Heterocyclic Amines and Polycyclic Aromatic Hydrocarbons

Hetero-what and polycyclic-who? Heterocyclic amines (HCAs) are chemicals formed when certain amino acids and sugars (both naturally occurring in meat) react together when exposed to high temperatures. Polycyclic aromatic hydrocarbons (PAHs) are present in emissions from wood and coal burning, automobiles, tobacco smoke, and in many foods. In grilling, they are formed when fats from the meat drip down into the open fire, causing PAHs from the flames to adhere to the meat’s surface. Both HCAs and PAHs bind to DNA, with the potential to cause mutations and changes, a major step in the process that ultimately leads to tumor formation. HCAs are on the National Institutes of Health’s list of known carcinogens.

Advanced Glycation Endproducts (AGEs)

AGEs are created when proteins and fats react with sugar when exposed to high heat. It is this reaction that creates the char on a steak, the browning of toast, and the singe on roasted marshmallows. Cooking techniques such as toasting, charring, and grilling are recognized for enhancing the flavor of foods and are often favored over healthier methods. The problem is that this reaction between sugar and protein doesn’t just change the color and taste of food, it also creates AGEs, which can be toxic. In the body, they cause damage to tissue and organs by binding to cellular receptors known as RAGEs (receptors of AGEs), which promote low-level inflammation. They also link with proteins in cells, causing permanent damage to the cellular structure and altering their function. They are also associated with a host of diseases, including type-2 diabetes, cardiovascular disease, Alzheimer’s disease, allergies and autoimmune diseases, cancers, gastrointestinal diseases, and even kidney failure. AGEs are also created in the body when excess blood glucose binds with proteins. When you think of AGEs, think “aging” because that is exactly what they do to the body.

It’s important to know that grilling is not the only cooking method that creates toxic compounds. Fried, smoked, and processed meats are all high in these dangerous compounds. In fact, it may be the cooking and processing methods of these meats that have earned them their unhealthy reputation, not the meat itself. The best bet is to stick to a diet high in natural and unprocessed foods, and when you do use a cooking technique like grilling, be sure to follow a few preparation techniques that will greatly reduce the formation of these damaging compounds.

Step One: Reduce all those acronyms

• Avoid cooking meats directly over very high heat and be sure to trim away any charred pieces before eating.
• Flip meat often. This helps keep HCA levels low.
• Keep a spray bottle filled with water handy to immediately put out any flare-ups; it’s the flames that contain the PAHs that can adhere to meat.
• Cook meats at lower temperatures for a longer time. Remember, LOW and SLOW is the way to go.
• Use marinades that incorporate citrus juice, antioxidant-rich herbs, and/or vinegars, which help to reduce the formation of AGEs and HCAs and help prevent PAHs from adhering to meat.
• Always clean your grill thoroughly to remove any leftover charred foods before grilling. These little bits of stuck on charred foods are loaded with HCAs and PAHs.
• Learn to use your grill in new ways. For example, meat can be roasted on a grill by heating one side and closing the lid, food is then slowly cooked on the non-heated side. Cast iron cookware can also be placed directly on the grill and used the same way you would on a stovetop.
• Use natural wrappers, such as corn husks and banana leaves, or parchment paper, to create grilling pouches that protect your food.
• Use your grill for more than meat. Veggies are wonderful grilled and much less likely to develop these harmful compounds.

Step Two: Increase your defenses

There are many antioxidant-rich foods that will help to protect your body from the dangerous effects of these chemicals. Nearly all veggies and fruits are rich sources of antioxidants and have a proven track record of protecting cells from the types of DNA damage caused by HCAs and PAHs. Serve lots of vegetables, especially cruciferous veggies like cabbage (coleslaw!) or broccoli, alongside your grilled meat, and serve a large fruit salad or grilled fruit for dessert. Veggies are also not vulnerable to the formation of these dangerous compounds, so load up the grill with kabobs skewered with button mushrooms, red onions, colorful bell peppers, and zucchini. Fill a grill tray with tender asparagus and thinly sliced lemon. Throw some marinated portabella mushrooms or thick slices of eggplant on the grill for a veggie style “steak.” Experiment with different veggies.

For even more protection, incorporate nature’s heavy hitters into your grilling—certain foods and spices have a big impact on preventing the formation of HCAs, PAHs, and AGEs. For example, when cherries are added to ground beef used to make hamburgers, the burgers contain only 10 percent of the HCAs normally found in a burger. A simple and highly effective way to reduce the formation of HCAs in your grilled meats is to add a little vitamin E directly to ground meat, or apply it to the surface of larger cuts. It doesn’t take much either—all you need is one 400 IU capsule of natural vitamin E (d-alpha tocopherol) to treat 10 pounds of hamburger. The flavonoids found in citrus can significantly reduce the formation of HCAs and help prevent PAHs from adhering to meat; try adding citrus juices to marinades. The Lactobacilli strains in yogurt have been shown to neutralize HCAs in the gut, preventing them from damaging DNA. Serve a yogurt-based sauce with your grilled meat or even yogurt and fruit for dessert. Nearly all spices offer antioxidant protection—turmeric, rosemary, ginger, paprika, oregano, cinnamon, and garlic powder are all good choices—and they can easily be added to rubs or marinades. While all of these additions are potent protectors for our bodies, they are also delicious and actually enhance the taste of the foods you are grilling.

Don’t let HCAs, PAHs, and AGEs ruin your summer barbeques. Make this summer the summer of conscious grilling by following some simple healthy preparation tips, building your antioxidant arsenal for extra protection, and experimenting with different foods to get the most out of grilling season!