phenomenon · claim-type · cross-domain-transfer · mechanism · claim-relation · replication-status · limitation — grounded in the full text| phenomenon | SCFA produced by saccharolytic fermentation in the colon act on gut epithelium, liver and peripheral tissues along a falling concentration gradient— “There is a strong biological gradient for each SCFA from the gut lumen to the periphery which leads to differing cell and tissue SCFA exposure” | |
| claim-type | mechanism— “These observations suggest that the roles of SCFA should be considered in each cell or tissue type within this biological gradient. The interplay between epithelial utilization and integrity, splanchnic utilization and peripheral availability requires delineation to determine whether increased production of all SCFA, or selective increases in… | |
| method — evidence | — “Thus translating the fiber supplementation rates from animal experiments, a daily fiber supplementation in the range 20.9 – 83.7 g/d for men and 16.3 – 65.3 g/d of dietary fiber would be broadly comparable with the 5 – 20% w/w diet loadings used in animal studies.” | |
| object of study — evidence | — “Short chain fatty acids (SCFA) are the primary end-products of fermentation of non-digestible carbohydrates (NDC) that become available to the gut microbiota. They represent the major flow of carbon from the diet, through the microbiome to the host.” | |
| research question — evidence | — “_Is the microbiome a passive substrate-degrading system or are signaling molecules actively involved in microbiome-host “crosstalk”?_ Undoubtedly the answer to this quandary is yes, the molecules produced through microbiota activity provide important regulatory signals to the host and in the “-omics” revolution, metabolomics is a key enabling… | |
| contribution — evidence | — “The field has been hampered by a lack of methodology to measure SCFA production directly in human studies, although recent work suggests that stable isotope techniques may hold promise. 18 Observations in humans have largely relied on the measurement of stool SCFA output, although it is unclear whether stool SCFA output is a suitable proxy… | |
| transfer | from animal nutrition: dry matter intake, a livestock-nutrition unit, used to convert rodent dietary fibre loadings into a comparable human daily intake— “Animal studies which use dietary fiber supplementation to manipulate colonic SCFA tend to use relatively high fiber supplementation; 5 – 20% w/w NDC in animal dry matter intake (DMI).” | transfers[0] |
| mechanism | butyrate raises intestinal barrier integrity by increasing claudin-1 and ZO-1 expression and redistributing occludin - the tight junction proteins— “Of the SCFA produced in the colon, butyrate appears to be the most important regulator of TJP and has been shown to enhance intestinal barrier function through increased expression of claudin-1 and Zonula Occludens-1 (ZO-1) and occludin redistribution; proteins which are critical components of the tight junction assembly.” | mechanisms[0] |
| mechanism | in the liver propionate is gluconeogenic while acetate and butyrate are lipogenic, so the propionate:acetate ratio determines how much colonic carbon reaches lipid stores— “In the liver, propionate is gluconeogenic while acetate and butyrate are lipogenic.” | mechanisms[1] |
| mechanism | butyrate is the preferred fuel of the colonocyte and the gut epithelium is where it is sequestered - the paper's own reason for the steep epithelial step in the gradient— “It is well established that SCFA, and butyrate in particular, are important substrates for maintaining the colonic epithelium. Butyrate is the preferred fuel utilised by coloncytes and the primary site of butyrate sequestration in the body is the gut epithelium.” | mechanisms[2] |
| mechanism | THE PAPER NAMES ITS OWN MECHANISM'S EXCEPTION IN THE NEXT SENTENCE: the `butyrate paradox` - proliferation in healthy colonocytes, apoptosis in transformed ones - is followed immediately by a mouse model where butyrate fuels hyper-proliferation in MSH2-deficient cells and enhances tumour formation— “However, in a mouse model of colorectal cancer, butyrate appears to fuel hyper-proliferation in… | mechanisms[3] |
| critiques | the animal SCFA literature, on the ground that its fibre loadings translate to 20.9-83.7 g/d for men against a habitual UK intake of 14.7 g/d | claim_relations[0] |
| critiques | the human SCFA literature, on the ground that it rests on association rather than intervention and on stool output rather than production Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | claim_relations[1] |
| extends | the seminal sudden-death-victim measurements of SCFA across the gut epithelium and liver, which this review turns into a general principle about tissue exposure Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | claim_relations[2] |
| sense | SCFA - AS DEFINED HERE: the primary end-products of fermentation of non-digestible carbohydrate that reach the gut microbiota, and the major flow of carbon from the diet through the microbiome to the host Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | senses[0] |
| sense | SCFA production - the quantity every claim in this literature is about, and the one with no method behind it in humans; STOOL SCFA OUTPUT is what is measured and its adequacy as a proxy is explicitly unsettled Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | senses[1] |
| sense | the biological gradient - SCFA concentration falling from gut lumen to periphery, so `an SCFA effect` is not one quantity but a different exposure in every tissue Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | senses[2] |
| control | the animal fibre dose is converted to a human-equivalent intake using national survey data before the animal findings are used — failed Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. — rules out an effect produced only by a dose no human diet reaches being read as a statement about human physiology Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | controls[0] |
| control | circulating SCFA concentrations in oral-feeding animal models are compared with the human normal range — failed Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. — rules out a concentration that is pathological in humans being treated as the physiological range Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | controls[1] |
