Diet and the Microbiota–Gut–Brain Axis: Sowing the Seeds of Good Mental Health

In the paper

“↓ Microbial diversity (observed OTUs | and Shannon's diversity) after Caf | diet”

• Also stated in: § Conclusions and Future Directions · plain

  “Deficits in place recognition task”

What the sources say

• Not checked yetcites [317] Beilharz, 2018, Cafeteria diet and probiotic therapy: cross talk among memory, neuroplasticity, serotonin receptors and gut microbiota in the rat, Mol Psychiatry source

In the paper

“↑ α-Diversity and changes in | β-diversity”

• Also stated in: § Conclusions and Future Directions · plain

  “↑ spatial | memory after intermittent | fasting”

What the sources say

• Not checked yetcites [319] Hassan, 2019, High-fat diet induces depression-like behaviour in mice associated with changes in microbiome, neuropeptide Y, and brain metabolome, Nutr Neurosci source

In the paper

“↑ Concentration of total anaerobic, | amylolytic and lactate-utilizing | bacteria in colon after HB diet (no | difference in cecum); cellulolytic | bacteria not different in colon”

What the sources say

• Not checked yetcites [339] Destrez, 2015, Changes of the hindgut microbiota due to high-starch diet can be associated with behavioral stress response in horses, Physiol Behav source

In the paper

“8 wk of high-fructose changed | microbial structure of community | but not α-diversity”

What the sources say

• Not checked yetcites [342] Li, 2019, Dietary fructose-induced gut dysbiosis promotes mouse hippocampal neuroinflammation: a benefit of short-chain fatty acids, Microbiome source

In the paper

“↓ Spatial recognition (novel | place recognition task) in Caf | but not cycle diet”

What the sources say

• Not checked yetcites [322] Leigh, 2020, Intermittent cafeteria diet identifies fecal microbiome changes as a predictor of spatial recognition memory impairment in female rats, Transl Psychiatry source

In the paper

“It is generally accepted that the consumption of a highfiber diet promotes an increase in bacterial diversity and leads to a bloom in the growth of beneficial bacteria (i.e., Bifidobacterium sp., Lactobacillus sp., Akkermansia sp., Faecalibacterium sp., Roseburia sp., Bacteroides sp., and Prevotella) as well as a reduction in potentially pathogenic bacteria (e.g., Enterobacteriaceae) (63)(64)(65)(”

What the sources say

• Not checked yetcites [63] Vanegas, 2017, Substituting whole grains for refined grains in a 6-wk randomized trial has a modest effect on gut microbiota and immune and inflammatory markers of healthy adults, Am J Clin Nutr source
• Not checked yetcites [64] Walker, 2011, Dominant and diet-responsive groups of bacteria within the human colonic microbiota, ISME J source
• Not checked yetcites [65] Salonen, 2014, Impact of diet and individual variation on intestinal microbiota composition and fermentation products in obese men, ISME J source

In the paper

“Variations in macronutrient ratios, amounts, and types are large drivers of the effect on microbiota composition (111), with specific microbes thriving on selective macronutrients, thereby increasing their abundance.”

What the sources say

• Not checked yetcites [111] Bear, 2020, The role of the gut microbiota in dietary interventions for depression and anxiety, Adv Nutr source

In the paper

“The core gut microbiota in adulthood is relatively stable, but environmental factors have been identified that can shape the gut microbial community (23,35,36).”

What the sources say

• Not checked yetcites [23] Rinninella, 2019, What is the healthy gut microbiota composition? A changing ecosystem across age, environment, diet, and diseases, Microorganisms source
• Not checked yetcites [35] Martinez, 2013, Long-term temporal analysis of the human fecal microbiota revealed a stable core of dominant bacterial species, PLoS One source
• Not checked yetcites [36] Yatsunenko, 2012, Human gut microbiome viewed across age and geography, Nature source

In the paper

“Thus, the study of whole-dietary approaches represents a more realistic path to the development of new dietary interventions and could inform national healthy eating guidelines and policies.”

In the paper

“Moreover, it has become clear that diet is one of the key factors involved in shaping the gut microbiota, having marked effects on microbial diversity, as well as the abundance and metabolic capacity of specific microbes (3)(4)(5).”

What the sources say

• Not checked yetcites (3)(4)(5)

In the paper

“Indeed, ω-3 fatty acids have been proposed to restore the eubiotic state in pathological conditions by increasing the beneficial bifidobacteria and decreasing enterobacteria, which in turn supports an anti-inflammatory environment through the production of SCFAs and suppression of endotoxemia (81,141).”

What the sources say

• Not checked yetcites [81] Watson, 2018, A randomised trial of the effect of omega-3 polyunsaturated fatty acid supplements on the human intestinal microbiota, Gut source
• Not checked yetcites [141] Costantini, 2017, Impact of omega-3 fatty acids on the gut microbiota, Int J Mol Sci source

In the paper

“SCFAs, specifically butyrate, have been implicated in gastrointestinal (main energy source of colonocytes, supporting gut barrier function) and metabolic (glucose homeostasis, lipid oxidation) health, exert anti-inflammatory and immunomodulatory properties, and can influence central functioning (as outlined in detail below) (119, 120).”

What the sources say

• Not checked yetcites [119] Machate, 2020, Fatty acid diets: regulation of gut microbiota composition and obesity and its related metabolic dysbiosis, Int J Mol Sci source
• Not checked yetcites [120] Blaak, 2020, Short chain fatty acids in human gut and metabolic health, Benef Microbes source

In the paper

“Results from animal studies show that medium-chain fatty acids (7-12 carbons) increase the abundance of Bifidobacterium, Bacteroides, and Prevotella and decrease the abundance of Clostridium histolyticum or Helicobacter (119, 124-126).”

What the sources say

• Not checked yetcites [119] Machate, 2020, Fatty acid diets: regulation of gut microbiota composition and obesity and its related metabolic dysbiosis, Int J Mol Sci source
• Not checked yetcites [124] Zhou, 2017, Effects of medium- and long-chain triacylglycerols on lipid metabolism and gut microbiota composition in C57BL/6J mice, J Agric Food Chem source
• Not checked yetcites [125] Djurasevic, 2018, Beneficial effect of virgin coconut oil on alloxan-induced diabetes and microbiota composition in rats, Plant Foods Hum Nutr source
• Not checked yetcites [126] Patrone, 2018, Differential effects of coconut versus soy oil on gut microbiota composition and predicted metabolic function in adult mice, BMC Genomics source

In the paper

“For example, high SFA intake has been shown to be associated with reduction in total bacterial abundance in humans (95) and in microbial diversity and richness (95,96), as well as an increase in proinflammatory bacteria (e.g., Bilophila wadsworthia) (96)(97)(98) in mice.”

What the sources say

• Not checked yetcites [95] Roytio, 2017, Dietary intake of fat and fibre according to reference values relates to higher gut microbiota richness in overweight pregnant women, Br J Nutr source
• Not checked yetcites [96] Devkota, 2012, Dietary-fat-induced taurocholic acid promotes pathobiont expansion and colitis in Il10−/− mice, Nature source
• Not checked yetcites [97] Zhuang, 2017, Arachidonic acid sex-dependently affects obesity through linking gut microbiota-driven inflammation to hypothalamus-adipose-liver axis, Biochim Biophys Acta Mol Basis Dis source

In the paper

“In humans, healthier polyunsaturated fatty acids (e.g., omega-3 PUFAs) promote the growth of beneficial bacteria, including butyrate producers such as Lactobacillus, Lachnospira, Roseburia, and Bifidobacterium (81), and are correlated with higher microbial diversity as well as taxa from the families Lachnospiraceae and Ruminococcaceae (82).”

