Modern diets are largely heat-processed and as a result contain high levels of advanced glycation end products (AGEs), also known as glycotoxins. Dietary advanced glycation end products (dAGEs) are known to contribute to increased oxidant stress and inflammation, which are linked to the recent epidemics of diabetes and cardiovascular disease.
Dry heat promotes new dAGE formation by 10-100 times above the uncooked state across food categories. Animal-derived foods that are high in fat and protein are generally rich in glycotoxins and prone to formation of new glycotoxins during cooking. Carbohydrate-rich foods such as vegetables, fruits, whole grains (but also milk) contain relatively few glycotoxins, even after cooking.
The formation of new glycotoxins during cooking was:
- prevented by the AGE inhibitory compound aminoguanidine
- and significantly reduced by
- cooking with moist heat,
- using shorter cooking times,
- cooking at lower temperatures,
- and by use of acidic ingredients (such as lemon juice or vinegar).
Advanced glycation end products (AGEs), are a diverse group of highly oxidant compounds with pathogenic significance in diabetes and in several other chronic diseases. Glycotoxins are created through a Maillard or browning reaction - it is a part of normal metabolism, but if excessively high levels of glycotoxins are reached in tissues and the circulation they can become pathogenic, which is related to their ability to promote oxidative stress and inflammation by binding with cell surface receptors or cross-linking with body proteins, altering their structure and function.
Glycotoxins also exist in foods: they are naturally present in uncooked animal-derived foods, and cooking results in the formation of new AGEs: grilling, broiling, roasting, searing, and frying propagate and accelerate new AGE formation. Recent studies clearly show that dAGEs are absorbed and contribute significantly to the body’s AGE pool.
Avoidance of dAGEs, glycotoxins in food, helps delay chronic diseases and aging in animals and possibly in human beings.
Glycotoxins in the diet represent pathogenic compounds that have been linked to the induction and progression of many chronic diseases. High temperature and low moisture consistently and strongly drive their formation in foods. Comparatively brief heating time, low temperatures, high moisture, and/or pre-exposure to an acidified environment are effective strategies to limit new formation in food.
A significantly reduced intake of dAGEs can be achieved by reducing intake of solid fats, fatty meats, full-fat dairy products, and highly processed foods, and by increasing the consumption of legumes, vegetables, fruits, and whole grains.
Low-AGE–generating cooking methods are
- poaching,
- steaming,
- stewing,
- boiling.
For example, the high AGE content of broiled chicken (5,828 kU/100 g) can be significantly reduced to 1,124 kU/100 g when the same piece of meat is either boiled or stewed.
Future studies should continue to investigate the health effects of AGEs and refine recommendations for safe dietary intakes. However, current data support the need for a paradigm shift that acknowledges that how we prepare and process food may be equally important as nutrient composition.
