Quick Hit Summary

Advanced Glycation End Products (AGEs) are found in many food products; most notably in meat and and foods with added fat. As discussed in Part I of this article, they appear to play a significant role in the development of many cardiometabolic diseases. Thus, to optimize our health, one should take measures to reduce exposure to dietary AGEs. This is best accomplished by including more vegetables in the diet and reducing intake of meat products that have been cooked under high dry heat conditions such as roasting, broiling, baking or grilling. For individuals who love meat, such as myself, I recommend cooking them under low moist heat conditions (ie- stewing, steaming, crock-potting) or adding an acidic marinade (vinegar based, lemon, etc) to them prior to cooking.

Advanced Glycation End Products (AGEs)

Chicken prepared with an acidic marinade. Great for taste, great for reducing dietary AGEs… Sounds like a winning combination to me!¹³

In Part I of this article, we discussed the negative effects of dietary AGEs on kidney disease, type 1 and 2 diabetes as well as general negative effects on cardiovascular health. If you have not already done so, I highly recommend reading that article to help you make sense of this one.

Reducing the AGEs in One’s Diet

Please note the serving sizes for the foods listed below ARE NOT EQUAL for all the comparisons. These sizes are used to reflect the more typical serving size.

Dietary AGEs appears to promote the development of various cardiometabolic diseases. Thus, the next logical question to tackle to tackle is “What foods contain the most AGEs and how can we minimize their formation?” As mentioned above AGEs result from a chemical reaction between carbohydrates and protein or lipids.

In an investigation completed by Uribarri and colleague, 549 different foods, prepared in various ways, were assessed for the AGEs content. The largest contribution of AGEs in our diet, is meat¹. You may be scratching your head a little bit wondering, “How does meat contribute so many AGEs in our diet since there isn’t any carbohydrates in it?” Here’s the answer… Although meat does not contain many carbohydrates, it does contain some. Remember, small amount of glycogen are present in all muscle tissue. Although it doesn’t add up to gram levels, these trace amounts quickly form AGEs when in the presence of protein. Cheeses that are aged and/or have high fat content also contain relatively large amounts of AGEs. If we rank foods in these groups based of AGE levels and prepared in similar ways, we get a list as seen in Table 2.

NOTE: Some literature discusses AGE Eq. 1 AGE Eq = 1000 kU¹⁸

Meats

• 1) Beef (ex- Grilled Beef Steak: 6,674 AGE kU/90 g)
• 2) Poultry (ex- Roasted Chicken Breast (with skin): AGE 5975 kU/90g; Roasted Turkey Breast: 4202 AGE kU/90 g)
• 3) Pork (ex- Pork roast from a Chinese take out: 3190 AGE kU/90g)
• 4) Fish (ex- Broiled Salmon Filet: 3012 AGE ku/90g; Baked Trout: 1924 kU/90g)
• 5) Eggs (Fried egg: 1237 kU/ 45g)

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A quick sidenote…

Before moving away from the meat category, I want to take a moment to highlight a specific type of fish that is often a big hit with the strength sport community due to its low cost and high protein content – Canned Tuna Fish.

Canned Tuna Fish

• White Albacore in Oil: 1566 kU/ 90g
• Chunk Light Tuna in Water: 407 kU/ 90g

I want to emphasize the difference in AGEs between these 2 types of canned tuna. Unfortunately, Uribarri and colleague did not investigate the AGEs content of canned white albacore in water (vs. oil) or chunk light in oil (vs. water). Thus, it’s hard to say if the differences in these two types are due to the type of tuna itself or the type of canning liquid – water vs. oil.

That being said, even if there is no actual difference in AGEs content between the two types of tuna, I still recommend chunk light tuna due to the high mercury content of Albacore tuna. Multiple research studies have shown that canned albacore has >300% the mercury content of chunk light tuna⁹¹⁰. High intake of mercury has been linked to various neurological diseases.¹¹”
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Cheese

• Processed American Cheese (white): 2603 AGE kU/30g
• Kraft® Grated Parmasean Cheese: 2535 AGE kU/15g
• Kraft® low fat American Cheese: 1212 AGE kU/30 g

Combination Foods containing cheese…

• Thin Crust Pizza: 6825 AGE kU/100g
• Macaroni and Cheese (baked): 4070 AGE kU/100g
• Macaroni and Cheese: 2728 AGE kU/100g

Milk

Regardless of skim or whole, has less than 10 AGE kU/250g. {If you’re like me, you’re probably wondering how the heck cheese is so high if milk is so low. The answer to this question has to due with the aging process of cheese as well as the much higher fat content in it vs. milk}. It should be noted that infant formula (Enfamil™) had 100x more dAGE vs. breast milk.¹⁷ Another reason why mothers should breast feed their children!

