Gut & Microbiome
butyrylated high-amylose starch (HAMSB) delivers butyrate
In plain terms: Can butyrylated starch carry the healthy fat butyrate to the gut?
Strong support Gut & Microbiome 🔬 Includes disconfirming
RefutedContestedStrong support
consensus score 0.79
Yes, it reliably delivers butyrate to the colon, but baking weakens this and no health benefit is proven yet.
📅 Last reviewed: 2026-07-15 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Human trials (RCT / n-of-1)
MechanismIn-vitroAnimalObservationalRCTMeta-analysis
How the studies fall
16 support 0 contradict 2 tested null 2 mixed · 20 sources, 16 independent groups
What the evidence shows
Esterified butyrate on high-amylose starch (HAMSB) survives small-intestinal passage and releases butyrate in the human colon — a real food-grade delivery format, and inulin-propionate ester was successfully baked into a bread roll with retained effect. BUT cooking/baking degrades the butyrylation advantage, and no human glycemic-outcome RCT exists yet: delivery proven, metabolic benefit not.
The evidence (21)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Nielsen TS, Bendiks Z, Thomsen B, Wright ME, Theil PK, Scherer BL, Marco ML 2019 · International journal of molecular sciences | animal | supports | moderate | Rodent (rats on high-protein meat diet): HAMSB diet substantially increased fecal butyrate concentration and pool compared with HAMS, HAPS, and control diets. |
| J Abell GC, Christophersen CT, McOrist AL, Clarke JM 2011 · Br J Nutr | animal | supports | moderate | HAMSB increased distal-colon butyrate and propionate vs low-RS starch in rats, shifting faecal microbiota. |
| Zhou Y, Xie L, Schröder J, Schuster IS, Nakai M, Sun G, Sun YBY, Mariño E, Degli-Esposti MA, Marques FZ, Grubman A, Polo JM, Mackay CR 2023 · The Journal of neuroscience : the official journal of the Society for Neuroscience | animal | supports | moderate | Rodent (5xFAD Alzheimer's mouse model): diets supplemented with high acetate/butyrate-yielding starch (HAMSAB) delayed cognitive decline, used as the delivery vehicle for colonic SCFA including butyrate. |
| Bajka BH, Topping DL, Cobiac L, Clarke JM 2006 · (rat) | animal | supports | moderate | RAT HAMSB resists amylolysis raises colonic/portal butyrate; cooking lowers caecal butyrate. ANIMAL |
| Toden S, Lockett TJ, Topping DL, Scherer BL, Watson EJ, Southwood JG, Clarke JM 2014 · Cancer Biol Ther | animal | supports | moderate | Increasing dietary HAMSB dose-dependently raised large-bowel and portal butyrate pools/concentrations in rats. |
| McOrist AL, Miller RB, Bird AR, Keogh JB, Noakes M, Topping DL, Conlon MA 2011 · J Nutr | RCT | supports | moderate | High-resistant-starch diet usually increased faecal butyrate concentration/excretion in healthy adults (wide inter-individual variation). |
| Cheng J, Zhou J 2024 · Frontiers in nutrition | observational | supports | moderate | Narrative review synthesizing human trials: HAMSB is 68% digestible and ~60% of attached butyrate is absorbed by the colon; three clinical trials consistently show HAMSB-linked shifts in fecal microbial profile alongside butyrate delivery. |
| Hald S, Schioldan AG, Moore ME, Dige A, Lærke HN, Agnholt J, Bach Knudsen KE, Hermansen K, Marco ML, Gregersen S, Dahlerup JF 2016 · PLoS One | RCT | tested-null | moderate | Arabinoxylan+resistant-starch diet raised faecal total SCFA, acetate and butyrate vs Western diet in metabolic-syndrome adults. |
| Clarke JM, Topping DL, Bird AR, Young GP, Cobiac L 2008 · Carcinogenesis | animal | supports | moderate | Rats fed HAMSB had higher large-bowel and portal-plasma butyrate than RS alone or tributyrin. |
| Le Leu RK, Winter JM, Christophersen CT, Young GP, Humphreys KJ, Hu Y, Gratz SW, Miller RB, Topping DL, Bird AR, Conlon MA 2015 · Br J Nutr | RCT | supports | high | 40g/d HAMSB with red meat raised human stool SCFA >20% and altered microbiota, confirming colonic butyrate delivery in humans. |
