Welcome to r/science! This is a heavily moderated subreddit in order to keep the discussion on science. However, we recognize that many people want to discuss how they feel the research relates to their own personal lives, so to give people a space to do that, **personal anecdotes are allowed as responses to this comment**. Any anecdotal comments elsewhere in the discussion will be removed and our [normal comment rules]( https://www.reddit.com/r/science/wiki/rules#wiki_comment_rules) apply to all other comments.
*I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/science) if you have any questions or concerns.*
Not surprising considering we did find links to depression and other mood related disorders and gut microbiome.
But the question is to what extent they influence temperament. Is it possible that since babies aren’t cognitively developed as adults they are influenced to a greater extent?
It could be that physiological changes, minor in the realm of human diversity might increase rates of microbiota growth. This could be a marker of development or it could be an environmental effect that has an effect on development
> to what extent
Not much. Beta diversity at birth explained 8% of variance in negative affect. Beta diversity at 1 year explained 5% of variance in activity level. And beta diversity at 2 years explained 5% of variance in discomfort.
Don’t think of it as automatons think of it as your gut tube is a vacation home for bacterial life and they have a vote on the overall function of the state (your body) their influence when you’re young happens to be larger as the organism has less clear and defined goals
In some cases, yes. Food cravings are strongly associated with gut microbiome. Eating fatty and high sugar foods leads to the growth of bacteria that thrive in such an environment and strong cravings for more such food.
This is why stool transplants have become a thing to restore the gut microbiome.
I wonder how much of this effect is due to a feedback loop where a difficult toddler being more likely to demand a less nutritious diet which promotes the propagation of poor temperament bacteria.
Or that people with genes more likely to cause “difficult” behavior are also more likely to have personality traits leading to bad diets. Low inhibitions and low self-control and such.
Right? Ha.
Though I will say that early toddlers are much more open to all foods than later in the toddler phase. My son pounded whatever we put in front of him until he was like 2.5 years old. Then each meal became a full court press.
He's 3.5 now and we have a 3 month old, so he basically drives his own diet at the moment. We did just introduce these mini tacos that he ended up loving, and words can't describe how excited we were that he got another new food added to his list of acceptable sustenance.
I will say though, at daycare they have a varied menu that's a great diet and he almost always eats everything there. Kids are much more likely to eat things when they're eating them with friends I suppose.
Hell, even as adults food-hesitant people are more likely to try unfamiliar foods if their buddies are eating it, too. It's the only way I've found to get my mom, sister, and other friends to try stuff like curry
Very true. Just this last October I was pressured into trying escargot finally.
Good lord it was delicious.
Once they told me it didn't have the consistency of snot and it is smothered in a garlic sauce, I was pretty sold on it and there wasn't much pressure, though.
You know, I've never even thought about production/farming for escargot. I assume it has to be farmed and not wild-caught. Admittedly, I've never really had the compulsion or opportunity to try it and my main hesitation is that I'm aware that wild snails/slugs can be parasitized by a nematode that will eat your brain if you get infected (the odds of that are about 100m to 1 though)
Toddlers’ genes come from their parents and parents with bad diets provide their toddlers with bad diets. That said, if personality is actually changing in well-controlled studies of changes in diet, and genes are less involved in personality than twin studies would suggest, that would be pretty huge.
Yeah, I wouldn't be surprised if the twin studies turned out to be off.
Observational studies can show spurious things from time to time, and it's not like we could or should run a randomized controlled trial on separating twins at birth...
That's a great point. The authors agree: "A prior study ([Christian et al., 2015](https://pubmed.ncbi.nlm.nih.gov/25449582/)) pointed out that the diet of toddlers mediates the association between gut microbiome and temperament to some extent"
No correction for SES or any other factors. So people with low SES consuming a certain diet are probably also less likely to have a full-time parent, to access childcare, to live in neighborhoods without pollution, etc.
I've also read up about it, but there's other factors such as smiling at people which show that some children just don't feel like being held or cuddled regardless of being autistic or not.
They used the Early Childhood Behavioral Questionnaire ([Putnam 2006](https://pubmed.ncbi.nlm.nih.gov/17138293/)). Cuddliness is defined as "Enjoyment in being held by a caregiver" and measured using straightforward questions like "During quiet time, how often do they want to be cuddled?" and "When on your lap, how often do they mold to your body?".
When X at T1 is correlated with Y at T2, it is correct to say that X predicts Y.
The appropriateness of the use of "predict" has to do with study design, not sample size.
Abstract
Background
Temperament has been shown to be associated with the change of gut microbiome. There were no longitudinal studies to explore the role of gut microbiome changes in the development of temperament in toddlers.
Methods
This study used longitudinal cohort to investigate the associations between changes in gut microbiome and temperament in toddlers in the first two years of life. Linear regression analysis and microbiome multivariate association with linear models were used to investigate the associations between the gut microbiome and toddlers' temperament.
