Doctor's Note

This closes out my four-part video series on the latest in probiotic science. I began with the two most established indications for their use in Preventing & Treating Diarrhea with Probiotics, then moved onto a more speculative use in Preventing the Common Cold with Probiotics? I then offered practical advice on how to best take probiotic supplements in Should Probiotics Be Taken Before, During, or After Meals?.

The colon removal story reminds me of the mastectomies they used to do for breast pain (see Plant-Based Diets For Breast Pain).

Why might a vegetarian diet alone have improved mood? Check out Plant-Based Diet & Mood, and the follow-up, Improving Mood through Diet—as well as my serotonin series that starts with Human Neurotransmitters in Plants.

More on treating chronic fatigue syndrome in:

What else might our good bacteria be doing for us? They may be helping with weight control (see Fawning over Flora and Gut Flora & Obesity), and serving up anti-cancer compounds! See Flax & Fecal Flora, and Sometimes the Enzyme Myth is True.

For more context, check out my associated blog posts: Probiotics & DiarrheaHow Should I Take Probiotics?How Probiotics Affect Mental Health; and Top 10 Most Popular Videos of 2013.

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  • emerson berlanda

    lactobacillus has anything to do with cow’s milk? and if it has, where the logic of this to say that we should not have any contact with dairy products? why the name lactobacillus?

    • emerson berlanda

      and more, how to restore the intestinal flora without milk products like yogurt?

      • mary p

        You can buy probiotics in pill form. There are also non-dairy yogurts with probiotics in them – soy, almond milk and coconut milk – and they’re readily available these days in grocery stores.

        • guest

          Yeah, and most of these are supplemented with synthetic vitamins. Try finding a vegan yogurt with no added vitamins.

          • Charzie

            Easy to make your own!

      • Patrick

        Fermented vegetables (sauerkraut, kimchi)

    • Many viewers here are vegan, and try to avoid products using animal products, even in the processing. Most lactobacilus supplements are initially grown on a dairy medium, but there are a few brands with vegan supplements (SunBiotics, Rainbow Light).

      The genus Lactobacillus (of which the species L. acidophilus is a member) are called such because they metabolize sugars to lactic acid. Its not a reference to the lactose sugar in dairy milk.

      This study found no significant difference in fecal Lactobacillus count between lacto-vegetarians and vegans, so it isn’t necessary to consume dairy products to introduce them to the gut:

    • Charzie

      Nope, it is just a type of bacteria that starts the fermentation process, and is present on all plants. Lactic acid is an organic compound, an alpha hyddoxy acid (AHA).

  • When you refer to a number of relevant lecture videos I wish you would just string them together like ABC does with its news. I want to hear all of them but I don’t want to sit at the keyboard to pull them up individually. I can multitask while I listen–after all, they are generally formatted as lectures. When there is show and tell I can always glance at the screen but I have to cook meals for my family which I am able to do while listening and learning.

  • Thea

    I love this series. There’s so much confusion about probiotics out there. I like how we are starting to figure out more about them and this series helps us to understand what we do and do not yet know. Very nice.

  • Richard

    Hi Dr,Greger!, Thank-you for the on-going ‘Meducation’. Have YOU seen and are aware of this site? I enjoy Raw Juicing too!

  • Seacliff2

    As a psychologist and psychoanalyst who has long lamented the mental health professions’ disregard of nutritional factors in psychological well-being, I’m heartened by this body of research inquiry. It’s about time we transcend the mind/body duality in our thinking and interventions. There are obviously many ways to work through one’s s–t, so to speak. Thanks Dr. Greger for your work!

  • Plantstrondoc

    Completely new meaning of “shit for brains”……;-)

  • Wegan

    A few years ago my husband took a refrigerated probiotic capsule prescribed for my daughter and had a hallucinogenic trip. I guessed it happened because it was past the expiration date. Last year he was on antibiotics and I gave him a Dr O. He said he felt strange and had global temporary amnesia. It went away a few hours later & $3,000 hospital bill. Coincidence?

    • Coacervate

      For my…research…what is the name and where do they sell that refrigerated probiotic Cap?

    • Recent research has indicated that often, what you see on the supplement label is not always what you get.

    • guest

      Similar experience. Probiotics have created some scary reactions in me.

  • Tante-Jef De Zwétte Mandam

    I wonder if the fecal transplanant from centenarians or slim people could be reduced to an advanced probiotics pill, with all the thousands strands of bacteria in the right proportion. Complex, yes, but not undoable.

  • Guest

    I’ve been vegan for 6 years. For 40 years before that I had frequent bouts of depression. Since being vegan I have only had a few ‘down’ days–no depression! Maybe gut flora is part of the connection between my mental health and my diet.

