How to Grill Foods to Maximize Flavor and Minimize Harmful AGEs
When summer finally arrives in the mountains where I live, grilling season is a cause for celebration. I can’t wait to fire up the grill and roll out my favorite barbecue recipes. But grilling can be a disaster when it comes to brain-healthy eating. It’s not just the foods that often end up on the grill, such as processed meats, sugar-laden barbecue sauces, and fatty cuts of meat. The method of cooking food over flames racks up substances that are harmful to the brain. These inflammatory substances are advanced glycation end products, or AGEs. A diet high in AGEs has been linked to cognitive decline, Alzheimer’s, and other types of dementia.
You don’t have to give up grilling for fear of consuming too many AGEs. I can’t imagine a summer without enjoying grilled chicken with a side of my cilantro chutney, cauliflower with roasted lemon salsa verde, or grilled corn on the cob slathered in avocado butter. Grilling can be a brain-friendly cooking technique. All it takes is a little know-how about shopping wisely, prepping foods with care, and managing the heat of the grill.
First, what exactly are AGEs and why are they detrimental for brain health? AGEs are glycotoxins—substances that bind proteins together in a process called crosslinking. When heat is applied to a food in the presence of sugar, the protein in the food becomes chemically transformed into these crosslinked AGEs. The sugar can be inherent in the food, as in peak-season corn on the cob, or applied to the food in the form of a sugary sauce. While much of our exposure to AGEs is from ingesting foods, we also create AGEs on our own. As we age, we synthesize AGEs more and more in a process that is akin to aging itself.
In culinary school, I learned about the Maillard reaction—a term for applying heat to food so that it becomes toasty brown, or caramelized, creating delicious aromas, flavors, and attractive textures. This chemical reaction also creates AGEs, or crosslinked proteins in the food. It happens when you slather chicken with barbecue sauce and place it directly on a hot grill, or when you fry bacon in a pan that turns it crispy and brown. When you bake bread and the crust becomes golden brown, that’s AGE formation too. It is nearly impossible to cook without creating AGEs.
After consuming AGE-laden foods, substances travel into the bloodstream and wreak havoc, causing inflammation and oxidative stress. AGEs accumulate on the surface of normally smooth structures, such as the interior of blood vessels, making them lose their elasticity. Damaged blood vessels are more likely to become sticky and attract blood clots. In the brain, this can cause a major blockage, or stroke, or many small ones—what we used to call multi-infarct dementia and is now called vascular dementia.
Chronically elevated blood sugar is one factor that accelerates AGE formation. Diabetics are especially prone to developing damaged blood vessels over time, which can lead to cardiovascular problems such as heart attack, stroke, and peripheral vascular disease. Eventually, AGEs accumulate in brain tissue, leading to more inflammation, a process thought to be the underlying factor in developing Alzheimer’s disease. Researchers identified a link between diabetes and Alzheimer’s decades ago. Most recently, studies have found that even having pre-diabetes, or a borderline high blood sugar, increases the chance of being diagnosed with Alzheimer’s two-fold.
Because AGE formation in foods is dependent on high heat cooking methods in the presence of protein and sugar, processed foods are especially high in AGEs. Now, researchers are looking at how AGE levels in our food supply correlate with markers for oxidative stress and inflammation in the body. Experts recommend a low AGE diet to combat the chronic inflammation of certain diseases, such as diabetes, cardiovascular disease and chronic kidney disease.
How AGEs accelerate brain aging
Researchers at the Icahn School of Medicine at Mt. Sinai in New York found an association between the level of AGEs in the body and cognitive decline. When they studied healthy elderly participants without dementia, they found higher blood levels of AGEs in those who consumed more AGE-rich foods. And, participants with the highest AGE levels had poorer memory testing over time compared to those with the lowest AGEs. (See chart: High AGE levels and memory testing.) A larger, prospective study over 9 years found that AGE levels in the body correlate with cognitive decline in both diabetics and non-diabetics. Other researchers have shown that AGEs promote the formation of amyloid plaques and tau tangles, both key features of Alzheimer’s. In addition, AGEs accumulate in key brain locations in victims of neurodegenerative disease. For example, AGEs cluster in the hippocampus of those with Alzheimer’s (where the disease attacks first). In those with Parkinson’s disease, AGEs riddle the substantia nigra. The spinal cord accumulates AGEs in those with amyotrophic lateral sclerosis, or ALS, aka Lou Gehrig’s disease.
Alzheimer’s, to the best of our knowledge, results from multiple factors leading to chronic inflammation in the brain. No one knows for sure if a high dietary AGE intake translates to an increased risk of Alzheimer’s and other dementias. A definitive cause and effect relationship between AGE levels and Alzheimer’s is not yet proven. Given the current correlation, however, it makes sense to limit our intake of high-AGE foods and minimize AGE production when we cook.
The AGE content of foods
The more a food is processed, the higher its AGE level. Ultra-produced foods, such as crackers, cookies, chips, and other snack foods, top the list of most AGE-ful foods. Meats are inherently high in AGEs and become even more AGE-ful when grilled, broiled, and seared over high heat. Lunch meat, salami, sausages, and hot dogs add much to the AGE load of many Americans’ diets.