What the sources say

• Not checked yetcites [81] Watson, 2018, A randomised trial of the effect of omega-3 polyunsaturated fatty acid supplements on the human intestinal microbiota, Gut source
• Not checked yetcites [82] Menni, 2017, Omega-3 fatty acids correlate with gut microbiome diversity and production of N-carbamylglutamate in middle aged and elderly women, Sci Rep source

In the paper

“Human consumption of resistant starch led to significant increases in Bifidobacterium, Faecalibacterium, and Eubacterium, while decreasing some Ruminococcus strains (74,75).”

What the sources say

• Not checked yetcites [74] Martínez, 2010, Resistant starches types 2 and 4 have differential effects on the composition of the fecal microbiota in human subjects, PLoS One source
• Not checked yetcites [75] Alfa, 2018, A randomized trial to determine the impact of a digestion resistant starch composition on the gut microbiome in older and mid-age adults, Clin Nutr source

In the paper

“The benefits of ω-3 (n-3) fatty acids for central functioning range from enhanced memory, mood, attention, and cognitive performance to a reduced risk of developing depression and regulation of stress sensitivity (131-138).”

What the sources say

• Not checked yetcites [131] Dauncey, 2009, New insights into nutrition and cognitive neuroscience: symposium on ‘Early nutrition and later disease: current concepts, research and implications”, Proc Nutr Soc source
• Not checked yetcites [132] Fontani, 2005, Cognitive and physiological effects of omega-3 polyunsaturated fatty acid supplementation in healthy subjects, Eur J Clin Invest source
• Not checked yetcites [133] Horikawa, 2018, Longitudinal association between n-3 long-chain polyunsaturated fatty acid intake and depressive symptoms: a population-based cohort study in Japan, Nutrients source
• Not checked yetcites [134] Hamazaki, 2000, Anti-stress effects of DHA, Biofactors source
• Not checked yetcites [135] Yehuda, 2000, Fatty acid mixture counters stress changes in cortisol, cholesterol, and impair learning, Int J Neurosci source
• Not checked yetcites [136] Denis, 2013, Omega-3 fatty acids and brain resistance to ageing and stress: body of evidence and possible mechanisms, Ageing Res Rev source
• Not checked yetcites [137] Firth, 2019, The efficacy and safety of nutrient supplements in the treatment of mental disorders: a meta-review of meta-analyses of randomized controlled trials, World Psychiatry source
• Not checked yetcites [138] Firth, 2020, A meta-review of “lifestyle psychiatry”: the role of exercise, smoking, diet and sleep in the prevention and treatment of mental disorders, World Psychiatry source

In the paper

“Although earlier human studies indicated detrimental effects on microbial diversity and composition (99, 100) and a more recent study linked consumption of nonnutritive sweeteners to a “dysbiosis” [an increasingly redundant term in microbiome research (171)] and a decrease in butyrate concentration (172), some reports have concluded that no clear effects of sweeteners on the microbiota can be”

What the sources say

• Not checked yetcites [99] Frankenfeld, 2015, High-intensity sweetener consumption and gut microbiome content and predicted gene function in a cross-sectional study of adults in the United States, Ann Epidemiol source
• Not checked yetcites [100] Suez, 2014, Artificial sweeteners induce glucose intolerance by altering the gut microbiota, Nature source
• Not checked yetcites [172] Farup, 2019, Are nonnutritive sweeteners obesogenic? Associations between diet, faecal microbiota, and short-chain fatty acids in morbidly obese subjects, J Obes source
• Not checked yetcites [170] Lobach, 2019, Assessing the in vivo data on low/no-calorie sweeteners and the gut microbiota, Food Chem Toxicol source

In the paper

“Several human and animal studies have indicated that consumption of fruit and vegetables leads to increased microbial diversity and function, a shift in the abundance of bacterial phyla, growth of beneficial bacteria, such as Bifidobacterium and Lactobacillus, and reduction in potentially harmful bacteria, including E. coli and Enterococcus (51)(52)(53)(54)(55).”

What the sources say

• Not checked yetcites [51] Paturi, 2017, Short-term feeding of fermentable dietary fibres influences the gut microbiota composition and metabolic activity in rats, Int J Food Sci Technol source
• Not checked yetcites [52] Guglielmetti, 2013, Differential modulation of human intestinal Bifidobacterium populations after consumption of a wild blueberry (Vaccinium angustifolium) drink, J Agric Food Chem source
• Not checked yetcites [53] Duque, 2016, An exploratory study on the influence of orange juice on gut microbiota using a dynamic colonic model, Food Res Int source

In the paper

“A recent systematic review and meta-analysis of randomized controlled trials on the effect of nut consumption on gut microbiota concluded that nut consumption shapes the microbiota at the genus level (e.g., increases in Clostridium, Dialister, Roseburia, and Lachnospira, decrease in Parabacteroides); however, the specific effects depend on the type and amount of nut consumed and the duration of”

What the sources say

• Not checked yetcites [184] Creedon, 2020, Nuts and their effect on gut microbiota, gut function and symptoms in adults: a systematic review and meta-analysis of randomised controlled trials, Nutrients source

In the paper

“For example, iron supplementation in a cohort of Kenyan children increased the abundance of pathogens such as Bacillus cereus, Staphylococcus aureus, Clostridium difficile, C. perfringens, and Salmonella, potentially contributing to gut inflammation (156)”

What the sources say

• Not checked yetcites [156] Jaeggi, 2015, Iron fortification adversely affects the gut microbiome, increases pathogen abundance and induces intestinal inflammation in Kenyan infants, Gut source

In the paper

“Switching to a high-protein, low-carbohydrate diet reduces the abundance of butyrate-producing bacteria and increases colonic protein fermentation and metabolites detrimental to health, such as branched-chain fatty acids (BCFAs) and concentrations of phenylacetic acid and Nnitroso compounds (121).”

What the sources say

• Not checked yetcites [121] Russell, 2011, High-protein, reduced-carbohydrate weight-loss diets promote metabolite profiles likely to be detrimental to colonic health, Am J Clin Nutr source

In the paper

“In another recent human study, consumption of a fermented dairy drink for 4 wk increased the abundance of a few specific genera (e.g., Holdemania, Gordonibacter, Lactobacillus, an unclassified Mollicutes (RF-9), and two unclassified genera from Clostridiales), and enriched some functions of the resident microbes (195).”

What the sources say

• Not checked yetcites [195] Alvarez, 2020, Safety and functional enrichment of gut microbiome in healthy subjects consuming a multi-strain fermented milk product: a randomised controlled trial, Sci Rep source

In the paper

“A recent systematic review concluded that significant changes can be observed after pulse consumption, but that results are inconsistent, especially in humans (185).”

What the sources say

• Not checked yetcites [185] Marinangeli, 2020, A systematic review of the effect of dietary pulses on microbial populations inhabiting the human gut, Benef Microbes source

In the paper

“Importantly, it has been shown that emulsifier consumption by germ-free (GF) animals (107) and animals with a highly restricted microbiota (180) did not elicit the same detrimental health effects, suggesting that microbial modulation may be required for the adverse effects of emulsifiers on host health.”

What the sources say

• Not checked yetcites [107] Chassaing, 2015, Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome, Nature source
• Not checked yetcites [180] Chassaing, 2017, Dietary emulsifiers directly alter human microbiota composition and gene expression ex vivo potentiating intestinal inflammation, Gut source

In the paper

“A recent systematic review summarizing the evidence available from human and animal studies on the impact of vitamin D on the gut microbiota suggests that vitamin D status or supplementation can modulate microbiota composition; but with inconsistent data, especially from human studies, no trend is emerging yet (147).”

What the sources say

• Not checked yetcites [147] Waterhouse, 2019, Vitamin D and the gut microbiome: a systematic review of in vivo studies, Eur J Nutr source

In the paper

“On the other hand, an 8 wk intervention with 56.7 g of almonds in young adults revealed an increase in α-diversity measures and a decrease in B. fragilis abundance (62).”

