How advanced glycation end products (AGEs) lead to disease and premature aging

Advanced glycation end products (AGEs) are formed from food and the way food is cooked. They occur when a sugar bonds to a protein or fat. In processed junk food this occurs when the ingredients of a food contain fats, sugars, and proteins. One such example is fried, coated chicken. The combination of fat and protein in the chicken, with the sugars in the flour coating, which are then cooked at high heat, results in a high level of AGEs. However, natural, traditional food can also result in a high reading of AGEs. Smoked salmon has a fairly low reading. In contrast, pan-fried salmon in olive oil has a reading that is over six times higher. Both the type of food and how it is cooked matter.

AGEs are a problem because they are now strongly linked to a number of diseases. They cause inflammation, oxidative stress, and premature aging. Over time, they accumulate in the organs and tissue. They congregate in the brain, the kidneys, the cardiovascular system, and the skin, causing damage to these organs.

The brain

People with higher AGE levels have poorer brain function as they age. This leads to cognitive decline. Such people are not able to think clearly or remember well; they become less sharp. In some cases, this build up of AGEs will manifest as Alzheimer’s disease. It can also show as Parkinson’s disease, amyotrophic lateral sclerosis (ALS), and other neurodegenerative diseases.

In Alzheimer’s disease AGEs accumulate in the hippocampus area of the brain. This is precisely the area of the brain most ravaged by Alzheimer’s disease. People with Alzheimer’s disease have a build up of amyloid plaques, tangles, and protein tau in their brain. The current thinking on Alzheimer’s disease is that it is the build up of these plaques and proteins that causes people to lose their memory. If the brain functions as an antenna that tunes in to new memories and thoughts, then these plaques are like rust, which prevents the antenna from working, forming because of AGEs. Effectively, AGEs coat regions of the brain like rust, stopping it from working.

To be sure, the majority of us will not get any of these diseases. However, it is probable that many of us will experience chronic cognitive decline, whereby we notice our memory, thought patterns, and possibly our speech are not as sharp. Ideas might not be expressed as clearly as we would like. Or, there is a delay in thinking up a name or a place. Sometimes people notice they can’t quite keep up with the thought and speech of younger people. This type of chronic cognitive decline is inevitable when diets are full of junk food and AGEs. But cognitive decline is not an inevitable part of aging, provided people find the right way to live.

The kidneys

For over 5,000 years traditional Chinese medicine doctors have known that the kidneys are linked to the brain. When a patient visits a traditional Chinese doctor and reports problems with their memory or thought then the diagnosis is usually one of deficient kidney energy. In the traditional Chinese system, the kidneys are the storage vessel for the primordial energy (jing) that is inherited from both parents, as well as acquired energy or qi. It is the kidneys that control aging, memory, energy, and death. One thing that wears down kidney energy, affecting cognition, is too much external stimuli. This is a problem in our current age due to being always switched on or having access to too much information. Acting out passions without restraint also damages the precious kidney energy. When a person is quick to anger, or violence, has addictions, or excessive or unusual sexual exchanges the kidneys are damaged. When people are young this damage can be contained. Once a person reaches their thirties, forties, or fifties, and still indulges their passions, and is exposed to excessive eternal stimuli in the form of messages, emails, news, or the online world generally, then their kidney energy declines. A loss of libido, hearing, heavy legs, poor motivation, fatigue, and cognitive problems are all a sure sign that kidney energy has been depleted. Many of us will recognize these signs of depleted kidney energy.

Science is starting to catch up with traditional Chinese medicine. The recent discovery of the glymphatic system demonstrates a direct link between the brain and the kidneys. At night, when we sleep, the brain clears out junk debris, eliminating proteins and wastes, via the glymphatic system. This system transports all the waste from the brain into the cerebral spinal fluid, then into a small space surrounding veins feeding the brain, and downwards into the neck. From the neck these proteins enter the lymph system, then into general blood circulation. These junk proteins, which originated in the brain, then combine with other waste products, before being filtered by the kidneys and exiting the body. If we don’t get adequate sleep these junk proteins cannot leave the brain; if our kidneys are not well then we do not filter these junk proteins properly. When this happens we are more prone to cognitive decline and neurodegenerative disease. The glymphatic system functions optimally when we have sufficient sleep, while lying on our side, rather than our back or belly.

The problem is that the kidneys are also targeted by AGEs. These products target and affect all the structures in the kidneys. This stress on the kidneys can cause chronic kidney disease, which in turn leads to low energy, fatigue, and, in some cases, a transplant or death. AGEs also target the vasculature and blood flow to and in the kidneys. With poor blood flow, or inflamed vasculature, the kidneys function poorly, which can lead to chronic kidney disease. This becomes a vicious circle: kidney health is required to filter junk proteins from the brain, but eating those junk proteins also weakens the kidneys. On top of this, according to the Chinese system, our kidneys are being pummeled by information overload and excessive connectivity that is a feature of our current time.