Soy

• Tofu (sautéed): 4251 AGE kU/90g
• Tofu (raw): 709 AGE kU/90g
• Boca Burger (soy burger only, no bun, etc): 131 AGE kU/30g

Outside of meats, other foods high in AGEs included high fat spreads such as butter, cream cheese and regular mayonnaise¹. These spreads were followed by nuts and various types of oil. On an interesting note, regarding monounsaturated fats, cocktail peanuts, which are cooked under high heat, had 150% more AGEs than blanched almonds (2500 AGE kU/30g serving vs. 1642 AGE kU/30g serving). Be careful though, buy almonds that have been manufactured with high dry heat techniques, such as roasting, and the AGEs start to creep up a little (1995 AGE kU/30g serving) With respect to solid monounsaturated sources, it’s hard to beat the good old Avocado (473 AGE kU/30g). Most oils have AGE content right around 500 AGE kU/5 ml serving. One exception to this is sesame oil which has double this amount.

Vegetables, fruits, breads and dry beans tested also tested well; most of options in those categories had <300-400 AGE kU/100mg. A couple of particular foods that I want to point out are starchy vegetables (corn, potatoes, etc). Once we add a little fat to them, AGEs content sky rockets…

Potatoes

• McDonalds® French Fries: 1,522 AGE kU/100g
• Roasted White Potato: 218 AGE kU/100g
• Boiled White Potato: 17 AGE kU/100g

In general, processed snack foods tend to be highest if they’ve had fat added to them (ie- cheese, butter, baked vs. regular fat, etc). Here’s a few items…

• Quaker® Peanut Butter and Chocolate Chunk Hard Granola Bar: 953 AGE kU/30g
• Frito Lay ® Potato Chips: 865 kU/30g
• Pepperidge Farms® Chedder Goldfish Crackers: 653 kU/30g
• Kellogg’s ® Nutrigrain Apple Cinnamon Bar: 642 kU/30g
• General Mills® Traditional Chex Mix: 352 kU/30g
• General Mills® Fruit Roll Up (sizzlin red): 294 kU/30g
• Frito Lay ® Baked Potato Crisps: 135 kU/30g
• Microwave Popcorn, General Mills® Fat Free: 10 kU/30g

Moving on to good old deserts …

• Kellogg’s ® Rice Krispies Treats: 576kU/30g
• Nabisco® Oreo Cookie: 531 kU/30g
• Kellogg’s ® Keebler Oatmeal Raisin Cookie: 411 kU/30g
• Starbucks® Sweet roll, Cinnamon Swirl Roll: 272 kU/30g
• Angel Food Cake: 8 AGE kU/30g
• Edys/Dryer’s ® Strawberry Sorbet: 3 kU/125g

Cooking Techniques on Dietary levels of AGEs

If you are a heavy meat eater, such as myself, you’re probably wondering how you can continue to enjoy meat while minimizing exposure to dietary AGEs. Fear not, their are two things you can focus on while preparing food: (1) Heating Methods and (2) Use of Acidic Marinades.

Heating Methods

As previously mentioned, how one cooks their food affects the amount of AGEs present in the food. Dry heat based cooking techniques tend to accelerate the formation of dietary AGEs whereas moist low heat methods minimize their formation. Here are a few examples:

Beef

• Stir Fried Beef Strips with 1tbsp Canola Oil: 6276 AGE kU/90g
• Stewed Beef (shoulder cut): 2007 AGE kU/90g

Chicken

• Grilled Chicken Breast: 4,364 AGE kU/90g
• Poached Chicken Breast (skinless for 15 minutes): 968 AGE kU/90g

Eggs

• Scrambled Egg (high heat with cooking spray): 101 AGE kU/30g
• Poached Egg: 27 AGE kU/90g

Practical application

If you really want to kill two birds with one stone, buy large chunks of meat and cook them in a crock pot (low temperature, moist heat). Simply throw a piece of meat into a crock pot, cover it with broth (or other liquid of choice) and set the heat on low. Come back 3-6 hours later and you’re primed for a tender piece of great tasting meat. Not only is prep time pretty minimal, but it makes great leftovers (assuming you originally cook a large enough piece of meat).

Use of Acidic Marinades

Interestingly enough, acidic meat marinades (vinegar based, lemon juice, etc) not only enhance the flavor of meat, but also reduce AGEs levels. Rather than explain the mind numbing chemistry on the “how’s” and “why’s” this method work, I’ll simply just say DO IT!! Here are a few examples:

Beef

• Ground beef, pan browned: 4435 AGE kU/90g
• Ground beef, pan browned, marinated 10 min with lemon juice: 3450 AGE kU/90g

(Yes, I realize that you’ll probably never add lemon juice to ground beef as this isn’t the most appealing combination. However, it is common to add other acidic marinades (ie- vinegar based) to beef products. Personally, I love a good steak that has been tenderized and bathed in a vinegar based marinade mix prior to grilling. Acidic marinades such as these exert a similar positive effect on AGE formation as well).