| control | the size of colonic propionate production is set against endogenous glucose production before propionate is called gluconeogenic at the whole-body level — held Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. — rules out a real but negligible flux being reported as a contributor to glucose homeostasis Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | controls[2] |
| weight | the animal SCFA literature, on the ground that its fibre loadings translate to 20.9-83.7 g/d for men against a habitual UK intake of 14.7 g/d — 0.95 Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | claim_relations[0] |
| weight | the human SCFA literature, on the ground that it rests on association rather than intervention and on stool output rather than production — 0.95 Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | claim_relations[1] |
| weight | the seminal sudden-death-victim measurements of SCFA across the gut epithelium and liver, which this review turns into a general principle about tissue exposure — 0.9 Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | claim_relations[2] |
| relation | cross-talk —same-as→ molecular signaling — the review names the intricate molecular signalling between gut microbiome and host 'cross-talk', in quotation marks, and uses the metaphor thereafter Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concept_edges[0] |
| weight | cross-talk —same-as→ molecular signaling — 0.9 Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concept_edges[0] |
| differs in (stated by the tagger, no quotation) | propionate —distinct-from→ acetate — metabolic fate in the liver: gluconeogenesis against lipogenesis | concept_edges[1] |
| relation | propionate —distinct-from→ acetate — in the liver they have OPPOSITE fates - propionate gluconeogenic, acetate lipogenic - so the two cannot be pooled as 'SCFA' for any metabolic claim Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concept_edges[1] |
| weight | propionate —distinct-from→ acetate — 0.95 Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concept_edges[1] |
| audit | energy harvesting —contrasted-with→ high-fiber diets — Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the span says the energy-harvesting hypothesis is not supported by evidence that high-fiber diets protect against weight gain; contrasted-with is loose. Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concept_edges[2] |
| differs in (stated by the tagger, no quotation) | energy harvesting —contrasted-with→ high-fiber diets — direction of the predicted effect of fermentation on body weight | concept_edges[2] |
| relation | energy harvesting —contrasted-with→ high-fiber diets — the energy-harvesting hypothesis predicts SCFA add calories in the obese; the observational human evidence runs the other way and the paper says so Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concept_edges[2] |
| weight | energy harvesting —contrasted-with→ high-fiber diets — 0.9 Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concept_edges[2] |
| relation | butyrate —causes→ intestinal barrier function — butyrate enhances barrier function through increased claudin-1 and ZO-1 expression and occludin redistribution Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concept_edges[3] |
| weight | butyrate —causes→ intestinal barrier function — 0.9 Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concept_edges[3] |
| outcome | control — failed Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | controls[0] |
| outcome | control — failed Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | controls[1] |
| outcome | control — held Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | controls[2] |
| limitation | THE FIELD HAS NO METHOD TO MEASURE ITS PRIMARY VARIABLE: SCFA production cannot be measured directly in humans, and it is unclear whether stool SCFA output - what is measured instead - is a suitable proxy for luminal production Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | limitations[0] |
| limitation | the appetite-regulation mechanism cannot be attributed to SCFA at all until such a method exists, which the authors state as a condition rather than a caveat Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | limitations[1] |
| limitation | the human evidence is associative rather than interventional, so high-level evidence from controlled trials is largely lacking Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | limitations[2] |
| limitation | there is insufficient evidence to inform any evidence-based clinical or public health intervention using SCFA formulations - stated in the paper's own introduction Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | limitations[3] |
| limitation | whether oral SCFA feeding in animals, which produces circulating concentrations far above the human normal range, is an appropriate model for human SCFA physiology requires further validation Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | limitations[4] |
| limitation | whether SCFA play an important role in mucosal maintenance and integrity in HUMAN models is stated by the authors as urgently needing further work Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | limitations[5] |
finding · quantity · variable · definition · key-term — grounded in the full text| finding | Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.findings[0] |
| finding | Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.findings[1] |
| finding | Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.findings[2] |
| finding | Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.findings[3] |
| finding | Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.findings[4] |
| finding | Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.findings[5] |
| quantity | g/d, mean dietary fibre intake for UK men aged 19-64, against a 20.9-83.7 g/d animal-equivalent supplementation range Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[0] |
| quantity | mg/kg/day of propionate for an 85 kg human, against endogenous glucose production of 2.2 mg/kg/min of which about 50% is gluconeogenic Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[1] |
