- Meat causes cancer vs. compounds in them?
- What are Advanced Glycation End Products (AGEs)?
- How to reduce AGEs in your diet
- How concerned should you be?
- How to reverse Advanced Glycation End Products?
Or how about the friend who sent back his BBQ chicken salad after discovering the bed of spinach it sat on was not USDA certified organic.
We can’t help but laugh at these people. They selectively follow nutritional fads for health benefits, while outright ignoring the elephants in the room; those things which science supports as being much more worrisome.
Despite what they claim, the vast majority of Americans do not really care about eating healthy, they only pretend to.
They’ll make a dietary change for health only if it allows them to keep eating what they love. Changing conventional for organic? No wonder that health trend is so popular among the masses, because it’s the easiest thing ever. It requires zero sacrifice, a pain-free change.
Often times whether your food is organic or not should be the least of your concerns. Much more important to your health may be how your food is cooked and processed. Does meat cause cancer if it is grilled or fried? Is smoked fish healthy or actually bad for you?
Meat causes cancer vs. compounds in them?
It may sound like semantics, but the only form which has been officially declared as causing cancer by the World Health Organization is processed meat, which in 2015 was categorized as “carcinogenic to humans” (Group 1).
They classify red meat as “probably carcinogenic to humans” (Group 2A) (43).
To be clear, no others have been classified as carcinogens. Unprocessed pork, chicken, and other white meats don’t have either of those designations. However both the WHO and the U.S. government have declared certain Advanced Glycation End Products – found in both red and white meat as well as fish – as being carcinogens. So while they do not label those foods as causing cancer, they admit that some compounds – which are naturally formed in them – are “reasonably anticipated to be a human carcinogen.”
Is that like saying cigarettes don’t cause cancer, only the chemicals in them do? Or are the levels found in food low enough to be completely risk-free? That’s for you to decide.
What are Advanced Glycation End Products (AGEs)?
There are two primary sources; those which form inside your body naturally and those which are already pre-formed, that you get in large quantities when eating certain types foods. Both are bad for you, but not to the same degree. You can’t avoid them in your diet entirely, but you can reduce exposure.
Those created inside your body
Inside your body when proteins and fats combine with sugars, glycation naturally occurs. During this process, it has been estimated that 0.1% to 0.4% of the molecules will fall off and spontaneously convert into methylglyoxal (1).
Methylglyoxal is not an end product though. Several end-products it spawns have been researched including MG-H1, MOLD, CEL, argpyrimidine, THP. Whether those or others, as the name implies these “end products” are compounds in their final forms, after being broken down.
Why are Advanced Glycation End products bad? Research has suggested that methylglyoxal interferes with your insulin signaling pathways (2). This is why the glycation from sugars are particularly problematic for both type 1 and type 2 diabetics.
Diabetics have much higher levels of methylglyoxal-derived AGEs in their blood. Higher levels are correlated with higher diabetic side effects such as nephropathy, neuropathy, and retinopathy (3).
But for non-diabetics, it’s not clear how bad methylglyoxal end products are for you. In fact, some research – albeit more controversial – has shown that methylglyoxal’s potential benefits may outweigh its toxic effects in non-diabetic adults (4). It has been suggested that methylglyoxal may act against a number of pathogenic microorganisms as well as malignant tumor cancer cells and those benefits may be worthwhile, even after considering the negative effects.
In short, end products created in your body are not good. But with the exception of diabetics, the amount of harm they do is less clear. What is clear are the negatives about those from diet.
AGEs from your diet
AGEs created outside of your body – from food – have a vast amount of research which suggests they are carcinogenic and may accelerate aging. Two of the most problematic dietary sources come from meat; heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs).
We’re not singling out the meat eaters, as another type of end product – acrylamide – is much more prevalent in plant-based carbohydrate-rich foods when they are cooked at high temperatures. For example, potato chips, French fries, and particularly instant coffee (versus paper filtered drip coffee, which is actually quite low since most of the acrylamide is in the coffee bean grind).
In short, the major dietary sources of potentially harmful Advanced Glycation End products fall under these three categories:
- Heterocyclic Amines (HCAs) – Entirely from cooked meats/animal products. None from environmental exposure.