What the sources say

• Not checked yetcites [62] Dhillon, 2019, Almond snacking for 8 wk increases alpha-diversity of the gastrointestinal microbiome and decreases Bacteroides fragilis abundance compared with an isocaloric snack in college freshmen, Curr Dev Nutr source

In the paper

“Polyphenols display a “prebioticlike” effect, increasing the growth of beneficial bacterial strains, such as bifidobacteria and lactobacilli, while reducing the number of potential pathogens, such as C. perfringens and C. histolyticum in a dose-dependent manner (83,84).”

What the sources say

• Not checked yetcites [83] Duenas, 2015, A survey of modulation of gut microbiota by dietary polyphenols, Biomed Res Int source
• Not checked yetcites [84] Ma, 2020, Polyphenol supplementation benefits human health via gut microbiota: a systematic review via meta-analysis, J Funct Foods source

In the paper

“In mice, animal-based protein increases potential detrimental gut microbes, e.g., Peptostreptococcaceae, Ruminococcaceae, Enterococcus, Streptococcus, Turicibacter, or Escherichia (92), and plant-based protein boosts the abundance of Bifidobacterium, Roseburia, and Lactobacillus and lowers the abundance of pathogens such as Bacteroides fragilis and Clostridium perfringens (37,42,80).”

What the sources say

• Not checked yetcites [92] Kostovcikova, 2019, Diet rich in animal protein promotes pro-inflammatory macrophage response and exacerbates colitis in mice, Front Immunol source
• Not checked yetcites [37] David, 2014, Diet rapidly and reproducibly alters the human gut microbiome, Nature source
• Not checked yetcites [42] Tomova, 2019, The effects of vegetarian and vegan diets on gut microbiota, Front Nutr source
• Not checked yetcites [80] Singh, 2017, Influence of diet on the gut microbiome and implications for human health, J Transl Med source

In the paper

“In a recent human intervention study, flavonoid-rich orange juice reduced depressive symptoms significantly compared with flavonoid-low orange cordial and enriched bacterial genera belonging to the Lachnospiraceae, Bifidobacteriaceae, and Bacteroidaceae families (167).”

What the sources say

• Not checked yetcites [167] Park, 2020, Flavonoid-rich orange juice intake and altered gut microbiome in young adults with depressive symptom: a randomized controlled study, Nutrients source

In the paper

“In a recent mouse study, kefir administration increased the abundance of L. reuteri, Eubacterium plexicaudatum, and Bifidobacterium pseudolongum, and decreased Lachnospiraceae bacterium 3_1_46FAA, Propionibacterium acnes, and Bacillus amyloliquefaciens, and shifted the functional potential of the gut microbiota toward the production of neuroactive metabolites (58).”

What the sources say

• Not checked yetcites [58] van de Wouw, 2020, Distinct actions of the fermented beverage kefir on host behaviour, immunity and microbiome gut-brain modules in the mouse, Microbiome source

In the paper

“It is well appreciated that the gut microbiota can synthesize certain vitamins, most notably vitamin K and B-group vitamins [e.g., cobalamin (B 12 ), folate, and riboflavin (144, 145)], some of which might be directly absorbed.”

What the sources say

• Not checked yetcites [144] Hill, 1997, Intestinal flora and endogenous vitamin synthesis, Eur J Cancer Prev source
• Not checked yetcites [145] Rowland, 2018, Gut microbiota functions: metabolism of nutrients and other food components, Eur J Nutr source

In the paper

“In mice, navy bean and black bean flours increased the abundance of Prevotella, S24-7, and Ruminococcus flavefaciens and SCFA production, and decreased the abundance of Ruminococcus gnavus, Oscillospira, Coprococcus, Lactococcus, Streptococcus, Coprobacillus, Parabacteroides, Adlercreutzia, and others compared with the basal diet.Some bean-specific changes were also observed, with black bean flour”

What the sources say

• Not checked yetcites [188] Monk, 2017, Navy and black bean supplementation primes the colonic mucosal microenvironment to improve gut health, J Nutr Biochem source

In the paper

“fermented soybean milk resulted in a decrease in coliform organisms and C. perfringens as well as increases in Bifidobacterium and Lactobacillus (57).”

What the sources say

• Not checked yetcites [57] Cheng, 2005, Effect of fermented soy milk on the intestinal bacterial ecosystem, World J Gastroenterol source

In the paper

“Similar to the Western diet, high-fat diets in animal studies reproducibly change gut microbial community structure, decreasing the overall microbiota diversity and beneficial bacteria (e.g., A. muciniphila, Bifidobacterium, Lactobacillus, and Lactococcus) and increasing the Firmicutes:Bacteroidetes ratio and the abundance of Enterobacteriales, Clostridium cluster XVIa, Mollicutes, and B. wadswort”

What the sources say

• Not checked yetcites [90] Hildebrandt, 2009, High-fat diet determines the composition of the murine gut microbiome independently of obesity, Gastroenterology source
• Not checked yetcites [91] Bisanz, 2019, Meta-analysis reveals reproducible gut microbiome alterations in response to a high-fat diet, Cell Host Microbe source
• Not checked yetcites [206] Turnbaugh, 2009, The effect of diet on the human gut microbiome: a metagenomic analysis in humanized gnotobiotic mice, Sci Transl Med source

In the paper

“Greater microbial diversity as well as higher abundance of health-promoting bacterial taxa (i.e., Clostridium cluster XIVa, F. prausnitzii, Roseburia, Eubacterium, B. thetaiotaomicron, Parabacteroides distasonis, Bifidobacterium adolescentis, and Bifidobacterium longum) have been associated with consumption of the Mediterranean diet (38)(39)(40).”

What the sources say

• Not checked yetcites [38] Jin, 2019, Metabolomics and microbiomes as potential tools to evaluate the effects of the Mediterranean diet, Nutrients source
• Not checked yetcites [39] Gutierrez-Diaz, 2016, Mediterranean diet and faecal microbiota: a transversal study, Food Funct source
• Not checked yetcites [40] Meslier, 2020, Mediterranean diet intervention in overweight and obese subjects lowers plasma cholesterol and causes changes in the gut microbiome and metabolome independently of energy intake, Gut source

In the paper

“These food components are detrimental to the microbiota and some studies have described consequences of ultraprocessed food consumption for gut microbial composition (208).”

What the sources say

• Not checked yetcites [208] Lane, 2020, The effect of ultra-processed very low-energy diets on gut microbiota and metabolic outcomes in individuals with obesity: a systematic literature review, Obes Res Clin Pract source

In the paper

“On the other hand, Firmicutes and Proteobacteria were more abundant in Italian children, with an overrepresentation of Enterobacteriaceae (e.g., Shigella and Escherichia).”

What the sources say

• Not checked yetcites [43] De Filippo, 2010, Impact of diet in shaping gut microbiota revealed by a comparative study in children from Europe and rural Africa, Proc Natl Acad Sci U S A source

In the paper

“More recently, a small pilot crossover study in humans showed a detrimental impact on the gut microbiota and associated metabolites within 4 d of adopting a Westernstyle diet, with increases in bile-tolerant microbes, including Collinsella, Parabacteroides, and B. wadsworthia, as well as increases in TMAO and decreases in the metabolites indole-3-lactic acid and indole-3-propionic acid (205).”

What the sources say

• Not checked yetcites [205] Zhu, 2020, Human gut microbiome composition and tryptophan metabolites were changed differently by fast food and Mediterranean diet in four days: a pilot study, Nutr Res source

In the paper

“Thus, characteristic patterns in the gut microbiota for these types of diets include high bacterial richness, increased numbers of Bifidobacterium, Lactobacillus, Ruminococcus, Eubacterium rectale, Roseburia, Prevotella, F. prausnitzii, and Anaerostipes, but lower abundance of Clostridium sensu stricto, C. perfringens, C. histolyticum, and Odoribacter (42,(45)(46)(47)(48)(49).”

