You’ve probably never heard of advanced glycation end products, or AGEs, but they are a big part of how well (or poorly) you age.
AGEs are formed by a chemical reaction between sugars and amino acids that crosslinks proteins and alters their structure and function. These compounds also bind to receptors called RAGEs, which alter cellular signaling and lead to inflammation and oxidative stress.
Foods such as grilled steak, fried chicken, barbecued ribs, French fries, eggs over easy, and other foods that are rich in protein and fat and prepared over high heat are significant sources of AGEs. But they’re by no means the only sources.
AGEs are also naturally generated in our blood and tissues as we process sugars. AGEs are systematically detoxified and removed via the kidneys, but problems arise when excessive levels overwhelm the body’s ability to eliminate them.
As you might suspect, AGEs are particularly problematic in diabetes, as high levels of blood sugar dramatically increase their production. Hemoglobin A1c, a blood test commonly used to diagnose and monitor diabetes, measures the concentration of AGEs in hemoglobin, a protein in red blood cells. A high A1c level is a sign of not only raised blood sugar but also elevated AGEs, inflammation, and oxidative stress throughout the body.
AGEs are a Modifiable Health Risk
Scientists have long known that AGEs play an important role in diabetic complications such as cardiovascular disease and nerve, kidney, and eye damage. Research now reveals that in addition to being a consequence of high blood sugar, AGEs are also a cause, as these toxic compounds injure insulin-producing cells in the pancreas, increase insulin resistance, and raise risk of metabolic syndrome and diabetes.
Diabetics aren’t the only people at risk. Excessive AGEs in the blood and tissues ramp up chronic inflammation and free radical damage and are associated with a wide range of health problems.
Accumulation in the joints, bones, and skin increases collagen stiffness and fragility and is linked with arthritis, bone brittleness, and wrinkling. AGEs are an underlying cause of cataracts and macular degeneration. They damage the blood vessels and are a factor in cardiovascular and kidney disease. RAGE receptors transport beta-amyloid proteins across the blood-brain barrier and contribute to neurodegeneration and Alzheimer’s disease. And because AGEs build up over time, they also speed up aging.
You can protect yourself by keeping your blood sugar under control with weight loss, a low-glycemic diet, exercise, and supplements such as berberine. Antioxidants, especially vitamins C and E, selenium, carotenoids, and alpha lipoic acid, counter the oxidative stress unleashed by AGEs. Benfotiamine, a vitamin B1 derivative, and L-carnosine, an amino acid combo, have specific anti-glycation properties. Several nutraceuticals are also protective, including spirulina, curcumin, EGCG (from green tea), quercetin, and grape seed extract.
There is another thing you can do to tame AGEs and RAGEs—and it starts in your kitchen.
AGEs and the Kitchen Connection
The chemical reaction that produces AGEs is responsible for the savory taste and browned surface of seared, roasted, and grilled meats, crispy fried foods, crusty lasagna, and other dishes cooked at high temperatures. Most people find these preparations tastier than boiled or steamed foods, which is why AGEs are so abundant in the average American diet.
For years, the diet connection was ignored because scientists believed that ingested AGEs were poorly absorbed by the body. We now know that eating lots of AGE-rich foods does raise blood and tissue levels and increases oxidative stress, inflammation, insulin resistance, and risk of chronic disease. Recent research also demonstrates that a diet low in AGEs reduces these risk factors—and, in animal studies, actually lengths lifespan.
A 2016 study examined the effects of dietary AGEs on obese patients with metabolic syndrome. One group was told to eat their regular high-AGEs diet, while the low-AGEs group was instructed to avoid frying, grilling, and baking in favor of steaming, poaching, and stewing. After a year on these diets, the low-AGEs group had modestly decreased weight and significant reductions in AGEs, inflammation, oxidative stress, and insulin resistance. All these markers increased in the high-AGEs group.
Practical Guidelines for Reducing AGEs
To recap, AGEs are most abundant in foods high in protein and fat, particularly those of animal origin, cooked over dry, high heat. Beef contains the highest levels, followed by poultry, pork, fish, and eggs, while vegetables, fruits, legumes, grains, and dairy are naturally low. However, processing and high-heat cooking dramatically increase AGEs content in most any food. For example, milk and yogurt are low but cheese and butter are high. French fries and a breaded fried chicken breast contain 10 times as many AGEs as a boiled potato and poached chicken.
Simply switching cooking methods makes a huge difference. In the above study, the low-AGEs group ate boiled eggs rather than fried, poached versus grilled chicken, and beef stew as opposed to grilled steak—changes that cut their daily AGEs intake by two-thirds. Researchers have also found that acidic marinades containing lemon or vinegar prior to cooking reduce AGEs formation in grilled and broiled meat by as much as 50 percent.
I’m not suggesting you give up barbeques and roasts—just don’t make them part of your daily diet. Poaching is an excellent way to prepare fish, and steamed foods can be jazzed up with herbs and spices. Microwaving produces relatively fewer AGEs, and slow cooking over very low moist heat is another option.
You can’t eliminate AGEs, but significantly reducing them is a step on the road to better health, reduced disease risk, and a longer healthspan.