There’s something intuitively wrong about food that’s a bit burnt and crispy at the edges. Maybe it’s because we instinctively feel that our food deserves a bit more care – or perhaps it’s a gut feeling that’s telling us all those chargrilled edges might be doing us some harm.
If you’ve heard of AGEs you’ll know where I’m going with this. If you haven’t, or aren’t sure what they are – you must read on.
AGEs or Advanced Glycation End Products (as they’re ‘snappily’ termed!) are compounds that naturally form in our bodies from the chemical reaction of sugars with proteins or fats (glycation). The formation of AGEs is a normal part of metabolism, but if these compounds build up to an excessive amount in the bloodstream, they can become harmful and cause damage to almost every bodily tissue and organ. AGEs are associated with increased oxidative stress, premature ageing and chronic inflammation – they bind with AGE receptors (RAGEs), which permanently triggers low-level inflammation. In fact, research is beginning to show that AGEs are directly involved with or accelerate the progression of many common chronic diseases including metabolic syndrome, type 2 diabetes, cardiovascular disease, Alzheimer’s disease and dementia, allergy and autoimmune diseases, and some forms of cancer to name just a few.
AGEs linked to diabetic complications
A large body of evidence also suggests that whilst hyperglycaemia is still considered the primary cause of diabetic complications, such as retinopathy, nephropathy and increased risk of atherosclerosis, AGEs are important pathogenic mediators of almost all complications too. For example, research has shown increased accumulation of AGEs in nerves of diabetic patients.
Are you feeding chronic disease?
Scientists have found that as well as endogenous production (AGEs produced within the body), AGEs also enter our bloodstream via the food we eat. Some foods naturally contain higher levels of AGEs than others. Cooking methods can have a big impact on the AGE content of food too. Research has shown that restricting dietary AGEs lowers markers of oxidative stress and inflammation. Researchers have suggested that there is significant potential to increase human lifespan, reduce risks of common chronic diseases such as Alzheimer’s and limit many of the longer-term complications that co-occur in Type 1 & 2 diabetes when dietary intake of AGEs is reduced.
How to reduce dietary AGEs in 3 steps:
Step 1 – Know high & low AGE foods
The first step to reducing intake of AGEs is to familiarise yourself with the amounts found in common foods. Below is a table summary of AGE content in foods. A more comprehensive version can be found here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3704564/table/T1/
You’ll notice that fruits, vegetables, most carbohydrates, legumes, soy, tofu, milk, eggs and yoghurt are low in AGEs. Most fast and processed foods and animal-derived products such as meat are higher in AGEs, however the content increases dramatically after cooking, especially after grilling, BBQ, roasting or frying. Have a look at the AGE content of boiled chicken with lemon (957 kU/100g) compared to fried bacon (91,577 kU/100g - yikes!). Fats such as butter and olive oil are high, and even nuts and seeds are relatively high, especially when roasted.
Step 2 – Choose cooking methods that minimize AGE formation
• Avoid high temperature dry heat cooking methods such as roasting
• Avoid grilling, chargrilling, frying, deep-frying, broiling and BBQ
• Choose foods cooked with moist heat, shorter cooking times and lower temperatures – eg. boiling, poaching and steaming
• Add acidic ingredients such as lemon juice or vinegar as this can help to reduce AGE production whilst cooking.
Step 3 – Sleep more, move more, stress less
People who are sleep deprived have higher circulating AGEs so make sure you are regularly getting a good night’s sleep. In addition, daily activity and stress reduction can help to reduce AGEs.
AGE Content of Common Foods
|Food Item||AGE Content kU/100g|
|Dairy milk (whole)||5|
|White rice, quick cook (10 mins)||9|
|Quaker oats, prepared||14|
|White potato, boiled||17|
|Sweet potato, roasted, 1 h||72|
|Egg, poached, below simmer, 5 min||90|
|Red kidney beans, raw||116|
|Tofu, soft, boiled 5 min + 2 min return to boil||628|
|Raw skinless chicken breast||769|
|Chicken boiled in water with lemon||957|
|Salmon fillet, poached||2,292|
|Sunflower seeds, raw, hulled||2,510|
|Dry roasted peanuts||6,447|
|Chicken nuggets, fast food (McDonalds)||8,627|
|Beef, steak, pan fried with olive oil||10,058|
|Chicken skin, back or thigh, roasted then BBQ||18,520|
|Bacon, fried 5 min, no added oil||91,577|
For a comprehensive list of AGE content in foods: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3704564/table/T1/