Anecdotally, I've been sick for a total of one day since I got deeply into fermentation as a hobby about a year ago (largely thanks to the Noma Guide to Fermentation). On an average day, I eat at least one live lacto-fermented item and drink kombucha, and at least every few days I have something that includes an uncooked live vinegar. I normally get sick at least a couple of times a year. My mood has also been consistently pretty good all year.
It's definitely anecdotal, but it's a significant enough shift for me to think it might have something to do with the fermentation. Bonus: it's delicious, and after much experimentation my kombuchas are now better than commercial kombucha.
2 days to 1 day for N=1 patients over 1 time period is not significant.
"Feeling better" could be real or it could just be cognitive bias. Did you use an app to record your mood multiple times a day? Were you taking less time (better contration) on cognitive tasks? Measurably fewer aches and pains? Better performance during workouts? Or did you have blood panels done and some values were better? Or none of those things?
That you say it's delicious is a confounding factor, as well, because eating food that tastes better improves your mood which can make you feel better without any nutritional or microbiome-related health effects.
To be clear, I'm not criticizing fermentation at all, just whether this anecdote provides any meaningful evidence for anything.
Also, even if there is some statistical significance since "a couple" apparently means far more than 2, since fermented foods displaced other things, what did they displace? Could those have been making you unhealthy rather than fermented foods making you healthier? You'd have to trial non-fermented dairy and tea and veggies as a control, and that control doesn't work very well with dairy because non-fermented dairy is high in simple sugar which can be bad all by itself.
"A couple of times a year" is not two days -- it's usually 6-10.
It was, as I said, quite anecdotal, and I'm very aware of the possibility of various cognitive biases. I also have enough stats knowledge to understand that I have not achieved a significant result. Even with that integrated, it has seemed noticeable enough for me to think it may be related.
I have no shortage of delicious food available, nutritional/live or not. I just pointed out that it's a reason to enjoy it anyway. I'm not doing it for a health experiment.
I can get everything on that list easily at a non-specialty store except for natto. I haven't seen it, but I admit my ability to read labels at the Japanese food store is rudimentary. Is it more widely available on the west coast?
I'm a little surprised that a paper basically concluding that there are no good papers about fermented foods is able to published and presented as research by these authors. Or maybe that field is just so lacking in knowledge that this passes for research. You would think that they'd take the next step and do some trials to advance the field.
My guess would be that, due to the very regional nature of many fermented foods, research into those foods is probably locked in the languages and localities of those foods. Heck, there's an entire Kimchi research institute in South Korea.
Ha ha, I was thinking the same thing. I was interested to read what the paper said and when I got through the abstract and found it said "there's really no research on this stuff" I was both surprised and a little disappointed.
I don't have any feelings on possible health benefits either way, but I like some fermented foods and was curious if there was something to learn. Oh well.
As someone who frequently conducts literature searches, I find these review papers critical to my work. If taken at face value, a it lets me know that I need not look further. If not, it is a starting point for cross-references.
That said, I would have liked to see a methods section with a list of search terms.
I don't understand the conclusion you draw from reading the paper (the full text is accessible for free from the link to the right). that there are "no" good papers studying fermented foods.
What I read is that the _majority_ of the studies are not good quality. There are very few high-quality studies e.g. double-blind randomised controlled trials and crossover studies, etc and most studies have a very small number of subjects. However, it's hard to fault a double-blind RCT for low quality because it has few subjects. Low statistical power, OK, but if the methodology is sound then the paper has merit.
Given that these studies go back a number of years and there is still no conclusive evidence for any health benefits from the consumption of fermented foods it is useful to have a summary of the current state of research.
The paper shows the fundamental flaw and short-sightedness that characterizes life sciences in general.
Every single fermented food is treated as if it were a high potency drug.
For example, in one study, for each day of a week people in the groups would eat either 110g of sourdough bread or 110g of white bread. Really, is that your experiment? You are trying to detect differences between eating 110g of two breads, once a day for one week?
Why would anybody in their right mind expect any change in the microbial composition of the gut? Or anything really...
Thus the reality is that not only there is almost no research in the field - that little that is performed is absurdly badly done.
i would expect yogurt and kimche to behave differently than just the byproducts of fermentation: alcohol, vinegar, pickles but both will have some impact on digestion, whether it be a live culture or a ph change.
even different sugars would digest through different pathways.
Yeah, those two in particular have very different common groups of active bacteria, even though both are lactic acid fermentations, so even if one were trying to isolate a specific set of cultures' effects it's really difficult to get that specific. The same sauerkraut at two weeks of fermentation and at four weeks is going to have a very different spread of dominant bacteria, in addition to the amount of sugar that has been converted.
That's really not outside the realm of possibility for something to change the microbiome. That's a quarter pound of bread, two servings and about 280 kcal on the loaf I have in front of me. That's a reasonable amount for someone to consume as part of a normal diet.
We know small changes in diet can have a large effect on the microbiome. For example, adding seaweed to a mouse diet can select for microbes with the ability to digest particular polysaccharides within seaweed (https://www.nature.com/articles/s41586-018-0092-4). A company spun out of the Sonnenburg lab at Stanford is using this tech for microbiome therapeutics in humans (Novome). Those mice were given 10% seaweed by weight, so that serving of sourdough is right in the same range.
