June 1, 2015

Metabolic Theory of Cancer: Speculation on the Causes of Cancer -- and How to Mitigate Them (Pt.4)

We’re in the midst of exploring a few potential causes of cancer, and ways to possibly reduce risk. Up today: carcinogens. (If you’re new here, this post is pretty far down the line in a series that started back in November 2014, in which we are exploring the metabolic theory of cancer. Click here for the first post. Each one will end with a link to the next.) 

I have been saying that sometimes, people can do “all the right things,” and still end up developing some pretty gnarly health issues. I have also said that some of the diet and lifestyle factors we suspect might cause cancer (mostly by way of disrupting mitochondrial function) probably apply less to little kids than they do to older folks. So, aside from what we’ve already covered—viruses, age, and freaky mutations to mitochondrial DNA, what else might be causing cancer in babies and other people with no obvious risk factors?


Let’s look at exposure to known and unknown carcinogens. In the modern landscape—especially the urban and suburban landscapes—you can’t move ten feet without coming into contact with something that has been “linked” to cancer: deodorant, artificial sweeteners, plastics, chemicals outgassing from carpet & vehicle upholstery, shampoo, pesticides, fungicides, cosmetics, vegetable oils, and, let’s not forget the most deadly substance known to mankind, which none of us should ever ingest, EVER: RED MEAT! (Dun-dun-dunnnnn! Cue the scary music!)

Nonsense about red meat aside, we really do live in a bit of a toxic cloud. If only those darn cows would stop farting and releasing so much methane. (Kidding!)

What is a carcinogen?

There are substances that are known to be carcinogenic. There are substances that are suspected to be carcinogenic. And there are substances that we just don’t know about yet. I hesitate to point a finger at any one specific thing, because, my guess is, it is less the effects of any one, single thing, and more likely the cumulative interactions of multiple questionable substances over some period of time. (How many substances, and how long? I don’t know. If I did know, then this wouldn’t be speculation, and I’d also probably be a zillionaire, in which case, I’d be sunning myself behind my villa in Greece or southern Spain, instead of writing blog posts for free.)  

I mean, here’s the thing: when They (with a capital T) say that something “causes cancer,” it is typically because they gave test animals—or exposed cultured cells to in vitro—whatever the substance is, in doses that no human being would be exposed to in the course of six lifetimes. At that level of exposure, everything is “toxic,” including air and water.

And then, there’s the other side of that coin: when something is declared “GRAS,” or “generally regarded as safe,” it is usually because it has been studied by itself. In isolation. But we aren’t exposed to food additives, pesticides, fluoride, secondhand cigarette smoke, flame retardants, vehicle exhaust, parabens, phthalates, BPA, etc., in isolation. We are bombarded with these things pretty much all day, every day, from the minute we’re born. (And even before then, too. Thanks a lot, placenta!) Studies that declare substance “X” to be safe—or, that is, safe in the doses a human being could reasonably expect to encounter it—focus only on substance X. Rarely is substance X evaluated for how it interacts with substances A through W, Y and Z. But this is how we interact with these things on a daily basis—in combination.

So the question is not whether “X” causes cancer, but rather, what does a lifetime (or even just a few years’ worth) of exposure to these multiple things do to us? Do these compounds interact synergistically, so that the sum of their effects is greater (read: more harmful) than any of them individually? And maybe, in the best case scenario of someone with a low overall burden, and with a liver and kidneys in tip-top shape, the body would be perfectly capable of “detoxifying” and clearing these substances out. But combined all together, and combined with our modern, processed diets, sedentary existences, livers that are struggling just to keep blood glucose and lipids in check, lack of fresh air and humanness, and who-even-knows-what other inputs or lack thereof, maybe our bodies just can’t keep up.

