Thanks again to everbody for all your responses.
I'm sorry to report that I now think my information about the magnesium was a red herring. Apologies for wasting people's time!
Basically the answer to my question (Is there something in my diet that protects me from the effects of Hypoglycemia?) is
Yes. It's simply the good, old-fashioned Ketogenic diet. I have low-carbed for years, and did learn some things about the Ketogenic diet way back when . . . but these details obviously slipped from my mind. Now that I have refreshed my memory and done some further research, for me things make very much more sense now.
The magnesium supplements certainly assisted the absorption of my Insulin, which may be interesting for diabetics by itself. There are many resources, including the one kindly provided by pumppimp, that give info about this.
I believe the protective (against Hypoglycemia) effects that I enquired about were simply the normal effects of a Ketogenic diet. Low-carbing was always pretty successful for me, and gave me pretty good control. But my brain was still Glucose-powered, via the small amount of carbs (sometimes larger amount of carbs if I was straying from the diet) and the gluconeogenesis from dietary protein. After I really got back on track with my diet, I effectively went down to No-carb, and also increased my consumption of fats rather than protein. At this point I believe my body really switched into a Modus Operandi of Ketosis, and my brain became Ketone-powered.
Based on the earlier responses, I guess that nobody will buy this. But the science seems clear (and also seems uncontroversial; I searched but find no arguments about it). In the sustained absence of enough Glucose (via dietary carbohydrates or via gluconeogenesis) the brain will use ketone bodies for fuel. These are created from fats and fatty acids by the liver.
This makes perfect sense to me. To take up Thundercat's metaphor of the broken fuel gauge . . . my body has switched into a Ketotic state where the brain is being powered by Ketone bodies. Therefore a fuel gauge (for Glucose) is no longer necessary. Therefore the warning signs for Hypoglycemia disappear. Hypoglycemia disappears.
I'm inclined to believe that Ketone-power is what the body is really designed for as the constant availability of carbohydrates is, in evolutionary terms, a very modern phenomenon. We have systems to take advantage of Carbs when they are readily available, but the human body certainly could not rely on it. Caveman did not have a Tesco Express anywhere nearby. He might go for a long time without a fresh kill. What happens when any carbs and his stores of protein are all used up? How can he use his brain to plan catching his next meal? His brain must continue to work somehow. How? The body switches to a Ketotic state, and fats in the body that have been laid down previously are used to create Ketone bodies that power the brain. T1 diabetics experience Ketosis (and then later its dangerous, runaway form, Ketoacidosis) in the period before diagnosis.
There are tons of books, and resources on the web, and discussions on the Diabetes forum, about Ketogenic diet so people can make their own decision whether I'm talking rubbish. I'm sorry that I did not remember about Ketosis and refresh my memory before making my Post. This would have answered my question.
To those that insist I must be having damaging episodes of Hypoglycemia, just without symptoms, I would give the following comparison. Years ago, before I was diabetic, I had a pretty normal Western diet. My body would give me "warning signs" of stomach-rumbling and hunger pangs every few hours, where my body was telling me it needed Glucose. After I switched to low-carb, I started to eat once per day without ever being hungry and my body not giving me these warnings. I never have interpreted this as a dangerous lack of symptoms. It is simply my body working in the way that is appropriate to the inputs that are being given to it. I think a very similar thing happens when you stop eating carbs completely and the brain becomes keto-adapted.
Thanks all and Regards
diamondnostril
(I've checked through dozens of diet books and resources to find what they say about Ketosis. Where Ketosis is mentioned, without exception every one states the science that the brain and nervous system will run on Ketones in the absence of carbohydrates. But I have not found any book that explicitly links this fact to protection against Hypoglycemia for T1 diabetics. I find this surprising. One book that goes much deeper into the subject of Ketosis than most, is "The Art and Science of Low Carbohydrate Living". I found this book really fascinating
).