Abstract

OBJECTIVE:

To assess the effectiveness of oral vanadium supplementation for glycaemic control in type 2 diabetes by conducting a systematic review of the literature.

DESIGN AND METHODS:

Eligible studies were identified by searching 14 databases using standardized terms. Experts, study authors and manufacturers were also contacted. Hand-searching was not undertaken. Selection criteria for inclusion in the review were controlled human trials of vanadium vs. placebo in adults with type 2 diabetes of minimum 2 months duration, and a minimum of 10 subjects per arm. Data extraction, assessment of study quality and outcome analysis were undertaken by two independent reviewers.

RESULTS:

One hundred and fifty one studies were found but none met the inclusion criteria. We proceeded to summarize the state of existing evidence and plan for a future clinical trial by applying revised, less restrictive criteria to our search, for clinical trials of 30-150 mg daily oral vanadium supplementation in diabetic humans. Only five were identified. These demonstrated significant treatment-effects, but due to poor study quality, must be interpreted with caution. Treatment with vanadium often results in gastrointestinal side-effects.

CONCLUSION:

There is no rigorous evidence that oral vanadium supplementation improves glycaemic control in type 2 diabetes. The routine use of vanadium for this purpose cannot be recommended. A large-scale randomized controlled trial is needed to address this clinical question.