| quantity | per cent - the estimated gut-microbiota-derived share of whole-body acetate flux, with the effect of different NDCs on that share largely unknown Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[2] |
| quantity | per cent reduction in serum free fatty acids after rectal infusion of acetate and propionate Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[3] |
| quantity | g/d of supplemented fibre, about 5-10% of dry matter intake, needed to induce appetite-regulation effects in the human studies that found them Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.quantities[4] |
| variable | dietary fiber supplementation Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.variables[0] |
| variable | tissue Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.variables[1] |
| variable | stool SCFA output Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.variables[2] |
| definition | short chain fatty acids (SCFA) Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.definitions[0] |
| definition | butyrate paradox Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.definitions[1] |
| definition | “energy harvesting” hypothesis Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.definitions[2] |
| concept | SCFA — not defined in this paper's own words; the four major fermentation end-products - formate, acetate, propionate, butyrate - treated collectively as one signalling class despite differing tissue exposures Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[0] |
| concept | butyrate — not defined in this paper's own words; the SCFA sequestered at the gut epithelium, preferred fuel of the colonocyte, and the one with a named paradox attached to it Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[1] |
| concept | propionate — not defined in this paper's own words; the gluconeogenic SCFA, taken up at the liver, whose daily production is small against endogenous glucose production Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[2] |
| concept | biological gradient — not defined in this paper's own words; the falling SCFA concentration from lumen to periphery, which makes tissue the unit of any SCFA claim Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[3] |
| concept | cross-talk — not defined in this paper's own words; the field's own metaphor for the molecular signalling between gut microbiome and host - a name the review adopts in quotation marks and never defines further Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[4] |
| concept | molecular signaling — not defined in this paper's own words; the exchange of small molecules between microbiome and host that 'cross-talk' names Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[5] |
| concept | acetate — not defined in this paper's own words; the lipogenic SCFA, the one that reaches the periphery, and the only one whose circulating concentration is not toxic at millimolar levels Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[6] |
| concept | intestinal barrier function — not defined in this paper's own words; the tight-junction-mediated integrity of the epithelium, indexed here by claudin-1 and ZO-1 expression and occludin redistribution Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[7] |
| concept | high-fiber diets — not defined in this paper's own words; the habitual dietary exposure the observational literature reports on, as against the supplemented loadings used in animal work Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[8] |
| concept | energy harvesting — not defined in this paper's own words; the proposal that SCFA contribute additional calories in the obese - advanced by a number of studies and refused here on observational grounds Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[9] |
| normal range | Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[0] |
| claim type | mechanism — a second reading reaching the same value; recorded: mechanism Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | alternatives.claim_type |
| method | review — a second reading DIFFERING from the recorded value; recorded: review Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | alternatives.method |
| phenomenon | how short chain fatty acids are formed by gut microbial fermentation and how they act on host metabolism — a second reading DIFFERING from the recorded value; recorded: SCFA produced by saccharolytic fermentation in the colon act on gut epithelium, liver and peripheral tissues along a fal Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | alternatives.phenomenon |
When we have changed our mind. Some entries in the table begin with a word in capitals and the reason for it. EVIDENCE CORRECTED — the finding still stands, but we had quoted the wrong sentence from the paper, and the quotation has been replaced with the right one. RETRACTED — the entry itself was wrong; it stays on the page, marked, with the reason, rather than being deleted. WITHDRAWN AND REPLACED — the entry was wrong, and a corrected version of it appears in the entries below. Each mark carries its own reason, in brackets, because the reasons differ from one entry to the next. An entry we have WITHDRAWN is removed from this page and kept in the record, with its reason. A line reading Audit and a date is a later re-reading of the entry against its whole sentence: DOUBTFUL means it was kept, and the reason says what is loose about it. Quotation marks inside the tagger's sentence. Where a tag is the tagger's own sentence, a phrase in quotation marks inside it is borrowed from the paper — the tagger's wording around it is not. The paper's own sentence is the evidence quote for that row; on this page it is withheld with the article, and the article is at its publisher. Nothing inside quotation marks anywhere on this page is ours: if it is quoted, it is the paper's. Whose words a concept carries. A concept entry records a term the paper itself uses, so the term, the sense given for it, and its evidence are the paper's own words, quoted where the paper fixes them. This is the opposite of a sense entry in the tag table, which is the tagger's sentence about how the paper uses a term. Where a concept entry could not be grounded in the paper's words, the entry says so on its own row.
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