  • June Siegel-Hill

    Dr. Greger,

    Can you tell me which brand of probiotics are the best? My mom was told to take them and has no idea what to get. Thanks again.

  • Millan Chessman

    My Grand
    daughter is feeding my Great Grandson egg yolk. Making me sick just to think about. Dr. Greger can you please send me info about eggs?? Pleeeeeeeeeeeeeeeese. thank you Millan Chessman. I will pay for it.

    • Toxins

      Here is the evidence

      Eggs are considered good sources of lutein and omega 3 as well as an excellent source of protein. For these reasons, they are considered health foods. Looking at these claims in detail, chickens have lutein due to the fact that they have a varietized feed, these nutrients are not inherent of eggs. Based on the nutrient data found on the USDA database, 10 grams of spinach has approximately 12 times more lutein then 10 grams of an egg.

      We cannot really consider eggs an appropriate source of this nutrient.

      Regarding Omega 3, current levels of omega 3 in eggs are highly inadequate and one must consume around 30 eggs to reach an acceptable level of omega 3 for the day. A male needs around 1.6 grams of omega 3 per day, a female needs around 1.1 grams a day. A large egg contains about .037 grams of omega 3. Omega 3 in the ALA form processes to EPA which is also processed to DHA. These fats are anti-inflammatory. Omega 6 processes down to arachadonic acid which is highly inflammatory. According to the National Cancer Institute, eggs are the number 2 top contributor of arachidonic acid in the American Diet.

      Based on this as well as the low omega 3 content of eggs, the benefits received from omega 3 are masked by the high quantity of preformed Arachidonic Acid. High intake of arachadonic acid is linked to autoimmune diseases such as rheumatoid arthritis, ulcerative colitis, as well as a clear link with cancer development.

      Eggs have been associated with heart failure as noted here. “After 13.3 years of follow-up in this cohort of approximately 14,000 white and African-American men and women, greater intake of eggs and of high-fat dairy foods were both associated with greater risk of incident HF, whereas greater intake of whole-grain foods was associated with lower risk of incident HF. These associations were independent of demographic characteristics, lifestyle factors, prevalent CVD, diabetes, hypertension, and other food groups.”

      As well as an association type 2 diabetes with egg consumption of 1 egg a day. “Overall, the observed increased risk of type 2 diabetes with daily consumption of eggs in the current study raises the possibility of undesirable health effects with high rates of egg consumption and may help explain previously reported increased risk of CHD that was restricted to individuals with type 2 diabetes in the Health Professional Follow-up Study”

      In the Canadian Journal of Cardiology, David Spence (director of the stroke prevention/atherosclerosis research center and one of the worlds leading stroke experts), David Jenkins (the inventor of the glycemic index) and Jean Davignon (director of atherosclerosis research group) posted a review on eggs claiming that the egg industry has been downplaying the health risks of eggs through misleading advertisements. As soon as you eat one egg, you expose your body to several hours worth of oxidative stress, inflammation of ones arteries, endothelieum impairment (what keeps you blood running smoothly) and increases the susceptibility of LDL cholesterol to oxidize (beginning stages of heart disease). The authors go into great detail regarding dietary cholesterol and it is a very fascinating read indeed. The author’s final words “In our opinion, stopping egg consumption after a myocardial infarction or stroke would be like quitting smoking after lung cancer is diagnosed: a necessary act, but late.”

      The egg industry has claimed that cholesterol from eggs is not important and does not raise cholesterol levels. The fundamental flaw in the study the egg industry has used to make this claim is that they measured fasting lipid levels at night and not levels through out the day after egg consumption. “Diet is not all about fasting lipids; it is mainly about the three-quarters of the day that we are in the nonfasting state. Fasting lipids can be thought of as a baseline; they show what the endothelium was exposed to for the last few hours of the night.”

      A single egg yolk contains approximately 215 to 275 mg of cholesterol. A safe upper limit can be capped at 200 mg if one is looking to prevent heart disease as recommended by the CDC as one of their nutritional recommendations as seen on page 92. One egg far exceeds this daily upper limit.

      The balance of science is clearly against even moderate egg consumption as this food is a packaged deal. We do not get the nutrients found in eggs without getting the cholesterol and saturated fat. This similarity can be seen with chicken in terms of cholesterol and arachidonic acid

      as well as even the leanest beef containing an undesirable quantity of saturated fat as well as cholesterol

      “Tolerable upper intake levels (ULs) set by the Institute of Medicine (IOM) are important, in part because they are used for estimating the percentage of the population at potential risk of adverse effects from excessive nutrient intake. The IOM did not set ULs for trans fat, saturated fat, and cholesterol because any intake level above 0% of energy increased LDL cholesterol concentration and these three food components are unavoidable in ordinary diets.”

