Glycation is a reaction that takes place when simple sugar molecules, such as fructose or glucose, become attached to proteins or lipid fats without the moderation of an enzyme. This results in the formation of rogue molecules known as advanced glycation endproducts (AGEs). This process, also known as non-enzymatic glycosylation, is normally governed by enzymatic activity, which is necessary to regulate the metabolic functioning of molecules. The lack of this catalyst deters the normal glycosylation of sugars to produced needed energy, however, and since it disrupts normal metabolic pathways and advances the circulation of AGEs, it can promote certain health risks.
Exogenous glycations, one form that occurs outside the body, are responsible for allowing foods to brown during cooking. This type is dubbed the Maillard reaction, in honor of the early 20th century French chemist who first observed how sugars react with fats or proteins while exposed to high temperatures. While crisp French fries and grilled meats may be tasty, the reaction that produces them also creates 2-propenamide, a suspected carcinogen that comes with the meal. In addition, exogenous AGEs are sometimes added to certain foods to enhance color and flavor, including baked goods, dark colas, and coffee.
Endogenous glycation, which occurs in the body, is associated with increased oxidative damage. AGEs and their by-products are linked to many age-related diseases, including Alzheimer’s. This process is of particular concern for diabetics, who already suffer from the effects of poor glucose control. In fact, elevated levels of AGEs contribute to a number of diabetes-related complications, including neuropathy, retinal disease, and kidney failure.
Elevated levels of AGEs also deplete nitric oxide levels, which promotes vascular damage and an increased risk for heart disease. As sugar molecules bind to high-density lipoprotein molecules — the “good” cholesterol — the latter are blocked from binding to receptor sites in the liver. The end result is that the liver is duped into thinking there’s a shortage of cholesterol and keeps manufacturing more to deposit into the bloodstream.
AGEs seem to age the human body faster than nature intended. In addition to limiting consumption of baked goods, fried foods, and other high content AGE-containing foods, studies have shown that certain nutrients may serve as inhibitors of this process. For instance, calcium pyruvate and carnosine not only appear to help prevent the reaction, but also stimulate proteolysis, or the degradation of glycated proteins. Certain plant extracts have also been studied for their potential to prevent glycation, at least in vitro. Among those that have shown promising results are cinnamon, black pepper, ginger, cumin, and green tea.