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| Psychobiotics are live organisms that, when ingested in appropriate amounts, confer a mental health benefit through association with the commensal bacteria of gut of the host organism <ref name=":0" /> . The aforementioned commensal bacteria play a key role in the bidirectional gut-brain axis. Psychobiotics can be subdivided into ], ], and ]. | |||
| '''Psychobiotics''' is a term used in preliminary research to refer to ] that, when ingested in appropriate amounts, might confer a ] benefit by affecting ] of the host organism.<ref name=":0" /> Under research is whether bacteria might play a role in the ]. As of 2018, there is no ] for any effect of gut bacteria on human brain function.<ref name="romijn">{{cite journal | vauthors = Romijn AR, Rucklidge JJ | title = Systematic review of evidence to support the theory of psychobiotics | journal = Nutrition Reviews | volume = 73 | issue = 10 | pages = 675–93 | date = October 2015 | pmid = 26370263 | doi = 10.1093/nutrit/nuv025 | url = https://academic.oup.com/nutritionreviews/article/73/10/675/1848054 }}</ref><ref name="lin">{{cite journal | vauthors = Liu B, He Y, Wang M, Liu J, Ju Y, Zhang Y, Liu T, Li L, Li Q | title = Efficacy of probiotics on anxiety-A meta-analysis of randomized controlled trials | journal = Depression and Anxiety | volume = 35 | issue = 10 | pages = 935–945 | date = July 2018 | pmid = 29995348 | doi = 10.1002/da.22811|url=https://onlinelibrary.wiley.com/doi/full/10.1002/da.22811 }}</ref> | |||
| == Types == | == Types == | ||
| ] | ] | ||
| In probiotic psychobiotics, the bacteria most commonly used are ],such as |
In experimental probiotic psychobiotics, the bacteria most commonly used are ], such as '']'' and '']'' families, as these do not contain ] chains, reducing the likelihood of an ].<ref name=":0">{{cite journal|vauthors=Sarkar A, Lehto SM, Harty S, Dinan TG, Cryan JF, Burnet PW|date=November 2016|title=Psychobiotics and the Manipulation of Bacteria-Gut-Brain Signals|journal=Trends in Neurosciences|volume=39|issue=11|pages=763–781|doi=10.1016/j.tins.2016.09.002|pmc=5102282|pmid=27793434}}</ref> ] are substances, such as ] and ], that induce the growth or activity of beneficial ]s, such as bacteria on being ] in the gut.<ref name=":0" /><ref name="2015defRev">{{cite journal|author1=Hutkins RW |author2=Krumbeck JA |author3=Bindels LB |author4=Cani PD |author5=Fahey G Jr. |author6=Goh YJ |author7=Hamaker B |author8=Martens EC |author9=Mills DA |author10=Rastal RA |author11=Vaughan E |author12=Sanders ME |title=Prebiotics: why definitions matter|journal=Curr Opin Biotechnol|year=2016|volume=37|pages=1–7|doi=10.1016/j.copbio.2015.09.001|pmid=26431716|pmc=4744122}}</ref> Multiple bacterial species contained in a single probiotic broth is known as a polybiotic.<ref name=":5">{{cite journal | vauthors = Bambury A, Sandhu K, Cryan JF, Dinan TG | title = Finding the needle in the haystack: systematic identification of psychobiotics | journal = British Journal of Pharmacology | date = December 2017 | pmid = 29243233 | doi = 10.1111/bph.14127 }}</ref> | ||
| Prebiotic psychobiotics are substances, such as ] and ], promote the growth of intrinsic commensal bacteria by their fermentation in the gut.<ref name=":0" /> | |||
| A combination of a prebiotic and a probiotic is known as a ]. Multiple bacterial species contained in a single probiotic broth is known as a polybiotic.<ref name=":5">{{cite journal | vauthors = Bambury A, Sandhu K, Cryan JF, Dinan TG | title = Finding the needle in the haystack: systematic identification of psychobiotics | journal = British Journal of Pharmacology | date = December 2017 | pmid = 29243233 | doi = 10.1111/bph.14127 }}</ref> | |||
| == Proposed mechanisms of action == | |||
| Pathological changes in gut microbiotia may activate pro-inflammatory pathways via the ] ] which has been identified as a potential trigger for ].<ref>{{cite journal | vauthors = Inserra A, Rogers GB, Licinio J, Wong ML | title = The Microbiota-Inflammasome Hypothesis of Major Depression | journal = BioEssays | volume = 40 | issue = 9 | pages = e1800027 | date = September 2018 | pmid = 30004130 | doi = 10.1002/bies.201800027 }}</ref> | |||
