High blood sugar greatly contributes to damage in our blood vessels. And, you don’t have to have blood sugars in the diabetic range for this damage to occur. We are now recognizing that diabetic complications like peripheral neuropathy, retinopathy, and nephropathy can occur in non-diabetics as well. This means that our diagnostic cut-offs for diagnosing diabetes are probably too lax.
How High Blood Sugar Causes Vascular Disease
Glycation: Glycation is a process in which sugar attaches to proteins and lipids producing advanced glycation end products (AGE products). These proteins and lipids with sugar attached to them begin to stick together (like molasses) hampering the function of these proteins and lipids.
High blood sugar causes glycation in two ways leading to vascular disease. First it causes glycation of LDL particles, the so-called bad cholesterol. Glycated LDL is easily oxidized and these oxidized LDL particles end up being deposit in the walls of blood vessels. This ultimately leads to atherosclerotic plaques.
Secondly, glycation of collagen occurs when blood sugars are too high. Collagen is a connective tissue that supports the walls of blood vessels. This leads to stiffening of blood vessels and contributes to the hardening of arteries.
Endothelial Dysfunction: The endothelium is the one-cell thick inner lining of blood vessels. The endothelium produces many chemical messengers and is influenced by many chemical messengers that regulate the diameter of blood vessels and blood flow. High blood sugar activates protein kinase C. This causes adhesion of molecules and increases uptake of some white blood cells into the walls of blood vessels. High blood sugar leads to constriction of blood vessels reducing blood flow and facilitates clumping of platelets contributing to the atherosclerotic process.
Increased Blood Clotting: High blood sugar increases the potential for blood clotting. High blood sugar stimulate increased production of thrombin, and decreased breakdown of fibrinogen. Together this increases the chance of a blood clot developing in an artery causing a sudden cessation of blood flow. If this happens to a coronary artery a heart attack occurs, and if it happens in a blood vessel in the brain a stroke occurs.
What’s a Healthy Blood Sugar?
In short, lower than what is currently recommended. Many consider a blood sugar less than 100 mg/dl or lower to be normal (at one time a blood sugar below 125 mg/dl was normal), but some studies suggest that the risk of cardiovascular disease related to blood sugar does not bottom out until a level of 85 mg/dl is achieved. Because of genetics some are simply not going to get to that level and there may be a day when we recommend diabetic drugs for people we now call non-diabetic.
As we continue to learn more recommendations regarding optimal blood sugars will change. The important thing to remember is that 85 mg/dl is better than 90 mg/dl, and 90 mg/dl is better than 95 mg/dl, and so on. So until we know more it seems wise to keep your blood sugar as low as possible by eating a low-glycemic diet and regular exercise which improves blood sugar control.
Avoid high blood sugar to avoid heart disease.
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