Doctor's Note

So in the purple cabbage test we want blue pee, but pink poo. The what test? See: Testing Your Diet with Pee & Purple Cabbage

More on colon cancer prevention in:

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  • tbatts666

    So if most drug absorption studies are performed on people who have alkaline poo and acidic pee, does these have an affect on vegans taking pharmaceuticals whose absorption and secretion is dependent on pH?

    • masobel

      That’s a very good question and I don’t think anyone has every looked into this potential since vegans represent a relatively small portion of the population. 60 Minutes ran a piece last year that looked at how some drug studies are only performed on men since women have “pesky hormones” that interfere with how the drugs react in the body. I would say it’s possible that the drugs react differently in vegans as well.

      • Arjan den Hollander.

        Damn!!! It was a little unsettling that the start of your video make me think of a certain basic instinct scene.
        I need to get out more…….

      • Joe Caner

        Wow, vive la différence!
        That is a fascinating story.
        Allopathic medicine is in the business of developing and delivering substances and procedures to treat symptoms as one would fight a war, head on, guns a-blazing where disease is the enemy and the patient is all to often the casualty.

        We have certainly come a long way from let food be thy medicine and medicine be thy food.

    • Neil

      Assuming drug companies performed such studies, they would likely suppress any negative findings:

  • Very interesting, I had no idea PH played such a major roll in colon health. Looks like beans & greens for the win again!

  • Arjan den Hollander.

    Question on the Swank diet. I went back to very low fat 4 days back (<15%, 5-6gr sat.) , and I seem to experience quite bad disruption in BP and maybe sugar homeostasis. I feel faint, dizzy and brain-fogged like hell, like a very bad hangover but without the stomach upset and headache.
    Anyone have experience with this and how long this phase might persist? Would be great to know so I can plan around it.

    • Trish

      Sounds a bit like hypoglycaemia to me. If you have reactive hypoglycaemia you need some fats in each meal as it slows absorption of carbohydrates. Maybe you increased carbs too ?

      Swank diet is low saturated fats but still supposed to have unsaturated fats.

      • Arjan den Hollander.

        I would prefer my stress hormones tone down instead of slowing my absorption rate by adding fat. I’ve observed a noticeable change in hue of some tissues (nails/tongue/gums) more towards pink, which is a really good sign. Those effects will be body wide so there are bound to be a few re-balancing issues. For now I’m not to worried about a few days of brain fog yet, I would be comforting to know though that this overshoot will re-adjust itself if given a little time.
        Stress and a history of it appears highly involved in autoimmune disease, so the situation and question shouldn’t be a unusual one.

        • Rosemary Guy

          try cranberry to balance the hormones and some cleansing type foods like ice berg lettuce, romaine lettuce, spagetti squash. perhaps the nut butters will give you good assess to the fats that you are eating

  • Gary Brown

    So I have read some information about colonoscopies. Dr. MCDougal infers that that sigmoidoscope exam is a much safer exam procedure vs most colonoscopiesjob minus the prep, mess, expence, and dangers of a perforated colon and possible issues with Anaesthesia.
    Additional I would assume risk factors decreased eating a Vegan lifestyle and further decreased consuming a balanced organic diet.

    • Charzie


    • Thea

      Gary Brown: I can’t thank you enough for your link to that Dr. McDougall article! I’m a few years off from having to make that decision myself, but I’ve been starting to think about it. After reading information about mammography that I got from Dr. McDougall (from the Cochrane fondation), I have to wonder how many other tests are a bad idea. The article you linked to above was extremely helpful not only for helping me make my own decisions, but for giving me something I can share with my loved ones. Thanks!

  • guest

    What if i drank a tablespoon of vinegar with every meal?

    • Joe Caner

      What if you ate more fiber rich whole food forms of fruits, grains and vegetables?

    • Jim Felder

      This is linear thinking that assumes that your alimentary canal is as inert as a garden hose and the acid in vinegar would pass unchanged through the stomach and small intestine to acidity the large bowl. As professor Campbell has pointed out, we need more whole-istic thinking and focus on whole foods and even more on whole diets and less reductionist thinking on single ingredients or worse single nutrients.

      • jj

        I so agree with this statement.

