ONE MORE FOOD CULPRIT

The good news is that modifying cooking methods can reduce exposure to AGEs

You scrutinize food labels for cholesterol, sodium, sugar and trans fats, the usual suspects for playing mischief with health. Let me now add a little more drama to your life by introducing yet another potential culprit, one you will not find listed on any label.

“Advanced glycation end products,” or “AGEs,” are formed in cooked or processed foods when amino acids or fats react with sugars. This wide array of compounds can enter the bloodstream upon ingestion and predispose individuals to oxidative stress and inflammation, factors that are believed to play a role in the causation of many chronic conditions that include Type 2 diabetes, cardiovascular disease, arthritis, cataracts, kidney problems, cancer and perhaps even Alzheimer’s and Parkinson’s disease. To complicate matters, AGEs can also form in our body and accumulate over time to play a role in aging as well as in triggering disease.

Before getting down to details about AGEs, a little clarification is in order as to why oxidative stress and inflammation should be a concern. Think of the body as a laboratory in which myriad chemical reactions, ranging from enzymes targeting potential toxins to oxygen combining with glucose to produce energy, are going on all the time. Some of these produce free radicals, highly reactive oxygen species that can damage proteins and DNA. Although our bodies have evolved various ways of neutralizing the reactive oxygen species, “oxidative stress” can occur when there is an imbalance between the production of free radicals and the ability to detoxify them or to repair the resulting damage. Such stress can happen when the body launches a chemical attack to eliminate AGEs, resulting in “friendly fire” in the form of free radicals.

Inflammation, the body’s way of initiating a healing response, is actually related to oxidative stress. If a cut or scrape swells and gets red, hot and painful, it is because immune cells, often using free radicals as weapons, rush to the area to deal with microbes or toxins that now have an entry into the bloodstream. Once the intruders have been dealt with, the inflammation subsides, but inflammation can also occur inside the body in response to potentially harmful substances. If these are continually present, as can be the case with AGEs, constant low-level inflammation ensues. As white blood cells gather to try to eliminate the intruder, they can end up damaging healthy tissue, as well.

Reducing oxidative stress and chronic low-grade inflammation is obviously desirable, and since AGEs have been implicated in these conditions, attempts to reduce exposure seem appropriate. Underlining this is the finding that AGEs may cause damage by another route as well: They can cross-link proteins, altering their properties and functions.

Although the proposal of a link between AGEs and disease is recent, the reaction by which AGEs form has been studied for more than a hundred years. In the early 20th century, French physician Louis Maillard, who had a particular penchant for chemistry, became interested in why foods like bread or meat turned brown on baking or cooking. He concluded that heat caused amino acids and fats in these foods to react with sugars, a process referred to as “glycation.” The Maillard Reaction, as it came to be known, eventually turned out to be extremely complex, as the initially formed glycation products were found to undergo a variety of further reactions resulting in the “advanced glycation end products” with the key factor in their formation being dry heat.

Evidence for the possible damage caused by AGEs comes both from animal and human studies. Mice have elevated circulating and tissue AGEs when fed a diet high in these substances and also exhibit a greater risk of atherosclerosis and kidney disease. When placed on an AGE-restricted diet, they show improved insulin sensitivity and live longer. Human evidence parallels these findings. Researchers at Mount Sinai Medical Center in New York randomized obese subjects into two groups, with one consuming a low-AGE diet and the other a standard American diet with high AGE content. After a year, the first group had lower blood levels of AGEs, a reduction in insulin resistance, and a decrease in markers for inflammation and oxidative stress.

Now that I have your attention about a substance that you probably didn’t even know exists, it is time for some good news. Regimens that reduce dietary AGEs and also curb their production in the body are the ones that are recommended anyway for the maintenance of health. Since sugar is a key ingredient in the Maillard reaction, reducing it in the diet will lessen the chance of AGEs forming in the body. It is no surprise that diabetics who have elevated sugar levels are more prone to AGE-associated diseases.

Most significantly, modifying cooking methods can effectively reduce exposure to AGEs. Foods rich in both protein and fat, mostly animal products, will contain lots of AGEs when broiled, grilled, fried or roasted, with many fast and processed foods falling into this category. Low temperature moist cooking, such as stewing or microwaving, results in low AGE content. Diets rich in fruits, vegetables, whole grains, legumes, fish and low-fat dairy, the Mediterranean diet being an example, are typically low in AGEs.

My preferred meat is chicken, and I have normally alternated between grilling, frying as schnitzel, or stewing as chicken paprikash. In light of the AGE revelations, I now gravitate more toward the paprikash. An added benefit here is that the tomatoes, green peppers, onions and paprika also provide antioxidants that have been shown to mitigate the production of AGEs. When I made my last batch, just for fun I put on a chef ’s hat that prompted my daughter to quip that I looked like a giant Q-tip. I’ll put that comment to use. Q: How do I reduce AGEs? Tip: If you stew, you won’t accrue.

Diets rich in fruits, vegetables, whole grains, legumes, fish and dairy are typically low in AGEs.