My point is, the researchers designing these experiments know what they're doing, and they're well thought out. You can't criticize something if you don't know the details of the field.
Your estimate is off by almost an order of magnitude. 100g is not 10% of a person's weight. Maybe you meant 10% of calories.
Also, look at the comparison. It is seaweed! Wouldn't
you expect that eating 10% of your weight in seaweed changes a microbiome? It is a massively different food than what we (or mice) typically eat - thus the microbiome has to adapt. I am not saying the discovery is not important - it is the right question, set up correctly.
Compare that to a human eating two slices of different breads for a week. The differences between bread are too subtle. The amount ingested is too little, the time is too short. Your microbiome is already set up for digesting bread. That's all I am saying -
I will stick to my story that there is very little chance that this would ever be sufficient to detect any change.
22 comments
[ 2.8 ms ] story [ 55.7 ms ] threadIt's definitely anecdotal, but it's a significant enough shift for me to think it might have something to do with the fermentation. Bonus: it's delicious, and after much experimentation my kombuchas are now better than commercial kombucha.
"Feeling better" could be real or it could just be cognitive bias. Did you use an app to record your mood multiple times a day? Were you taking less time (better contration) on cognitive tasks? Measurably fewer aches and pains? Better performance during workouts? Or did you have blood panels done and some values were better? Or none of those things?
That you say it's delicious is a confounding factor, as well, because eating food that tastes better improves your mood which can make you feel better without any nutritional or microbiome-related health effects.
To be clear, I'm not criticizing fermentation at all, just whether this anecdote provides any meaningful evidence for anything.
Also, even if there is some statistical significance since "a couple" apparently means far more than 2, since fermented foods displaced other things, what did they displace? Could those have been making you unhealthy rather than fermented foods making you healthier? You'd have to trial non-fermented dairy and tea and veggies as a control, and that control doesn't work very well with dairy because non-fermented dairy is high in simple sugar which can be bad all by itself.
It was, as I said, quite anecdotal, and I'm very aware of the possibility of various cognitive biases. I also have enough stats knowledge to understand that I have not achieved a significant result. Even with that integrated, it has seemed noticeable enough for me to think it may be related.
I have no shortage of delicious food available, nutritional/live or not. I just pointed out that it's a reason to enjoy it anyway. I'm not doing it for a health experiment.
I can get everything on that list easily at a non-specialty store except for natto. I haven't seen it, but I admit my ability to read labels at the Japanese food store is rudimentary. Is it more widely available on the west coast?
You can get it at Mitsuwa in the Bay Area. 99 Ranch might carry it as well.
Not sure about elsewhere.
I don't have any feelings on possible health benefits either way, but I like some fermented foods and was curious if there was something to learn. Oh well.
As someone who frequently conducts literature searches, I find these review papers critical to my work. If taken at face value, a it lets me know that I need not look further. If not, it is a starting point for cross-references.
That said, I would have liked to see a methods section with a list of search terms.
What I read is that the _majority_ of the studies are not good quality. There are very few high-quality studies e.g. double-blind randomised controlled trials and crossover studies, etc and most studies have a very small number of subjects. However, it's hard to fault a double-blind RCT for low quality because it has few subjects. Low statistical power, OK, but if the methodology is sound then the paper has merit.
Given that these studies go back a number of years and there is still no conclusive evidence for any health benefits from the consumption of fermented foods it is useful to have a summary of the current state of research.
Every single fermented food is treated as if it were a high potency drug.
For example, in one study, for each day of a week people in the groups would eat either 110g of sourdough bread or 110g of white bread. Really, is that your experiment? You are trying to detect differences between eating 110g of two breads, once a day for one week?
Why would anybody in their right mind expect any change in the microbial composition of the gut? Or anything really...
Thus the reality is that not only there is almost no research in the field - that little that is performed is absurdly badly done.
even different sugars would digest through different pathways.
We know small changes in diet can have a large effect on the microbiome. For example, adding seaweed to a mouse diet can select for microbes with the ability to digest particular polysaccharides within seaweed (https://www.nature.com/articles/s41586-018-0092-4). A company spun out of the Sonnenburg lab at Stanford is using this tech for microbiome therapeutics in humans (Novome). Those mice were given 10% seaweed by weight, so that serving of sourdough is right in the same range.
My point is, the researchers designing these experiments know what they're doing, and they're well thought out. You can't criticize something if you don't know the details of the field.
Also, look at the comparison. It is seaweed! Wouldn't you expect that eating 10% of your weight in seaweed changes a microbiome? It is a massively different food than what we (or mice) typically eat - thus the microbiome has to adapt. I am not saying the discovery is not important - it is the right question, set up correctly.
Compare that to a human eating two slices of different breads for a week. The differences between bread are too subtle. The amount ingested is too little, the time is too short. Your microbiome is already set up for digesting bread. That's all I am saying -
I will stick to my story that there is very little chance that this would ever be sufficient to detect any change.
- Why Dirt and Microbes Could Be Good for Us: https://www.youtube.com/watch?v=xlEFI5A3QFM
- The Microbes Within Us (I Contain Multitudes): https://www.youtube.com/watch?v=UOymDhGxS9Q
- What Role Does our Microbiome Play in a Healthy Diet?: https://www.youtube.com/watch?v=-LUuqxQSaFQ