        “we need more whole-istic thinking and focus on whole foods and even more on whole diets and less reductionist thinking on single ingredients or worse single nutrients.”

  • How does all this relate to the “alkalize or die” stuff we’ve previously been hearing for years at places like ? Is this another one of these 180-degree reversals that keep happening in the popular nutrition press?

    • Jim Felder

      Bruce, we need both, alkaline blood and acid poo. And as the video points out, the exact same diet does both! Once again strong compelling evidence that evolution has set us up to eat plant and avoid animal foods.

    • dogulas

      The same food is the perfect solution for all the ideals: whole plant foods cause more alkaline urine and more acidic stools. It’s not a 180, it’s the same message. Whole plant foods are an alkaline diet. And the fiber in the alkaline diet, as stated in the video, has the fiber to make the fermented results in the stools more acidic, as is desirable.

    • Rami_RD2B
  • smith

    I just read interesting article of women in france eat 3 eggs a day live to 115 and she say that is the secret of her longevity.

    • Megan Markowski

      Looking at individual cases can be highly misleading. You have to look at populations of centenarian’s diets to get a more accurate representation of the diet for the “secret of longevity”. For example, Japan a huge population of centenarian’s and they eat a mostly plant based diet.

    • jj

      And how does she know that it’s the 3 eggs a day?

    • Rami_RD2B

      There are those that smoke cigarettes there whole life and live a very long time. This in itself is not evidence that cigarettes promote longevity. Please see here for more on eggs

  • Kitsy Hahn

    “—9 out of 10 could produce a stool on demand. Stuffed from head to tail
    with plants they could give you a stool sample at any time, as easy as
    getting a urine sample.”

    They’re loose cannons, is that what you’re saying? They could explode at any moment? Eeeeww. ;-)

    • Wade Patton

      As Dr. Greger jokingly says in one of his annual speeches, “Vegans are just regular people.” Even before I began my study of nutrition it was a no-brainer that regular elimination is far healthier than “holding” it in for days.

  • Excellent video, thank you!

  • JM


    Here’s an apparent argument for not taking baking soda or any alkalizing substances or supplements into your food or gut!!

    Here is an apparent argument for not taking anything that claims to alkalize your system!! – as so many people who are into healthy eating do every day.

    Now I can see a possible explanation for why so many people who have been eating healthy for years still develop bowel cancer?


    • Psych MD

      Watch the video again. That is not the message, as is stated in several of the preceding comments.

      • JM

        I realized what you’re saying when I posted. I saw the preceding comments.

        However, we will just have to disagree on the interpretation of the science. My comment stands, at least for me.

        • b00mer

          Your original comment does not make any cogent points on the interpretation of the science with which to agree or disagree:

          “Here is an apparent argument for not taking anything that claims to alkalize your system!!”

          What system? We are talking about the colon and stool samples here. There are other bodily systems. The body is not one big “system” with one single desirable pH.

          “[…] as so many people who are into healthy eating do every day.”

          If we agree to define the “system” in this case as the colon/stool, then no, people who eat healthy are not creating an alkaline environment in the colon. Though again, you include no indication of what “healthy” is – is this standard american “healthy” e.g. chicken, fish, greek yogurt and limited starches?

          If we define a healthy diet as a diet rich in high fiber plant foods, this leads to increased acidity in the colon, whether pseudoscientific health gurus out there want to believe it or not. This is not a point up for varied interpretation.

          “so many people who have been eating healthy for years still develop bowel cancer”

          Again, who qualifies as healthy, and where exactly is this population of healthy eaters who are developing bowel cancer at some significant rate? All the research points to those eating a high fiber plant based diet as having lower risk of colon cancer. Of course, even if eating such a diet could reduce your chances by 99%, there will still be some who eat healthy and get colon cancer. However using that as a line of reasoning to question the results is like questioning the impact of smoking on lung cancer since there are still people who get lung cancer who don’t smoke. It’s not a productive or sensible line of reasoning.

          • JM

            We’ll just have to agree to disagree.

            Many viewing the video will agree with my thoughts. No amount of the above circumlocution or degreed names will weaken their take of common sense.


