There has been recent speculation about the benefits of blood letting in Type 2 diabetes. However in 2008 L. Mascitelli, F. Pezzetta, M. R. Goldstein wrote
…dietary factors, which inhibit iron absorption (i.e. low-fat dairy consumption and habitual coffee intake), have been shown to be associated with a substantially lower risk of type 2 diabetes
They went on to conclude that a few basic lifestyle interventions might make more sense……
…we suggest that, in patients with or at high risk for type 2 diabetes, improving insulin sensitivity with physical exercise, metformin therapy and low-carbohydrate diet might break the vicious circle of insulin resistance, increased intestinal iron absorption and further worsening of insulin resistance.
Liz & Glyn Wainwright 