The many positive health impacts of vitamin D have dominated the supplement world in recent years. Similarly, the growing worldwide epidemic of type 2 diabetes has also been in the spotlight – with an estimated 400 million people affected currently, and this number expected to be 642 million by 2040. As type 2 diabetes rates continue to soar, there is an urgent need to find effective ways to tackle this disease. Vitamin D supplementation has emerged as a possible solution. But how effective is it really?