          • b00mer

            My entire post was based on requests for you to be more specific in regards to your own quoted statements, and yet you characterize my post as vague? Rovian projection at its finest here. There is no conversation if you don’t make clear, specific statements, and don’t respond to requests for clarification. It’s a shame we couldn’t actually discuss anything of substance, maybe next time.

  • mrjansanman

    I love it when you talk about colon health!

    • Arjan den Hollander.

      Groupy spotted! :)

  • Jamey Burger

    Stop taking drugs made by big Pharma! Stop drinking Homogenized milk! The animal protein gets squeezed down to nanoparticle size and absorbed into the blood stream in excess and causes inflammation which clogs the arteries.

    • largelytrue

      Stop imagining that non-homogenized milk is magically better in all crucial ways. Stop supposing that all drugs patented by large corporations are bad in all circumstances.

  • Reading these non-stop pseudo-psycho-sociopathic comments is beyond my tolerance. Was it Clemens who said, “It is wrong to teach a pig to sing, it wastes your time and annoys the pig.” Cripes is there anything so ignorant as the north american peasant? I know this will get me booted off. I hope my rancor rattles just one person into learning to practice critical thinking and onto a path to some self reflection… as I hold my breath…good bye my NF friends. Coacervate, the primitive pre-biotic life form has pupated. I’ve turned into a large and noticeably clumsy beetle, living under the couch on rotting food scraps. (Hear this next bit in the voice of Inpector Clouseau: ” He who don’t know nothing must know something, eh?” Live long and proliferate!

    I am Gregor

    • Arjan den Hollander.

      You are either at the end on your enlightened phase already sensing the darkness coming or you already find yourself in it.
      Either way I hope you can find the strength to fight it once more.

      If you haven’t tried something like my egg timer method before, consider trying it for a few weeks, it is not perfect but it has helped me.
      Every 20 – 30 min kick yourself in the butt and a quick 10 exercise repetitions that involve most of your body, to reactivate yourself.
      It is a grueling tour de force but re-enlightenment is worth fighting for.

      This uneducated fool hopes to see more of you after your battle is done, may the life force be with you!

    • Veganrunner

      Coacervate I doubt this comment will get you kicked off. Thank goodness because I enjoy your comments and humor. We can only hope that as people are exposed to the science they start to understand how to think critically. I run into this all the time as people send me info on new supplements. Should I take this? I say, “just eat your veggies.”

    • JM

      Samuel also had a few other things to say, and since you seem to appreciate his intellect:

      “Likewise tolerance and charitable views of men and things cannot be acquired by vegetating in our corner of the earth.”

      This one’s almost axiomatic to Greger’s site and philosophy of challenging ‘settled’ health beliefs –
      “Never let your schooling get in the way of your education!”

      Mark Twain (1835 – 1910)

      “What is tolerance? It is the consequence of humanity. We are all formed of
      frailty and error; let us pardon reciprocally each other’s folly – that
      is the first law of nature.”


      “Anger and intolerance are the enemies of correct understanding.”

      – Mohandas K. Gandh

      “It is wiser to find out than suppose.”

      – More Maxims of Mark, Johnson, 1927

    • b00mer

      What a beautiful iridescent exoskeleton! Can you still type with your little beetle tarsi? I hope you stick around. Say it with me, serenity now…

  • fred

    The bottom line is that glucosamine supplementation lowers human mortality

    Glucosamine and Chondroitin Sulfate have already been shown in a large epidemiological study to lower overall mortality and reduce cancer risks – a 5-year study of 77,719 elderly residents of Washington State. We found several publications based on different analyses of data based on this population.


    For most of the supplements we examined, there was no association with total mortality. Use of glucosamine and use of chondroitin were each associated with decreased mortality.”

    Both of these papers were done on the same group of 77,719 people. We note that this is as great an effect as combining vegan diet and fish consumption! We find this quite surprising. Glucosamine appears to have a comparable or greater effect on mortality reduction and lifespan extension than Metformin, Rapamycin, 2DG, Veganism, and Resveratrol in nematodes and rodents.

    RESULTS: Persons reporting use of glucosamine + chondroitin on 4+ days/week for 3+ years had a non-statistically significant 45 % lower Colorectal Cancer risk than non-users

    Epidemiological evidence exists that glucosamine and chondroitin supplementation reduces inflammatory biomarkers.

