Short-chain fatty acids (SCFAs) are fatty acids of two to six carbon atoms.[1] The SCFAs lower limit is interpreted differently, either with 1, 2, 3 or 4 carbon atoms. Derived from intestinal microbial fermentation of indigestible foods, SCFAs in human gut are acetic, propionic and butyric acid. They are the main energy source of colonocytes, making them crucial to gastrointestinal health.[1][2] SCFAs all possess varying degrees of water solubility, which distinguishes them from longer chain fatty acids that are immiscible.

List of SCFAs

Lipid number Name Salt/Ester Name Formula Mass
(g/mol) 		Diagram
Common Systematic Common Systematic Molecular Structural
C2:0 Acetic acid Ethanoic acid Acetate Ethanoate C2H4O2 CH3COOH 60.05
C3:0 Propionic acid Propanoic acid Propionate Propanoate C3H6O2 CH3CH2COOH 74.08
C4:0 Butyric acid Butanoic acid Butyrate Butanoate C4H8O2 CH3(CH2)2COOH 88.11
C4:0 Isobutyric acid 2-Methylpropanoic acid Isobutyrate 2-Methylpropanoate C4H8O2 (CH3)2CHCOOH 88.11
C5:0 Valeric acid Pentanoic acid Valerate Pentanoate C5H10O2 CH3(CH2)3COOH 102.13
C5:0 Isovaleric acid 3-Methylbutanoic acid Isovalerate 3-Methylbutanoate C5H10O2 (CH3)2CHCH2COOH 102.13
C5:0 2-Methylbutyric acid 2-Methylbutyric acid 2-Methylbutanoate 2-Methylbutanoate C5H10O2 CH3CH2CH(CH3)COOH 102.13

Functions

SCFAs are produced when dietary fiber is fermented in the colon.[1][3] Macronutrient composition (carbohydrate, protein or fat) of diets affects circulating SCFAs.[4]

Acetate, propionate and butyrate are the three most common SCFAs.[3]

SCFAs and medium-chain fatty acids are primarily absorbed through the portal vein during lipid digestion,[5] while long-chain fatty acids are packed into chylomicrons, enter lymphatic capillaries, then transfer to the blood at the subclavian vein.[1]

SCFAs have diverse physiological roles in body functions.[1][2] They can affect the production of lipids, energy and vitamins.[6] They can also affect appetite and cardiometabolic health.[4] Additionally they may have an impact on mental health and mood.[7] The three main SCFAs, acetate, propionate and butyrate, were shown to lower blood pressure in experimental models,[8][9][10][11] and clinical trials to determine their effect on hypertensive patients are underway.[12] Butyrate is particularly important for colon health because it is the primary energy source for colonocytes (the epithelial cells of the colon).[1][2] The liver can use acetate for energy.[13]

See also

References

  1. ^ a b c d e f Brody T (1999). Nutritional Biochemistry (2nd ed.). Academic Press. p. 320. ISBN 978-0121348366. Retrieved December 21, 2012.
  2. ^ a b c Canfora EE, Jocken JW, Blaak EE (October 2015). "Short-chain fatty acids in control of body weight and insulin sensitivity". Nature Reviews. Endocrinology. 11 (10): 577–591. doi:10.1038/nrendo.2015.128. PMID 26260141. S2CID 1263823.
  3. ^ a b Wong JM, de Souza R, Kendall CW, Emam A, Jenkins DJ (March 2006). "Colonic health: fermentation and short chain fatty acids". Journal of Clinical Gastroenterology. 40 (3): 235–243. doi:10.1097/00004836-200603000-00015. PMID 16633129. S2CID 46228892.
  4. ^ a b Mueller NT, Zhang M, Juraschek SP, Miller ER, Appel LJ (March 2020). "Effects of high-fiber diets enriched with carbohydrate, protein, or unsaturated fat on circulating short chain fatty acids: results from the OmniHeart randomized trial". The American Journal of Clinical Nutrition. 111 (3): 545–554. doi:10.1093/ajcn/nqz322. PMC 7049528. PMID 31927581.
  5. ^ Kuksis A (2000). "Biochemistry of Glycerolipids and Formation of Chylomicrons". In Christophe AB, DeVriese S (eds.). Fat Digestion and Absorption. The American Oil Chemists Society. p. 163. ISBN 978-1893997127. Retrieved December 21, 2012.
  6. ^ Byrne CS, Chambers ES, Morrison DJ, Frost G (September 2015). "The role of short chain fatty acids in appetite regulation and energy homeostasis". International Journal of Obesity. 39 (9): 1331–1338. doi:10.1038/ijo.2015.84. PMC 4564526. PMID 25971927.
  7. ^ Merchak A, Gaultier A (December 2020). "Microbial metabolites and immune regulation: New targets for major depressive disorder". Brain, Behavior, & Immunity - Health. 9: 100169. doi:10.1016/j.bbih.2020.100169. PMC 8474524. PMID 34589904.
  8. ^ Kaye DM, Shihata WA, Jama HA, Tsyganov K, Ziemann M, Kiriazis H, et al. (April 2020). "Deficiency of Prebiotic Fiber and Insufficient Signaling Through Gut Metabolite-Sensing Receptors Leads to Cardiovascular Disease". Circulation. 141 (17): 1393–1403. doi:10.1161/CIRCULATIONAHA.119.043081. hdl:10536/DRO/DU:30135388. PMID 32093510. S2CID 211476145.
  9. ^ Marques FZ, Nelson E, Chu PY, Horlock D, Fiedler A, Ziemann M, et al. (March 2017). "High-Fiber Diet and Acetate Supplementation Change the Gut Microbiota and Prevent the Development of Hypertension and Heart Failure in Hypertensive Mice". Circulation. 135 (10): 964–977. doi:10.1161/CIRCULATIONAHA.116.024545. hdl:10536/DRO/DU:30113061. PMID 27927713. S2CID 207639406.
  10. ^ Bartolomaeus H, Balogh A, Yakoub M, Homann S, Markó L, Höges S, et al. (March 2019). "Short-Chain Fatty Acid Propionate Protects From Hypertensive Cardiovascular Damage". Circulation. 139 (11): 1407–1421. doi:10.1161/CIRCULATIONAHA.118.036652. PMC 6416008. PMID 30586752.
  11. ^ Kim S, Goel R, Kumar A, Qi Y, Lobaton G, Hosaka K, et al. (March 2018). "Imbalance of gut microbiome and intestinal epithelial barrier dysfunction in patients with high blood pressure". Clinical Science. 132 (6): 701–718. doi:10.1042/CS20180087. PMC 5955695. PMID 29507058.
  12. ^ Rhys-Jones D, Climie RE, Gill PA, Jama HA, Head GA, Gibson PR, et al. (July 2021). "Microbial Interventions to Control and Reduce Blood Pressure in Australia (MICRoBIA): rationale and design of a double-blinded randomised cross-over placebo controlled trial". Trials. 22 (1): 496. doi:10.1186/s13063-021-05468-2. PMC 8313879. PMID 34315522.
  13. ^ Roy CC, Kien CL, Bouthillier L, Levy E (August 2006). "Short-chain fatty acids: ready for prime time?". Nutrition in Clinical Practice. 21 (4): 351–366. doi:10.1177/0115426506021004351. PMID 16870803.

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