(Healthline) – Overeating and obesity are known to cause serious health problems. They increase your risk of developing insulin resistance, diabetes, and heart disease (1Trusted Source).
However, studies have found that harmful compounds called advanced glycation end products (AGEs) may also have a powerful effect on your metabolic health — regardless of your weight.
AGEs accumulate naturally as you age and are created when certain foods are cooked at high temperatures.
This article explains all you need to know about AGEs, including what they are and how you can reduce your levels.
What are AGEs?
Advanced glycation end products (AGEs) are harmful compounds that are formed when protein or fat combine with sugar in the bloodstream. This process is called glycation (2Trusted Source).
AGEs can also form in foods. Foods that have been exposed to high temperatures, such as during grilling, frying, or toasting, tend to be very high in these compounds.
In fact, diet is the biggest contributor of AGEs.
Fortunately, your body has mechanisms to eliminate these harmful compounds, including those involving antioxidant and enzymatic activity (3Trusted Source, 4Trusted Source).
Yet, when you consume too many AGEs — or too many form spontaneously — your body can’t keep up with eliminating them. Thus, they accumulate.
While low levels are generally nothing to worry about, high levels have been shown to cause oxidative stress and inflammation (5Trusted Source).
In fact, high levels have been linked to the development of many diseases, including diabetes, heart disease, kidney failure, and Alzheimer’s, as well as premature aging (6Trusted Source).
Furthermore, people who have high blood sugar levels, such as those with diabetes, are at a higher risk of producing too many AGEs, which can then build up in the body.
Therefore, many health professionals are calling for AGE levels to become a marker of overall health.
AGEs are compounds formed in the body when fat and protein combine with sugar. When they accumulate in high levels, they increase the risk of many diseases.
Modern diets are linked to high levels of AGEs
Some modern foods contain relatively high amounts of AGEs.
This is mostly due to popular methods of cooking that expose food to dry heat.
These include barbecuing, grilling, roasting, baking, frying, sautéing, broiling, searing, and toasting (7Trusted Source).
These cooking methods may make food taste, smell, and look good, but they may raise your intake of AGEs to potentially harmful levels (8Trusted Source).
In fact, dry heat may increase the amount of AGEs by 10–100 times the levels of uncooked foods (7Trusted Source).
Certain foods, such as animal foods that are high in fat and protein, are more susceptible to AGE formation during cooking (7Trusted Source).
Foods highest in AGEs include meat (especially red meat), certain cheeses, fried eggs, butter, cream cheese, margarine, mayonnaise, oils, and nuts. Fried foods and highly processed products also contain high levels.
Thus, even if your diet appears to be reasonably healthy, you may consume an unhealthy amount of harmful AGEs just because of the way your food is cooked.
AGEs can form inside your body or the foods you eat. Certain cooking methods can cause their levels in food to skyrocket.
When AGEs accumulate, they can seriously damage health
Your body has natural ways of getting rid of harmful AGE compounds.
However, if you consume too many AGEs in your diet, they’ll build up faster than your body can eliminate them. This can affect every part of your body and is linked to serious health problems.
In fact, high levels are associated with the majority of chronic diseases.
These include heart disease, diabetes, liver disease, Alzheimer’s, arthritis, kidney failure, and high blood pressure, among others (9Trusted Source, 10Trusted Source, 11Trusted Source, 12Trusted Source).
One study examined a group of 559 older women and found those with the highest blood levels of AGEs were almost twice as likely to die from heart disease than those with the lowest levels (11Trusted Source).
Another study found that among a group of individuals with obesity, those with metabolic syndrome had higher blood levels of AGEs than those who were otherwise healthy (13Trusted Source).
Women with polycystic ovary syndrome, a hormonal condition in which levels of estrogen and progesterone are unbalanced, have been shown to have higher levels of AGEs than women without the condition (14Trusted Source).
What’s more, high consumption of AGEs through diet has been directly linked to many of these chronic diseases (5Trusted Source, 15Trusted Source).
This is because AGEs harm the body’s cells, promoting oxidative stress and inflammation (16Trusted Source, 17Trusted Source, 18Trusted Source).
High levels of inflammation over a long period can damage every organ in the body (19Trusted Source).
AGEs can build up in the body, causing oxidative stress and chronic inflammation. This increases the risk of many diseases.
Low-AGE diets may improve health and reduce the risk of disease
Animal and human studies suggest that limiting dietary AGEs helps protect against many diseases and premature aging (20Trusted Source).
Several animal studies have shown that eating a low-AGE diet results in a lower risk of heart and kidney disease, increased insulin sensitivity, and lower levels of AGEs in blood and tissues by up to 53% (21Trusted Source, 22Trusted Source, 23Trusted Source, 24Trusted Source, 25Trusted Source).
Similar results were observed in human studies. Restricting dietary AGEs in both healthy people and those with diabetes or kidney disease reduced markers of oxidative stress and inflammation (26Trusted Source, 27Trusted Source, 28Trusted Source).
