A little background here. Personally, I think there is nothing more important to the human physiology as managing the relationship between our cells, glucose, insulin and our pancreas. There is nothing more crucial to our longevity than this. Period.
Our pancreas is composed of two main types of endocrine cells. The alpha cells release a hormone called glucagon. Glucagon helps us to keep a steady level of glucose in the bloodstream so we don’t do bad things like slip into a hypoglycemic coma. The other cell is the beta cell that produces insulin.
The beta cells, however, have a problem. They can only do so much work for so long. Anything that damages them worsens our ability to manage glucose. Chronic intakes of poor quality diets will do this. Some diabetic drugs (the sulfonylureas are notorious for burning out the beta cells of the pancreas!) will also contribute to the death of the beta cells.
In a sick twist, high levels of glucose produce oxidative stress within a cell. The beta cells of the pancreas, the very cells that we need to produce insulin and protect us from high blood sugar, are poorly protected against oxidative stress and vulnerable to dying off when blood sugar is elevated.
Because of this, anything we can do to protect and support the beta cells is a very good thing. This particular study finds that Vitamin D, among the seemingly hundreds of other benefits, also supports the health of the beta cell.