      In terms of saturated fat, the link below displays the top food sources of cholesterol raising fat.

      • Mike Quinoa

        Wow…thanks Toxins—amazing work.

      • Annamaria Polgar

        Great job, thanks so much for the info! :-) But this I assume is mainly caused by egg yolk and not so much whites? Many studies don’t make a difference between these two parts of the egg and it is misleading to many. Don’t get me wrong, you are amazing and I am thrilled to see these studies, but I am just saying….:-)

  • Stephen Lucker Kelly

    I was just thinking so that would also mean people eating cows might be affected by there germs. Also it means people who have a transplant of a heart or something along these lines… maybe this is what is also affecting their mental state. That is very interesting! :-)

  • Anne Clarke

    So I have a simple question: which biotics are the good ones? are there soy or other plant yogurts that contain them?.
    I just made a batch of soy yogurt; in this heat it took all of five mins plus a couple of hours wait. I assume that I could inoculate other plant milks that I prefer taste wise (almond, rice, coconut) similarly and have a good supply of probiotics to take with every meal. Am I correct?
    Someone mentioned kefir which I love; how do you make plant based kefir?

    • LA Rose

      85% of all soy in this country is GMO — it’s even contaminated the “organic” soy supply. It is, sadly, best avoided altogether as GMO damage far ourweighs the positives of the phytoestrogens of soy. (It is tragic how we are not just allowing, but enabling, the permanent destruction of our food supply.)

      • RobiDon

        This is an unwarranted conclusion. Organic, non-GMO soy is a treasure house of nutrient treasure. Enjoy!

  • Geoffrey Levens

    Dr. Greger, you might find this article amusing.

    Actually good info presented in a way that might grab some otherwise uninterested attention. I laughed until tears came at some parts.

  • Mena

    I’d really appreciate advice on which probiotics are best, and perhaps food-based ways to improve one’s gut flora.

  • Patrick

    Dr. Greger, I appreciate your work so much! I’m wondering if you have any material regarding correlations between quality of microflora (symbiotic vs. pathogenic) and quality of diet (whole plant foods vs. animal). I’m particularly interested in what you might have to say about the consequences of animals without carnivore-strength gastric acid and long intestines eating a high protein calorie ratio, and what quality of microflora would grow in the intestines in response to high levels of incompletely metabolized protein to eat. And then, what happens to this animal’s microflora when it reduces protein consumption to match its HCL/pepsin production capacity?

    • Joseph Gonzales R.D.

      Hi Patrick. Have you seen his videos on gut health? Also, his video about how gut flora and obesity. See if any of the studies in those videos help? Some may discuss protein and gut health, too. If you can’t find any I’ll look into more. Thanks for your comment.

  • Tom Toccagino

    Can not open videos. What app do I need?

  • Danielle

    The visuals on this video aren’t showing up in my window just the sound, is anyone else having this problem?

  • Tory

    I have chronic fatigue syndrome and find that probiotics make feel a little bit better physically but make me very depressed. It is exactly the same effect that antibiotics have on me. Could you please explain why this might be? Thanks

  • DanielFaster

    I’m all in favor of probiotics from food. There are a lot probiotic type foods out there, e.g., kombucha (but NF has videos against this due to 3-4 anecdotal cases of lactic acidosis in immune compromised patients), miso/amazake (no videos), natto (no videos), lacto-fermented veggies (kimchi, cabbage, cucumbers etc., NF has videos against this because some people get stomache cancer from too much, e.g. the China Study), kvass and wild yeast fermented beer (sour beer etc. Gregor has videos against the least little bit of alcohol being carcinogenic). Dairy (yogurt e.g.) is verboten. Pills are not properly labeled or made and go against the admonishment to avoid supplements in favor of whole foods. It’s not fair to put out a set of videos touting the benefits of probiotics when there are all the other NF videos emphasizing the risks. I’d like to see some information balancing the risks and benefits of probiotic/fermented foods on a case by case basis cf. the NF video on heart health benefit vs. cancer/hepatotoxin risk for alcohol.