    Glucosamine supplementation may be protective against lung cancer.

    * A 2010 publication suggests that taking high doses of glucosamine or prolonged use of glucosamine reduces levels of SIRT1, leads to apoptosis of pancreatic cells and could increase the risk of developing diabetes.

    * caution….study probably done with people on SAD diet and/or eating institutional food as provided in nursing homes

    • Frank

      NON-statistically significant means there is NO REAL difference. Sometimes people just die or don´t die, it´s just part of rolling the cosmic dice, so you can expect that sometimes more people die in one group doing something, than in an other doing something else, this can be predicted using statistical methods. Results are ONLY relevant, if the difference is greater than what is expected by chance.
      In the studies you (how are these related to the topic anyway???) cited, the researchers have no significant results, so basically what they really say is: we saw no difference if one took these suplements or not, only they do it in a way that shows that they would have wished they saw something, but they didn´t.
      The buttom line is save your money and the poor shellfish, sharks etc.

    • Frank

      The limitations of the current study should be considered in the interinterpretation of our results. The generalizability of our results may be limited to the extent that characteristics that modify the associations differ in the broader population compared with the VITAL cohort (44). Further, although the HRs were adjusted for many many factors associated with supplement use and mortality, confounding by unmeasured factors may be present. If this confounding was due to unmeasured healthy behaviors being more common in supplement users than nonusers, this bias would cause the HRs to be spuriously low (ie, the estimated benefit

      Maybe this has been overreadby the author of the page you cite.

  • Kitsy Hahn

    “Significantly lower fecal pH in those eating the traditional rural
    plant-based diets, compared to those eating the traditional western
    diet, who were eating far fewer whole plant foods than the black

    Okay, here’s a “what if.” Let’s say somebody scarfed down lots of plant-based foods every day — veggies, especially — BUT, no more than 2 or 3 times a week, added a small portion of organic animal protein to a meal. In other words, the eater follows neither a strict WFPB diet nor a paleo one. Would the research results change all that much, do you think?

    • Rosemary Guy

      the issue is always keeping the amount of animal protein to this level as these foods can be addictive…….It’s easier to keep your taste buds adapted to a WFPB diet.
      What difference it would make would be towards the alkaline for poo just like the white bread and opposite to the orange

    • Tom Goff

      To be honest, I think this is what the traditional rural plant based diets are, ie plant based foods every day and the occasional small piece of meat on holidays/feast days. You’d need to look at the papers referred to in the video to see if there is a detailed food list but my understanding is that traditional rural plant based diets are not completely vegetarian. They are just very low in animal foods.
      The old “Sunday Roast” style of eating was similar in that basically you ate potatoes, cabbage and bread in the week but on Sundays you ate some meat and fruit if you had the money. Like Rosemary Guy says though, you’d need to make sure your portions are very small and infrequent. Even then, a regular small serving could have consequences. As the Harvard meat study found:

      “One daily serving of unprocessed red meat (about the size of a deck of cards) was associated with a 13% increased risk of mortality”

      Now this was a daily serving but but regular meat eating every 2 or 3 days will probably also have consequences.

      • Kitsy Hahn

        Well, all I know is I must be doing something right. I haven’t had a cold or the flu since the winter of 2000. Sure, there’s more to good heath than so-called right diet, and I could give a list of the things I do every day (for instance, avoid docs and their deadly prescription drugs), but my way certainly isn’t the highway. Everybody is different.

    • Wade Patton

      Flexitarian I’m calling myself now because that’s how i was able to be (flex) fruitarian a few years back. Very strict 5 days, not so strict on the weekend. WORKS GREAT for me. I only quit that to get through the process of killing the nicotine addiction. But never could get started back. Now i eat beans, greens, nuts, tea, and fruit all week long, and have some “nasties” on the weekend-which makes things SO much simpler when dealing with the SAD rest of the world. That’s how I encourage folks to start eating better–one meal at a time, then a day, then a week–but you never have to feel “trapped” if you leave some “cheat” days in the schedule. Doesn’t mean you have to. More plant foods, more better-it is NOT an all or nothing proposition.

