50 grams to 6.0 grams daily, with follow-ups ranging from 5.0 to 365 days. Taurine supplementation significantly reduced SBP (WMD, −4.0 mmHg), diastolic blood pressure (WMD of 1.5 mmHg), fasting blood glucose (WMD of 5.9 mg/dL), triglyceride (WMD of 18.3 mg/dL), but not HDL (WMD of 0.6 mg/dl) compared to control groups. Meta-regressions showed dose-dependent decreases in diastolic blood pressure (coefficient -0.01 mm of Hg per gram) and fasting blood glucose (coefficient -0.05 mg/dL per gram). There were no notable detrimental effects compared to controls. A meta-analysis of treatment-associated adverse effect rates found no significant difference between the taurine and control groups (OR, 1.5).

Taurine significantly decreased serum and diastolic blood pressure compared to controls, which is related to increased nitric oxide availability and hydrogen sulfide generation, which promote dilatation of blood flow. Taurine also lowers fasting blood glucose levels, potentially enhancing glycemic management through mechanisms like decreased hepatic glucose synthesis, suppression of glucagon activity, increased uncoupling protein-1 levels, improved insulin clearance, and support for beta-pancreatic cell health. It may also increase adiponectin messenger ribonucleic acid (mRNA) expression, which improves insulin sensitivity and overall metabolic health. Taurine also lowers total cholesterol by promoting bile acid synthesis and enhancing LDL receptor activation.

The study found that taurine supplementation can dramatically lower risk factors for metabolic syndrome (MetS), such as high blood pressure, low blood pressure, high blood glucose, and high total cholesterol. The findings indicate that taurine supplementation can be used as a supplemental treatment for MetS, providing a multidimensional approach to glycemic control and cardiovascular health. Future clinical trials should focus on finding the appropriate taurine dosage and therapy duration, particularly in MetS-prone groups. Further study can help to bridge knowledge gaps and support clinical guidelines for using taurine as a nutraceutical to prevent and treat MetS.