As for how some of these things might cause cancer, I think the same holds true here as for viruses: they probably somehow derail mitochondrial function. Actually, I don’t have to speculate here. There are substances that are known inhibitors of some of the enzymes and complexes in the electron transport system. (Remember when we talked about the ETS way back in this post?) So you can see what would happen there. I mean, the ETS is pretty much our mitochondria’s whole raison d’etre. Their purpose is to generate energy. But if the enzymes and complexes are being disrupted/inhibited because of substances that directly “mess with” proper function, then it doesn’t take a genius to see how that might cause cancer. (With cancer being the evolutionarily conserved mechanism that keeps cells alive by feeding them massive amounts of glucose when their mitochondria lose the ability to metabolize fats and ketones. [Dont’cha love how I insert these little reminders & reviews?])

I’m not saying everything in the modern world is poisonous, and I’m not saying everything is safe. What I’m actually saying is: we just don’t know.


How can we strengthen our bodies against known and unknown carcinogens?

I think part of it comes from doing just that: supporting the body’s natural detoxification pathways, and the other part comes from limiting exposure to these substances in the first place.

Support the body’s natural defenses

Regarding the detox pathways: Our bodies have lots of ways of taking out the trash, so to speak. The most obvious are: urination, defecation, and sweating. (But if we think of CO2 as a metabolic and respiratory “waste product,” then breathing also helps, as does donating blood, particularly for people with excessive iron/hemochromatosis.)

Way back in the post about the large intestine from the digestion series, I explained the role of chronic constipation in affecting mood. Well, if defecation is one of the primary ways we get rid of waste products and things the body doesn’t want, then it’s probably not good to be plugged up on a regular basis. I don’t think you need to worry if you don’t go every single day, at the same time, like clockwork. But certainly, at least a few times a week, something should be coming out. ;-)  Remember: when waste sits in the colon for too long, the body sometimes re-absorbs substances it was trying to get rid of.

The kidneys are another option for filtering wastes (as well as normal byproducts of healthy metabolism) out of the blood. Nobody wants to read about urine, and I sure don’t want to talk a whole lot about it. Let’s just say that, barring supplements or some intensely pigmented food (like beets), which may temporarily give your urine an uncharacteristic color, if your urine is…um…a color other than what you would expect, do look into it. You do not want to mess around with kidney function. (Aside: how come there’s so much talk about poop in the holistic nutrition world and so little about pee?)

The other biggie when it comes to detoxification in the body is the liver. The liver uses multiple enzyme systems, amino acids, and other nutrients in order to help the body get rid of things it doesn’t want building up inside it. Myriad nutrients are involved in these processes, but the short list includes: sulfur-containing amino acids, such taurine and cysteine (the latter of which is required to synthesize glutathione); glucuronic acid (this is why calcium-d-glucarate is recommended for women [and men] who need to get rid of excess estrogen); molybdenum (a cofactor for xanthine and sulfite oxidase enzymes…sensitive to sulfites in things like wine and dried fruit, or have “multiple chemical sensitivity?” Maybe you’re low on Mo.). Specific herbs, such as dandelion root and milk thistle (silymarin) are known to aid liver function as well. 

I am not an expert in how the liver works, but there’s no doubt it is one of the body’s most impressive multitaskers. Here is an abbreviated list of all the things our livers do for us: store glycogen and release glucose to help regulate blood sugar; synthesize lipoproteins to transport cholesterol, fatty acids, and fat-soluble nutrients; synthesize bile; synthesize ketones for use by the rest of the body (hepatic cells, themselves, can’t use ketones); and, of course, “detoxify” almost everything – alcohol, excess steroid hormones, caffeine, acetaminophen, urea, and more.

So yeah, the liver performs a ton of tasks simultaneously. It’s not like if the liver is “busy” conjugating excess estrogen it’ll be unable to do anything else. But I do suspect there might be a “saturation point” of sorts, when it comes to the liver’s detox mechanisms. The enzyme systems the liver uses to clear out wastes & toxins aren’t one-trick ponies. Meaning, for example, the enzymes that make up the cytochrome P450 system are employed in getting rid of many substances, not just one. So let’s say one of the enzymes is constantly—constantly—taxed with getting rid of caffeine. (Or metabolites of your statin, your metformin, your PPI, or pain relievers.) Maybe it’s so preoccupied clearing those things that it doesn’t have time to get rid of potentially carcinogenic substances “a, b, and c.”