| The brain-gut axis and ] have been linked. The brain cannot store tryptophan and requires a constant supply of this substance. Reduced peripheral tryptophan levels have been associated with depressive phenotype, and tryptophan levels and availability have been found to be directly influenced by the gut microbiota with ''Bifidobacteria'' being shown to increase peripheral tryptophan in animal models. Bacteria play a role in serotonin synthesis from tryptophan in the gut ]s and germ-free mice which are treated with probiotics show threefold increases in serotonin production.<ref name=":5" /> | |||
| Some intestinal microbes have been found to produce psychotropic effects in animal models by secreting ] and neurotransmitter precursor molecules such as ], ], ], ], ], and ] and also by regulating ] expression.<ref>{{Cite book | vauthors = Wall R, Cryan JF, Ross RP, Fitzgerald GF, Dinan TG, Stanton C | title = Bacterial neuroactive compounds produced by psychobiotics | journal = Advances in Experimental Medicine and Biology | volume = 817 | pages = 221–39 | date = 2014 | pmid = 24997036 | doi = 10.1007/978-1-4939-0897-4_10 | isbn = 978-1-4939-0896-7 }}</ref><ref>{{Cite journal|last=Hsiao|first=E|last2=McBride|first2=S.W.|last3=Hsien|first3=S|last4=Sharo|first4=G|last5=Hyde|first5=E.R.|last6=McCue|first6=T|date=2013|title=Microbiota modulate behavioral and physiological abnormalities associated with neurodevelopmental disorders|url=|journal=Cell|volume=151|pages=1451-1463|via=}}</ref> | |||
| The greatest area of uncertainty lies with the dosage of psychobiotics and how to overcome the transient nature of probiotic bacterial species. | |||
| == Research == | == Research == | ||
| As of 2018, there had been several clinical trials of psychobiotics; reviews of these trials concluded that there is no good evidence that psychobiotics are safe and effective in humans.<ref |
As of 2018, there had been several clinical trials of psychobiotics; reviews of these trials concluded that there is no good evidence that psychobiotics are safe and effective in humans.<ref name=romijn/><ref name=lin/> | ||
| ⚫ | ===Species=== | ||
| Preclinical studies have been conducted in ] such as rats and mice. ] demonstrate heightened physiological reactions to psychological stress compared to animals with a normal microbiome, and that these phenomena were reversible by promoting the formation of a healthy microbiome using probiotic treatment.<ref name=":0" /> Psychobiotic treatment of mice exposed to a ] model of anxiety and depression has been found to prevent the fall in physical performance and raised pro-inflammatory ] levels associated with untreated mice, and treatment of mice with '']'' probiotics has been found to reduce activation of the ] in similar circumstances. These mice also expressed fewer depressive and anxious behaviors.<ref name=":0" /> In a similar maternal stress model the psychobiotic species '']'' was able to reduce corticosterone markers of increased HPA axis activity in mice.<ref name=":6">{{cite journal | vauthors = Liu YW, Liong MT, Tsai YC | title = New perspectives of Lactobacillus plantarum as a probiotic: The gut-heart-brain axis | journal = Journal of Microbiology | volume = 56 | issue = 9 | pages = 601–613 | date = September 2018 | pmid = 30141154 | doi = 10.1007/s12275-018-8079-2 }}</ref> | |||
| A very small number of studies have looked at the psychophysiological effects of prebiotics, particularly the role of galacto-oligosaccharides (GOS) and fructo-oligosaccharides (FOS). These prebiotics act as a source of nutrient for ''Bifidobacteria'' and ''Lactobacilli'' and aid in the bacteria's ability to propagate within the gut <ref name=":0" />. Bimuno-GOS and FOS prebiotic supplementation has been found to have neuroprotective activity in animal models, and to raise BDNF levels in the ].<ref name=":5" /> for Short chain fatty acids (SCFAs) such as ], ] and ] are produced in increased amounts following administration of prebiotics in animal models. Butyrate has been demonstrated to have antidepressant effects, can cross the ], and has neuroprotective activity. SCFAs also affect the local gut mucosal immune system, a potential mechanism by which modulation of the HPA axis may occur.<ref name=":5" /> | |||
| There is a correlation between eating a ] over a long period of time and a reduced risk of major depressive disorder;<ref>{{cite journal |last1=Psaltopoulou |first1=T |last2=Sergentanis |first2=TN |last3=Panagiotakos |first3=DB |last4=Sergentanis |first4=IN |last5=Kosti |first5=R |last6=Scarmeas |first6=N |title=Mediterranean diet, stroke, cognitive impairment, and depression: A meta-analysis. |journal=Annals of Neurology |date=October 2013 |volume=74 |issue=4 |pages=580–91 |doi=10.1002/ana.23944 |pmid=23720230}}</ref> a 2017 review suggested that analysis of the gut flora of people on such diets might identify bacterial strains with potential psychobiotic activity.<ref name=":5" /> | |||
