What is glycation and how does sugar damage your cells from the inside?
Sugar damages your cells through a chain of chemical reactions that affect proteins, power plants, and small blood vessels. The mechanism is well described and provides a concrete reason to take persistently high blood sugar seriously.
Glycation is a chemical reaction in which sugar molecules spontaneously attach to proteins, without the body having any control over the process. Through a series of steps, waste products called AGEs are formed. These accumulate in tissues as you age, and do so more rapidly when blood sugar remains persistently elevated.
AGEs disrupt cell function by chemically altering intracellular molecules. They have been linked to age-related diseases such as diabetes, cardiovascular disease, kidney disease, and Alzheimer's disease. In the skin, glycation primarily affects collagen, the protein that keeps skin firm and elastic. The result: wrinkles, loss of elasticity, and a yellowish complexion. UV radiation accelerates this process further.
A large part of the damage is driven by harmful oxygen radicals (free radicals). Chronically high blood sugar activates several metabolic pathways that produce an excess of these radicals. At the same time, high blood sugar suppresses the cell's own defence systems that normally clear those radicals away. The consequence: the cell's power plants become damaged, cells die off more rapidly, and cell membranes are compromised.
AGEs also bind to a specific receptor on the cell surface known as the RAGE receptor. This binding activates inflammatory pathways and damages the walls of small blood vessels, particularly in the eyes, kidneys, and nerves. The same processes, oxidative stress, mitochondrial damage, and inflammation, are also found in the brains of people with Alzheimer's disease. There are indications that AGEs form a bridge between diabetes and that brain condition, although the evidence for this is not yet conclusive.
The RAGE receptor does more than process AGEs, incidentally. Following a heart attack, a protein released during cell damage has been shown to activate the same receptor and cause additional heart damage. This makes RAGE a broader alarm receptor in multiple disease processes, not exclusively in sugar-related damage.
All claims are based on published research (PMID 36364850, 27156888, 33248932, 40048937, 28137665, 39411860). The core of glycation and AGE-related damage is well substantiated; the link with Alzheimer's disease is plausible but has not yet been definitively proven.