Fatty spreads — butter, margarine, cream cheese and mayonnaise — are among the most AGE-ful foods. Slathering these spreads onto a protein source over high heat on the grill is a recipe for a high-AGE meal. Some cooking oils, such as sesame, grapeseed, rice bran, soybean and palm oil, accumulated excessive amounts of AGEs because of the heat-expelled techniques required to extract the oil.
Raw, minimally cooked, and fresh foods are lowest in AGEs, especially grains, legumes, fruits, and vegetables. (Sounds a lot like the Mediterranean diet, doesn’t it?) Breads are sometimes low in AGEs. Breads prepared with added fats, such as biscuits, have more than 10 times the amount of dietary AGEs found in low-fat breads, rolls, or bagels.
For a comprehensive list of AGEs in foods, take a look at this study: Journal of the American Dietary Association, June 2010.) Just about every food item you can think of contains AGEs. It’s important to look at the AGE kU/serving column when comparing food items. Some foods clock in extremely high in AGEs but are only eaten in small amounts. It may seem obvious that a highly-processed meat like bacon ranks high in AGEs, but so do roasted nuts and granola bars. And most of the drinks Americans reach for—diet and sugary colas— contribute to the AGE load.
What to grill to minimize AGEs
Choosing foods that are low in AGEs in the first place is the first step to brain-healthy grilling. Because fresh, unprocessed foods, such as vegetables and fruits, are low in AGEs, you can grill them until brown and crispy and still end up with a low-AGE meal. My favorite vegetables for grilling include broccoli, cauliflower, asparagus, sweet peppers, zucchini, bitter lettuces, red onions, and eggplant. I also love grilling fruit, such as sliced peaches and pineapple, to serve as a part of a salsa with the main dish, or as a dessert with Vanilla Cashew Cream.
Choose leaner, thinner cuts of meat, such as a skirt steak over a rib-eye. Trimming meat of any visible fat means less flaming and AGE-rich char. Removing skin from poultry, such as chicken breasts and thighs, can also reduce AGE formation and saturated fat.
Marinating meats reduces AGE formation
Marinating not only tenderizes meat and creates depth of flavor, it slashes AGE formation in half. Meat and poultry benefit from a pre-grill bath in an acidic marinade for a least an hour. Choose acidic liquids with vibrant flavor profiles: yogurt, orange juice, lemon juice, mustard, wine, soy sauce, vinegars, and dark beer are all good choices. Pour the marinade off and blot the meat dry with a paper towel before grilling. It’s always a good idea to make extra marinade to use as a sauce, but be sure to discard what has been in contact with raw meat.
Keep your grill clean
A clean grill not only makes food taste better, it minimizes AGEs. Remove charred pieces of food leftover from your last grilling session. Clean your grill every time you use it: Once hot, scrub it with a stiff brush. Coat a wadded-up piece of paper towel or half an onion with a heat-stable oil, such as avocado oil. Thoroughly coat the grill to prevent food from sticking. Using a clean grill basket can also keep your food from getting too hot, sticking and charring.
Grill low and slow
The next step in brain-friendly grilling is to know how to safely apply heat to the food. Because AGEs thrives in conditions of direct, high heat, make “low and slow” your new grilling mantra. Create a high heat zone and a low heat zone on your grill. Instead of placing foods directly over the hottest coals or close to the flame, grill over indirect heat. This type of grilling takes a little longer but results in more tender, flavorful meats with less burning.
Using a grill basket or some other barrier to the high heat is another way to minimize AGE formation. Roasting broccoli florets in a grill basket over indirect heat, for example, will create less AGEs than placing right over the flames. And because broccoli is a food that is inherently low in these substances, you can brown it until it’s crisp without racking up excessive AGEs.
Grilling over a cedar plank provides a barrier to high heat with the added bonus of infusing foods with a woodsy aroma. This method works well for retaining the beneficial omega-3 fats and vitamin D in fish, which otherwise seep out when exposed to high heat.
Grilling with hardwood chips or charcoal briquettes will make it easier to cook foods at lower temperatures. Avoid overcooking and charring of meats. Those black, charred lines harbor concentrations of AGEs that get into the bloodstream and trigger inflammation. And, grill marks are known to contain heterocyclic amines (HCAs), substances long-considered carcinogenic. Watch grilled meats for the formation of grill marks, and flip just as they are starting to show.
Serve grilled foods with a big salad and veggies
There is some evidence that eating grilled foods with an abundance of vegetables can offset their AGE load. Leafy greens, including herbs like basil, parsley, and cilantro, have intrinsic antiglycation properties, preventing the formation of AGEs in the first place and interfering with how they get absorbed in the body. Ideally, most of your plate is full of leafy greens and other vegetables. The MIND diet recommends limiting red meat consumption to less than four 3-ounce servings each week. (A 3-ounce serving is roughly the size of a deck of cards.)
Go ahead and enjoy the season of cooking and eating out of doors. With a little attention to brain-friendly grilling techniques, it’s possible to cut back on the consumption of AGE-rich foods. As studies have shown, reducing AGEs in the bloodstream by at least half can directly translate into less oxidative stress and inflammation in blood vessels and the brain.
Read more about the link bewteen AGEs and health in this review article: Advanced Glycation End Products (AGEs) May Be a Striking Link Between Modern Diet and Health.
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