The heart

The veins serving the kidneys are not the only blood vessels that are targeted by AGEs. There is a form of tissue called the endothelium. This is a single layer of cells that lines various organs, blood vessels, and especially the heart. When AGEs are eaten they cause this layer of cells—the endothelium—to dysfunction, leading to stiff arteries, commonly known as atherosclerosis. Plaque forms on the inside of the arteries, alongside the stiffness, restricting blood flow, and eventually leading to a heart attack or stroke. It’s quite a high price to pay for endless or frequent junk food.

The skin

There is another major organ that is attacked by AGEs. Namely, the skin. AGEs stress the skin. This is due to oxidative stress on the skin. If a person eats too many AGEs, doesn’t eat enough vegetables and fruit, lives in a polluted city, and over- or underexercises (as both are harmful), then oxidative stress occurs. This affects all internal organs and also the largest external organ, which is the skin. When this happens the skin loses its youthful look. It’s why some people of the same age look different ages, or why some people age better than others. It’s why some people look haggard and unhealthy or have more wrinkles. But looking after the skin by avoiding AGEs is not just about vanity. The production of oxidative stress causes structural changes in the skin. This affects how the skin uses vitamin D, and it affects immune function.

Prevention

Paleo versus vegan

One of the benefits of a low-carb or Paleo diet is that it eliminates junk food. Done properly, such a diet can increase antioxidant protection if lots of vegetables are eaten. However, for many people, a low-carb diet rapidly becomes a meat feast. The problem with this is that proteins from meat are the highest source of AGEs. If a high amount of meat is paired with insufficient antioxidant protection from plants, then, over time, AGEs will build up.

At the opposite end of the dietary spectrum, one of the benefits of a vegan diet is that it virtually eliminates AGEs, while simultaneously ramping up antioxidant protection from a wide variety of plant foods. However, it should be noted that it’s very possible to eat a processed, junk food vegan diet, high in unhealthy refined carbohydrates and sugars. For some people with health complaints, a temporary, short-term natural vegan diet can act as a type of medicine. People do report improved health and energy on such a diet. Junk food is eliminated, as are AGEs, and there is a great deal of antioxidants from plant foods. Long term, a vegan diet may not suit many people. Important nutritional deficiencies such as vitamin B12 are very possible, and some people simply put on weight with too many carbohydrates, due to various genetic variations inherited from their ancestors.

Dairy products

Dairy products are an interesting case. They are an animal protein food that is low in AGEs. Even ice-cream, with its mix of sugars and proteins, is low in AGEs. Some dairy products are extremely low in AGEs. Consider this: fried chicken has a rating of 7,000, whereas whole milk has a rating of just 12. Remember earlier we said that AGEs damage the kidneys, and that traditional Chinese medicine doctors are especially concerned about damage to kidney energy. One remedy for kidney weakness, recommended by traditional Chinese doctors, is to eat dairy products, the very food that is among the lowest in AGEs. It’s a myth that traditional Chinese doctors do not recommend dairy products, probably first peddled by hippie American alternative health people in the 1970s.

A traditional diet

Therefore, a diet low in AGEs seems to be somewhere between a Paleo diet and a vegan diet. It contains meat, but not too much. It contains fish and dairy, but not huge slabs of unlimited cooked cheese. And, it contains lots of vegetables and some fruits. Plant foods rich in polyphenols and flavonoids have been shown to be especially beneficial in reducing the harmful effects of AGEs. These foods include berries and oats. Grains, whether gluten containing or not, rice and starches, should be had according to one’s ancestral heritage. Some people simply cannot tolerate starches, again due to either ancestral heritage or genetic variations. People with autoimmune diseases often, but not always, have a tough time with gluten.

Cooking food

How the food is cooked is also of the utmost importance. Overcooked meat, fried foods, carbohydrates and proteins cooked together (such as macaroni cheese), are all much higher in AGEs. Therefore, cooking foods gently, with smaller pieces of meat in a broth or stew, will reduce the overall amount of AGEs.

Exercise

There is now emerging evidence that exercise can reduce circulating levels of AGEs in people. The studies are conflicting. For example, Tai-Chi was found to lower levels of AGEs, whereas more intense forms of exercise were not. There are good reasons for this conflicting evidence. Namely, overtraining causes oxidative stress just like AGEs. If this happens—and it often does for many people who exercise, because people like to push themselves—then the body cannot clear the AGEs. In contrast, doing the right amount and intensity of exercise, with adequate recovery, produces an anti-inflammatory and antioxidant effect, which allows the body to eliminate AGEs. Again, there are important genetic variations at play here. Some people have a higher innate antioxidant capacity, and their ancestors were engaged in forms of activity different to other people’s ancestors. It’s important to choose the right type of exercise for your body and inheritance, and the right dose of exercise.

Levels of advanced glycation end products (AGEs)

In 2010 a group of senior researchers from the Mount Sinai School of Medicine in New York completed a major project looking at the effects of AGEs upon the health of people across a wide range of ethnicities. As part of the project they compiled a list of the amounts of AGEs in hundreds of common foods. They concluded that people with a daily intake of under 15,000 AGE/units were generally healthy, but suggested that under 7,500 AGE/units was probably better. It’s not very hard to exceed even the higher level: a cheese burger and fries will take you way over the higher limit.