There has been many debates over the fact that type 3 diabetes exists, but so far majority of medical professionals have come to a consensus that Alzheimer's disease is in fact type 3 diabetes. Or rather Alzheimer's is a side effect because it results from your brain's resistance to insulin which is the extreme form of diabetes.
Scientists and the medical fields are now exploring the new take on diabetes, a type 3 diabetes. This recent find has been proposed for Alzheimer's disease which results from resistance to insulin in the brain. The insulin resistance to the brain is alarming researchers into closely looking into the effects of the correlation of diabetes and alzheimer's.
From my non-medical perspective I do not believe in the existence of the so-called Type 3 diabetes. I am of the opinion that most if not all of these cases diagnosed have a root or can otherwise be explained away by the lifestyle and dietary choices of those afflicted by it.