- Polycyclic Aromatic Hydrocarbons (PAHs) – Majority is from cooked meats/animal products, minority is from environmental pollution. Some from unwashed plants.
- Acrylamide – Primarily from some cooked plants and environmental exposure. Very small amounts in meat (5).
We have covered acrylamide extensively and out of these 3 major categories of AGEs from food, you should be most worried about HCAs and PAHs. Even for those on the typical American diet who regularly chow down on highly-heat cooked vegetables like potato chips and French fries, research has shown that the vast majority of dietary or exogenous AGEs come from meat.
Upon the testing of 549 different food – from all categories and types – it was found that “based on standard serving sizes, the meat group contained the highest levels of AGEs” (6).
Regarding AGEs from plant-based foods: “In contrast, carbohydrate-rich foods such as vegetables, fruits, whole grains, and milk contain relatively few AGEs, even after cooking.”
Not only are most of your AGEs in food coming from both red and white meat, but the types they contain – HCAs and PAHs – have a large body of research linking them to cancer. And unlike the AGEs we create in our body such as those from methylglyoxal, there are absolutely no associated health benefits with the HCAs and PAHs that are problematic. Everything about them is bad news.
Of course, acrylamide should be minimized as much as reasonably possible too, but the elephants in the room are clearly the HCAs and PAHs in your diet.
What are heterocyclic amines (HCAs)?
HCAs are the name given to the category of chemical compounds which contain at least one heterocyclic ring; atoms from 2 or more different elements and 1 or more nitrogen atoms. Why are the heterocyclic amines in meat bad? Because they can interact with DNA by forming what is called covalent adducts.
In plain English, that means they latch onto your DNA and alter its biology. When that occurs, it can damage the DNA and cause a permanent mutation.
HCAs are formed during cooking from a combination of:
- a creatine molecule
- an amino acid
- a form of sugar, which increases production but is not required
Do plants contain creatine? No, only animals create creatine. It’s found in an animal’s muscle. There’s no such thing as vegan creatine. For that reason, HCAs are found only in meats and animal-based foods.
A vegan diet contains zero creatine and a vegetarian diet contains much less than what omnivores eat, since most is found in meats like beef and chicken rather than dairy like milk and cheese. All animals as well as humans naturally produce whatever creatine we need, which is why having zero from dietary intake (i.e. meat) is no problem at all.
What the government say about them?
There are 20 advanced glycation end products within the HCA umbrella but the four most studied are PhIP MeIQ, MeIQx, and IQ. This is because they are the most prevalent in foods and by far have the most evidence linking them to cancer.
Does eating meat cause cancer? Mandated by congress, every few years the Department of Health and Human Services must issue the Report on Carcinogens, which is a science-backed public health document. In 2004 (11th edition) they added the 4 main HCAs to their official list of known carcinogens, labeling each as “Reasonably anticipated to be a human carcinogen” (7).
Unfortunately – yet not surprising – no sort of dietary guidelines or regulations have been enacted by the US government to help consumers reduce their intake. Most likely the special interests prevented that.
If a restaurant put a single speck of a cigarette ash on your steak, they might very well go to jail. But they can burn the steak ’til its black and that’s perfectly acceptable, at least according to our dietary guidelines.
Just the existence of totally optional food preparation tips, if promoted by the USDA, would greatly help consumers and restaurants cook their meats using methods which would reduce heterocyclic amines.
Official carcinogen? That’s not the scariest part
The most frightening part are the numerous studies which led to the US government’s decision to identify those 4 heterocyclic amines as being likely cancerous in humans.
Just several months before the 11th Report on Carcinogens was published, here’s one study titled Heterocyclic amines: mutagens/carcinogens produced during cooking of meat and fish (8). Coming from Japan’s National Cancer Center in Tokyo.
By feeding very high HCA diets, researchers were able to induce cancer and in a relatively short amount of time at that.
A = colon cancer induced by IQ in rat
B = colon cancer induced by PhIP in rat
C = colon cancer induced by Glu-P-1 in rat
D = liver cancer induced by MeIQx in rat
E = liver cancer induced by IQ in monkey
That’s just one example of many studies. There are numerous animal studies demonstrating cancer correlation of the breast, skin, lung, prostate, and other organs.