  • Youcef

    Back to what was known about pH and cancer long ago : acidosis (an acidic cellular environment) is unfavourable to the development of cancer cells [1]. Nobel Prize Laureate Warburg further explained a low pH makes cancer cells unable to use sugars therefore to produce energy required for their survival.

    [1] Reding, Rene, L’Equilibre acide‑base et L’Equilibre
    ionique dans le Cancer et le Precancer. Le Cancer, No. 2, 1928,
    Brussels. Reviewed by Elnora C. Folkmar in Jour. Amer. Assn. for
    Medico‑Physical Research, October, 1928.

    More recent research on acidity and apoptosis :

    Williams AC, Collard TJ, Paraskeva C: An acidic environment leads
    to p53 dependent induction of apoptosis in human adenoma and carcinoma
    cell lines: implications for clonal selection during colorectal
    carcinogenesis. Oncogene 1999, 18:3199–3204.

    Park HJ, Lyons JC, Ohtsubo T, Song CW: Acidic environment causes apoptosis by increasing caspase activity. Br J Cancer 1999, 80:1892–1897.

    • JM

      Has anyone ever done a Meta-Analysis to see if GI cancers were statistically more prevalent in those using
      long-term antacids and or with HCL gastric deficiencies?

      • Youcef

        Have you looked for one yet?
        I haven’t, but it rings a recent bell. If my memory is correct, it was epidemiologist Devra Davis [1] who refered to a particular pattern in digestive cancers. The pattern looked at comparable countries, and pointed out that from a country to another the distribution of digestive cancers was different but the total was similar.
        From that, it was hypothesized that when a part of the digestive tract doesn’t do it’s work properly, other parts overwork to compensate, and statistically develop more cancers. The hypothesis may not have been tested, but you may find in her book pointers or names of epidemiolosgists in this particular field that may be able to answer your question precisely.
        [1] The Secret History of the War on Cancer

  • Neal

    In this video you say, “Significantly lower fecal pH in those eating the traditional rural plant-based diets, compared to those eating the traditional western diet, who were eating far fewer whole plant foods than the black children.” I thought the lower the pH the more acidic (with “7” being neutral). I’m confused.

    • KWD – NF Volunteer

      Neal, you’re right, the stool was more acidic. I didn’t review all of the sources cited (see the button beside the video), but the few I did review correlate lower pH with more fiber in the diet and/or with lower incidence of colorectal cancer. Several of the articles are full text so you might be interested to take a look at them.

      • Neal

        Got it. Thanks. I just confused myself in my reading of the transcript.

  • Sebastian Vaisov


    I was just googling about Vermox which was prescribed for my fiancee and me to get rid of possible parasites. I was very sceptical about this drug as I don’t like drugs at all, but what I found is a bit shocking. Accidentally I found that Vermox can be used to cure cancer. Here’s the link to the Medpub:!po=8.43023

    I’d like to know if this could be possible that Vermox can be helpful against cancer while it’s just lack of tests being done on humans. Would be great to get any advice regarding this drug, whether it can be used as additional method to treat the cancer and even more important whether it can be used as regular precaution method to keep cancer away?

  • Wade Patton

    I trust my pee test results well enough (as well as my diet) to avoid attempting a poo test.

  • Julian Everett

    So what about people who consume of high plant based diet as well as multiple serves of meat a day? Is the plant based component of the diet protective against rising acidity levels? Also how many grams a day are we talking about to provide some type of colon protection?

  • Bret Iron

    What’s the risk, if any, of eating too much dietary fiber foods? (Getting too much fiber)

  • Interesting video but it helps to dig deeper into the details. Resistant starch is getting a lot of press because it is naturally in foods like beans and legumes, underripe bananas, and cooked and cooled starchy plant foods, it is fermented in the gut (which lowers the pH) and massively shifts the microbiota, changing the expression of hundreds of genes. The pH is only one variable in the massive shifts occurring from the fermentation of resistant starch – changes in bacteria, changes in the quantity and type of short-chain fatty acids, etc. I think you’re focusing on the wrong biomarker. The reduced pH is a side-effect, not a driver of the beneficial effects. #resistantstarch #metabolism