Poultry

• Roasted Turkey Breast: 4202 AGE kU/90g
• Broiled Turkey Breast (skinless), marinated in orange juice: 3949 AGE kU/90g

Pork

• Pork Chop (pan fried): 4277 AGE kU/90g
• Pork Chop Marinated w/ Balsamic vinegar, BBQ: 3001 AGE kU/90g

Carbohydrates and Advanced Glycation End Products

Thus far, I’ve explained how meats generally contain the highest level of dAGEs. However, I want to remind you that AGEs are also formed naturally in the body, particularly when overloaded with carbohydrates¹⁴. Remember, carbohydrates are broken down into sugar once inside the body. The two most common types of sugars in the American diet are glucose and fructose. Although excess of either of these sugars is not good, fructose may be more worrisome from an AGE standpoint. In fact, in-vitro studies have shown it to 10x more effective at producing AGEs than glucose (the main type of sugar found in white potatoes, rice, bread, etc)¹⁵. Animal studies also indicate that fructose promotes AGEs more so than normal glucose¹⁶. [To my knowledge there has not been any studies that have confirmed/denied this effect in humans.] Taking into account this information, I want to stress that I’M NOT RECOMMENDING A DIET HIGH IN CARBOHYDRATES AND LOW IN FAT/MEAT PROTEIN. I’m also NOT recommending a fructose deficient diet. Just giving you some food for thought on the topic (I’m already afraid that by saying just that, all the fructose “haters” will use this as ammunition in their battle to wipe out fruit eating! Thus, I want to cut them off and say that I have no problem against moderate fructose intake from natural sources¹⁹)

In my opinion, to best optimize one’s diet one should consume moderate amounts of meat . Preferably that which has been cooked under slow, moist heat conditions. If you choose to grill the meat or use another form of dry high heat, add an acidic marinade prior to cooking. Healthy fats are a must as well. Vegetables are a great source of carbohydrates. Depending on the individual and their goals, 3-4 servings of fruit/day is a good idea as well. (As a FYI, I’m referring to WHOLE fruit; not fruit juice which has had many of it’s health benefits stripped away. Also 1 serving of fruit DOES NOT equal 1 piece of fruit. Due to genetic manipulation, most fruits are “super-sized.” Thus, a single apple, banana, etc, may actually be closer to 2 servings of fruit.). Foods that have been highly processed or have added sugars get the veto on my list if we’re eating for optimal health.

A Word of Caution

In the preceding sections, I’ve described how low heat cooking methods are preferable to high heat cooking methods with respect to the formation of AGEs in meats and eggs. That being said, I want to emphasize that I’m not recommending that you under-cook your food. Eating meat, eggs, etc, that haven’t been properly prepared (ie – heated) greatly increases your risk of food poisoning¹². Furthermore, even raw meats contain some AGEs (ie – raw beef steak: 720 AGE kU/90g; raw skinless chicken breast: 692 AGE kU/90g). Therefore, cook your foods either at a reduced temperature (for a longer period of time) or use one of the above cooking techniques to reduce your exposure to these harmful compounds. Even if cooking your animal based foods a little more increases AGEs levels, it sure beats vomiting and diarrhea! If you like your meat pink—>great! Just make sure you cook the outer surface of the meat, killing the bacteria along it’s outer surfaces (ie- sear the meat). Please know that this applies to “muscle” meat (ie – large pieces of whole meat); not meat that has been processed (hamburger, brats, etc). I recommend cooking this latter type more thoroughly.

The other thing I’d like to briefly touch upon is the fact that dietary AGEs are only 1 of the many factors that contribute to cardiometabolic disease. When selecting foods to dine on, make sure you pay attention to factors such as trans fat, sugar content, overall kcal, etc.

Bottom Line

We’ve covered a lot of ground in this 2 part article on dietary AGEs. There are a few key take home points to remember. First, dietary AGEs are present in many foods, particularly meats and foods with fat added to them prior to cooking. Second, diets high in sugar, accelerate the formation of AGEs within the body. To reduce the amount of AGEs in your diet, cook foods with moist low heat techniques vs. high heat dry methods. However, do not confuse low heat cooking with eating undercooked meats/eggs. Food borne illness (ie- food poisoning) can cause many undesirable short term consequences. On a final note, remember that AGEs are only one part of the cardiometabolic disease equation. Remember to pay attention to other dietary factors such as trans fat, total sugar, kcal, etc.

All values for specific food items (ie-not whole meals) were obtained from reference #1¹

References

¹ Uribarri J, Woodruff S, Goodman S, Cai W, Chen X, Pyzik R, Yong A, Striker GE, Vlassara H. Advanced glycation end products in foods and a practical guide to their reduction in the diet. J Am Diet Assoc. 2010 Jun;110(6):911-16.e12.