If you have dry or wet Age-Related Macular Degeneration (AMD), glaucoma, or know someone that has either, you may be interested in the recent research which demonstrates that high intakes of AGEs result in higher deposits in the inner retinal layers, causing inflammation and neovascularization of the ocular tissues (9). The word “neovascular” literally means “new vessels” which is the big problem in late stage or wet AMD; abnormal blood vessels grow underneath the retina, causing vision loss (10).
Obviously no one’s going to allow these same types of studies to be done on humans (and for good reason). But there is extensive scientific research which has evaluated human participants and their patterns of meat consumption and cooking techniques. The findings? In humans, high consumption of well-done meats, fried meats, and barbecued meats is associated with increased risks of colorectal cancer (11), pancreatic cancer (12, 13), and prostate cancer (14, 15).
Much less serious albeit more concerning for some people is that advanced glycation end products and skin aging may be linked. They have been detected in the epidermis, collagen, and elastin of skin (41).
This is why if you care about excess UV exposure and wear natural sunscreens, you should also be concerned about the damage you’re doing to your skin based on what you eat.
When and where they’re found?
When do the HCAs form when cooking meat? Burnt meat will contain the most, but it’s impossible to avoid them altogether. How much forms is largely dependent on (16):
- dryness of meat
- time of cooking
For each of these 3 variables, generally the higher amounts, the more the heterocyclic amines will form. This is why high-temperature cooking methods such as grilling over an open flame, pan frying, and roasting are some of the worst offenders. Using fresh meat is not safer than frozen, as research has suggested both create equal amounts when cooked (17). Organic vs. conventional meat will also make no difference.
Here’s a look at how much can be found in ground beef (18).
|HCAs In Cooked Ground Beef – Max Amount Per 3 Ounce Serving (in ng)|
Whether we’re talking beef, chicken, fish, or pork, the PhIP and MeIQx amounts are often times the highest.
While less studied, norharman and harman are two other HCAs scientists are quite worried about. Not all, but in some meats they can be found in very high dosages.
Like pan-fried bacon, which contains about 400% more norharman than PhIP and MeIQx. Ironically, bacon is the worst meat for total HCA while being one of the best meats for antioxidants per its ORAC value. But that’s not saying much, as we’re talking about bacon relative to other meats. On average, plant-based foods have 6,400% more antioxidants than meats. Contrary to public perception, fish – even raw salmon – are some of the worst meats for antioxidant content. Bacon has about 28x more than salmon.
Oven-baked salami pizza topping isn’t far behind bacon for total HCAs, with harman levels of up to 24.7 (ng/g) and 186.1 for norharman. That’s 2,100 and 18,600, respectively, in a 3 ounce serving for that type of salami (19).
There is a widespread belief among the public that grilled chicken is one of the healthiest meats you can eat. Chic organic eateries to fast food chains will often tout their organic or non-GMO grilled chicken (i.e. Chipotle) as being a great choice for you.
Sure, grilled chicken might be lower fat, but should you actually avoid it because of AGEs?
To hold chicken in a higher regard over other meats doesn’t quite match up with the science, at least when it comes to heterocyclic amines.
|The 5 Worst Grilled Foods For HCAs (20)|
|Food||HCAs (ng per 100g)|
|Chicken breast, skinless, boneless, grilled, well done||14,000|
|Steak, grilled, well done||810|
|Salmon, grilled with skin||166|
|Hamburger, grilled, well done||130|
But wait, it gets worse. Nearly all of the HCAs in chicken are PhIP.
This is another example of public perception differing from what the science says. Your healthier (not healthy, but healthier) choice for lunch may be a $4 Whopper versus that $14 grilled chicken breast sandwich from the corner cafe. Cholesterol you say? Chicken breasts actually have more than ground beef.
Obviously neither would be ideal. The point we’re trying to make is that it’s wrong to demonize the fast food chains as toxic poison, while giving your favorite restaurants a free pass. Because in reality, they all may be serving you unhealthy food. At least McD’s is only charging you a fraction of the price for it!
What are polycyclic aromatic hydrocarbons (PAHs)?
Scientifically, they are the name given to any organic compound with 2 or more fused aromatic (or benzene) rings.