What the sources say

• Not checked yetcites [42] Tomova, 2019, The effects of vegetarian and vegan diets on gut microbiota, Front Nutr source
• Not checked yetcites [45] Liszt, 2009, Characterization of bacteria, clostridia and Bacteroides in faeces of vegetarians using qPCR and PCR-DGGE fingerprinting, Ann Nutr Metab source
• Not checked yetcites [46] Losasso, 2018, Assessing the influence of vegan, vegetarian and omnivore oriented westernized dietary styles on human gut microbiota: a cross sectional study, Front Microbiol source

In the paper

“For example, members of the Lachnospiraceae family (related to Clostridium clostridioforme, C. bolteae, C. celerecrescens, or C. sphenoides), Ruminococcus, and Bacteroides were negatively associated with processed food groups (e.g., processed meat and savory snacks), whereas Lachnospiraceae (Fusicatenibacter saccharivorans), Blautia, and Clostridium were positively associated with processed food”

What the sources say

• Not checked yetcites [210] Matsuyama, 2019, Dietary intake influences gut microbiota development of healthy Australian children from the age of one to two years, Sci Rep source

In the paper

“Long-term consumption of a Western diet in humans and animals can lead to the extinction of beneficial microbes, decrease bacterial diversity, and drive the microbiota to a predominant Bacteroides-driven enterotype (13,14,116,88).”

What the sources say

• Not checked yetcites [13] Sonnenburg, 2016, Diet-induced extinctions in the gut microbiota compound over generations, Nature source
• Not checked yetcites [14] Vangay, 2018, US immigration westernizes the human gut microbiome, Cell source
• Not checked yetcites [116] Precup, 2019, Gut Prevotella as a possible biomarker of diet and its eubiotic versus dysbiotic roles: a comprehensive literature review, Br J Nutr source

In the paper

“Likewise, an increased Firmicutes:Bacteroidetes ratio (41) and decreases in protective SCFA-producing bacteria (e.g., F. prausnitzii) (89, 204) are often observed.”

What the sources say

• Not checked yetcites [41] De Filippis, 2016, High-level adherence to a Mediterranean diet beneficially impacts the gut microbiota and associated metabolome, Gut source
• Not checked yetcites [89] Agus, 2016, Western diet induces a shift in microbiota composition enhancing susceptibility to adherent-invasive E. coli infection and intestinal inflammation, Sci Rep source
• Not checked yetcites [204] Ganesan, 2018, Causal relationship between diet-induced gut microbiota changes and diabetes: a novel strategy to transplant Faecalibacterium prausnitzii in preventing diabetes, Int J Mol Sci source

In the paper

“Although the specific microbial composition depends on the degree of adherence to a plant-based diet, generally favorable microbial patterns have been observed.”

In the paper

“More specifically, these children had a microbial profile specialized for indigestible polysaccharide metabolism, enriched in Bacteroidetes and Actinobacteria, with Prevotella, Xylanibacter, and Treponema exclusively represented in their microbiota compared with children from Italy.”

What the sources say

• Not checked yetcites [43] De Filippo, 2010, Impact of diet in shaping gut microbiota revealed by a comparative study in children from Europe and rural Africa, Proc Natl Acad Sci U S A source

In the paper

“During the prenatal period, maternal factors, including diet, not only influence the offspring's microbial profile but may also exert lasting effects on infant cognition and behavior.”

In the paper

“Animal studies have demonstrated that administration of probiotics (e.g., Lactobacillus plantarum, L. rhamnosus, B. longum) can have anxiolytic and antidepressive effects (222, 223) and can impact aspects of cognitive function (224).”

What the sources say

• Not checked yetcites [222] Abildgaard, 2017, Probiotic treatment reduces depressive-like behaviour in rats independently of diet, Psychoneuroendocrinology source
• Not checked yetcites [223] Barros-Santos, 2020, Effects of chronic treatment with new strains of Lactobacillus plantarum on cognitive, anxiety- and depressive-like behaviors in male mice, PLoS One source
• Not checked yetcites [224] Ni, 2019, Lactobacillus and Bifidobacterium improves physiological function and cognitive ability in aged mice by the regulation of gut microbiota, Mol Nutr Food Res source

In the paper

“Establishing direct links between the gut microbiota and brain function in humans is more difficult and of correlational nature.”

In the paper

“Especially in the first years of life the microbial community is dynamic and some bacteria that become part of the adult microbiota already colonize the gut during the first months of life (230-232).”

What the sources say

• Not checked yetcites [230] Bergstrom, 2014, Establishment of intestinal microbiota during early life: a longitudinal, explorative study of a large cohort of Danish infants, Appl Environ Microbiol source
• Not checked yetcites [231] Jost, 2015, Impact of human milk bacteria and oligosaccharides on neonatal gut microbiota establishment and gut health, Nutr Rev source
• Not checked yetcites [232] Hill, 2017, Evolution of gut microbiota composition from birth to 24 weeks in the INFANTMET Cohort, Microbiome source

In the paper

“Likewise, in nonhuman primates, an unhealthy diet during pregnancy has been linked to poorer cognitive outcomes, enhanced stress responses, and behavioral disruptions in the offspring (242),”

What the sources say

• Not checked yetcites [242] Sullivan, 2014, Maternal high fat diet consumption during the perinatal period programs offspring behavior, Physiol Behav source

In the paper

“On the other hand, another recent meta-analysis and systematic review concluded that the current evidence from human trials does not support the efficacy of probiotics, prebiotics, and fermented food in affecting cognitive function, although the quality and quantity of the available data limit firm conclusions (229);”

What the sources say

• Not checked yetcites [229] Marx, 2020, Prebiotics, probiotics, fermented foods and cognitive outcomes: a meta-analysis of randomized controlled trials, Neurosci Biobehav Rev source

In the paper

“for example, there is lack of studies investigating the same strain of probiotic or type of prebiotic, and probiotic-and prebiotic-specific effects are often observed.”

What the sources say

• Not checked yetcites [229] Marx, 2020, Prebiotics, probiotics, fermented foods and cognitive outcomes: a meta-analysis of randomized controlled trials, Neurosci Biobehav Rev source

In the paper

“Additionally, prebiotic human milk oligosaccharides (HMOs) can be fermented by the resident microbes, promoting the growth of beneficial bacteria (260).”

What the sources say

• Not checked yetcites [260] Bode, 2012, Human milk oligosaccharides: every baby needs a sugar mama, Glycobiology source

In the paper

“In human studies, early introduction of solid food was associated with a higher risk of obesity (274, 275) or immunological diseases (276).”

What the sources say

• Not checked yetcites [274] Pluymen, 2018, Early introduction of complementary foods and childhood overweight in breastfed and formula-fed infants in the Netherlands: the PIAMA birth cohort study, Eur J Nutr source
• Not checked yetcites [275] Differding, 2020, Potential interaction between timing of infant complementary feeding and breastfeeding duration in determination of early childhood gut microbiota composition and BMI, Pediatr Obes source
• Not checked yetcites [276] Nwaru, 2013, Timing of infant feeding in relation to childhood asthma and allergic diseases, J Allergy Clin Immunol source

In the paper

“At birth, neonates are exposed to the first large number of microbes that colonize the gastrointestinal tract and differences in the microbiota composition based on birth mode have been reported.”

In the paper

“Following birth, colonization of the infant gut is majorly determined by the early feeding mode, with distinguishable microbial compositions between breast-and formula-fed infants (254, 255).”

What the sources say

• Not checked yetcites [254] Ku, 2020, Microbiome study of initial gut microbiota from newborn infants to children reveals that diet determines its compositional development, J Microbiol Biotechnol source
• Not checked yetcites [255] Matsuyama, 2019, Breastfeeding: a key modulator of gut microbiota characteristics in late infancy, J Dev Orig Health Dis source

In the paper

“Thus, naturally born infants are exposed to the mother's vaginal bacteria, whereas babies born by C-section are first introduced to bacteria of the mother's skin, the hospital environment, or the healthcare workers (237).”