² Lin RY, Choudhury RP, Cai W, Lu M, Fallon JT, Fisher EA, Vlassara H. Dietary glycotoxins promote diabetic atherosclerosis in apolipoprotein. E-deficient mice. Atherosclerosis. 2003;168:213-220.

³ Zheng F, He C, Cai W,Hattori M, Steffes M, Vlassara H. Prevention of
diabetic nephropathy in mice by a diet low in glycoxidation products. Diabetes Metab Res Rev. 2002;18:224-237.

⁴ Sandu O, Song K, Cai W, Zheng F, Uribarri J, Vlassara H. Insulin resistance and type 2 diabetes in high-fat-fed mice are linked to high glycotoxin intake. Diabetes. 2005;54:2314-2319.

⁵ Peppa M, He C, Hattori M, McEvoy R, Zheng F, Vlassara H. Fetal or neonatal low-glycotoxin environment prevents autoimmune diabetes in NOD mice. Diabetes. 2003;52:1441-1445.

⁶ Negrean M, Stirban A, Stratmann B, Gawlowski T, Horstmann T, Götting C, Kleesiek K, Mueller-Roesel M, Koschinsky T, Uribarri J, Vlassara H, Tschoepe D. Effects of low- and high-advanced glycation endproduct meals on macro- and microvascular endothelial function and oxidative stress in patients with type 2 diabetes mellitus. Am J Clin Nutr. 2007 May;85(5):1236-43.

⁷ Vlassara H, Cai W, Crandall J, Goldberg T, Oberstein R, Dardaine V, Peppa M, Rayfield EJ. Inflammatory mediators are induced by dietary glycotoxins, a major risk factor for diabetic angiopathy. Proc Natl Acad Sci U S A. 2002 Nov 26;99(24):15596-601. Epub 2002 Nov 12.

⁸ Birlouez-Aragon I, Saavedra G, Tessier FJ, Galinier A, Ait-Ameur L, Lacoste F, Niamba CN, Alt N, Somoza V, Lecerf JM. A diet based on high-heat-treated foods promotes risk factors for diabetes mellitus and cardiovascular diseases. Am J Clin Nutr. 2010 May;91(5):1220-6. Epub 2010 Mar 24.

⁹ Burger J, Gochfeld M. Mercury in canned tuna: white versus light and temporal variation. Environ Res. 2004 Nov;96(3):239-49.

¹⁰ Gerstenberger SL, Martinson A, Kramer JL. An evaluation of mercury concentrations in three brands of canned tuna. Environ Toxicol Chem. 2010 Feb;29(2):237-42.

¹¹ Castoldi AF, Coccini T, Manzo L. Neurotoxic and molecular effects of methylmercury in humans. Rev Environ Health. 2003 Jan-Mar;18(1):19-31.

¹² ServSafe Essentials: with the Certification Exam Answer Sheet. NRA Educational Foundation. Wiley; 4 ed. April 21, 2006.

¹³ Image taken by Csaszar.viktor. Accessed on October 1st, 2010 from: http://commons.wikimedia.org/wiki/File:LemonChicken.JPG

¹⁴ Seneff S, Wainwright G, Mascitelli L. Nutrition and Alzheimer’s disease: the detrimental role of a high carbohydrate diet.

¹⁵ McPherson JD, Shilton BH, Walton DJ. Role of fructose in glycation and cross-linking of proteins. Biochemistry. 1988 Mar 22;27(6):1901-7

¹⁶ Levi B, Werman MJ. Long-term fructose consumption accelerates glycation and several age-related variables in male rats. J Nutr. 1998 Sep;128(9):1442-9.

¹⁷ Mericq V, Piccardo C, Cai W, Chen X, Zhu L, Striker GE, Vlassara H, Uribarri J. Maternally transmitted and food-derived glycotoxins: a factor preconditioning the young to diabetes? Diabetes Care. 2010 Oct;33(10):2232-7. Epub 2010 Jul 13.

¹⁸ Uribarri J, Cai W, Ramdas M, Goodman S, Pyzik R, Chen X, Zhu L, Striker GE, Vlassara H. Restriction of advanced glycation end products improves insulin resistance in human type 2 diabetes: potential role of AGER1 and SIRT1.Diabetes Care. 2011 Jul;34(7):1610-6.

¹⁹ Madero M, Arriaga JC, Jalal D, Rivard C, McFann K, Pérez-Méndez O, Vázquez A, Ruiz A, Lanaspa MA, Jimenez CR, Johnson RJ, Lozada LG. The effect of two energy-restricted diets, a low-fructose diet versus a moderate natural fructose diet, on weight loss and metabolic syndrome parameters: a randomized controlled trial. Metabolism. 2011 Nov;60(11):1551-9. Epub 2011 May 31.