How many different types of Polycyclic Aromatic Hydrocarbons are there? Over 100, but only 15 are listed as “reasonably anticipated to be human carcinogens” in the 13th Report on Carcinogens, published by the National Toxicology Program within the Department of Health and Human Services.
The big difference between PAHs and HCAs is that the latter is found exclusively in cooked meats. We don’t get it from anything else. But they both have something in common – they both mutate your DNA.
PAHs can come from cooked meat, but also environmental exposure from the burning of coal, petroleum products, tobacco, wood, and other organic substances. They’re found practically everywhere, the asphalt you drive on to the exhaust coming out of your car, and PAHs are used to make plastics, pesticides, medicines, dyes, and even food coloring and additives (23).
Your home’s heat – whether it’s a natural gas furnace or a wood-burning fireplace – is an emitter of airborne PAHs. Not only the food you eat, but the gas or kerosene burning stove-top used to make it is also a source. Though as you can imagine, consuming a highly-concentrated food source contains far more than whatever you’re breathing in from normal indoor and outdoor air pollution.
An extensive study published in 1992 concluded that for the average non-smoking American male, over 70% of carcinogenic PAH intake was from diet (24).
A more recent study for United States has not been done to the best of our knowledge, but we would predict that diet now represents significantly more than 70%.
Why? Because despite the fact that overall pollution in the world is worsening, the fact is that in our country at least, automobiles have become much more efficient during the past couple decades. Whether you love or hate the EPA is besides the point, the fact is that due to increasing restrictions on emissions in recent history, air quality on a national basis has improved by 77% from 1990 versus. 2014 (25).
So no, your biggest PAH problem is not that your neighbors are Tundras instead of Teslas. Rather, it’s those barbecued ribs you love which as hard as it is to admit, may not be healthy for you.
However since it’s a pollutant, potentially any and every food can contain them. PAHs are found in the soil and air, even more so in urban areas since there is more fossil fuel combustion there.
Foods that contain the highest amounts of PAHs:
- charcoal-broiled meats
- smoked meats
- fats and oils
- grains and some vegetables (however with these, you can remove by washing)
Is charred food carcinogenic? As mentioned there are 15 types of PAHs (out of over 100) which have been suggested as being carcinogenic. Excluding from pollution, not all of those are normally found in food. Among those which are found in cooked and charred meats is benzo(a)pyrene, which is classified as a Group 1 carcinogen by the IARC (26).
That doesn’t mean it’s “probably” or “possibly” carcinogenic, it means it’s definitely carcinogenic according to the IARC. As of 2016, only 118 agents on earth have that classification and most are only (or should only) be found in industrial settings such as radioactive forms of radium (which represent 4 of the 118 agents), things like asbestos, and viruses hepatitis B and C.
When something found in food is in the same category as plutonium, you should probably take notice.
|Amount of PAH Benzo[a]pyrene In U.S. foods|
|Concentration (μg/kg)||Food Category||Source|
|0.01–4.86||Beef and chicken||Kazerouni N, et al.,Analysis of 200 food items for B[a]P and estimation of its intake in an epidemiologic study. Food and Chemical Toxicology. 2001;39:423–436 (27)|
|0.02–0.56||Bread, salty snacks, cereals and grains|
|0.01–0.48||Fruit and vegetables|
|0.01–0.47||Sweets and desserts|
|0.01–0.18||Dairy products, fat products and beverages|
Here’s the bad news:
“For the average American diet, the intake of carcinogenic PAHs was estimated to be 1–5 μg/day, with unprocessed grains and cooked meats the greatest sources of the compounds.”
Meats will always create PAHs during cooking. You can definitely reduce exposure by cutting off the heavily blackened and charred meat pieces, but it will still contain PAHs.
But the good news is that with grains and vegetables it’s largely an environmental toxin that we have a lot of control over, according to the 2010 report: World Health Organization’s Guidelines for Indoor Air Quality: Selected Pollutants. Within it they do quite a bit of comparing and contrasting of dietary vs. environmental exposure and both the aforementioned quote as well as the following is from that report.
“However, the PAH load on leafy vegetables and grains can be removed by washing.”
