I am a newly diagnosed type 1 diabetic and doing research into how to manage everything. I keep seeing to keep blood sugar under 180mg/dl and damage starts there. But why?
Wouldn’t everyone be different? Also what is so damaging at that number? I understand the damage to the kidneys overworking to clean the sugar out but why would it hurt blood vessels in the extremities and eyes?
Is it just that the sugar thickens the blood too much or something?
Basically I understand that high blood sugar causes damage but why? And why specifically at 180mg/dl?
In: Biology
For me, I understand it this way (as a type one diabetic)
when my blood gets too high, each of my cells has more sugar than what it’s supposed to. This is why you get thirsty. your cells take in water to try to balance out how much sugar there is in there. Your cells can swell, and if you go into DKA your blood can become acidic. This is all in the short term, but still.
indicator of metabolic failure/imbalance. blood sugar is the fuel powering your cells. either you’re overloading your highways with too much fuel or your cells aren’t burning at their normal/expected rates.
something is broken.
Glucose (i.e. “blood sugar”) *itself* becomes toxic at high concentrations. It literally starts to damage blood vessels, so if the problem is chronic then it leads to all sorts of downstream problems like heart disease, kidney damage, nerve damage, eye problems, etc.
Why 180mg/dL? Because as the saying goes in toxicology: “the dose makes the poison.” High enough concentrations of *anything* are bad for your health. That ~180mg/dL line is just where glucose starts to be a problem.
When it comes to diabetes and blood sugar being too high, you should separate into acutely high and chronically high.
For acutely high, this can cause diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS, only seen in type 2 diabetes). The physiology of it is complex, but basically the sugar gets super high which causes you to pee a lot and get dehydrated and a lot of acid builds up in the blood, both of which are really dangerous. This can be treated and resolved relatively quickly.
For chronically high blood sugar, we typically split the complications into microvascular (small blood vessel) and macrovascular (large blood vessel) complications. For microvascular, the sugar leaks into the small blood vessel walls and causes damage to those blood vessels, causing them to narrow. This then causes decreased blood flow and oxygen to organs which damages them. That’s why you can get kidney damage and eye damage.
For macrovascular complications, too much sugar hurts the cells that line the inside of the large blood vessel that normally keep things from leaking out. When these cells are hurt, this allows more cholesterol to leak into blood vessels and you start to develop plaques, which ultimately increases your risk of heart attacks and strokes.
Too much sugar also can go into nerves and cause too much water to go into those nerves, which damages them and leads to neuropathy.
Also type1 here. No insulin means your body cant use glucose for energy, it can only use stored fat it burns. This produces ketones, acids that end up in your blood. Staying high, like 300+ for too long will turn your blood to acid and your organs will start shutting down. It feels about how it sounds, last time I lost my insurance I lasted 11 days before I could barely walk across a room and I was throwing up everywhere, shit myself and forgot who my wife and child were. Dam near died, probably should have.
So while the sugar does do some damage, it takes a while, and the more immediate effects are much more dangerous in the short term. Also 180 is pretty high, you should shoot for around 100. Get a dexcom continuous blood sugar monitor, it makes it much easier than those shitty finger sticks
My partner ignored and denied his ever growing symptoms of diabetes until he was in keto acidosis and almost died. He now has moderate nerve damage in his hands and feet (this gives him pain when he uses them) and struggles to open pickle jars. He’s only early 40’s. High sugars kill.
Sugar in your blood can’t be used as effectively (or at all, depending on degree of diabetes) for fuel so it hangs around until it can get stored as fat. As it is hanging around it makes your blood acidic and that causes organ and cell damage over months and years. A diabetic friend jokes that he’s like the alien in Aliens, but with nicer teeth.
Blood doesn’t “thicken” due to high blood sugar, a common misconception. It is a symptom in and of itself, it means that your cells aren’t taking in sugar from the blood stream to burn as energy due to lack of insulin (which tells cells to take in sugar to burn as energy) or insulin resistance (cells start ignoring the insulin).
The problem with this is that cells don’t get the energy that they require to function and start to die and lose nerve endings starting with the feet (diabetic neuropathy), the blood sugar killing happens after diabetic neuropathy sets in, any damage to the foot can’t be felt and can easily become infected without the person realizing it, leading to infections entering the blood stream (this is why diabetics sometimes end up having a foot/feet amputated).
Also your body starts burning fat stores instead of using the readily available sugar which can cause too many acids in the blood stream called ketoacidosis. The extra thirst is due to your body trying to flush out the extra sugar through the kidneys.
You should really aim to keep your blood sugar under 130 not 180. That number has been researched over the years and it has been scientifically proven that having blood sugar continuously over 180 is where most if not all of the harm to the body occurs.
There are several ways excessive glucose can damage the body. In addition to the way already mentioned, high glucose levels interrupt the cross-linking of collagen fibers which form much of the structure of the human body. This eventually leads to tissue breakdown.
The average persons blood has sugar in it so our muscles can suck it up to break down to make energy. But just like most poison the most important thing is the DOSE over time.
Sugar is very sticky and sticks to the inside of your veins and arteries and also nerves if it is at high levels hanging around in the blood and not being used. Your blood vessels are tubes and like to be alllll the way open without anything sticking to the sides as this risks a blockage. If there’s a blockage then blood (and ultimately oxygen) can’t flow.
If your vessels are blocked with too much sugary coating over time it can lead to blockage in the vessels of the brain (stroke), heart (heart attack), kidneys (kidney failure) or blockage of vessels in the legs (can lead to amputation).
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