You should be fine to take this if you have diabetes, it's about 95% chance that it won't cause an issue, but it is best to check with your doctor prior to taking. 

In 2009, Biochemistry and Biophysical Research Communications published a study out of Auburn University that explored how supplementing with turmeric can help reverse diabetes.

The study discovered that curcumin in turmeric is literally 400 times more potent than Metformin (a common diabetes drug) in activating AMPK which improves insulin sensitivity which can help reverse Type 2 Diabetes.