Short-chain fatty acids (SCFAs) are fatty acids of two to six carbon atoms. The SCFAs' lower limit is interpreted differently, either with one, two, three or four 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. 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. Macronutrient composition (carbohydrate, protein or fat) of diets affects circulating SCFAs. Acetate, propionate and butyrate are the three most common SCFAs. Butyrate is particularly important for colon health because it is the primary energy source for colonocytes (the epithelial cells of the colon). The liver can use acetate for energy.
SCFAs and medium-chain fatty acids are primarily absorbed through the portal vein during lipid digestion, while long-chain fatty acids are packed into chylomicrons, enter lymphatic capillaries, then transfer to the blood at the subclavian vein.
SCFAs have diverse physiological roles in body functions, affecting the production of lipids, energy, and vitamins. They may affect appetite and cardiometabolic health.
See also
- List of carboxylic acids
- Medium-chain fatty acid (MCFA), fatty acid with aliphatic tails of 6 to 12 carbons, which can form medium-chain triglycerides
- Long-chain fatty acid (LCFA), fatty acid with aliphatic tails of 13 to 21 carbons
- Very long chain fatty acid (VLCFA), fatty acid with aliphatic tails of 22 or more carbons
- Odd-chain fatty acid
References
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- ^ 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.
- ^ 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.
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- 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.
- 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.