Overall: the liver has enough to do just taking care of hormones, lipids, ketones, blood glucose, bile, and the normal, endogenous byproducts of metabolism. So maybe it’s not such a great idea to bombard it with endless amounts of stuff from the outside. (Not that I’m about to give up wine or coffee…more on the quality of life issue in a bit.) Think of it like your car—a machine that is also great at multitasking: the car can have all of the following going simultaneously: the radio, the GPS, the engine, the defroster, the windshield wipers, and the heat or air conditioning. But if the radio is already tuned to a station, it can’t be tuned to a second and third station at the same time.

Again, I’m not a liver expert; I’m just thinking out loud here. But maybe if the specific enzymes involved in conjugating/detoxifying a bunch of substances are quite “saturated” with those substances, then if we introduce additional substances that require the same enzymes for detoxification, those additional substances will get put on the back burner, and end up accumulating in the body. (Some people believe this is a potential cause of obesity—in a protective move, the body sequesters these built-up toxins inside adipose tissue, rather than allowing them to circulate endlessly through the bloodstream. Seems plausible to me, though I’m not sure of the biochemical mechanisms that would be involved. All I know is, there are very obese people who actually feel terrible for a little while when they are actively losing body fat, especially a lot of it, and fairly rapidly, because the toxins that had previously been locked away are now making their way through the body in order to be excreted. It’s not a classic Herxheimer reaction or “die-off,” but it does fit the phrase, “You’ll feel worse before you feel better.”Her)

Whoa. I’m getting way off message here. But you know me, queen of the 1000-word tangents. Let’s get back on point.

Avoid overtaxing the body outright…

We just talked about some of the organs and systems involved in helping the body rid itself of potential carcinogens. Beyond supporting these systems with the appropriate nutrients, the other main way to mitigate the risks of potential carcinogens is to avoid flooding the body with them in the first place.

Mostly, this involves reducing our total exposure or overall “toxic burden,” but I am also firmly of the belief that we shouldn’t be so concerned with not dying that we forget to actually live. Yes, you could drink only filtered water, eat only organic/biodynamic food, and avoid all personal hygiene & cosmetic products that contain anything questionable. You could use only baking soda and vinegar to clean your home, and you could give up your car. (I attended a thyroid seminar once where Dr. David Brownstein shared some pretty scary stuff about the effect of bromides outgassing from vehicle plastics & upholstery…bromine being a halogen element that can displace iodine in the body, just like fluoride.)

…But don’t swing too far in the other direction

Here’s the thing. Even the most careful among us, and the most dedicated to living as “cleanly” as possible, will still be exposed to untold amounts of scary stuff. First of all, organic foods are not usually free of pesticides; they’re just treated with pesticides that are not currently prohibited by U.S. organic certification laws. Second, even if you buy organic foods, what kind of water are they using to irrigate the crops? Does it come from a municipal supply where they add fluoride and chlorine? If you’re buying packaged produce (even organic) from the supermarket, do the plastic bags impart anything to the food itself? What about the “inert” gases they use to help keep the produce looking pretty so you’ll want to buy it?

What about the carpet in your home? Or in your vehicle? Or in your friends’ homes and vehicles? What about all the pollutants that become airborne? You cannot escape everything.


