Kombucha

Standard memberwildgrass
Science 21 Jun '18 17:30
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    21 Jun '18 17:301 edit
    Sonhouse stated in a prior thread that kombucha causes liver failure. I accept that there is no scientific evidence (seems like the jury is still deliberating) for the broadly defined health benefits, but does it really kill people? And if so, why is it everywhere for public consumption with no warning labels?

    Per wikipedia:
    "Adverse effects associated with kombucha consumption include severe hepatic (liver) and renal (kidney) toxicity as well as metabolic acidosis. At least one person is known to have died after consuming kombucha, though the drink itself has never been conclusively proved a cause of death."

    The references here refer to studies that show that "kombucha consumption may impact the results of laboratory test results" and another that describes patients with liver failure and also states "They both drank Kombusha tea in ceramic container, which was covered by glaze made of lead."

    It seems like if the risk is there for adverse health effects (and death), they shouldn't be putting huge jars of it in the middle of the grocery store with no warning label. Right?
  2. Subscribersonhouse
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    21 Jun '18 18:07
    Originally posted by @wildgrass
    Sonhouse stated in a prior thread that kombucha causes liver failure. I accept that there is no scientific evidence (seems like the jury is still deliberating) for the broadly defined health benefits, but does it really kill people? And if so, why is it everywhere for public consumption with no warning labels?

    Per wikipedia:
    "Adverse effects associate ...[text shortened]... dn't be putting huge jars of it in the middle of the grocery store with no warning label. Right?
    Sure, right along side those '5 hour energy' bottles of liquid death. That stuff has put people in hospital too but that crap is still in every grocery store.

    Of course along side tobacco and we all know how safe THAT is......
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    21 Jun '18 18:22
    Originally posted by @sonhouse
    Sure, right along side those '5 hour energy' bottles of liquid death. That stuff has put people in hospital too but that crap is still in every grocery store.

    Of course along side tobacco and we all know how safe THAT is......
    Cigarettes say "Warning: this will kill you" right on the box. All kombucha says is "Do not shake. Do not consume if you are avoiding alcohol."
  4. Standard memberDeepThought
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    22 Jun '18 12:55
    Originally posted by @wildgrass
    Sonhouse stated in a prior thread that kombucha causes liver failure. I accept that there is no scientific evidence (seems like the jury is still deliberating) for the broadly defined health benefits, but does it really kill people? And if so, why is it everywhere for public consumption with no warning labels?

    Per wikipedia:
    "Adverse effects associate ...[text shortened]... dn't be putting huge jars of it in the middle of the grocery store with no warning label. Right?
    Fermented tea, yum! Other than sounding somewhat revolting, whenever I hear of health benefits of anything like this I immediately ask if there's been a Randomised Controlled Trial (or anything like that). According to the Wikipedia page none of the studies that have been performed have found any high quality evidence of benefits and there is scant low quality evidence. Here high quality evidence means statistically significant results in a large randomised controlled trial, moderate quality evidence implies that the trial is not an RCT, low quality evidence points to non-significant results in small RCTs (where the lack of a significant result is explainable by the size of the study), where significance depends on subgroup analysis, expert opinion, and the like. There is evidence of harms. The standard for the presence of harms is much lower (you have to prove their absence, not their presence). The concoction contains usnic acid, a known hepatotoxin, as a consequence of the peculiar microbial culture. This indicates to me that there is no good evidence for benefits, there is evidence of harms, including death. Personally, I'd be looking at banning its sale, or at the very least putting a dire warning on the label.
  5. Standard memberwolfgang59
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    26 Jun '18 01:24
    Originally posted by @wildgrass
    Cigarettes say "Warning: this will kill you" right on the box. All kombucha says is "Do not shake. Do not consume if you are avoiding alcohol."
    They were causing lung cancer even BEFORE the labels were put on! 😉
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    26 Jun '18 14:272 edits
    Originally posted by @deepthought
    Fermented tea, yum! Other than sounding somewhat revolting, whenever I hear of health benefits of anything like this I immediately ask if there's been a Randomised Controlled Trial (or anything like that). According to the Wikipedia page none of the studies that have been performed have found any high quality evidence of benefits and there is scant lo ...[text shortened]... y, I'd be looking at banning its sale, or at the very least putting a dire warning on the label.
    It's actually quite tasty, if you like tea.

    Of course, we all know that "toxin" can mean almost anything at the right dosage. Usnic acid, I think, is a commonly used preservative and found in edible lichens. I could not find anything other than anecdotal evidence for direct harm caused by commercial kombucha. The few isolated examples that seem to show a direct link were from home brew operations probably due to contamination from other bacterial / fungal strains.