What the sources say

• Not checked yetcites [237] Dominguez-Bello, 2010, Delivery mode shapes the acquisition and structure of the initial microbiota across multiple body habitats in newborns, Proc Natl Acad Sci U S A source

In the paper

“Animal studies have shown that this early exposure to microbes is essential for neurodevelopment and that some behavioral effects related to a missing or altered microbiota cannot be reversed later in life or can only be reversed during a specific period of time (218, 245, 252).”

What the sources say

• Not checked yetcites [218] Sudo, 2004, Postnatal microbial colonization programs the hypothalamic-pituitary-adrenal system for stress response in mice, J Physiol source
• Not checked yetcites [245] Buffington, 2016, Microbial reconstitution reverses maternal diet-induced social and synaptic deficits in offspring, Cell source
• Not checked yetcites [252] Clarke, 2013, The microbiome-gut-brain axis during early life regulates the hippocampal serotonergic system in a sex-dependent manner, Mol Psychiatry source

In the paper

“Supplementation with oligosaccharides from birth in a mouse model modulated the microbiota composition and diversity, increased saccharolytic and decreased proteolytic fermentation while also resulting in improved social and anxiety-like behavior (268),”

What the sources say

• Not checked yetcites [268] Szklany, 2020, Supplementation of dietary non-digestible oligosaccharides from birth onwards improve social and reduce anxiety-like behaviour in male BALB/c mice, Nutr Neurosci source

In the paper

“In piglets, early weaning stress impairs intestinal barrier function (271) and increases inflammation (272) and oxidative stress (273).”

What the sources say

• Not checked yetcites [271] Moeser, 2017, Weaning stress and gastrointestinal barrier development: implications for lifelong gut health in pigs, Anim Nutr source
• Not checked yetcites [272] Pie, 2004, Weaning is associated with an upregulation of expression of inflammatory cytokines in the intestine of piglets, J Nutr source
• Not checked yetcites [273] Yin, 2014, Development of an antioxidant system after early weaning in piglets, J Anim Sci source

In the paper

“however, some of these microbial and behavioral alterations could be reversed by supplementation with a prebiotic mixture (galactooligosaccharide, fructooligosaccharide), suggesting that microbiota-targeted diet interventions could be used to alleviate some of the negative effects associated with Csection (251).”

What the sources say

• Not checked yetcites [251] Morais, 2020, Enduring behavioral effects induced by birth by caesarean section in the mouse, Curr Biol source

In the paper

“Human milk harbors a unique microbial community, including commensal, mutualistic, and probiotic bacteria, some of which can be found as first colonizers of the neonatal gut (258, 259).”

What the sources say

• Not checked yetcites [258] Cabrera-Rubio, 2012, The human milk microbiome changes over lactation and is shaped by maternal weight and mode of delivery, Am J Clin Nutr source
• Not checked yetcites [259] Solis, 2010, Establishment and development of lactic acid bacteria and bifidobacteria microbiota in breast-milk and the infant gut, Anaerobe source

In the paper

“Generally, breast-fed infants harbor a less diverse and species-rich microbiota that is dominated by Bifidobacterium species, whereas the microbiota of formulafed infants is functionally more similar to that of an adult and is often enriched in microbial taxa such as Klebsiella, Enterococcus, Peptostreptococcaceae, Akkermansia, Veillonella, and C. difficile (256, 257).”

What the sources say

• Not checked yetcites [256] Vandenplas, 2020, Factors affecting early-life intestinal microbiota development, Nutrition source
• Not checked yetcites [257] Davis, 2017, The role of early life nutrition in the establishment of gastrointestinal microbial composition and function, Gut Microbes source

In the paper

“Altering the timing of weaning could result in a pathological imprinting of the immune response and increased susceptibility to later immunopathologies (270).”

What the sources say

• Not checked yetcites [270] Al Nabhani, 2019, A weaning reaction to microbiota is required for resistance to immunopathologies in the adult, Immunity source

In the paper

“Although these differences can dissipate a few weeks or months after birth (248), it has been suggested that some microbes acquired during the first years of life will be important residents of the adult microbiota (249).”

What the sources say

• Not checked yetcites [248] Chu, 2017, Maturation of the infant microbiome community structure and function across multiple body sites and in relation to mode of delivery, Nat Med source
• Not checked yetcites [249] Litvak, 2019, The founder hypothesis: a basis for microbiota resistance, diversity in taxa carriage, and colonization resistance against pathogens, PLoS Pathog source

In the paper

“Due to the known profound effects of the microbiota on host development, accelerated maturation of the gut microbiota has been proposed as a contributing pathway to the detrimental effects of early weaning on host processes (275).”

What the sources say

• Not checked yetcites [275] Differding, 2020, Potential interaction between timing of infant complementary feeding and breastfeeding duration in determination of early childhood gut microbiota composition and BMI, Pediatr Obes source

In the paper

“These associations are observed across the age range, including in early adolescence, which represents the primary age of onset for mental disorders (292, 310).”

What the sources say

• Not checked yetcites [292] Jacka, 2010, Associations between diet quality and depressed mood in adolescents: results from the Australian Healthy Neighbourhoods Study, Aust N Z J Psychiatry source
• Not checked yetcites [310] Jacka, 2011, A prospective study of diet quality and mental health in adolescents, PLoS One source

In the paper

“Adolescence is also a critical time period for neuroanatomical change and maturation, which translates into behavioral development, including cognitive function, social cognition, and executive function (285, 286).”

What the sources say

• Not checked yetcites [285] Blakemore, 2006, Development of the adolescent brain: implications for executive function and social cognition, J Child Psychol Psychiatry source
• Not checked yetcites [286] Burnett, 2011, The social brain in adolescence: evidence from functional magnetic resonance imaging and behavioural studies, Neurosci Biobehav Rev source

In the paper

“In a mouse model of adolescence, exposure to a cafeteria diet for 21 d resulted in decreased species evenness (measured by the Shannon diversity index) and abundance of Roseburia, Turicibacter, and Enterorhabdus, and, although no behavioral manifestations were observed, altered gene expression involved in neuroimmunity and neurotransmission in the prefrontal cortex and amygdala (294).”

What the sources say

• Not checked yetcites [294] Fulling, 2020, Adolescent dietary manipulations differentially affect gut microbiota composition and amygdala neuroimmune gene expression in male mice in adulthood, Brain Behav Immun source

In the paper

“Supplementing children with moderate acute malnutrition with a microbiota-directed complementary food prototype shifted the microbiota as well as markers of neurodevelopment toward that of healthy children, indicating that the immature microbiota is causally linked to unhealthy growth and development, but can be rescued by microbiota-targeted food therapy (282).”

What the sources say

• Not checked yetcites [282] Gehrig, 2019, Effects of microbiota-directed foods in gnotobiotic animals and undernourished children, Science source

In the paper

“Unhealthy eating or dieting with failure to meet recommended intake of fruits and vegetables and excess intake of fat or high-sugar foods and drinks can be characteristic of the adolescent period (288-290).”

What the sources say

• Not checked yetcites [288] Larson, 2007, Trends in adolescent fruit and vegetable consumption, 1999-2004: project EAT, Am J Prev Med source
• Not checked yetcites [289] Moreno, 2010, Trends of dietary habits in adolescents, Crit Rev Food Sci Nutr source
• Not checked yetcites [290] Schneider, 2000, International trends in adolescent nutrition, Soc Sci Med source

In the paper

“Indeed, animal studies demonstrated that early exposure to some dietary components shifted the microbiota composition, which could favor systemic inflammation and influence the brain, such as altering blood-brain barrier (BBB) permeability (277).”