Even so, like I said, it’s probably not a bad idea to reduce overall exposure. I’m not trying to fear-monger here. I’m only pointing out that if you try to avoid every single thing that might potentially harm you, you are going to have a stressful, anxious, fearful, sexless, and lonely life as a complete shut-in in your hermetically sealed, sterilized bubble of a home. You will likely become alienated from friends and family when you refuse to participate in shared meals because you don’t know what kind of dish soap someone used to wash their plates six meals ago, and they might serve you coffee made with water that was not filtered by reverse osmosis, and you won’t go on vacation with them because God only knows what kind of chemicals are outgassing from airplane seat upholstery! (Never mind that you just know those airplane peanuts aren’t organic! And never mind that you don’t eat peanuts anyway, because they’re legumes, and there’s phytate, and aflatoxin, and you might as well just put a loaded gun to your temple and pull the trigger.) <--Sarcasm, in case you’re new to the blog and don’t get my humor yet.

See what I mean? It’s naïve to try to avoid everything. In the process, you’ll risk turning into a total nutcase who is unable to participate in society at large, and even if you are able to, no one will want you around, because, well, you’re a total nutcase.

That being said, there is most certainly a place for reducing, limiting, and mitigating our exposure to some of this stuff. To the extent that you are ready, willing, and able to, sure, buy more organic food; filter your water; limit your use of utterly unnecessary body sprays, lotions, perfumes & colognes; don’t microwave food in plastic; try not to live directly downwind or downstream of a manufacturing plant that belches out tons of smoke or wastewater; swap out some of your cleaning products for ACV and baking soda; and get enough sunlight to keep you human, but not so much that your skin burns on a regular basis.

But I’d like to say again, don’t let a relentless focus on not dying prevent you from living. I read a fair amount of comments on various health blogs & forums, and I swear, I can feel the anxiety radiating from people sometimes. (And who knows: maybe that constant, unrelenting terror is, itself, a carcinogen…)  

That’s more than enough for now. Next time, we’ll cover diet & exercise, then after that, hypoxia. And then, we’ll get to what I really want to talk about: THE KETOGENIC DIET! (Yes, it’s a separate thing to tackle from regular ol’ diet.) And I’m happy to report the hypoxia post will have us getting back to more solid science.

Remember: Amy Berger, M.S., NTP, is not a physician and Tuit Nutrition, LLC, is not a medical practice. The information contained on this site is not intended to diagnose, treat, cure, or prevent any medical condition.


  1. Yes, that's all very well, Amy, but if you're going to talk about scary stuff and carcinogens, you must at least mention low density lipoproteins at some point. Everyone knows that fatty red meat increases your LDL. Fatty red meat also causes cancer. Therefore, LD lipoproteins cause cancer. Rightly so, forums are full of people who are absolutely petrified of them and will digest some seriously weird things to reduce their number.

    Perhaps you should have also mentioned LDL particle number, because as far as I can tell by all the brilliant gurus' sage advice and nodding to each other in sync, LDL-P is seriously scary shite. I haven't seen anyone actually explain why having a particular number of particles suddenly gives you heart disease, but I figure it must be along the lines of what happens when you get too many economists in a room - one of them will invariably start talking about how getting unemployed people to break windows and dig holes and then fill them in again will fix the economy. That's pretty much the equivalent of dunking a bucket of blood into a small tank full of tiger sharks. The economists (sharks/lipoproteins) go mental and start trashing the place (your arteries).

    Just how they determine what number is safe and what isn't, remains a mystery. Possibly along the lines of: think of a number between 500 and 1000, multiply that by the number of bowel movements you have in a 3 day period and divide by two if you've ever been sucked in to a 'meatless Monday'. If your LDL-P is lower than the number you end up with, you get to brag to the internet. If your LDL-P is over, you're publicly shamed and forbidden from giving an opinion on anything. Ever.

    If only the people in white coats could develop a drug that lets you defecate lipoproteins, we'd be right as rain. Knowing my luck, someone would then publish a study entitled "Being a smart arse and overdoing sarcasm - causes cancer."

    Then we'll both be stuffed.

    Alright, now ignore all my nonsense. I was thinking about people being scared to live and that's what I though of. It's your fault I trashed your excellent blog post.

    Have a good one.

