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CLL Support Association
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Probiotics are mostly useless and can actually hurt you

This is the outcome of a study into the effects of probiotics on healthy people, not those immunocompromised!

“Relying on faecal samples as an indicator of what goes on inside the gut is inaccurate and wrong” says immunologist Elinav Eran Elinav of the Weizmann Institute of Science in Israel after he and colleagues studied the microbiome of healthy volunteers directly using endoscopies and colonoscopies. The study "found that the probiotic colonisation patterns were highly dependent on the individual. That tells us that the concept that everyone can benefit from a universal probiotic bought from the supermarket is empirically wrong, he says."

The study investigated what happened to the microbiome of three groups. 'The microbiome of the first group was allowed to recover by itself, whereas the second group was given probiotics. The third group was treated with a dose of their own original pre-antibiotic microbiome by a faecal microbiota transplant.' and found surprising results:


"The take-home message is that probiotics don’t always live up to their harmless reputation, and to be effective, their formula needs to be tailored to the individual." and for us if we are neutropenic, probably best avoided.


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This is a complex subject. Other articles I read suggest that a more diverse microbiome comes from fermented vegetables, and that it supports your own microbiome. What really interests me on the topic is that it is said that the immune system depends on the health of the gut flora, and that cancer is an immune system disease. Makes me want to continue to support the gut flora with fermented food


There is certainly growing evidence that fermented food is beneficial for the health of our gut biota, but we have much to learn yet.


For reference, the study cited by New Scientist is:


Personalized Gut Mucosal Colonization Resistance to Empiric Probiotics Is Associated with Unique Host and Microbiome Features

While I think the new study cited in the New Scientist article offers very useful analysis, I think it is needlessly alarmist for people with normal gut and immune systems. It's also based on a very small set of subjects - only 29 normal people. Several larger studies of probiotics in both normal and diseased people have had hundreds of patients, and shown some benefit for specific probiotics.

There are numerous current projects to research the whole idea of gut microbiomes in general. The biggies are:



humanfoodproject.com/americ... - I participated in this project myself.


Most diversity studies have used 16S rRNA to analyze the families of microbes:


Note that rRNA is the product of rDNA transcription.

Scientists use 16S to examine diversity because it's easy to do - especially for fecal samples. But it doesn't tell us the species of microbes - only their larger families. There are good e-coli species, and bad e-coli species, good streptcoccus, and bad. In a given family, there are toxic species and species that are vital for digestion.

I think the whole issue of gut diversity has been oversold to the public. It's based on comparing fecal samples from people from urban societies to supposedly non-modern people in third world countries. It's really not clear that the selected tribes are actually representative of pre-modern societies, nor that their diet represents a truly historical paleo diet for any particular region of the world. The diversity results could also much explain the higher rate of death from digestive disease among such tribes due to contaminated food and water.

I think most commercial dairy based products are generally safe and well tolerated by normal people. However, I think that the fashionable trend of consuming non-commercial fermented foods in particular is dangerous, even for normal people. There are pathogenic bacteria and fungi everywhere around us. Fermentation and lack of pasteurization can encourage the growth of strains harmful to the average person.

In the U.S., the lack of regulation for pill form probiotics is something I think we should be concerned about due to poor historical quality control. Before buying, Americans should have a look at test results of such products published by:


Or as Neil has suggested in the past, try to find Australian sourced products, because Australian laws are more stringent.

As Neil suggested, those of us who are neutropenic should be particularly careful what we eat. Fresh foods are risky. We should consider that what causes a day of diarrhea in a normal person could be a trip to the hospital or worse for some of us. I haven't seen any study that analyzes such foods for hypogammaglobulinemic patients (low immunoglobulin).

On the other hand, some people have been dramatically helped by fecal transplants. But science cannot yet generalize from whom to get the fecal transplant. To my knowledge, large studies of fecal transplants have not yet been done to establish statistical risk. So it's still a therapy of last resort, I believe.