    RCT on food products in general are extraordinarily weak, and I'm frequently amazed by what can get published in this realm. Probably, the journals like these studies because they bring it up on the Today show. Google "coffee" and "randomized controlled trial" and you'll find hundreds of studies done with seemingly contradictory conclusions. There is good molecular biology and in vitro neuroscience, but very few of these studies have rigorous methodology (and sample size) that would be required to make definitive conclusions on human health.

    So yes, there is no evidence for human health benefits of consuming kombucha. But the same can be said of green peppers. I have not yet seen any evidence that would lean towards banning its sale. Maybe I'm missing something though.
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    26 Jun '18 14:29
    Originally posted by @wolfgang59
    They were causing lung cancer even BEFORE the labels were put on! 😉
    Good point. Once the evidence was clear, the warning labels followed. Is the evidence clear on kombucha?
  8. Standard memberDeepThought
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    26 Jun '18 15:19
    Originally posted by @wildgrass
    It's actually quite tasty, if you like tea.

    Of course, we all know that "toxin" can mean almost anything at the right dosage. Usnic acid, I think, is a commonly used preservative and found in edible lichens. I could not find anything other than anecdotal evidence for direct harm caused by commercial kombucha. The few isolated examples that seem to show ...[text shortened]... seen any evidence that would lean towards banning its sale. Maybe I'm missing something though.
    When you say "anecdotal evidence", do you mean anecdotes or case studies? I'd regard a case study as being more reliable than mere anecdote as it's at least gone through peer review, and confounders and so forth have been considered. Below is a link to a case study where a female body builder was taking a supplement containing amongst other things a preparation containing usinic acid. She needed a liver transplant.

    The key thing is that evidence for benefits is going to be difficult as one has to prove they're there. Evidence for harms isn't required to be so good. I don't think that green peppers are marketed strongly on their health giving benefits (I don't remember seeing any marketing whatsoever to be honest), so there is no problem with an absence of evidence of positive effects on human health. I'm not aware of any evidence of harms from eating green peppers, so I don't think your example is relevant. With Kombucha, it shouldn't be marketed as being health giving or restoring, there is no evidence for this. There is evidence for harms and that evidence doesn't have to be all that good.

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3076034/
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    26 Jun '18 18:211 edit
    Originally posted by @deepthought
    When you say "anecdotal evidence", do you mean anecdotes or case studies? I'd regard a case study as being more reliable than mere anecdote as it's at least gone through peer review, and confounders and so forth have been considered. Below is a link to a case study where a female body builder was taking a supplement containing amongst other things a ...[text shortened]... ence doesn't have to be all that good.

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3076034/
    Yes, case studies are anecdotal, albeit much more formally presented than your neighbors juice cleanse. That does not make them useless, just anecdotal.

    Again, very important rule about toxicity: it is entirely dependent on dosage. Solanine is a compound produced by green peppers (as well as many other vegetables) and is proven to be very poisonous (and deadly) at high concentrations. However, green peppers don't kill people. Usnic acid is in my toothpaste, but I don't have liver failure.

    As to your posted study, when you put a bunch of weird stuff in a supplement and combine that with extreme physical activity and dietary / lifestyle choices, the sequence causing the liver failure is clearly lost in the flood of confounding variables. They have no idea if usnic acid caused it, but they certainly spend a lot of paragraphs talking about it before declaring "Hepatotoxicity due to usnic acid appears to be idiosyncratic". In the discussion of this case report, they refer to the paper describing the in vitro mouse study that showed liver toxicity from usnic acid [1]. The substance was present in their culture media of a hepatic cell line at 5 uM for a day. This is a very high dose for this type of experiment, and in figure 2 you can see there is no measurable cell death at 2 uM or below. You can find hundreds of safe chemicals (including vitamins) that kill cells at that concentration.

    Your point about burdens of proof for benefit vs. harm is well-taken. As you mention, the harm arm of evidence is simpler to demonstrate, but I still don't see where that evidence is for kombucha. From an evidence standpoint, is it justified to conclude that kombucha (or usnic acid) is a health risk?

    Marketing is a whole different beast. In my opinion, it depends a lot on the precise wording of what they're actually claiming vs. what users claim, and whether they are trying to state something as scientifically or medically-proven.

    [1] https://www.ncbi.nlm.nih.gov/pubmed/15037196
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