Abstract: Results of only a limited number of studies could be combined, in view of different types of interventions and variable quality of data. We found six trials of proprietary herbal mixtures and one of whole system Ayurvedic treatment. These studies enrolled 354 participants ( 172 on treatment, 158 on controls, 24 allocation unknown). The treatment duration ranged from 3 to 6 months. All these studies included adults with type 2 diabetes mellitus. With regard to our primary outcomes, significant reductions in glycosylated haemoglobin A1c (HbA1c), fasting blood sugar (FBS) or both were observed with Diabecon, Inolter and Cogent DB compared to placebo or no additional treatment, while no significant hypoglycaemic response was found with Pancreas tonic and Hyponidd treatment. The study of whole system Ayurvedic treatment did not provide data on HbA1c and FBS values. One study of Pancreas tonic treatment did not detect a significant change in health-related quality of life. The main adverse effects reported were drug hypersensitivity (one study, one patient in the treatment arm); hypoglycaemic episodes (one study, one participant in the treatment arm; none had severe hypoglycaemia) and gastrointestinal side effects in one study (1 of 20 in the intervention group and 0 of 20 participants in the control group). None of the included studies reported any deaths, renal, hematological or liver toxicity. With regard to our secondary outcomes, post prandial blood sugar (PPBS) was lower among participants treated with Diabecon, was unchanged with Hyponidd and was higher in patients treated with Cogent DB. Treatment with Pancreas tonic and Hyponidd did not affect lipid profile significantly, while patients treated with Inolter had significantly higher HDL- and lower LDL-cholesterol as well as lower triglycerides. Cogent DB treated participants also had lower total cholesterol and triglycerides. Studies of treatment with Diabecon reported increased fasting insulin levels; one study of treatment with Diabecon reported higher stimulated insulin levels and fasting C-peptide levels in the treatment group. There was no significant difference in fasting and stimulated C-peptide and insulin levels with Hyponidd, Cogent DB and Pancreas tonic treatment. The study of Inolter did not assess these outcomes. No study reported on or was designed to investigate diabetic complications, death from any cause and economic data. Although there were significant glucose-lowering effects with the use of some herbal mixtures, due to methodological deficiencies and small sample sizes we are unable to draw any definite conclusions regarding their efficacy. Though no significant adverse events were reported, there is insufficient evidence at present to recommend the use of these interventions in routine clinical practice and further studies are needed.

Plain-language summary: This review examines the efficacy and safety of the use of various Ayurvedic treatments for diabetes mellitus. We found seven trials which included 354 participants (172 on treatment, 158 on control, 24 could not be classified). All these studies included adults with type 2 diabetes mellitus. Six studies tested five different types of herbal mixtures (proprietary drugs) and only one tested 'whole system' Ayurvedic treatment. The duration of treatment ranged from three to six months. One study each of Diabecon, Inolter and Cogent DB (proprietary herbal mixtures) found significantly lower glycosylated haemoglobin A1c (HbA1C) levels at the end of the treatment period compared to controls. Two studies of Diabecon, and one study of Cogent DB (proprietary herbal mixtures) found significantly lower fasting blood sugar levels at the end of the study period in the treatment group. No deaths were observed in these trials and side effects did not differ significantly between intervention and control groups. One study of Pancreas tonic reported no significant change in health-related quality of life. No study reported on or was designed to investigate diabetic complications, death from any cause and costs. Despite positive results in some studies, and absence of serious side effects, firm conclusions cannot be drawn due to weak methods and small number of participants in the evaluated studies. Further research is needed to assess the efficacy of these treatments. Ayurvedic physicians generally use a mixture of various herbs or proprietary preparations along with diet, exercise and mode of living. The treatments are usually individualised taking into account the balance of three 'doshas'. It is possible that the interventions in the trials analysed have not replicated actual Ayurvedic practice but only assessed some components individually.