By Mary Jane Brown, RD
Overeating and obesity are known for causing serious health problems. They increase your risk of developing insulin resistance, diabetes and heart disease (1).
However, studies have found that advanced glycation end products (AGEs) may also have a powerful effect on your metabolic health — regardless of weight.
AGEs are harmful compounds. They 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.
Person Taking a Roasted Chicken out of the Oven, Large
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 (2).
AGEs can also form in foods. Foods that have been exposed to high temperatures, as in grilling, frying or toasting, tend to be very high in these compounds.
In fact, diet is the biggest contributor of AGEs.
Luckily, your body has ways to eliminate these harmful compounds, including with antioxidants and enzymes (3, 4).
Yet when you consume too many AGEs, or too many form spontaneously, your body cannot keep up with eliminating them and they will accumulate.
While low levels are generally nothing to worry about, high levels have been shown to cause oxidative stress and inflammation in the body (5).
High levels have been linked with the development of many different diseases, such as diabetes, heart disease, kidney failure, Alzheimer’s and even premature aging (6).
Furthermore, people who have high blood sugar levels, such as diabetics, are at a higher risk of producing too many AGEs, which can then build up in the body.
Because of this, many health professionals are calling for AGE levels to become a marker of overall health.
Bottom Line: 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 developing many different diseases.
Modern Diets Are Linked to High Levels of AGEs
Modern diets are linked to AGEs building up in the body.
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 (7).
These cooking methods may make food taste, smell and look good, but they raise AGEs to dangerous levels (8).
In fact, dry heat causes AGE formation to increase by 10 to 100 times the levels in uncooked foods (7).
Certain foods, such as animal foods high in fat and protein, are more susceptible to AGE formation during cooking (7).
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.
So even if your diet appears reasonably healthy, you may consume an unhealthy amount of harmful AGEs just because of the way your food is cooked.
Bottom Line: AGEs can be made inside the body during digestion, or can be consumed in the foods you eat. Certain cooking methods can cause their levels in food to skyrocket.
When AGEs Accumulate, They Can Seriously Damage Health
The 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 the body, causing serious health problems.
In fact, high levels are associated with the majority of chronic diseases seen today.
These include heart disease, diabetes, liver disease, Alzheimer’s, arthritis, kidney failure and high blood pressure, among others (9, 10, 11, 12).
One study examined a group of 559 older women and found those with the highest levels of AGEs in the blood were almost twice as likely to die from heart disease than those women with the lowest levels (11).
Another study found that among a group of obese individuals, those with metabolic syndrome had higher blood levels of AGEs than those who were obese but had no other health issues (13).
Women with polycystic ovary syndrome, a hormonal condition where the levels of estrogen and progesterone are out of balance, have been shown to have higher levels of AGEs in their bodies than women without the condition (14).
What’s more, a high consumption of AGEs through the diet has been directly linked to all of these chronic diseases (5, 15).
This is because AGEs easily bind with receptors on many different cells. This damages the cells and promotes oxidative stress, the production of free radicals that can damage all cells, causing inflammation (16, 17, 18).
High levels of inflammation over a long period of time can cause damage to every organ in the body (19).
Bottom Line: AGEs can build up in the body, causing oxidative stress and chronic inflammation. This increases the risk of many different diseases.
Low-AGE Diets May Improve Health and Reduce the Risk of Disease
Findings from both animal and human studies suggest that limiting dietary AGEs helps protect against many diseases and premature aging (20).
Several animal studies have shown that eating a low-AGE diet results in lower levels of AGEs in blood and tissues by up to 53%, plus a lower risk of heart and kidney disease, as well as increased insulin sensitivity (21, 22, 23, 24, 25).
Similar results were found in humans. Restricting dietary AGEs in patients with diabetes or kidney disease, as well as in healthy people, reduced markers of oxidative stress and inflammation (26, 27, 28).
A one-year study gave 138 obese people a low-AGE diet. Participants benefited from increased insulin sensitivity, a modest decrease in body weight, lower AGE levels and lower levels of oxidative stress and inflammation (29).
Those in the control group, on the other hand, followed the regular-AGE diet. They consumed more than 12,000 AGE kilo units per day. AGE kilo units 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 (29).
Although a reduction in dietary AGEs has been shown to have clear health benefits, there are no guidelines for safe and optimal intake just yet (7).
Bottom Line: Limiting or avoiding dietary AGEs has been shown to reduce levels of inflammation and oxidative stress, meaning a lower risk of developing other chronic diseases.
So How Much Is Too Much?
The average AGE consumption in New York is thought to be around 15,000 AGE kilo units per day, with many people consuming much higher levels (7).
Therefore, a high-AGE diet is often referred to as anything significantly above 15,000 kilo units daily and anything well below this is considered low.
To get a rough idea of whether you’re consuming too many AGEs, have a look at your diet. Do you regularly eat grilled or roasted meats, solid fats, full-fat dairy and highly processed foods? If so, you’re probably consuming fairly high levels of AGEs.
On the other hand, if you eat a diet rich in plant foods such as fruit, vegetables, legumes and whole grains, and consume low-fat dairy and less meat, 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 the amount of AGEs in common foods (7):
- 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
Bottom Line: If you regularly cook foods at high temperatures or consume large amounts of processed foods, your AGE levels are probably too high.
Tips to Reduce Your AGE Levels
The good news is there are lots of things you can do to reduce levels of AGEs in the body. Here are some suggestions:
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 of time, all help keep AGE production low (7).
In addition, cooking meat with acidic ingredients, such as vinegar, tomato juice or lemon juice can reduce AGE production by up to 50% (7).
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 foods 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 (7).
Try to eliminate or limit these foods and instead choose whole, fresh and natural foods, which are naturally lower in AGEs.
For example, foods such as fruits, vegetables and whole grains have lower levels, even after cooking (7).
Eat a Diet Full of Antioxidant-Rich Foods
Kiwifruit and Other Fruits and Vegetables
In laboratory studies, natural antioxidants, such as vitamin C and quercetin, have been shown to hinder AGE formation (30).
Moreover, several animal studies have shown that some natural plant phenols can prevent the negative health effects of AGEs (31, 32).
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 also help (31, 32).
Therefore, a diet full of colorful fruits, vegetables, herbs and spices may help protect against the damaging effects of AGEs on the body.
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 (33, 34).
One study among 17 middle-aged women found that those who increased the number of steps they took per day experienced a reduction in AGE levels (33).
Bottom Line: 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.
Take Home Message
Modern diets are contributing to higher levels of harmful AGEs in the body.
This is concerning, since high AGE levels are linked to the majority of chronic diseases you see today. The good news is that you can make choices to lower your levels.
Choose healthy, whole and fresh foods, healthier cooking methods and an active lifestyle to protect your health.