The prevalence of diabetes is increasing. Several antidiabetic drugs are available to treat the disease, however, none has been effective in halting the progression decline in β-cell function and insulin sensitivity. Plant-derived nutraceuticals provide therapeutic potential and are widely used in integrative medicine. However, clinical trials that evaluated the efficacy of antidiabetic nutraceuticals have been inconsistent in their findings. This study assessed the quality of the clinical trials that investigated the effects of berberine, cinnamon, or fenugreek seeds on glucose and lipid metabolism. Five databases (UB Wahlstrom, PubMed, Cochrane Library, CINAHL, and Science Direct) were systematically searched for randomized controlled studies that investigated the effects of berberine, cinnamon, or fenugreek seeds on glucose and lipid metabolism in prediabetes and diabetes. Forty-three studies (11, 20, 12 on berberine, cinnamon, and fenugreek, respectively), involving 3, 459 study participants were retrieved. The studies were appraised for trial quality using the Jadad scale and the CONSORT checklist. The included berberine, cinnamon, and fenugreek studies had a Jadad score of 3.2, 3.4, and 2.4, respectively. The studies, combined, had a Jadad score of 2.98 and only 62.7% had a score ≥3. Appraisal for reporting quality showed that 33% of the trials were identified in the title or abstract as randomized. Allocation concealment, random sequence generation, and baseline demographics and clinical characteristics were reported in 35, 44 and 74% of the trials, respectively. The included studies had suboptimal methodological and reporting qualities. The studies were not efficacious enough to support their use in clinical decision making. Further RTCs with emphasis on methodological and reporting quality and comparative effectiveness need to be conducted to determine efficacious conclusions.


I. Abdi: None.

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