What the sources say

• Not checked yetcites [277] Marungruang, 2018, Impact of dietary induced precocious gut maturation on cecal microbiota and its relation to the blood-brain barrier during the postnatal period in rats, Neurogastroenterol Motil source

In the paper

“In general, microbial diversity decreases and numbers of beneficial bacteria (bifidobacteria, lactobacilli, Clostridium cluster XIVa, F. prausnitzii) reduce, whereas facultative anaerobes and opportunists or even proinflammatory pathogenic bacteria (Escherichia spp., Enterobacteriaceae spp., Bacteroides spp., C. difficile, etc.) increase when compared with younger individuals (235, 295, 296).”

What the sources say

• Not checked yetcites [235] Nagpal, 2018, Gut microbiome and aging: physiological and mechanistic insights, Nutr Healthy Aging source
• Not checked yetcites [295] Salazar, 2017, Nutrition and the gut microbiome in the elderly, Gut Microbes source
• Not checked yetcites [296] Askarova, 2020, The links between the gut microbiome, aging, modern lifestyle and Alzheimer's disease, Front Cell Infect Microbiol source

In the paper

“While the effects of probiotics and prebiotics on the microbiota and mood or cognition have been more widely studied (12), investigations into whole-food and diet approaches are scarce.”

What the sources say

• Not checked yetcites [12] Long-Smith, 2020, Microbiota-gut-brain axis: new therapeutic opportunities, Annu Rev Pharmacol Toxicol source

In the paper

“On the other hand, poor dietary habits (such as the Westernstyle diet), intake of low-quality, processed, or high-fat/sugar foods and malnutrition (over-and undernutrition) can be related to poorer mental health (305, 306), impaired cognitive function (298), and increased risk of developing anxiety (307), depression (292, 308, 309), or other mental illnesses.”

What the sources say

• Not checked yetcites [305] O'Neil, 2014, Relationship between diet and mental health in children and adolescents: a systematic review, Am J Public Health source
• Not checked yetcites [306] Lai, 2014, A systematic review and meta-analysis of dietary patterns and depression in community-dwelling adults, Am J Clin Nutr source
• Not checked yetcites [298] Sarris, 2015, Nutritional medicine as mainstream in psychiatry, Lancet Psychiatry source

In the paper

“While some evidence from preclinical studies shows the triangular relation between diet, microbiota, and brain/behavior, similar studies in human populations are lacking and most clinical studies investigating the effect of diet on anxiety, depression or cognition did not explore microbiota compositional changes (199, 311, 312).”

What the sources say

• Not checked yetcites [199] Jacka, 2017, A randomised controlled trial of dietary improvement for adults with major depression (the 'SMILES' trial), BMC Med source
• Not checked yetcites [311] Parletta, 2019, A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: a randomized controlled trial (HELFIMED), Nutr Neurosci source
• Not checked yetcites [312] Martinez-Lapiscina, 2013, Mediterranean diet improves cognition: the PREDIMED-NAVARRA randomised trial, J Neurol Neurosurg Psychiatry source

In the paper

“These extended maturations can pose an additional sensitive period for microbial priming of the maturing adolescent brain and provide opportunities to improve adolescent mental wellbeing (219, 287).”

What the sources say

• Not checked yetcites [219] Cowan, 2020, Annual Research Review: Critical windows – the microbiota-gut-brain axis in neurocognitive development, J Child Psychol Psychiatr source
• Not checked yetcites [287] Neufeld, 2016, What’s bugging your teen?—The microbiota and adolescent mental health, Neurosci Biobehav Rev source

In the paper

“Transfer of fecal samples from undernourished children to GF mice elicited metabolic and immune dysregulations in the mouse model similar to those observed in the human host, suggesting that the manifestations of malnutrition could in part be attributed to the absence of certain beneficial microbes (280).”

What the sources say

• Not checked yetcites [280] Smith, 2013, Gut microbiomes of Malawian twin pairs discordant for kwashiorkor, Science source

In the paper

“Although the Mediterranean diet is the dietary pattern most studied in regard to health outcomes, including mental health (201), traditional dietary patterns from many parts of the world (e.g., the Norwegian and Japanese diets) also show protective associations (302, 303) and are correlated with reduced risk of developing depression or Alzheimer's disease as well as a general slowing of cognitive”

What the sources say

• Not checked yetcites [302] Munoz, 2008, Adherence to the Mediterranean diet is associated with better mental and physical health, Br J Nutr source
• Not checked yetcites [303] Opie, 2017, Dietary recommendations for the prevention of depression, Nutr Neurosci source
• Not checked yetcites [201] Psaltopoulou, 2013, Mediterranean diet, stroke, cognitive impairment, and depression: a meta-analysis, Ann Neurol source

In the paper

“From the existing literature, a clear interaction between diet and the microbiota-brain communication across the lifespan emerges.”

In the paper

“Additionally, SCFAs can stimulate neurotrophic factors [nerve growth factor, BDNF, and glial cell line-derived neurotrophic factor (352)] or neurotransmitter synthesis [glutamate, glutamine, and GABA (353)], thus regulating the growth, survival, differentiation, and excitability of neurons and synapses in the CNS (352) and playing an important part in learning, memory, stress, and mood.”

What the sources say

• Not checked yetcites [352] Moris, 2003, Neurotrophic factors: basis for their clinical application, Neurologia
• Not checked yetcites [353] Frost, 2014, The short-chain fatty acid acetate reduces appetite via a central homeostatic mechanism, Nat Commun source

In the paper

“Importantly, the microbiota composition was rescued prior to cognitive changes and the positive effects of β-glucan were eliminated with antibiotic treatment (321), suggesting a potential causal relation between diet-induced microbial alterations and cognitive function.”

What the sources say

• Not checked yetcites [321] Shi, 2020, β-Glucan attenuates cognitive impairment via the gut-brain axis in diet-induced obese mice, Microbiome source

In the paper

“In the NU-AGE cohort, Mediterranean diet-induced increases in microbial taxa were associated with improved cognition and reduced risk of frailty and inflammation in elderly individuals who followed a customized Mediterranean diet for 12 mo (300).”

What the sources say

• Not checked yetcites [300] Ghosh, 2020, Mediterranean diet intervention alters the gut microbiome in older people reducing frailty and improving health status: the NU-AGE 1-year dietary intervention across five European countries, Gut source

In the paper

“Among the interventional studies using whole-dietary approaches published to date, only one included healthy adults as volunteers, and reported improved nutritional behaviors and intrapersonal emotional competence following a diet rich in inulin-type fructans (331).”

What the sources say

• Not checked yetcites [331] Hiel, 2019, Effects of a diet based on inulin-rich vegetables on gut health and nutritional behavior in healthy humans, Am J Clin Nutr source

In the paper

“While there is existing evidence from clinical interventions showing improvements in depression and anxiety symptoms following dietary manipulation (199, 311, 326), these studies have not, to date, collected gut microbiota data.”

What the sources say

• Not checked yetcites [199] Jacka, 2017, A randomised controlled trial of dietary improvement for adults with major depression (the 'SMILES' trial), BMC Med source
• Not checked yetcites [311] Parletta, 2019, A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: a randomized controlled trial (HELFIMED), Nutr Neurosci source
• Not checked yetcites [326] Francis, 2019, A brief diet intervention can reduce symptoms of depression in young adults—a randomised controlled trial, PLoS One source

In the paper

“Likewise, even short-term diet exposure (2 wk) shifted the microbiota composition in a way that was associated with inflammationrelated pathways and memory deficits (325), indicating rapid effects on microbiota and brain function.”

What the sources say

• Not checked yetcites [325] Beilharz, 2016, The effect of short-term exposure to energy-matched diets enriched in fat or sugar on memory, gut microbiota and markers of brain inflammation and plasticity, Brain Behav Immun source

In the paper

“In juvenile rats, positive correlations between a diet-linked increase in Lactobacillus and mRNA expression of neuronal activation and serotonin (5-HT) receptors were described (316), suggesting that effects of diet on brain chemistry are mediated by certain microbes.”