A 1-year study investigated the effects of a low-AGE diet in 138 people with obesity. It noted increased insulin sensitivity, a modest decrease in body weight, and lower levels of AGE, oxidative stress, and inflammation (29Trusted Source).
Meanwhile, those in the control group followed a diet high in AGEs, consuming more than 12,000 AGE kilounits per day. AGE kilounits per liter (kU/l) are the units used to measure AGE levels.
By the end of the study, they had higher AGE levels and markers of insulin resistance, oxidative stress, and inflammation (29Trusted Source).
Although a reduction in dietary AGEs has been shown to offer health benefits, currently there are no guidelines regarding safe and optimal intake (7Trusted Source).
Limiting or avoiding dietary AGEs has been shown to reduce levels of inflammation and oxidative stress, thus lowering the risk of chronic disease.
So how much is too much?
The average AGE consumption in New York is thought to be around 15,000 AGE kilounits per day, with many people consuming much higher levels (7Trusted Source).
Therefore, a high-AGE diet is often referred to as anything significantly above 15,000 kilounits daily, and anything well below this is considered low.
To get a rough idea of whether you’re consuming too many AGEs, consider your diet. If you regularly eat grilled or roasted meats, solid fats, full-fat dairy, and highly processed foods, you’re probably consuming fairly high levels of AGEs.
On the other hand, if you eat a diet rich in plant foods, such as fruits, vegetables, legumes, and whole grains, and consume low-fat dairy and less meat, your AGE levels will likely be lower.
If you regularly prepare meals with moist heat, such as soups and stews, you’ll also be consuming lower levels of AGEs.
To put this in perspective, here are some examples of AGE amounts in common foods, expressed as kilounits per liter (7Trusted Source):
1 fried egg: 1,240 kU/l
1 scrambled egg: 75 kU/l
2 ounces (57 grams) of toasted bagel: 100 kU/l
2 ounces of fresh bagel: 60 kU/l
1 tablespoon of cream: 325 kU/l
¼ cup (59 ml) of whole milk: 3 kU/l
3 ounces of grilled chicken: 5,200 kU/l
3 ounces of poached chicken: 1,000 kU/l
3 ounces of French fries: 690 kU/l
3 ounces of baked potato: 70 kU/l
3 ounces (85 grams) of broiled steak: 6,600 kU/l
3 ounces of braised beef: 2,200 kU/l
If you regularly cook foods at high temperatures or consume large amounts of processed foods, your AGE levels are probably high.
Tips to reduce AGE levels
Several strategies can help you reduce your levels of AGEs.
Choose different cooking methods
The most effective way to reduce your intake of AGEs is to choose healthier cooking methods.
Rather than using dry, high heat for cooking, try stewing, poaching, boiling, and steaming.
Cooking with moist heat, at lower temperatures, and for shorter periods, all help keep AGE formation low (7Trusted Source).
In addition, cooking meat with acidic ingredients, such as vinegar, tomato juice, or lemon juice, can reduce AGE production by up to 50% (7Trusted Source).
Cooking over ceramic surfaces — rather than directly on metal — can also reduce AGE production. Slow cookers are thought to be one of the healthiest ways to cook food.
Limit foods high in AGEs
Fried and highly processed foods contain higher levels of AGEs.
Certain foods, such as animal foods, also tend to be higher in AGEs. These include meat (especially red meat), certain cheeses, fried eggs, butter, cream cheese, margarine, mayonnaise, oils, and nuts (7Trusted Source).
Try to eliminate or limit these foods and instead choose fresh, whole foods, which are lower in AGEs.
For example, foods such as fruits, vegetables, and whole grains have lower levels, even after cooking (7Trusted Source).
Eat a diet full of antioxidant-rich foods
In laboratory studies, natural antioxidants, such as vitamin C and quercetin, have been shown to hinder AGE formation (30Trusted Source).
Moreover, several animal studies have shown that some natural plant phenols can reduce the negative health effects of AGEs (31Trusted Source, 32Trusted Source).
One of these is the compound curcumin, which is found in turmeric. Resveratrol, which can be found in the skins of dark fruits like grapes, blueberries, and raspberries may likewise help (31Trusted Source, 32Trusted Source).
Therefore, a diet full of colorful fruits, vegetables, herbs, and spices may help protect against the damaging effects of AGEs.
Aside from diet, an inactive lifestyle can cause AGE levels to skyrocket.
In contrast, regular exercise and an active lifestyle have been shown to reduce the amount of AGEs in the body (33Trusted Source, 34Trusted Source).
One study in 17 middle-aged women found that those who increased the number of steps they took per day experienced a reduction in AGE levels (33Trusted Source).
Choosing healthier cooking methods, limiting foods high in AGEs, eating more antioxidant-rich foods, and exercising regularly can all help reduce AGE levels in the body.