Is there any connection between poor nutrition and diabetes?
Depends on what type of diabetes. One type has nothing to do with nutrition, the other might actually be caused by poor nutrition (coupled with physical inactivity).
Diabetes Type I, or insulin dependent diabetes, is when the immune system mistakes the pancreas for a foreign body and attacks it. As the pancreas cells get destroyed the pancreas produces less insulin, which is needed to get glucose into the cells. This kind of diabetes can only be treated by taking insulin.
Diabetes Type II is when the body's cells become resistant to insulin. The sensitivity to insulin can basically be reversed by exercise and a low carbohydrate or low calorie diet. ...It is almost like the body's way of saying "for the love of God, exercise me now!"
It is important to eat enough potassium when you have diabetes because when glucose enters the cell to form glycogen, it takes potassium with it. This has the potential to cause a very dangerous, life threatening drop in blood potassium. If a diabetic has kidney failure at the same time, potassium presents a problem for which I have no solution. Also diabetics excrete vitamin B-1 (thiamine) at a much higher rate than normal people ( http://news.bbc.co.uk/2/hi/health/6935482.stm ). A vitamin B-1 deficiency is much more dangerous to the heart if potassium is adequate, so if potassium is increased, it is very important that vitamin B-1 be adequate at the same time (for a further discussion see http://members.tripod.com/~charles_W/diabetes.html )