Fermented foods, neuroticism, and social anxiety: An interaction model
ncbi.nlm.nih.gov
ncbi.nlm.nih.gov
> To determine participants׳ consumption of foods, they were first asked to think of their food intake over the past 30 days (see Appendix). This was followed by a list of 10 items consisting of the following: 1.fruits and vegetables of all kinds, including fresh, canned, frozen, cooked, raw, and juices; 2. yogurt, 3. kefir, or food or beverages that contain yogurt; 4. soy milk, or foods or beverages that contain soy milk; 4. miso soup; 5. sauerkraut; 6. dark chocolate; 7. juices that contain microalgae; 8. pickles; 9. tempeh; and 10. kimchi. Participants were asked to indicate how often they consume each of the foods using the following 7-point scale: 1 (never); 2 (1–3 times in the past month); 3 (1–3 times per week); 4 (1–3 times per day); 5 (3–5 times per day); 6 (5–7 times per day); and 7 (more than 8 times per day). Scores were converted to monthly frequencies of 0, 2, 8, 60, 120, 180, and 240, respectively.
And the Conclusion:
> This study provides the first connection between natural fermented food consumption patterns and anxiety. Increased consumption of fermented foods likely to contain probiotics was associated with fewer social anxiety symptoms. This effect was qualified by an interaction with neuroticism; those who were highly neurotic showed fewer symptoms of social anxiety with greater consumption of fermented foods. Also of note, increased frequency of exercise was associated with decreased social anxiety. Taken together with the results of previous preclinical and clinical studies (Rao et al., 2009, Silk et al., 2009, Messaoudi et al., 2011 and Tillisch et al., 2013), the current results suggest that fermented foods likely to contain probiotics may have a protective effect against social anxiety symptoms for those at higher genetic risk, as indexed by trait neuroticism. While a follow-up prospective cohort study or clinical trial is necessary to determine the direction of causality, these results suggest a possible clinical benefit of fermented foods, a low-risk intervention, on social anxiety.
1) The size of the effect is not reported. Without any indication of what the dose-response curve is other than it has a positive slope (at what significance level?) we know nothing about the relevance of this result to clinical practice.
For example, it is true that if you pay very careful attention to the sidewalk you will increase the amount of dropped money you find. It's not going to make anyone rich, though, any more than just any measurable effect is going to make one less anxious to a useful degree. There is zero indication of how big the effect is, other than it is measureable in a large population. The lack of indication of effect size suggests that it is really small.
2) Self-report via recollection is a lousy data collection technique. Was a food log app really too much trouble? So the raw data are incredibly noisy and may contain systematic errors that are related to the phenomenon under test.
3) They've subsetted the data by pulling out neuroticism, thereby dramatically reducing the significance of any result by an unknown amount (how many other characteristics did they investigate?)
This is the greatest sin. Any time you see a paper that says, "The effect was particularly large in sub-population X" the first question to ask it, "How many sub-populations did you look at?" The next question to ask is, "What is your calculated probability that any one of your sub-populations would have had such a large effect by chance?" These numbers should be reported in the abstract because people subset their data all the time and then analyze the subset that shows an effect as if it was the only one. This is either incompetence or dishonesty.
Statisical significance rolls off with astonishing speed as you subset the data, and if you don't have a formal discipline for subsetting as part of the experiment design that is fixed prior to analysis, any result on a subset is necessarily insignificant because you could have kept subsetting until you found a 'significant' result. If you don't have a formal discipline that says, "We will cut the data in these N ways and only these N ways" you are going fishing on an infinite ocean, where you will certainly catch the kind of fish you are looking for.
More importantly, food is inherently cultural and varies on class and it might be that neuroticism/social anxiety does as well. I posted this because I thought it sounded like a week study with an overly strong conclusion.
Let me see if I understand: you posted (the abstract of) a study you consider not worth taking seriously so that you could read criticisms of the study by people who know more than you; is that correct?
If not, then please explain more about your motivation for posting because I'm a little confused on that point.
http://neurosciencenews.com/lymphatic-system-brain-neurobiol...
Generally lymphatic systems flow away from organs (the lymph vessels in your arms flow back to the heart). How would something in your gut travel to the brain through the lymph system?
Supplementing a rat's diet with Lactobacilus Rhamnosus reduces their anxiety level.
Cut the vagus nerve, the effect disappears.
http://www.pnas.org/content/108/38/16050
This doesn't mean that other bacteria may affect the brain through the immune system, though.
Let's wait until someone conducts a double blind study before drawing too many conclusions from this.
It's pretty good so you're not at loss anyways! I find sauerkraut enjoyable too, vegetables are too bland for me, a little bit of this stuff is a sauce replacement for me.
> until after you gather all your results.
Not all of them; you only need to be blinded for each unit. Once the data is collected for that unit, then you can unblind yourself (and this is the easiest way to go).
> my experience is that alcohol can affect the gut flora.
So? You don't know if the alcohol effect would be to enhance or reduce the supposed calming effect or not affect that at all.
[1] As a stand-in for all fermented foods that contain or are likely to contain probiotics.
Scroll up for the link.
http://www.generalbiotics.com/
It didn't seem to do anything at all for me, but I'm already fairly healthy.
This paper is questionable for other reasons.
E. coli is a little more complicated: some E. coli spp. produce toxins, and other species are enteroinvasive and actually can outcompete the gut flora (confusingly enough, other species of E. coli are also in the normal gut flora).
The main reason that some species of E. coli can make it to your gut and cause disease are that they have a variety of pathogenic factors that definitely would not be found in bacteria in 'probiotic' foods.
(and I see who you are replying to just edited their response to add 'bad' E. coli)
In general, you want to buy high-quality probiotics, and finding the good ones isn't easy mainly because of the huge amount of astroturfing from manufacturers.
So here goes (note that these work for me, IANA doctor, YMMV yada yada):
VSL#3 and Therelac are the best broad-spectrum probiotics. Both have very high concentrations of bacteria, and require refrigeration. These are expensive, and typically used if you're trying to fix some condition. I make sure I always have a bottle of either stocked, and take it only if I feel I need to.
For day-to-day use, the following work great: Culturelle and Jarrow Formulas S. Boulardii. They're reasonably priced, don't require refrigeration, and the effects are noticeable in a day. I typically take a capsule of each twice a day (morning/night.)
Finally, make sure you get digestive enzyme supplements and take them religiously with meals that are hard on the digestive system (e.g., meat.) Twinlab Super Enzymes are what I typically get.
In general, the key effects I've noticed are: much improved digestion, lower anxiety, corrects GI issues, improvements in skin and oral health, and simply a better overall sense of well-being.
What's particularly cool is if you take them with foods that you love but typically upset you (burgers, pizza, other greasy stuff), extra doses of these probiotics right after the meals (along with the digestive enzymes) completely eliminate negative aftereffects.
Good probiotics are incredible, and I wish more doctors better understood them. Meanwhile, I highly recommend trying the above, experimenting (with good judgement), and finding what works for you.
People who eat fermented foods have less anxiety, but we don't know if lower anxiety means people are more likely to eat fermented food or if eating fermented food reduces anxiety.
It's just fascinating and exciting how much we're learning about the role the gut plays in physical and mental health. The really great thing is that it seems pretty easy to control (with poop pills, or whatever) so a lot of people may benefit for very little cost.
I drink homemade Kefir (with a bit of honey) every morning. Whether the effect is real or not, I feel better on the days I have it than the days I don't.