Question: What happens if I treat high blood sugar by giving more sugar?
A reader from the First Aid Forum is asking why first aid manuals advise to give sugar to any confused diabetic. What happens if you give someone with high blood sugar more sugar?
Answer: In the short term, nothing happens. However, that doesn't mean high blood sugar isn't a problem.
Understanding why this is the case starts with understanding how your body gets energy and the difference between low blood sugar (hypoglycemia) and high blood sugar (hyperglycemia).
Alternative Fuels: Running on Sugar or on Fat
The body basically runs on two different fuels: fat and sugar. The premium fuel is sugar -- it burns cleaner and much more efficiently. Every carbohydrate and protein you eat is eventually broken down into sugar for your cells to use as fuel.
However, your body is a versatile engine. It needs more than one type of fuel, you know, just in case. That's why we can also use fat as a fuel. It's not clean burning -- kind of like the difference between high octane racing gas and coal -- but it gets the job done in a pinch. In fact, some of us are well prepared in the event of a worldwide famine (at least that's my excuse for the extra pounds).
Now, all cells in your body are not alternative fuel capable. Some of the cells are high-performance, and only the premium fuel will do. The brain is just such an elite machine. Brain cells cannot burn fat. It's like the guy with the Jaguar that lives in the mansion; the brain is just too good for a second-rate fuel like fat.
When the bloodstream runs low on sugar, the body tries to save it for the brain. When the blood sugar gets too low, the brain starts to sputter and die -- and the victim becomes dizzy, confused and weak. Nothing will work other than sugar, the premium, high-octane racing fuel for the body.
High blood sugar (hyperglycemia) is a different mechanical problem entirely. Sugar builds up in the bloodstream because there isn't enough insulin in there to use it. For most cells other than the brain, insulin is the fuel pump. It moves sugar from the bloodstream into the cells by binding with the sugar. Without insulin, sugar can't get into most types of cells.
When the insulin production facility -- the pancreas -- breaks down, there's not enough insulin to use sugar. The body switches to the back-up plan, which is to burn fat instead. All except for the brain, which is still happily running on sugar (of which there is now plenty because the rest of the body isn't using it).
High Blood Sugar and the Brain
Victims of high blood sugar can get confused, weak and dizzy -- just like victims of low blood sugar -- but for a completely different reason. It's not the lack of fuel for the brain; it's the pollution that comes from burning fat. When the rest of the body is burning fat, byproducts known as ketones are released into the bloodstream. Ketones are very acidic and the brain is finicky; it can't work in an environment with too much acid and begins to malfunction. It's a condition known as diabetic ketoacidosis (DKA).
It takes quite a bit of the ketones to affect the brain, so high blood sugar levels don't often affect the brain for days -- sometimes weeks. In that time, the actual sugar levels can go up or down. It's the lack of insulin and burning the fat, rather than the presence of extra sugar, that causes the problem.
So, giving sugar to people with high blood sugar isn't going to help -- they already have too much. It's not going to hurt, either.
On the other hand, giving sugar to someone with low blood sugar could save a life. In most cases when a victim known to have diabetes becomes confused, the cause is low blood sugar and the victim will get better after eating sugar.
The most important thing is to recognize when giving sugar didn't help and get the victim to a doctor as soon as possible or call 911.