Taurine supplements help reduce risk factors for metabolic syndrome

In a recent study published in the journal Nutrition & Diabetes, researchers conducted a meta-analysis of randomized clinical trials (RCTs) to evaluate the effects of taurine supplementation on parameters associated with metabolic syndrome (MetS).

Metabolic syndrome is an international health problem defined by abdominal obesity, hypertension, hyperglycemia, hypertriglyceridemia, and low high-density lipoprotein (HDL) values. This condition increases the risk of cardiovascular disease, type 2 diabetes, and stroke. Research points to taurine as a possible treatment for MetS due to its involvement in mitochondrial function, osmoregulation, cell membrane integrity, antioxidant defense, and regulation of cation balance. However, conflicting results make it difficult to assess whether taurine reduces the risk of MetS.

About the study

In this meta-analysis, the researchers conducted meta-regressions to evaluate the effects of taurine on MetS parameters, indicating its effectiveness in reducing risk factors in the general population.

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

The researchers used meta-regressions to examine dose-response associations depending on the total taurine dose during treatment. Secondary outcomes included body composition parameters [weight and body mass index (BMI)], glycemic control [glycated hemoglobin (HbA1c), fasting insulin, and homeostasis model assessment (HOMA)], lipid profile [total cholesterol (TC) and low-density lipoprotein (LDL)], and adverse events.

The researchers compared taurine supplementation with other treatments and assessed parameters associated with MetS diagnosis in humans, providing pre- and post-intervention data. They excluded non-rigorous clinical trials, short follow-up periods, herbal remedies with unknown active ingredients, studies without pre- and post-intervention data on intermediate and endpoints, studies that did not examine the outcomes of interest, and those that tested the immediate effects of energy drinks.

Two investigators first assessed the titles and abstracts of identified records to determine their relevance, then conducted a full-text review. They hand-searched other databases and examined reference lists for relevant meta-analyses. They used the Cochrane risk of bias (RoB 2) tool for RCTs to assess the methodological quality of included studies and examined adherence to the intervention using per-protocol methodology.

For continuous outcomes, the researchers estimated the weighted mean difference (WMD), and for categorical outcomes, they used odds ratios (OR). The study used the I2 statistic to assess heterogeneity between studies, performed a sensitivity analysis when removing one study to determine whether removing a study significantly changed the effect size, and visually inspected the distribution of effect sizes in the funnel plot to assess publication bias.

Results and discussion

The researchers initially identified 2517 records, excluding 2476 after title and abstract screening and 13 records after full-text screening. After applying eligibility criteria, they analyzed 1024 people included in 25 studies. Of the records, 18 were at risk of bias due to missing allocation concealment information, seven were at low risk, and none were at high risk. Funnel plot examination for all outcomes revealed no evidence of publication bias, and the distribution of effect sizes was symmetrical, as confirmed by Egger's regression test.

Taurine doses in studies ranged from 0.5 grams to 6.0 grams per day, with follow-up periods ranging from 5 to 365 days. Taurine supplementation significantly reduced SBP (WMD, -4.0 mmHg), diastolic blood pressure (WMD 1.5 mmHg), fasting blood glucose (WMD 5.9 mg/dL), triglycerides (WMD 18.3 mg/dL), but not HDL (WMD 0.6 mg/dL) compared with controls. Meta-regressions showed dose-dependent reductions in diastolic blood pressure (coefficient -0.01 mmHg per gram) and fasting blood glucose (coefficient -0.05 mg/dL per gram). No significant adverse effects were observed compared with controls. A meta-analysis of the incidence of treatment-related adverse events found no significant difference between taurine and control groups (OR 1.5).

Taurine significantly reduced serum and diastolic blood pressure levels compared to control groups, which is attributed to increased nitric oxide availability and hydrogen sulfide generation, which promote blood flow expansion. Taurine also reduces fasting blood glucose levels, potentially improving glycemic control through mechanisms including decreasing hepatic glucose synthesis, suppressing glucagon activity, increasing thermogenesis-inducing protein-1 levels, improving insulin clearance, and supporting pancreatic beta cell health. It can also increase adiponectin mRNA expression, which improves insulin sensitivity and overall metabolic health. Taurine also reduces total cholesterol by promoting bile acid synthesis and enhancing LDL receptor activation.

The study showed that taurine supplementation can significantly reduce metabolic syndrome (MetS) risk factors such as high blood pressure, high blood glucose, and high total cholesterol. These findings suggest that taurine supplementation may be used as an adjunctive treatment for MetS, providing a multidimensional approach to glycemic control and cardiovascular health. Future clinical trials should focus on finding the appropriate taurine dose and duration of therapy, especially in MetS-prone populations. Further research may help fill knowledge gaps and support clinical recommendations for the use of taurine as a nutraceutical for the prevention and treatment of MetS.