You may not have heard of advanced glycation endproducts (AGEs), but chances are you've eaten them. AGEs are chemical compounds created by a "browning reaction" when cooking foods—grilling a steak, for example. They can also be created by the body's metabolic processes.
WHAT THE EVIDENCE SAYS
AGEs can accumulate in our bodies as we age, and higher AGE levels correlate with many age-related diseases. Research suggests that they can exacerbate aging of the arteries, muscle, and bone . They can also activate receptors that trigger certain biological processes. The most well-known receptor—the aptly named receptor for advanced glycation endproducts (RAGE)—can prompt chain reactions of inflammation, oxidative damage, and even the beta-amyloid pathology of Alzheimer's disease . However, RAGE activity is strongly influenced by many other factors and the AGEs that we consume may not play a central role .
In small clinical trials, AGE levels in diet have had a modest effect on aspects of health such as systemic inflammation, increasing one measure of inflammation but not others . These trials were brief, lasting no more than four months. And only half of the longer-term observational studies conducted to date found higher levels of inflammation in people with diets high in AGEs . No clinical trials have yet examined cognition or cognitive decline in response to changes in dietary AGEs. One very small observational study tracked healthy elderly people over time and reported that people who consumed more AGEs showed a faster decline in memory. However, no difference was seen on overall cognition or major aspects of brain function such as attention or language .
It's unclear exactly what level of AGEs may cause harm. Most of the clinical trials to-date have been rated as lower quality . Researchers are also working to overcome challenges with how AGEs are measured. The levels of AGEs measured in the blood don't necessarily correspond to levels in other parts of the body. There are also many types of AGEs, with some more damaging than others, yet researchers working to understand the effects of AGEs have often relied on measurements of a single type .
WHAT YOU CAN DO
The level of AGEs in our body depends on the amount that we eat, the amount produced internally, and the rate at which they are cleared by our kidneys and metabolism. Some researchers have called for reducing AGEs in our diets to help lower levels in the body .
The amount of AGEs in food varies based on both the type of food and how it's cooked. Levels are generally higher in full-fat dairy and meat than in whole grains, vegetables, fruits, and milk. (AGE levels of common foods are available in a public database, based on the levels of one AGE called carboxymethyllysine .) Cooking at higher temperatures, particularly in dry heat, drastically increases AGE content. For example, roughly the same amount of AGEs is produced by 5 minutes of cooking at 300°F versus 3 hours of cooking at 215°F. Conversely, adding acidic ingredients such as lemon juice or vinegar can lower levels .
While the AGEs that you consume may adversely affect the health of your brain and body, the evidence is not yet conclusive. However, some of the strategies to lower AGE intake are likely to lead to health benefits for completely separate reasons. Using lower cooking temperatures can preserve nutrients in some foods. And substantial evidence indicates that shifting your diet toward foods with lower AGE levels such as fish, whole grains, legumes, vegetables and other staples of the Mediterranean and MIND diets will benefit the health of your brain and body.
Dr. Penny Dacks was previously the Director of Aging and Alzheimer’s Disease Prevention at the Alzheimer's Drug Discovery Foundation. She was trained in neuroscience at the Mount Sinai School of Medicine, the University of Arizona, and Queen's University (Canada) with individual fellowships from the National Institute of Health, the Evelyn F. McKnight Brain Research Foundation, the ARCS Foundation and the Hilda and Preston Davis Foundation. She has authored over 18 peer-reviewed scientific articles and is a member of the Society for Neuroscience, the Gerontological Society of America, the Endocrine Society and the Association for Women in Science.
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