| ⚫ | == |
||
| ] | ] | ||
| Several species of bacteria have been used in probiotic psychobiotic |
Several species of bacteria have been used in probiotic psychobiotic research:<ref name=":5" /><ref>{{Cite journal|last=Dinan|first=Timothy|last2=Stanton|first2=Catherine|last3=Cryan|first3=John|date=November 2013|title=Psychobiotics: A Novel Class of Psychotropic|url=|journal=Biological Psychiatry|volume=74|pages=720-726|via=}}</ref> | ||
| * ] | * ] | ||
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| *] | *] | ||
| *'']'' | *'']'' | ||
| A small number of studies have been done that investigate the psychophysiological effects of prebiotics. | |||
| * ] (GOS) | |||
| * ] (FOS) | |||
| == References == | == References == | ||
| {{reflist}} | |||
| <references /> | |||
| {{Dietary supplement}} | {{Dietary supplement}} | ||
Revision as of 16:49, 7 December 2018
 | This article needs more reliable medical references for verification or relies too heavily on primary sources. Please review the contents of the article and add the appropriate references if you can. Unsourced or poorly sourced material may be challenged and removed. Find sources: "Psychobiotic" – news · newspapers · books · scholar · JSTOR (December 2018) |  |
Psychobiotics is a term used in preliminary research to refer to live bacteria that, when ingested in appropriate amounts, might confer a mental health benefit by affecting microbiota of the host organism. Under research is whether bacteria might play a role in the gut-brain axis. As of 2018, there is no clinical evidence for any effect of gut bacteria on human brain function.
Types
In experimental probiotic psychobiotics, the bacteria most commonly used are gram-positive bacteria, such as Bifidobacterium and Lactobacillus families, as these do not contain lipopolysaccharide chains, reducing the likelihood of an immunological response. Prebiotics are substances, such as fructans and oligosaccharides, that induce the growth or activity of beneficial microorganisms, such as bacteria on being fermented in the gut. Multiple bacterial species contained in a single probiotic broth is known as a polybiotic.
Research
As of 2018, there had been several clinical trials of psychobiotics; reviews of these trials concluded that there is no good evidence that psychobiotics are safe and effective in humans.
Species
_Lactobacillus_acidophilus_(D%C3%B6derlein_bacillus).jpg)
Several species of bacteria have been used in probiotic psychobiotic research:
- Lactobacillus helveticus
- Bifidobacterium longum
- Lactobacillus casei
- Lactobacillus plantarum
- Lactobacillus acidophilus
- Lactobacillus delbrueckii subsp. bulgaricus
- Bifidobacterium breve
- Bifidobacterium infantis
- Streptococcus salivarius
- Lactobacillus rhamnosus
- Lactobacillus gasseri
References
- ^ Sarkar A, Lehto SM, Harty S, Dinan TG, Cryan JF, Burnet PW (November 2016). "Psychobiotics and the Manipulation of Bacteria-Gut-Brain Signals". Trends in Neurosciences. 39 (11): 763–781. doi:10.1016/j.tins.2016.09.002. PMC 5102282. PMID 27793434.
- ^ Romijn AR, Rucklidge JJ (October 2015). "Systematic review of evidence to support the theory of psychobiotics". Nutrition Reviews. 73 (10): 675–93. doi:10.1093/nutrit/nuv025. PMID 26370263.
- ^ Liu B, He Y, Wang M, Liu J, Ju Y, Zhang Y, Liu T, Li L, Li Q (July 2018). "Efficacy of probiotics on anxiety-A meta-analysis of randomized controlled trials". Depression and Anxiety. 35 (10): 935–945. doi:10.1002/da.22811. PMID 29995348.
- Hutkins RW; Krumbeck JA; Bindels LB; Cani PD; Fahey G Jr.; Goh YJ; Hamaker B; Martens EC; Mills DA; Rastal RA; Vaughan E; Sanders ME (2016). "Prebiotics: why definitions matter". Curr Opin Biotechnol. 37: 1–7. doi:10.1016/j.copbio.2015.09.001. PMC 4744122. PMID 26431716.
- ^ Bambury A, Sandhu K, Cryan JF, Dinan TG (December 2017). "Finding the needle in the haystack: systematic identification of psychobiotics". British Journal of Pharmacology. doi:10.1111/bph.14127. PMID 29243233.
- Dinan, Timothy; Stanton, Catherine; Cryan, John (November 2013). "Psychobiotics: A Novel Class of Psychotropic". Biological Psychiatry. 74: 720–726.