Glycation

Glycation is a chemical reaction that occurs spontaneously, without the help of enzymes. Glucose in the blood attaches to amino groups on the surface of proteins. Over time, the structure changes, forming substances that no longer detach. These final substances are called advanced glycation end products (AGEs). The reaction is also called the Maillard reaction, after the French chemist Louis Camille Maillard, who first described it in 1912.

You can easily see this reaction in the kitchen. Bread crust turning brown, the savory aroma of grilled meat, and the deepening flavor of coffee during roasting all involve the same family of reactions. Inside our bodies, these reactions occur much more slowly at body temperature, with products accumulating over months and years.

In Korean, both reactions are called by the same term, making them easy to confuse.

• Glycation: A reaction that occurs without enzymes. It occurs more extensively when blood glucose is higher and more time passes. This is the reaction discussed in this article.
• Glycosylation: A reaction in which enzymes inside cells attach sugar chains at designated sites. It is a normal finishing process that enables proteins to function properly.

The process referred to in the discussion of collagen in Volume 4 of Integrative Manual Therapy (IMT) is closer to the latter. It explains that after collagen chains are formed, they undergo modifications such as hydroxylation and sugar attachment, producing slightly different forms even from the same gene. It also notes that type IV collagen, which forms basement membranes, has particularly large amounts of attached sugars.

Glycation accumulates in long-lived proteins. Collagen in the skin, tendons, ligaments, and blood vessel walls is a typical example. When glycation products form bridges between collagen fibers, collagen cross-linking increases. An appropriate amount of cross-linking is necessary for tissues to withstand force, but too much makes tissues stiffer and less elastic. These changes accumulate gradually with age and occur faster when blood glucose remains high for a long time. This is why glycation is often mentioned when explaining tissue changes associated with aging.

The glycated hemoglobin (HbA1c) blood test works on the same principle. Measuring the proportion of hemoglobin in red blood cells that has glucose attached provides an indication of average blood glucose levels over the past two to three months. For a detailed interpretation, see Metabolic blood markers.

Glycation is not a reaction that produces symptoms you can directly feel. However, it is linked to the following everyday habits and experiences.

• Frequently consuming sugary foods and drinks over a prolonged period increases the time blood glucose stays high.
• Foods cooked at high heat, such as by frying or grilling over a direct flame, contain high levels of AGEs. Boiled or steamed foods contain relatively less.
• Without exercise, muscles have fewer opportunities to use glucose.
• Several factors contribute to the feeling that joints and tendons no longer move as smoothly with age. Increased cross-linking within tissues is discussed as one of them.

Glycation cannot be prevented entirely, but some habits can influence its rate.

• Try a gentle walk after meals. Even 10–15 minutes of walking after a meal helps muscles use glucose.
• Try reducing refined sugar intake. Choosing water or unsweetened tea instead of sugary drinks can reduce the burden.
• Vary your cooking methods. Rather than relying only on grilling and frying, include steamed or simmered dishes as well.
• Keep up stretching and strength training. Stimulating tissues through movement helps collagen fibers align along their natural orientation.
• Consult a healthcare professional about whether you need blood glucose management. If a health screening shows elevated blood glucose or glycated hemoglobin, it is a good idea to seek a consultation tailored to your individual condition.