Studies in Sweden and by the Harvard School of Public health may have found a link between breastfeeding and protection against Type 1 diabetes.

The study showed that children who were breastfed exclusively for longer periods of time may have natural protection against developing diabetes. It was particularly true in children who were breastfed exclusively for longer than five months.

The Harvard study also found that breastfeeding helped protect children from diabetes regardless of whether their mothers were overweight or had health problems. This certainly will be another reason to breastfeed babies for longer periods of time, as the Harvard study also indicated that babies that were breastfed for at least a year had the best protection.
One possible explanation considered by both studies is that breastfed babies have a steadier and slower growth, while formula fed babies have growth spurts. Breastfed babies are also more likely to be fed on demand rather than on a schedule.

I am sure that more research will be done regarding this. Is it breast milk itself that has the benefits or would bottle fed babies have the same protection if they were fed on the same sort of schedule? I am looking forward to reading more on this issue as the whole debate about breast versus bottle just became even more heated.