But even if you eat unwashed grains and veggies, they still contain up to 90% less PAHs than beef, chicken, and fast food meat.
Unfortunately as far as processed foods are concerned, there’s no way you can control how thoroughly – or not – they wash the grains beforehand.
Among the meats, pork is the healthiest as far as the PAH benzo[a]pyrene is concerned.
How to reduce AGEs in your diet
If you eat meat, it’s virtually impossible to avoid advanced glycation end products. That being said, there are some tips you can use to minimize the amount you’re taking in.
1. Avoid the grill
You really need to re-think your 4th of July BBQ party, being that grilled meats – whether they’re chicken, steak, turkey, cod, tilapia, you name it – test out as having the highest amount of HCAs and therefore, are perhaps the worst cooking method.
Those charred and blackened grill marks are chock full of advanced glycation end products. When you tell this to someone, often they laugh it off as a myth or attack the messenger. Sometimes they reply the burnt meat parts are their favorite. As mentioned at the start, no matter how overwhelming the evidence, most people are only interested in hearing health tips which are pain-free to follow.
At restaurants, it isn’t always easy to avoid grilled food since due to sheer ignorance, even the “healthy” and “organic” restaurants these days are totally obsessed with grilling everything, due to the false perception that it’s better for you.
2. Avoid pan-frying
Depending on the meat type, you either see the grilled or pan-fried food as testing the worst.
The fact that bacon is the worst (or 2nd, depending on the study) really demonstrates how bad using a frying pan can be. Because bacon is pork and typically, a meat with a lower level of HCAs and PAHs. It’s one of the reasons why BBQ’d pork has about 94% less HCAs than a well-done grilled chicken breast (see above).
But once you put that pork in a frying pan, the concentration of heat combined with the drying effect really accelerates the creation of AGEs.
3. Use lower temperatures
Not only does this apply to HCAs and PAHs, but pretty much all advanced glycation end products including acrylamide from carbohydrates/sugars.
The National Cancer Institute points out that “high temperatures, especially above 300ºF” are most problematic for HCAs and PAHs (28).
4. Cook for shorter amounts of time
Even when cooking temperatures aren’t exceedingly high (such as the 640ºF from a propane grill), studies have shown that usually the longer you cook a meat, the more AGEs which will form.
That’s why the more rare the meat, the better. Though you still need to cook it thoroughly to kill bacteria. Use a thermometer to ensure the inside reaches the recommended safe temperature for the particular type of meat you are cooking.
5. The more moisture, the better
Moisture is one of the best ways of how to reduce advanced glycation end products.
Marinades usually help, but sometimes hurt since sugar can increase production and the amount of that in your average store-bought BBQ sauce is alarming.
Studies suggest that boiling may be the best method overall.
Does smoked meat cause cancer? It should come as no surprise that the levels of PAHs in them are often quite high. But if you insist on eating smoked fish or other meat, using apple-tree or alder wood may be the lesser of the evils. Avoid using wood from the spruce tree since it appears to produce the most (42).
How concerned should you be?
It’s easy to freak out when you hear that a type of polycyclic aromatic hydrocarbon in meats is a Group 1 Carcinogen according to the WHO.
Though it’s important to remember that Ultraviolet radiation is also a Group 1 Carcinogen. Our guess is you’re not reading this hunkered down in a subterranean cave, totally isolated from sunlight, with only LED light bulbs (since those emit no UV). No, you still go outside and live your life.
But then again, UV radiation is actually good for you in moderation – it’s how your body makes vitamin D. It’s in excess that it becomes a problem and causes cancer. With these particular AGEs, there’s no such thing as a good or moderate healthy amount… they are always bad for you regardless of amount.
How much your risk of cancer increases
Is DNA damage automatically dangerous? No. It’s always bad, but it doesn’t mean harmful side effects will always result.
This is because our bodies do an excellent job at repairing damage, but not all can be fixed. It is estimated that fewer than 1 out of 1,000 are permanent. Those permanent ones are a mutation (29).
Less than 0.1% being permanent sounds quite trivial and it is when viewed out of context, but consider the big picture.
It’s impossible to measure the number of cell mutations the average human has per day. Viewing microscopic cellular behavior throughout all parts of your body while you are alive is impossible (and when you’re dead, so are your cells so that’s not helpful).