    1. HA! Oh man...it is a jungle out there! I try to just be level-headed, but I know I could / "should" take a harder stance on some things. I guess I figure there are enough crazies out there without me adding to the mix. And I will never be a food purist, myself. Not right now, anyway. There are things in my life that need improving way more than my diet, at the moment, and I'll take the crutches when I need them, but to the least extent possible. :-/

  2. Amy, I thought of you when I read this yesterday:


    1. Yeah, it's fantastic news. I've been following Andrew on Twitter for a few months. Really promising stuff. It's so great that his doctor is on board...think how many more people they'll reach when they devise some sort of trial protocol. :)

  3. Thanks again for the series...I really enjoy your way with words. I, myself eat meat or eggs, daily, which likely will cause somethin' somethin' anyhow, I recently ran into Vegan stuff with the highly touted EPIC study from Rich Roll, etc. .
    Argh. So, a good read from you and Anthony Colpo was my remedy. It's hard for a doctor to read their tripe and listen to Pharma sales reps....at the end of the day we can only try to help people find whatever works best for them.

    1. I've have Sean Croxton's interview with Rich Roll on my iPod for a few weeks now and keep putting off listening to it. Just don't know if I can take it. But I'm not going to argue if the guy feels well on his diet. I try to stay open minded. All I know is what works for *me* (and many other people), and that's LCHF. ;-)

  4. I am new to your blog and enjoy what I am reading so far. (And yes I do get your sense of humour.) I have so far read your Food Partitioning series, the Alzheimers series and this MTC series. I had thoughts about glucose being a driver force in cancer over a decade ago when I read "The Zone" by Barry Sears. He explained that he had done some work in cancer research and it was noticed that cancer cells ordered your body to build blood vessels for it and that cancer cells could also only burn glucose as fuel. They also noticed that the vessel walls were more porous than normal, which probably enables glucose uptake even faster.

    Any way, thanks for the great posts and I am looking forward to the next MCT post. (Get with it it's been 2 months already:) )

    1. Thanks Mark! Welcome to my little corner of the blogosphere. ;-) To be honest, I'm running out of steam on the cancer series. But I know people really like it. (At least, the small following it has, anyway. Small, but very loyal!) And I know it's been a while since the last one. The next one won't be too hard to write, but a couple after that are going to require some more digging through papers & quoting the research. It's a bit intimidating, which is why I procrastinate. But I know once I get started, I do enjoy writing them.

      There'll definitely be a few more. Can't promise when, though. (Not *too* much longer. I do try to keep the audience happy, hehheh.)

  5. Great so far Amy.

    Can't wait for to complete it.

    1. Thanks for reading all of it! That's no small feat to do it as quickly as you did. As you can see, it's been a long time since I've added anything. I know this series was pretty popular, and a lot of people are waiting for me to pick it back up. I will soon, but I have a couple of other projects that need my time first. It's definitely not finished yet, though. I haven't even gone into the ketogenic diet and hyperbaric oxygen yet! Lots of good stuff yet to cover.

  6. Hi Amy.
    You are probably aware of this but just in case.

    Restricting calorie input works well for lowering Glucose and Insulin, all to the good and puts stress on cancer cells both through higher Ketone levels and lower Glucose.

    However some cancers can utilize Glutamine as an alternative to Glucose so lowering Glucose may not be enough. Good news here is that Green Tea polyphenols can target and disrupt Glutamine metabolism in the presence of low Glucose. So the simple answer is to supplement intermittent fasting with Green Tea consumption.

    Here's the link.


    Seyfried also mentions this here.


    As I said before you are probably well aware of this but to me its new.

    One other point you may or may not find interesting.
    I have monitored glucose and ketones in three different scenarios, low carb with normal eating (for me this is, or was, two meals per day approx 50 g/carb) low carb plus intermittent fasting (1 meal/day so 23:1 fasting again about 50g/day carbs) and low carb plus aggressive intermittent fasting (complete fasting 2 days per week with 23:1 for the rest of the week, i.e. 5 meals per week, somewhat higher than 50 g/day carbs).

