The term advanced glycation end products (AGEs) is a mouthful for a group of compounds that are formed both in the body and in food by the reaction between sugars with proteins and lipids (fats). The sugars literally coat proteins and lipids, which causes them to not function well. In addition, these adulterated, now “new to nature” molecules are not easily recognized by the immune system and will cause body-wide attacks by the upregulated (overactive) immune system. Auto-immune conditions have increased markedly over the last decade and I believe our diet is largely to blame.
AGEs are also aptly named glycotoxins and you’ll soon see why. The reaction that produces AGEs is known as the Maillard reaction, or the browning reaction because when foods are heated and browned, AGEs are created. Brenda has blogged recently about AGEs in the diet.
Small amounts of AGEs form naturally in the body through normal metabolism and as a result of the aging process. That’s right, AGEs will gradually age you. On the other hand, high levels of AGEs are commonly found in people with diabetes, cardiovascular disease, Alzheimer’s disease2 or any condition that involves oxidative stress.3 Whether AGEs are produced in the body or ingested through food, both are thought to have the same physiological effects: they increase inflammation and oxidative stress, which leads to all kinds of damage inside the cells.
It is now known that cells react to AGEs by creating receptors on their cell surfaces called receptors of AGEs, and you can guess the acronym—RAGES. This means the cells take the AGE message via the receptor into the cell that then sends out protein messengers to ramp up (or upregulate) a pathological immune response, as well as cause intracellular damage in the process.
In a recent review article published in the journal Integrative Medicine, AGEs researcher and professor of medicine at The Mt Sinai Hospital, Jaime Uribarri, MD discussed the human clinical research behind the benefits of a low-AGE diet.4 In general, foods cooked at high heat produce AGEs that are then absorbed though the intestinal lining and into blood circulation, increasing the body’s total AGE burden.5
Both healthy and unhealthy people can harbor high AGE levels. In a study involving 172 young and old healthy individuals, those with high levels of certain AGEs were also found to have high levels of inflammation, oxidative stress, endothelial dysfunction (a condition that leads to atherosclerosis, or plaque buildup in the arteries), and other abnormalities associated with chronic disease.6
Uribarri explained, “These findings suggest that healthy persons habitually consuming high AGE diets may have abnormally high levels of serum AGEs that may exceed the capacity of native defenses to remove or neutralize them, leading to high oxidative stress, a common denominator for most chronic diseases.”
A low-AGE diet involves food that, when cooked, is boiled, poached, stewed, or steamed. Foods that are fried, baked, or grilled are avoided. Think of those foods that are browned when cooked—they are high in AGEs, and they will age you. I know, these very foods are often delicious, and I think that to eliminate them completely would only end badly. As I always say, “Everything in moderation.”
You would do well do limit your browned, high-temperature cooked foods. Enjoy them occasionally, but try to work in more foods that are low in AGEs. Raw foods are particularly recommended. Low-AGE diets have been found to lower circulating AGE levels as well as markers of inflammation and oxidative stress.4 In people with diabetes, the diet also lowers insulin resistance. Because inflammation is the common underlying feature of most, if not all, chronic disease, lowering your exposure to AGEs through healthy eating is one way of staying healthy in an increasingly unhealthy world.
- B.K. Kilhovd, et al., “Serum levels of advanced glycation end products are increased in patients with type 2 diabetes and coronary heart disease.” Diabetes Care. 1999 Sep;22(9):1543-8.
- V. Srikanth, et al., “Advanced glycation endproducts and their receptor RAGE in Alzheimer’s disease.” Neurobiol Aging. 2011 May;32(5):763-77.
- H. Vlassara, et al., “Advanced glycation end product homeostasis: exogenous oxidants and innate defenses.” Ann N Y Acad Sci. 2008 Apr;1126:46-52.
- J. Uribarri, “Effects of a diet low in advanced glycation end products in humans.” Int Med. Oct 2012. 11(5):46–49.
- J. Uribarri, et al., “Advanced glycation end products in foods and a practical guide to their reduction in the diet.” J Am Diet Assoc. 2010 Jun;110(6):911-16.e12.
- J. Uribarri, et al., “Circulating glycotoxins and dietary advanced glycation endproducts: two links to inflammatory response, oxidative stress, and aging.” J Gerontol A Biol Sci Med Sci. 2007 Apr;62(4):427-33.