| Nielsen TS, Canibe N, Larsen FH 2018 · Foods (Basel, Switzerland) | in-vitro | mixed | moderate | In-vitro fermentation model: organocatalytically butyrylated maize/potato starches were characterized by NMR; increasing degree of substitution (butyrylation) paradoxically lowered in-vitro fermentation capability, i.e., did not deliver mor |
| Gill PA, Muir JG, Gibson PR, van Zelm MC 2022 · Am J Clin Nutr | RCT | mixed | moderate | Independent RCT: dietary resistant/fermentable starch raised colonic and peripheral-blood SCFA (incl. butyrate) in healthy humans. |
| Bajka BH, Clarke JM, Cobiac L, Topping DL 2008 · Carcinogenesis | animal | supports | moderate | 20% HAMSB doubled large-bowel digesta butyrate vs HAMS in rats; raised hepatic portal butyrate, indicating colonic delivery. |
| Humphreys KJ, Conlon MA, Young GP, Topping DL, Hu Y, Winter JM, Bird AR, Cobiac L, Kennedy NA, Michael MZ, Le Leu RK 2014 · Cancer prevention research (Philadelphia, Pa.) | RCT | supports | high | Human (randomized crossover, 23 volunteers): fecal butyrate increased with the high-red-meat + HAMSB (40 g/day) diet compared to high-red-meat alone. |
| West NP, Christophersen CT, Pyne DB, Cripps AW, Conlon MA, Topping DL, Kang S, McSweeney CS, Fricker PA, Aguirre D, Clarke JM 2013 · Exerc Immunol Rev | RCT | supports | moderate | HAMSB ingestion in healthy active adults raised fecal/colonic butyrate concentration vs control starch; limited immune effects. |
| Byrne CS, Chambers ES, Preston T, Tedford C, Brignardello J, Garcia-Perez I, Holmes E, Wallis GA, Morrison DJ, Frost GS 2019 · (RCT) | RCT | tested-null | moderate | Inulin-propionate ester baked into a bread roll retained the appetite effect |
| Ni D et al 2025 · medRxiv | RCT | supports | moderate | Human (food-allergic children on peanut OIT, RCT sub-study): HAMSB supplementation transiently increased fecal SCFA production including butyrate and propionate over 1 year vs low-amylose starch control. |
| Clarke JM, Topping DL, Christophersen CT, Bird AR, Lange K, Saunders I, Cobiac L 2011 · (human ileostomy) | RCT | supports | high | HUMAN crossover n=16 cooked HAMSB delivered ~57% esterified butyrate to colon; fecal butyrate up vs HAMS |
| Pedersen SS, Prause M, Sørensen C, Størling J, Moritz T, Mariño E, Billestrup N 2023 · International journal of molecular sciences | animal | supports | high | Rodent (db/db diabetic mice): HAMSB-fed mice had 8-fold higher fecal butyrate concentration compared to control-diet-fed mice, alongside improved glucose metabolism. |
| Xu Q, Guo M, Wang H, Liu H, Wei Y, Wang X, Mackay CR, Wang Q 2024 · International journal of molecular sciences | animal | supports | moderate | Rodent (mouse acute alcoholic liver injury model): HAMSB supplementation was compared with oral sodium butyrate and was superior for alleviating liver injury, consistent with effective colonic butyrate yield from the starch vehicle. |
| Bell KJ, Saad S, Tillett BJ, McGuire HM, Bordbar S, Yap YA, Nguyen LT, Wilkins MR, Corley S, Brodie S, Duong S, Wright CJ, Twigg S, de St Groth BF, Harrison LC, Mackay CR, Gurzov EN, Hamilton-Williams EE, Mariño E 2022 · Microbiome | observational | supports | moderate | Human (single-arm pilot, adults with type 1 diabetes): 6 weeks of HAMSAB supplementation increased concentrations of acetate, propionate, and butyrate in both stools and plasma. |
Disagree, or know a study we missed?
We grade by evidence, not opinions. The way to weigh in is to point us to a study we haven't cited (check the evidence table above first), or to flag a problem with one we have. Every submission is reviewed; if it holds up, the grade updates and shows in Science Changes Its Mind.
Opens a short form. You'll sign in with Google so submissions are tied to a real account — we don't display your identity, and we only accept a link we can verify (PubMed, DOI, ClinicalTrials.gov).
Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.