I read the article in Cell journal and found it rather confusing. They seemed to be using a scattergun approach to look at several aspects of the gut biome, while not doing anything very thorough in any of them. For instance at one point they compare the mouse caecum with the human caecum in response to 'human probiotics', but that didn't seem to be the main purpose of the study. The very small sample size (25 people in one investigation and 21 in another) seemed rather lacking, and certainly not deserving of the big headlines in some of our (British) press. There are other issues, but you can check them out for yourself. As you may recall, I am currently conducting my own investigation into Kefir in my own gut (sample size of 1!), and was a little concerned to read about the purported negative outcomes (referred to in your own title). I recall you posted another somewhat anti-probiotic paper which had a sample size of 79 if I recall correctly, in which one person suffered a lactobacillus overgrowth in the gut, along with an excessive production of D-lactate (which can cause brain problems). I'm hoping this isn't happening to me in my Kefir test (although I'm not using much). 😉



My primary care internist is also an HIV doc with many immune suppressed patients. He likes raw saurkraut as food for the gut that is not "over the top". I saw the NewScientist article and found it very interesting. There are some CLL patients in some sites who wax poetically about probiotics and I've become tired of being a voice of caution. (Personally, I think some of them are MBL so it won't matter much what they do, even if they declare that particular diet or mantra is why their CLL has not developed.) note .. I'm pretty new here at HU, so please be warned I'm not always warm and fuzzy but I do care. :) [I am eleven years with CLL having flunked out of the US NIH clinical trial for Ibrutinib after developing NSCLC, then had Gazyva in 2015 with Dr. Jeff Sharman and am now happily on Venetoclax with Coutre out of Stanford.]


Hi everyone.

Just bought a jar of sauerkraut- to eat, or not to eat? And should Paul not eat it... he’s the one with CLL?

Life is tricky sometimes!

Fran 😉


If it is jarred... then it should be fine... nothing alive left in it...due to the canning process.


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Thank you 😊


On Radio National NZ recently there was someone discussing seaweed as a probiotic- I didn’t note details except it seemed quite an easy thing to do, but did find this article.



That's mouse model research and I expect final results will be subject to the same challenges identified in the research I posted about. Obviously much more research is needed in what is obviously an early phase of our understanding of how to influence our microbiota. Good to see plenty is being done.

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But the cow and seaweed research is interesting 😂

Interestingly CLL is not as common in Japan.


Lots of interesting research happening. With regard to CLL and Japan, CLL is rare in Asia. Is it diet, genetics or a combination? Japan is particularly interesting, given the high life expectancy for that country, so you would expect the age related factor to be more evident than for neighbouring countries, making the discrepancy even more marked.


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Diet? Thinking about how successful Mediterranean Diet is for some people ( unfortunately not for me as genetic high cholesterol)

But can’t look at everyone as same.

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And from MedPageToday, 'The mass marketing of unregulated probiotics for general human health is coming under fire.


Pieter A. Cohen, MD, of Harvard Medical School in Boston, in a viewpoint article in JAMA Internal Medicine, pointed out that advertised indications notwithstanding, no large, long-term clinical trials have proven that probiotics offer clinical benefits for people who are already healthy. Yet U.S. manufacturers are free to promote supplements as doing just that: "There are few restrictions on structure and/or function claims, such as 'boosts digestive health' or 'supports the immune system' on supplement labels, and information about potential adverse effects is not required."


And in a 2017 analysis of 14 Cochrane reviews on studies of probiotics for GI disorders, Elizabeth Parker and associates found that the majority reported insufficient evidence to confirm benefit. This analysis also highlighted problematic inconsistencies, with many studies failing to specify the strain(s) in the probiotic and most not specifying any follow-up beyond the initial intervention.

In the consumer setting, Cohen noted that many companies do not follow FDA-recommended best practices for manufacturing dietary supplements, and commonly fail to establish the strength, purity, and composition of the final products, with some found to contain contaminants and unlisted live microorganisms.' (My emphasis)

Full article: medpagetoday.com/primarycar...


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