To most folks, a fried or grilled piece of meat smells great when it’s cooking and tastes wonderful when you eat it.

But your brain isn’t as pleased as your taste buds when you chow down on those types of foods.

For once, the problem isn’t carbs, or the evils of red meat or something like that. It’s the toxins that form when you cook at the high temperatures required by grilling or frying. At large enough doses, over a long enough time, these toxic substances can scramble your brain and increase your risk of Alzheimer’s disease.

Eat Browned and Blackened Meat, Lose Memory

A chief problem with these foods begins with chemicals called advanced glycation end products (AGEs) – harmful substances that can increase drastically during cooking.

These chemicals are naturally present in the body, but they multiply in a big way when food (particularly meat) is cooked at a high temperature. Research shows that AGEs boost your chances of many illnesses – notably cancer — because they lead to oxidative stress on a cellular level and accelerate harmful inflammation.

These compounds cling to receptors in the body called RAGE (receptors for AGEs). When engaged in this way, these receptors carry beta-amyloid proteins, the substances that form plaque, through the blood-brain barrier and play a role in advancing the progress of Alzheimer’s disease.1

A study at the Mount Sinai School of Medicine in New York tested the effect of cooking temperature on more than 540 foods. The researchers showed that every uptick in the temperature used to cook food causes an uptick in the food’s quantity of AGEs.2

And when an international group of researchers looked at the diets of countries around the world, they found that those places where people cooked their foods at the highest temperatures – which usually meant cooking without using water in the cooking process – had the highest rates of Alzheimer’s disease.3

This goes along with a four-year study at Mount Sinai that discovered that even among seniors in their 60s and 70s who didn’t have dementia or other memory problems when the study started, those who ate the most AGEs experienced “a faster rate of decline in memory” than other people whose diets included less of these chemicals.4

Contributes to Immune Cell Dysfunction

A clue to how AGEs can impact your memory was recently discovered by researchers at the University of Bath. They found that AGEs associated with high blood sugar can inactivate an enzyme called MIF (macrophage migration inhibitory factor).

When this enzyme is sidelined, it alters the behavior of immune cells called glia which are supposed to protect brain cells from waste products and debris. (Microglia are sometimes called “the brain’s janitors” because they clean up waste.) Without functional MIF enzyme, the glia make the brain’s inflammatory destruction worse instead of helping to control damage.

Steps to Take

To keep your consumption of AGEs down to a safe level, you should generally limit the amount of meat you eat. Meat tends to be highest in AGEs. According to researchers at Mount Sinai, beef and cheeses contain the most AGEs. If you want to go the last mile to avoid these toxins, then please know that poultry, pork, fish and eggs rank next after beef and cheese. Lamb is relatively low in AGEs.

Cheeses can contain a large amount of AGEs because they are pasteurized at high temperatures. That’s just one more mark against pasteurization – there’s plenty of other evidence that it damages the nutritional benefits of milk products.

As for cooking methods – frying, broiling, grilling, and roasting produces more AGEs than boiling, poaching, stewing or steaming – the “water methods.” And braising meat – slow-cooking in liquid at low temperatures — is one of my favorite methods.

Spreads like butter, cream cheese, margarine and mayonnaise are also rich in AGEs.5

Marinating meat in an acidic solution like lemon juice and vinegar before cooking cuts the amount of AGEs in half.

You can certainly eat as many vegetables as you want, because these foods are relatively low in these destructive compounds. And as I’m sure you know, vegetables contain a wealth of health-boosting natural substances.

Worth Worrying About?

Do AGEs contribute to cancer and dementia is a major way? Both these diseases are caused by multiple factors, and no one has produced any figures for the specific dangers of AGEs. I think grilling and frying should be kept to a minimum. They’re a treat to enjoy every once in a while, not a routine way to prepare your food.

We can all get away with a couple of vices. The question is – how many? Where do AGEs fit into your overall “toxic load” consisting of ALL the things you do that you probably shouldn’t be doing?


  1. https://www.ncbi.nlm.nih.gov/pubmed/19579173
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3704564/
  3. https://www.ncbi.nlm.nih.gov/pubmed/25633677
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4167353/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3704564/