What the sources say

• Not checked yetcites [316] Mika, 2018, Feeding the developing brain: juvenile rats fed diet rich in prebiotics and bioactive milk fractions exhibit reduced anxiety-related behavior and modified gene expression in emotion circuits, Neurosci Lett source

In the paper

“In a pilot study with 47 healthy young medical students, consumption of a fermented milk drink containing L. casei strain Shirota was able to reduce physical symptoms of stress such as abdominal pain or cold symptoms, prevented the increase in salivary cortisol observed in the placebo group, and could potentially normalize stress-induced aberration in tryptophan metabolism and improve 5-HT”

What the sources say

• Not checked yetcites [344] Kato-Kataoka, 2016, Fermented milk containing Lactobacillus casei strain Shirota prevents the onset of physical symptoms in medical students under academic examination stress, Benef Microbes source

In the paper

“For example, B. longum 1417 modulated resting neural activity as well as neural responses to social stress, while supplementation with β-galactooligosaccharide reduced the salivary cortisol awakening response, a biochemical measure of stress, and improved emotional information processing (329), and an oligofructose-enriched inulin improved memory and mood in healthy volunteers (330).”

What the sources say

• Not checked yetcites [329] Schmidt, 2015, Prebiotic intake reduces the waking cortisol response and alters emotional bias in healthy volunteers, Psychopharmacology (Berl) source
• Not checked yetcites [330] Smith, 2015, An investigation of the acute effects of oligofructose-enriched inulin on subjective wellbeing, mood and cognitive performance, Nutrients source

In the paper

“Interestingly, prior treatment with a probiotic (VSL#3, containing 3 strains of bifidobacteria, 4 strains of lactobacilli, and 1 strain of Streptococcus) was able to prevent dietinduced cognitive deficits in the hippocampal-dependent place recognition task and rescue specific bacterial taxa that were decreased by exposure to a cafeteria diet (317).”

What the sources say

• Not checked yetcites [317] Beilharz, 2018, Cafeteria diet and probiotic therapy: cross talk among memory, neuroplasticity, serotonin receptors and gut microbiota in the rat, Mol Psychiatry source

In the paper

“Likewise, strong associations between increased behavioral reactivity and a microbial profile elicited by a high-starch diet, as well as more settled behaviors associated with microbes promoted by a highfiber diet, were observed in horses (323).”

What the sources say

• Not checked yetcites [323] Bulmer, 2019, High-starch diets alter equine faecal microbiota and increase behavioural reactivity, Sci Rep source

In the paper

“In addition, SCFAs, specifically butyrate, were also shown to enhance BBB integrity by increasing occludin expression (355, 356), thereby protecting the brain from potential neurotoxic factors.”

What the sources say

• Not checked yetcites [355] Li, 2016, Sodium butyrate exerts neuroprotective effects by restoring the blood-brain barrier in traumatic brain injury mice, Brain Res source
• Not checked yetcites [356] Sun, 2016, Antidepressant-like effects of sodium butyrate and its possible mechanisms of action in mice exposed to chronic unpredictable mild stress, Neurosci Lett source

In the paper

“Recently, the administration of microbial metabolites that were found to be differentially increased after intermittent fasting resulted in improved cognitive function, partially supporting a causal role for microbial metabolites in improving cognition in animals (320).”

What the sources say

• Not checked yetcites [320] Liu, 2020, Gut microbiota mediates intermittent-fasting alleviation of diabetes-induced cognitive impairment, Nat Commun source

In the paper

“In an animal model, administration of SCFAs reduced behavioral deficits (depressive-like behavior), stress responsiveness and intestinal permeability associated with psychosocial stress (354)”

What the sources say

• Not checked yetcites [354] van de Wouw, 2018, Short-chain fatty acids: microbial metabolites that alleviate stress-induced brain–gut axis alterations, J Physiol source

In the paper

“In another recent animal study, supplementation with the prebiotic β-glucan abrogated microbiota alterations and cognitive impairment as well as microglia activation and neuroinflammation induced by a high-fat, fiber-deficient diet (321).”

What the sources say

• Not checked yetcites [321] Shi, 2020, β-Glucan attenuates cognitive impairment via the gut-brain axis in diet-induced obese mice, Microbiome source

In the paper

“In an obese population, a nutrition education program focusing on the gut microbiota (increase in fiber-containing and fermented foods) resulted in a decrease in the depression score and an increase in selfrated health, as well as an increase in α-diversity and abundance of beneficial bacteria such as B. bifidum and S. thermophilus (332).”

What the sources say

• Not checked yetcites [332] Uemura, 2019, Obesity and mental health improvement following nutritional education focusing on gut microbiota composition in Japanese women: a randomised controlled trial, Eur J Nutr source

In the paper

“Kynurenine can cross the BBB and be further metabolized to neuroactive glutamatergic products, such as kynurenic and quinolinic acid.”

In the paper

“While a direct effect of intestinally produced 5-HT on the brain is unlikely as it cannot penetrate the BBB, stimulation of vagal afferents and regulation of the immune responses could be potential signaling pathways (388, 389).”

What the sources say

• Not checked yetcites [388] Mawe, 2013, Serotonin signalling in the gut—functions, dysfunctions and therapeutic targets, Nat Rev Gastroenterol Hepatol source
• Not checked yetcites [389] Shajib, 2017, Diverse effects of gut-derived serotonin in intestinal inflammation, ACS Chem Neurosci source

In the paper

“Additionally, the production of 5-HT can affect peripheral tryptophan availability and, thus, indirectly affect brain 5-HT levels, suggesting that peripheral alterations in 5-HT can affect the central 5-HT signaling system (390, 391).”

What the sources say

• Not checked yetcites [390] Muller, 2016, The serotonin system in autism spectrum disorder: from biomarker to animal models, Neuroscience source
• Not checked yetcites [391] Elliott, 2019, Role of tryptophan in microbiota-induced depressive-like behavior: evidence from tryptophan depletion study, Front Behav Neurosci source

In the paper

“BCFAs could be especially important microbial messengers in scenarios of high-protein, low-complex carbohydrate (i.e., dietary fiber) consumption, as studies have shown that consumption of these diets can increase the microbial production of BCFAs (121, 380, 381).”

What the sources say

• Not checked yetcites [121] Russell, 2011, High-protein, reduced-carbohydrate weight-loss diets promote metabolite profiles likely to be detrimental to colonic health, Am J Clin Nutr source
• Not checked yetcites [380] Aguirre, 2016, Diet drives quick changes in the metabolic activity and composition of human gut microbiota in a validated in vitro gut model, Res Microbiol source
• Not checked yetcites [381] Hald, 2016, Effects of arabinoxylan and resistant starch on intestinal microbiota and short-chain fatty acids in subjects with metabolic syndrome: a randomised crossover study, PLoS One source

In the paper

“SCFAs also activate vagal afferents in the gastrointestinal tract (364), transducing electric signals to modulate neurotransmitter levels in the brain and brain function.”

What the sources say

• Not checked yetcites [364] Lal, 2001, Vagal afferent responses to fatty acids of different chain length in the rat, Am J Physiol Gastrointest Liver Physiol source

In the paper

“These metabolites serve as important bioactive messengers in the microbiota-brain communication and can be modulated by dietary intake, specifically protein.”

In the paper

“As an antagonist to the N-methyl-d-aspartate (NMDA) receptor, kynurenic acid is usually neuroprotective, whereas quinolinic acid acts as an agonist to the NMDA receptor and exerts neurotoxic effects (393).”

What the sources say

• Not checked yetcites [393] Stone, 2001, Kynurenic acid antagonists and kynurenine pathway inhibitors, Expert Opin Investig Drugs source

In the paper

“The effect of SCFAs on inflammation can be mediated by improvement of the intestinal barrier (361), thereby potentially preventing immune molecules and bacterial LPS translocating into the periphery and thus reducing systemic inflammation and ultimately neuroinflammation (362).”

