Doctor's Note

Here are some more videos on gut bacteria:
Stool pH and Colon Cancer
Gut Feelings: Probiotics and Mental Health
Preventing Ulcerative Colitis with Diet
Carnitine, Choline, Cancer and Cholesterol: The TMAO Connection
The Leaky Gut Theory of Why Animal Products Cause Inflammation

Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on weight loss. Also, there are 1,686 other subjects covered in the rest of my videos--please feel free to explore them as well!

For some context, please check out my associated blog posts: Boosting Gut Flora Without Probiotics and How Probiotics Affect Mental Health

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  • Michael Greger M.D.

    Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on weight loss. Also, there are 1,449 other subjects covered in the rest of my videos–please feel free to explore them as well!

  • 2RHealth

    For vegans who don’t eat yogurt, what is a good source for probiotics? Probably not Kimchi, as you noted its harmful effects in another video!

    • Michael Greger M.D.

      Commercial yogurt of any kind (soy, rice, cow, or coconut) is an insufficient source of the level of probiotic bacteria found effective in treating diarrheal illnesses, inflammatory bowel disease, and irritable bowel syndrome. A plant-based diet appears to naturally modulate one’s gut flora, but if you need to bring out the big guns for therapeutic usage or to repopulate your gut after a round of antibiotics, allow me to refer you to the advice of one of my medical mentors, Dr. Michael Klaper, who has some great probiotic tips and insight.

      • Art

        Thanks for all of your information. But I was wondering, what about kefir grains? There are milk kefir grains and also water kefir grains used to ferment beverages. And do you know of any reliable comparison of yogurt and kefir, such as how many organisms are found in homemade yogurt and kefir? Thanks again.

  • Carl B. Nelson

    Dr. Greger, many thanks for your fine, concise, science based videos on so many subjects. My wife is battling stage 4 breast cancer. Due to the experience we’ve had I decided to put together a blog ( to share resources I found that have helped my wife to save others from some of the distress we’ve experienced. Many of your videos dealing with cancer are posted on my blog.

    Here’s my question: I’ve probably heard over a hundred times people recommending the fruit and a tea (made from the leaves) of the soursop fruit tree. The common phrase is that it’s “10,000 times more powerful than chemo” (it’s even on YouTube). There’s clearly a bucket of hyperbole in that statement but I’m wondering if the sheer volume of people that place such faith in this magical fruit indicate that there’s at least some truth to the legends. Have you heard of any studies that shed some light of science on this legend? I’d appreciate your help in evaluating if it would be worth including this fruit (and tea from its leaves) in my wifes cancer management treatment plan.

    We are following predominately the integrative treatment system advocated by Dr. Keith Block (author of Life Over Cancer).

  • Nicole Lucas Haimes

    Can you please help guide me for what are the best sources of probiotics? Pills, yoghurt, Kefir? It would be valuable to know this, short of going for a fecal transplant. Thanks!

    • Nicole Lucas Haimes

      P.S. I love your posts, and appreciate your hard work and service. Thank you for all you do!

  • David

    Among Dr. Greger’s Greatest Hits:

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

    THANK YOU DR. GREGER: Devotee/7:00 Central/Weedays/Every Week/for past several years

    The David