    What I found was that the aggressive fasting regime dramatically boosted ketone levels, while providing somewhat lower Glucose. What this means is that I regularly get into Seyfrieds management zone i.e. K/G ratio less than 1 on a weekly basis- Glucose in the low 3s or very high 2s, lowest is about 2.8 mmol/l and ketones at 5 mmol/l or above, I saw 5.8 mmol/l this morning with Glucose at 3.6 mmol/l. I am going to do a run doing both Glucose and Ketones over the entire 48 hour period to see how fast and how long I get into this zone.

    I should clarify what I mean by fasting. Its not water only, I take my version of BPC which contains heavy cream, coconut milk, almond milk and cocoa powder, so not strict fasting but close.

    I tolerate this regime extremely well, don't know how others would do it, but I never feel hungry and have abundant energy especially on day 2 of the two day near-fast. PLUS I FEEL GREAT - cant overemphasive that. I have been keto adapted for a long time so this probably helps.

    I will be adding Green Tea to the BPC to target Glutamine in the future.

    Looking forward to reading the next installment.


    1. Are you a cancer survivor, Tim, or just experimenting with optimization? Don't forget to relax and enjoy things once in a while amidst all that math and fasting. ;-)

  7. Yes I will.

    Just experimenting, my health is very good and both parents are in their 90s and still going strong so I expect I'm ok. I needed another project. When I retired I got interested in Finance/Economics and researched that to death, but there is so little meat there it got boring, I'm a data geek and you just can't model it (well you can but not beyond very simple means and most economics is pure bunk). After 10 years its on to something else. I got interested in health/nutrition when my doc originally told me to ease up on the carbs as Glucose was getting high (too many cruises). I had thought I was indestructible up to that point but was brought down to earth. As I researched I became intrigued. As I found in Economics there is a vast amount of unneeded complication and simplicity is sought but somehow systematically evaded, in finance anyway, mostly because of vested interests/money etc, but in the end there are a few simple rules that ensure success all the rest is hype. In nutrition and health I am beginning to come to similar conclusions. From Price to Warburg to Seyfried the thread seems to run simply to sound nutrition (whole foods) and exercise. On the other is side the vast and seemingly unnecessay complication of DNA mapping, the carpet bombing of chemotherapy and radiation, vested interests, careers, and all the rest. Im an engineer, or was, and one thing I found time and again is that when things are complicated and you run into roadblocks everywhere you turn, by far the best thing to do is go back to the beginning and start again. Understanding the problem usually takes time and lots of detours but the solution more often than not is relatively simple. It's like Eisenhower said plans are useless but the process of planning is absolutely essential.

    Take care.

  8. Oooh, Amy, you've left us hanging here. :-) I've just read thru your MTC series to this point and am yearning for the continuation. I know you've spent so much time on AD and other topics (so much to do, so little time) and I've got plenty of catching up with your blog to do to fill my appetite for your writing, but pleeeeaaase get back to this series soon.

    I'm fascinated by this whole thing and am anxious to see how you wrap it up. Thanks for all you do.

    1. Thanks, Nathan! I can't believe it's been almost a *year* since I've added to the cancer series. I definitely haven't forgotten about it, and believe me, I want to get back to it probably as much as other people want me to get back to it. ;-) Probably sometime later this month or in June. Hopefully soon, though.

    2. I totally understand the demands on your time. Again, so much to do, so little time. Your blog has risen to the top of my reading stack since I've just recently discovered it. I love your approach to health/nutrition and I look forward to learning more and more; and laughing a bit in the process. :-)

    3. Thanks! Glad you like what you've read so far. :)

  9. Hi Amy, Have you given up, or have I missed the link to the next installment? Is Ketogenic diet where you land up? I hope to hear from you soon! Sarah