Chemistry:Short-chain fatty acid
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 | C 2H 4O 2 |
CH 3COOH |
60.05 |  |
| C3:0 | Propionic acid | Propanoic acid | Propionate | Propanoate | C 3H 6O 2 |
CH 3CH 2COOH |
74.08 |  |
| C4:0 | Butyric acid | Butanoic acid | Butyrate | Butanoate | C 4H 8O 2 |
CH 3(CH 2) 2COOH |
88.11 |  |
| C4:0 | Isobutyric acid | 2-Methylpropanoic acid | Isobutyrate | 2-Methylpropanoate | C 4H 8O 2 |
(CH 3) 2CHCOOH |
88.11 |  |
| C5:0 | Valeric acid | Pentanoic acid | Valerate | Pentanoate | C 5H 10O 2 |
CH 3(CH 2) 3COOH |
102.13 |  |
| C5:0 | Isovaleric acid | 3-Methylbutanoic acid | Isovalerate | 3-Methylbutanoate | C 5H 10O 2 |
(CH 3) 2CHCH 2COOH |
102.13 |  |
| C5:0 | 2-Methylbutyric acid | 2-Methylbutyric acid | 2-Methylbutanoate | 2-Methylbutanoate | C 5H 10O 2 |
CH 3CH 2CH(CH 3)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
- 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
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Nutritional Biochemistry (2nd ed.). Academic Press. 1999. p. 320. ISBN 978-0121348366. https://books.google.com/books?id=n2fgyhDUaTEC&pg=PA320. Retrieved December 21, 2012.
- ↑ 2.0 2.1 2.2 "Short-chain fatty acids in control of body weight and insulin sensitivity". Nature Reviews. Endocrinology 11 (10): 577–591. October 2015. doi:10.1038/nrendo.2015.128. PMID 26260141.
- ↑ 3.0 3.1 "Colonic health: fermentation and short chain fatty acids". Journal of Clinical Gastroenterology 40 (3): 235–243. March 2006. doi:10.1097/00004836-200603000-00015. PMID 16633129.
- ↑ 4.0 4.1 "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. March 2020. doi:10.1093/ajcn/nqz322. PMID 31927581.
- ↑ "Biochemistry of Glycerolipids and Formation of Chylomicrons". Fat Digestion and Absorption. The American Oil Chemists Society. 2000. p. 163. ISBN 978-1893997127. https://books.google.com/books?id=t5FNYzGEUDsC&pg=PA163. Retrieved December 21, 2012.
- ↑ "The role of short chain fatty acids in appetite regulation and energy homeostasis". International Journal of Obesity 39 (9): 1331–1338. September 2015. doi:10.1038/ijo.2015.84. PMID 25971927.
- ↑ "Microbial metabolites and immune regulation: New targets for major depressive disorder". Brain, Behavior, & Immunity - Health 9: 100169. December 2020. doi:10.1016/j.bbih.2020.100169. PMID 34589904.
- ↑ "Deficiency of Prebiotic Fiber and Insufficient Signaling Through Gut Metabolite-Sensing Receptors Leads to Cardiovascular Disease". Circulation 141 (17): 1393–1403. April 2020. doi:10.1161/CIRCULATIONAHA.119.043081. PMID 32093510.
- ↑ "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. March 2017. doi:10.1161/CIRCULATIONAHA.116.024545. PMID 27927713.
- ↑ "Short-Chain Fatty Acid Propionate Protects From Hypertensive Cardiovascular Damage". Circulation 139 (11): 1407–1421. March 2019. doi:10.1161/CIRCULATIONAHA.118.036652. PMID 30586752.
- ↑ "Imbalance of gut microbiome and intestinal epithelial barrier dysfunction in patients with high blood pressure". Clinical Science 132 (6): 701–718. March 2018. doi:10.1042/CS20180087. PMID 29507058.
- ↑ "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. July 2021. doi:10.1186/s13063-021-05468-2. PMID 34315522.
- ↑ "Short-chain fatty acids: ready for prime time?". Nutrition in Clinical Practice 21 (4): 351–366. August 2006. doi:10.1177/0115426506021004351. PMID 16870803.
Further reading
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