What the sources say

• Not checked yetcites [361] Bach Knudsen, 2018, Impact of diet-modulated butyrate production on intestinal barrier function and inflammation, Nutrients source
• Not checked yetcites [362] Leigh, 2020, Diet, inflammation and the gut microbiome: mechanisms for obesity-associated cognitive impairment, Biochim Biophys Acta Mol Basis Dis source

In the paper

“Microbial proteolytic activity not only influences the availability of amino acids to the host (375), but also results in the production of bioactive metabolites [e.g., neurotransmitters, BCFAs, amines, phenols, and indoles (376)].”

What the sources say

• Not checked yetcites [375] Metges, 2000, Contribution of microbial amino acids to amino acid homeostasis of the host, J Nutr source
• Not checked yetcites [376] Macfarlane, 1992, Estimation of short-chain fatty acid production from protein by human intestinal bacteria based on branched-chain fatty acid measurements, FEMS Microbiol Ecol source

In the paper

“HDACs have been implicated in a range of neuropsychiatric disorders [e.g., depression and schizophrenia (358)] and HDAC inhibitors could be potential cognitive enhancers in anxiety-and fear-related disorders (359).”

What the sources say

• Not checked yetcites [358] Volmar, 2015, Histone deacetylases (HDACs) and brain function, Neuroepigenetics source
• Not checked yetcites [359] Whittle, 2014, HDAC inhibitors as cognitive enhancers in fear, anxiety and trauma therapy: where do we stand?, Biochem Soc Trans source

In the paper

“Lastly, a large research focus has also been placed on the microbial production of trimethylamine (TMA) from dietary choline.Once absorbed, TMA is converted to TMAO, which has been implicated in various chronic diseases, especially those related to the circulatory system [e.g., stroke (386)].”

What the sources say

• Not checked yetcites [386] Farhangi, 2020, Gut microbiota-associated metabolite trimethylamine N-oxide and the risk of stroke: a systematic review and dose-response meta-analysis, Nutr J source

In the paper

“Microbially derived secondary bile acids are hypothesized to be interkingdom signaling molecules due to their ability to influence the composition and function of the gut microbiota as well as host physiology (407, 408).”

What the sources say

• Not checked yetcites [407] Ridlon, 2015, The human gut sterolbiome: bile acid-microbiome endocrine aspects and therapeutics, Acta Pharm Sin B source
• Not checked yetcites [408] Joyce, 2016, Bile acid modifications at the microbe-host interface: potential for nutraceutical and pharmaceutical interventions in host health, Annu Rev Food Sci Technol source

In the paper

“However, bioavailability and some biological activity might also be dependent on conversion by the gut microbiota (413), which is the case in the interaction between polyphenols, microbiota, and associated beneficial effects (507).”

What the sources say

• Not checked yetcites [413] Pasinetti, 2018, The role of the gut microbiota in the metabolism of polyphenols as characterized by gnotobiotic mice, J Alzheimers Dis source
• Not checked yetcites [507] Espin, 2017, The gut microbiota: a key factor in the therapeutic effects of (poly)phenols, Biochem Pharmacol source

In the paper

“Some reports suggest that bile acids can cross the BBB, whereas other bile acid conjugates have been shown to signal directly to the brain as neuroactive ligands, either by binding to farnesoid X receptor and Takeda G protein-coupled receptor 5 (TGR5) present in the CNS or indirectly by binding these receptors in the gastrointestinal tract and initiating a signaling cascade (411).”

What the sources say

• Not checked yetcites [411] Mertens, 2017, Bile acid signaling pathways from the enterohepatic circulation to the central nervous system, Front Neurosci source

In the paper

“In rats, bile acids were also demonstrated to increase permeability of the BBB (412), which could increase the flow of other neuroactive metabolites or neurotoxins into the brain and affect brain function and behavior.”

What the sources say

• Not checked yetcites [412] Quinn, 2014, Bile acids permeabilize the blood brain barrier after bile duct ligation in rats via Rac1-dependent mechanisms, Dig Liver Dis source

In the paper

“For example, ferulic acid, a phenolic compound found in plant stems and various herbs, is broken down by the esterase activity of Lactobacillus spp.into 4-vinylguaiacol and hydroferulic acid (414) and further converted into caffeic and vanillic acids.”

What the sources say

• Not checked yetcites [414] Knockaert, 2012, Carrot β-carotene degradation and isomerization kinetics during thermal processing in the presence of oil, J Agric Food Chem source

In the paper

“An increase in indole-3-lactic acid and indole-3-propionic acid, which have been shown to confer beneficial effects on neuronal cells, was observed after the Mediterranean diet, but these metabolites were decreased after the fast-food diet.”

In the paper

“Additionally, indoles increase the expression of inflammation-associated genes by binding to certain receptors (e.g., aryl hydrocarbon receptor) and can bind to 5-HT receptors to impact behavior and gut motility (405).”

What the sources say

• Not checked yetcites [405] Tomberlin, 2017, Indole: an evolutionarily conserved influencer of behavior across kingdoms, Bioessays source

In the paper

“Thus, an individual response to fiber could depend on the initial target bacterial levels and those individuals with the lowest fiber intakes and a limited microbial richness at baseline potentially might have the most to gain from increasing fiber intake and exhibit greater microbiota changes (505).”

What the sources say

• Not checked yetcites [505] Jefferson, 2019, The effects of intact cereal grain fibers, including wheat bran on the gut microbiota composition of healthy adults: a systematic review, Front Nutr source

In the paper

“Recently, abnormal bile acid metabolism was described in neurological diseases, suggesting a role for the transformation of bile acids by gut microbiota as a factor in Alzheimer's disease development/progression and cognitive decline (409, 410).”

What the sources say

• Not checked yetcites [409] MahmoudianDehkordi, 2019, Altered bile acid profile associates with cognitive impairment in Alzheimer’s disease—an emerging role for gut microbiome, Alzheimers Dement source
• Not checked yetcites [410] Bhargava, 2014, Gut microbiome and multiple sclerosis, Curr Neurol Neurosci Rep source

In the paper

“Thus, a relatively stable microbiota might benefit from a stable diet, whereas an unstable microbiota could mean a flexible response to dietary intervention and constant re-evaluation of the optimal diet (506).”

What the sources say

• Not checked yetcites [506] Hughes, 2019, The role of the gut microbiome in predicting response to diet and the development of precision nutrition models. Part II: results, Adv Nutr source

In the paper

“In a human intervention study, network complexity analysis revealed that in nonresponders the negative interactions between microbial species increased after the intervention, meaning that more species competed for the same substrate, whereas in responders the positive interactions between species and the complexity of interactions increased after the intervention (70).”

What the sources say

• Not checked yetcites [70] Kovatcheva-Datchary, 2015, Dietary fiber-induced improvement in glucose metabolism is associated with increased abundance of Prevotella, Cell Metab source

In the paper

“Moreover, although there is some evidence for the use of probiotics as supplements, manipulating the microbiota through diet might be more feasible in the longer term and an economically cheaper solution than probiotic supplementation.”

In the paper

“The authors not only showed that GF status or antibiotic treatment abolished the antiseizure effect of the ketogenic diet, but fecal transplant of a microbiota induced by the ketogenic diet also elicited seizure protection.”

What the sources say

• Not checked yetcites [341] Olson, 2018, The gut microbiota mediates the anti-seizure effects of the ketogenic diet, Cell source

In the paper

“While the evidence from intervention studies in humans is limited, the existing data consistently support increasing the intake and variety of plant foods and reducing or eliminating ultraprocessed foods.”

In the paper

“Thereby, the missing microbes do not necessarily have to be supplied by probiotic supplements, but could be consumed through food products containing beneficial bacteria, such as fermented foods.”

In the paper

“Likewise, dietary studies in animal models may not always be translatable to human populations as animal diet formulations used in the studies often provide doses that are outside of the daily intake in human populations, so that the translational capacity of these studies should be considered.”