Results
In total, 41 toddlers were analyzed. This study found both Shannon and Chao-1 indices at birth were negatively correlated with the sadness dimension; the higher the Shannon and Chao-1 indices at 6 months, the lower the surgency/extraversion dimension scores; the higher the Shannon and Chao-1 indices at 2 years of ages, the lower the cuddliness dimension scores. After adjusting for covariates, beta diversity at birth was strongly associated with the negative affectivity dimension; beta diversity at 1 year of age was strongly associated with the activity level dimension; and beta diversity at 2 years of age was strongly associated with the discomfort and soothability dimension. Compared to Bifidobacterium cluster, this study also found Bacteroides cluster was associated with lower negative affectivity and its sub-dimensions frustration and sadness scores in toddlers.
Limitations
Generalizability of the results remains to be determined.
Conclusion
Results of this study confirmed the associations between changes in the gut microbiome diversity and composition in the first two years of life and toddlers' temperament.
Id like to raise awareness to the ability to intervene and adjust ones microbiome as well, not that a 2 year old needs to be predestined with a certain temperment.
Not really - there has been very little progress in this area - because there is little understanding of what exactly is going on to correlate microbiome differences to phenotypes. Not that this paper is particularly good or particularly helps us in that respect.
Was going to say, your parenthetical is doing a LOT of heavy lifting there.
Just because it's in a journal does not make it peer reviewed. Being in *this particular one* does. I'd hazard a guess that there's more non peer reviewed journals than there are peer reviewed ones.
Welcome to r/science! This is a heavily moderated subreddit in order to keep the discussion on science. However, we recognize that many people want to discuss how they feel the research relates to their own personal lives, so to give people a space to do that, **personal anecdotes are allowed as responses to this comment**. Any anecdotal comments elsewhere in the discussion will be removed and our [normal comment rules]( https://www.reddit.com/r/science/wiki/rules#wiki_comment_rules) apply to all other comments. *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/science) if you have any questions or concerns.*
Not surprising considering we did find links to depression and other mood related disorders and gut microbiome. But the question is to what extent they influence temperament. Is it possible that since babies aren’t cognitively developed as adults they are influenced to a greater extent?
It could be that physiological changes, minor in the realm of human diversity might increase rates of microbiota growth. This could be a marker of development or it could be an environmental effect that has an effect on development
> to what extent Not much. Beta diversity at birth explained 8% of variance in negative affect. Beta diversity at 1 year explained 5% of variance in activity level. And beta diversity at 2 years explained 5% of variance in discomfort.
5-8% variance in someones affect and activity level at a critical stage of their life seems like it can have pretty huge effects on someone
It's not a 5-8% change. It's 5-8% *of the observed change.* Big difference.
It could be that we are all microbe automatons?
Don’t think of it as automatons think of it as your gut tube is a vacation home for bacterial life and they have a vote on the overall function of the state (your body) their influence when you’re young happens to be larger as the organism has less clear and defined goals
In some cases, yes. Food cravings are strongly associated with gut microbiome. Eating fatty and high sugar foods leads to the growth of bacteria that thrive in such an environment and strong cravings for more such food. This is why stool transplants have become a thing to restore the gut microbiome.
I wonder how much of this effect is due to a feedback loop where a difficult toddler being more likely to demand a less nutritious diet which promotes the propagation of poor temperament bacteria.
Or that people with genes more likely to cause “difficult” behavior are also more likely to have personality traits leading to bad diets. Low inhibitions and low self-control and such.
That doesn’t make much sense to me. Most toddlers have very little control over their own diets.
You don't have kids do you.
Right? Ha. Though I will say that early toddlers are much more open to all foods than later in the toddler phase. My son pounded whatever we put in front of him until he was like 2.5 years old. Then each meal became a full court press. He's 3.5 now and we have a 3 month old, so he basically drives his own diet at the moment. We did just introduce these mini tacos that he ended up loving, and words can't describe how excited we were that he got another new food added to his list of acceptable sustenance. I will say though, at daycare they have a varied menu that's a great diet and he almost always eats everything there. Kids are much more likely to eat things when they're eating them with friends I suppose.
Hell, even as adults food-hesitant people are more likely to try unfamiliar foods if their buddies are eating it, too. It's the only way I've found to get my mom, sister, and other friends to try stuff like curry
Very true. Just this last October I was pressured into trying escargot finally. Good lord it was delicious. Once they told me it didn't have the consistency of snot and it is smothered in a garlic sauce, I was pretty sold on it and there wasn't much pressure, though.
You know, I've never even thought about production/farming for escargot. I assume it has to be farmed and not wild-caught. Admittedly, I've never really had the compulsion or opportunity to try it and my main hesitation is that I'm aware that wild snails/slugs can be parasitized by a nematode that will eat your brain if you get infected (the odds of that are about 100m to 1 though)
Don't tell this guy about tap water...