    • Thea

      DanielFaster: I understand your point, but to be fair, I do think Dr. Greger has provided a solution. He has argued in favor of feeding your gut properly with pre-biotics and raw fruits and veggies in order to foster healthy good bacteria in your tummy. re:

      From an article/blog post: “Unless one has suffered a major disruption of gut flora by antibiotics or an intestinal infection—in other words unless one is symptomatic with diarrhea or bloating—I would suggest focusing on feeding
      the good bacteria we already have, by eating so-called prebiotics, such as fiber. … Altogether, this suggests that the
      advantages of prebiotics—found in plant foods—outweigh those of probiotics. And by eating raw fruits and vegetables we may be getting both! Fruits and vegetables are covered with millions of lactic acid bacteria, some of which are the same type used as probiotics. So when studies show eating more fruits and
      vegetables boosts immunity, prebiotics and probiotics may be playing a role.”

      That may not fully address your concern, but I thought it was worth pointing out.

      Also, here is a bit of practical advice:

      Just some thoughts for you.

      • DanielFaster

        Thanks, Thea, great point and it did get me to do some thinking about why I’m not giving up any fermented foods just yet.

        That being said there does seem to be a bit of a double standard on these items, e.g., the kombucha warning is based on a handful of poorly documented anecdotal cases in immune-compromised individuals yet the probiotic and antioxidant benefits are ridiculed by referencing some non-scientific publications, whereas conjugated linolenic acid (CLA – the main transfat found in animal flesh) has some studies showing as an extract/isolate it may be marginally beneficial to heart health despite being a meat based transfat verboten per the standards of NF (and me as well).

        It’s just that I think if you look at the studies and the NF videos, fermented foods unfairly (IMO) get a bad rap in some of the videos without any mention of the usually huge benefits of naturally occurring probiotics, prebiotics, antioxidants and vitamins etc. It should also be pointed out that the bacteria have different strains in different geographical locations and also depend a lot on the enterotype, e.g., H pylori European strain vs. South American enterotype leads to high incidences of cancer in South America in modern times (recent Science article). Actually studies on probiotics and probiotic rich foods would seem to be woefully lacking if there is no discussion of the patient’s enterotype or microbiome.

        The old adage that anything times zero is still zero comes to mind. The kimchi vid is based on a case controlled study of prostate cancer in China where the incidence is 1.7/100k. If pickled veggies raised the risk factor by 10 (and this is not clear since moderate consumption decreased the relative risk ratio and the cases consumed less than half the fresh veggies/fruits of the controls) then the incidence would be 17/100k. I’d take my chances with that based on the seemingly universal risk of prostate cancer in the US.

        • Thea

          DanielFaster: Fair enough. While I think Dr. Greger’s videos on this topic are helpful in pointing out potential issues (and it is clear from the video that he is talking as you say about small single studies), your post also provides great information for discussion/evaluation. It helps to move the discussion forward. Thanks.

  • Ana

    Very interesting. Which probiotics did they use in the study?

  • Robert Petricca

    Any comments on kefir and its potential health benefits? I wasn’t able to find any information on this topic on the site… please advise, thanks!

    • Thea

      Robert: While you may not find much on this site in regards to kefir in general, you will find *plenty* on this site in regards to dairy. Kefir is just concentrated dairy with some probiotics thrown in. As you have seen, probiotics are great. But there are safer ways to get it than with kefir.

      Here is more information about dairy:

  • GS

    An interesting article in Fast Company mag. A lot of startups doing work in the field of gut flora to find a cure for many illnesses. Gut Check.

  • Jan

    Bacteroidetes? You talk about these helping to lose weight – where can I find
    them and which probiotic contains these that help with weight loss?

    • Joseph Gonzales R.D.

      Hi Jan. Here is the video you are referencing. I watched again I I think the take home message was that polyphenols (antioxidants found in plants, especially dark blue, purple and red foods) can modulate the ratio Firmicutes to Bacteroidetes. ​Here is a great Q&A written by Dr. Greger on​ probiotics. He recommends dietary changes for weight loss, not simply using a probiotic. In fact, Dr. Greger doesn’t recommend a probiotic for everyone and certainly not for weight loss. I am uncertain if a probiotic alone will alter the bacteria in a meaningful way beyond helping with diarrhea. As I dietitian, I always push whole foods first! See if these links help? And look for more info from Dr. Klaper (found in the Q&A I linked above).

      Thanks for your question,


  • Jan

    and preferably a proboitic that is “free from” maltodextrin, gluten, wheat, diary, soy etc. and one that really does stop the bloat

    • Joseph Gonzales R.D.

      Please see my below comment. Thanks!

  • David

    Among Dr. Greger’s Greatest Hits:

    2003: About time for an updated version/Eh Dr. Greger?

  • Jonathan P

    Is there a good resource to understand what type of intestinal bacteria we should be promoting or introducing? For mental and physical health? Also, one that would be in line w/ a whole food plant based diet. For instance, I don’t want to promote my tummy brain’s yearning for cheeseburgers.