To view in real time and measure them would literally require internal probes which are able to view every cell in your body, all 37.2 trillion of them (30). Even if that were possible, the probes themselves would likely be creating additional oxidative stress and therefore, changing how much DNA damage and mutations are occurring.
All scientists can do is estimate. It is thought that naturally occurring oxidative DNA damages arise at least 10,000 times per cell, per day. How many result in mutations is unknown, but as mentioned, it is suspected to be less than 0.1%, possibly far less.
Regardless of what you eat or do in life, you are experiencing countless numbers of permanent DNA mutations every day. What causes aging? No one can conclusively say, but many theorize the accumulation of permanent DNA damage is what causes aging. You can’t avoid this. You age, you die, and you will face your creator some day.
Prudent precautions vs. statistical odds
What you can avoid is eating foods which are shown to be more likely to cause DNA damage and therefore, mutations. Your death in this life is guaranteed, but will eating smarter increase longevity or least provide a better quality of living while you’re here?
As a general rule, a healthier lifestyle is more likely (but certainly not a guarantee) of living a longer life, though no one can conclusively claim how much dietary choices such as these may slow down or speed up the clock.
The random nature of where on your sequences of DNA a mutation occurs is like rolling a dice, which makes any kind of predictions or guarantees impossible. You can be a 5 year old and experience a DNA mutation which causes cancer. Or you can go 55 years before that happens. We can only rely on the statistics of likelihood, but there’s no way to know what’s around the corner for you regardless of how young or old you may be.
The one thing that can conclusively be said about DNA mutations is that the more of them you have, the higher the probability that one will be harmful to you (i.e. turn into cancer).
That doesn’t mean you will get cancer. You could live a life of 80 years and eat burnt meat daily for dinner, smoke a pack a day, all with zero exercise…. and just by luck, never have a DNA mutation morph into cancer. But the accumulation of permanent DNA damage – and those mutations on top of mutations – statistically correlate with cancer. It’s the reason why cancer is rare in children, but extremely common in older adults. Your odds of getting cancer is directly correlated with age. That’s why half of all cancer cases are diagnosed at age 70 and above (31).
That’s for all types of cancer in the UK, excluding melanoma skin cancer. The data was compiled by Cancer Research UK, the largest and most respected cancer charity in that country. It’s comparable to our American Cancer Society.
And no, your odds of getting cancer do not peak in your early to mid 70’s. The reason the number of cases declines after that is because that’s the average lifespan. Fewer people are living beyond that and hence, fewer cases.
How to reverse Advanced Glycation End Products?
Once DNA mutates, nothing can fix it. You can’t reverse it. That’s why the only sure way to reduce food AGEs is by cutting them out of your diet as much as you reasonably can. Most people can accept burnt and charred food may be carcinogenic and should be avoided. Few are able to accept the theory that meat does cause cancer.
Some research has suggested certain nutrients and compounds can breakdown or inhibit formation of AGEs in vitro (meaning in the laboratory). They are not proven effective in human biology. Measuring that in vivo (inside the human body) has not been done and would be quite difficult, for the same reasons measuring mutations is quite challenging.
The most common AGE in the human body – glucosepene – no compound has been shown in vitro to be effective at breaking down.
So to be 100% clear, the following compounds are only suggested in vitro at reducing AGEs coming from diet such as heterocyclic amines, acrylamide, and polycyclic aromatic hydrocarbons. In alphabetical order they are:
- L carnosine
- alpha lipoic acid (32)
- aspirin (33) (34)
- benfotiamine (32)
- metformin (36)
- pentoxifylline (36)
- pimagedine (37)
- pioglitazone (36)
- pyridoxamine (32)
- taurine (38)
- vitamin C (39)
Compounds unique to cruciferous vegetables, such as broccoli, cauliflower, kale, cabbage, and Brussels sprouts, have been shown in vitro to inhibit the formation of AGEs (40).
Among those in the list above – for a few years now – we have followed research on how to prevent glycation using L carnosine (in vitro). Among the compounds listed, that is the one whose research has been most promising to date, at least in our opinion. We take a 500 mg capsule prior to each meal.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.