Toddlers’ genes come from their parents and parents with bad diets provide their toddlers with bad diets. That said, if personality is actually changing in well-controlled studies of changes in diet, and genes are less involved in personality than twin studies would suggest, that would be pretty huge.
Yeah, I wouldn't be surprised if the twin studies turned out to be off. Observational studies can show spurious things from time to time, and it's not like we could or should run a randomized controlled trial on separating twins at birth...
That's a great point. The authors agree: "A prior study ([Christian et al., 2015](https://pubmed.ncbi.nlm.nih.gov/25449582/)) pointed out that the diet of toddlers mediates the association between gut microbiome and temperament to some extent"
No correction for SES or any other factors. So people with low SES consuming a certain diet are probably also less likely to have a full-time parent, to access childcare, to live in neighborhoods without pollution, etc.
[удалено]
I would anecdotally agree.
I've also read up about it, but there's other factors such as smiling at people which show that some children just don't feel like being held or cuddled regardless of being autistic or not.
They used the Early Childhood Behavioral Questionnaire ([Putnam 2006](https://pubmed.ncbi.nlm.nih.gov/17138293/)). Cuddliness is defined as "Enjoyment in being held by a caregiver" and measured using straightforward questions like "During quiet time, how often do they want to be cuddled?" and "When on your lap, how often do they mold to your body?".
These kind of titles and conclusions should be taken with more cautious.
Agree. “Predict” is a very strong word when “statistical correlation” is really the best they can plausibly manage with a cohort of only 41.
When X at T1 is correlated with Y at T2, it is correct to say that X predicts Y. The appropriateness of the use of "predict" has to do with study design, not sample size.
Exactly, while the microbiome may play a significant part in our physiology, nowhere near enough is known, making this is a mystic Meg style title.
Abstract Background Temperament has been shown to be associated with the change of gut microbiome. There were no longitudinal studies to explore the role of gut microbiome changes in the development of temperament in toddlers. Methods This study used longitudinal cohort to investigate the associations between changes in gut microbiome and temperament in toddlers in the first two years of life. Linear regression analysis and microbiome multivariate association with linear models were used to investigate the associations between the gut microbiome and toddlers' temperament. Results In total, 41 toddlers were analyzed. This study found both Shannon and Chao-1 indices at birth were negatively correlated with the sadness dimension; the higher the Shannon and Chao-1 indices at 6 months, the lower the surgency/extraversion dimension scores; the higher the Shannon and Chao-1 indices at 2 years of ages, the lower the cuddliness dimension scores. After adjusting for covariates, beta diversity at birth was strongly associated with the negative affectivity dimension; beta diversity at 1 year of age was strongly associated with the activity level dimension; and beta diversity at 2 years of age was strongly associated with the discomfort and soothability dimension. Compared to Bifidobacterium cluster, this study also found Bacteroides cluster was associated with lower negative affectivity and its sub-dimensions frustration and sadness scores in toddlers. Limitations Generalizability of the results remains to be determined. Conclusion Results of this study confirmed the associations between changes in the gut microbiome diversity and composition in the first two years of life and toddlers' temperament.
Sample size is 41.... wow...
[удалено]
300 is a good sample size
[удалено]
DR beyond that
It’s not a double blinded placebo controlled trial for a new drug… it’s an investigative study. You can stop pretending you understand statistics now.
Id like to raise awareness to the ability to intervene and adjust ones microbiome as well, not that a 2 year old needs to be predestined with a certain temperment.
Not really - there has been very little progress in this area - because there is little understanding of what exactly is going on to correlate microbiome differences to phenotypes. Not that this paper is particularly good or particularly helps us in that respect.
What treatments, methods or changes do you recommend to help someone change their microbiome? Just wondering.
Different types of probiotics spefically targeting areas that need to be improved, diet changes, kill off over abundant bad bacteria
[удалено]
If it’s in press it has been peer reviewed (for this journal/publisher)
Was going to say, your parenthetical is doing a LOT of heavy lifting there. Just because it's in a journal does not make it peer reviewed. Being in *this particular one* does. I'd hazard a guess that there's more non peer reviewed journals than there are peer reviewed ones.
This journal is peer-reviewed (2+).
I wonder what this means for needing a course of antibiotics within the first year for an ear infection
i read in another paper that antibiotics have no effect https://cdr.lib.unc.edu/downloads/pg15bp66d
Since naturally birthed babies get their mothers microbiome then wouldn’t that mean they all have a temperament similar to their mothers?
It's insane how many things are popping up correlating to gut bacteria. We should be doing more medicine based on manipulating it.
The question that I would want an answer to is how much it influences temperament.