Advanced Glycation End Products

They predict higher risk of chronic diseases

They’re common in Western diets, but you can limit them

Advanced glycation end products is a mouthful! What does it mean, anyway? Advanced glycation end products (AGEs) are complex organic molecules produced from the reaction of certain sugars (such as glucose and fructose) and amino acid groups attached to proteins, fats, or nucleic acids. This reaction is known as the Maillard Reaction, discovered in 1912, and is responsible for the browning of toast. Evidence links higher concentrations of AGEs in humans to the aging process, yet it’s still uncertain if AGEs cause accelerated aging.

AGEs occur in many foods, increasingly so in those that are processed at high temperatures and under dry conditions. Examples include animal-derived items such as dried meat, cheese, and powdered milk. Cooking at heat and dry conditions (grilling, frying, roasting) can increase the AGEs concentration by 10 to 100 times that of the uncooked foods.

A team of researchers analyzed the AGEs concentrations of 549 foods obtained from the Mt. Sinai cafeteria and local retailers in New York City. They found wide differences in AGEs concentrations. Examples of foods with high AGEs concentrations per serving included broiled chicken thigh with skin, steak pan-fried in olive oil, broiled ground beef, broiled chicken breast, bacon, American cheese, and french fries. Carbohydrate-based foods (beans, crackers, fresh milk, vegetables) tended to have the lowest AGEs concentrations.

Animal and human studies suggest that increased consumption of AGEs predicts decreased insulin sensitivity and possibly higher risk of type 2 diabetes. Researchers in Australia designed a clinical trial that used the gold standard (insulin clamp) for measuring insulin sensitivity. Participants included twenty overweight men and women with an average age of 34 years. All participants ate a diet either high or low in AGEs for two weeks followed by a 4-week washout period followed by two weeks of the other AGEs diet. The two diets were matched in macro-nutrient composition. The two-week diet of low AGEs resulted in significantly greater insulin sensitivity compared to the high AGEs diet. This in spite of the fact that the high AGEs diet was not vastly higher in AGEs (about 50 percent) than the low AGEs diet.

AGEs occur in both healthy people and in people with diabetes. But concentrations can be 50 percent higher in diabetics, due to their high blood sugar levels. In diabetics, AGEs contribute to micro and macrovascular complications, such as reduced kidney function. Australian and American researchers conducted a meta-analysis of 24 studies that evaluated the links between diets with low and high levels of AGEs and cardiometabolic factors. Results showed that low-AGEs diets predicted significantly healthier levels of total cholesterol, LDL-cholesterol, adiponectin (a hormone that protects against insulin resistance), and a trend toward lower fasting insulin. Eating foods with lower levels of AGEs and cooking those foods at lower heat under moister conditions might improve your cardiometabolic health.

A recent review tempered enthusiasm for reducing AGEs to support better health. The authors provided the following cautions: 1) Most studies investigate 1-3 AGEs and not all of those (about 15) found in food. 2) Different analytical techniques can yield markedly different results on AGES concentrations in foods and blood samples. 3) Nearly all studies are cross-sectional (and cannot discern cause-and-effect) or short-term clinical trials. Nevertheless, it seems prudent to reduce your exposure to AGEs by changing your food buying and cooking habits. The authors offer three suggestions: 1) Eat vegetables and fruits raw, boiled, or steamed. 2) Avoid processed carbohydrates, high-fructose corn syrup and browned and fried foods, 3) Cook meats at low temperatures (such as, beef stew in a crock pot) and do not fry or use high heat.

You may be frowning after reading this blog post. “Are you saying, Alan, that those juicy grilled steaks I love are filled with AGEs?” Yes, that’s correct. But remember that you probably don’t eat those juicy grilled steaks very often. I suggest reserving the juicy grilled steaks for special occasions that you will anticipate with great enthusiasm and relish with every bite. Plus, someday your kidneys will thank you for your forbearance.

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