{{short description|Medium-chain fatty acids}} {{use dmy dates|cs1-dates=ly|date=January 2024}} {{cs1 config|name-list-style=vanc|display-authors=6}} [[File:Medium-chain Triglyceride Structural Formula V.2.svg|thumb|250px|Typical example of a medium-chain triglyceride, containing three medium chain fatty acids ([[caprylic acid]] in blue and [[capric acid]] in red)]] A '''medium-chain triglyceride''' (MCT) is a [[triglyceride]] with two or three [[fatty acid]]s having an [[aliphatic compound|aliphatic]] tail of 6–12 carbon atoms, i.e. a '''medium-chain fatty acid''' (MCFA). Rich food sources for commercial extraction of MCTs include [[palm kernel oil]] and [[coconut oil]].
==Sources of MCTs== MCTs are found in palm kernel oil and coconut oil and can be separated by [[fractionation]].<ref>{{Cite book | vauthors = Gervajio GC |chapter=Fatty Acids and Derivatives from Coconut Oil |doi=10.1002/047167849X.bio039 |title=Bailey's Industrial Oil and Fat Products |year=2005 |isbn=978-0471678496 |s2cid=98315975}}</ref><ref>{{cite book | vauthors = Raymond ER, Kent JA | chapter = Soap, Fatty Acids, and Synthetic Detergents |title=Riegel's Handbook of Industrial Chemistry | edition = 10th |chapter-url= https://books.google.com/books?id=j3AwCqvqIzEC&pg=PA1100 |access-date=20 October 2012 |year=2003 |publisher=Springer |isbn=978-0-387-23816-6 |pages=1100–1117 | doi = 10.1007/0-387-23816-6_27 }}</ref> They can also be produced by [[Interesterified fat|interesterification]].<ref>{{cite journal | vauthors = Mensink RP, Sanders TA, Baer DJ, Hayes KC, Howles PN, Marangoni A | title = The Increasing Use of Interesterified Lipids in the Food Supply and Their Effects on Health Parameters | journal = Advances in Nutrition | volume = 7 | issue = 4 | pages = 719–729 | date = July 2016 | pmid = 27422506 | pmc = 4942855 | doi = 10.3945/an.115.009662 | doi-access = free }}</ref> Retail MCT powder is MCT oil embedded in starch and thus contains carbohydrates in addition to fats. It is manufactured by spray drying.{{Citation needed|date=January 2022|reason=Oil does not evaporate. How can it be spray dried?}}
==List of MCFAs== <!--not a list of MCTs--> {| class="wikitable" |- ! rowspan="2" | Lipid<br />number ! colspan="2" | Name ! colspan="2" | Salt/ester name ! colspan="2" | Formula ! rowspan="2" | Mass<br /><small>(g/mol)</small> ! rowspan="2" | Appearance ! rowspan="2" | Chemical<br />structure |- ! Common ! Systematic ! Common ! Systematic ! Molecular ! Structural |- | C6:0 | [[Hexanoic acid|Caproic acid]] | Hexanoic acid | Caproate | Hexanoate | {{chem2|auto=1|C6H12O2}} | {{chem2|CH3(CH2)4COOH}} | 116.16 | Oily liquid | [[File:Caproic acid acsv.svg|76px|right]] |- | C8:0 | [[Caprylic acid]] | Octanoic acid | Caprylate | Octanoate | {{chem2|C8H16O2}} | {{chem2|CH3(CH2)6COOH}} | 144.21 | Oily liquid | [[File:Caprylic acid.svg|96px|right]] |- | C10:0 | [[Decanoic acid|Capric acid]] | Decanoic acid | Caprate | Decanoate | {{chem2|C10H20O2}} | {{chem2|CH3(CH2)8COOH}} | 172.26 | White crystals | [[File:Decanoic acid acsv.svg|116px|right]] |- | C12:0 | [[Lauric acid]] | Dodecanoic acid | Laurate | Dodecanoate | {{chem2|C12H24O2}} | {{chem2|CH3(CH2)10COOH}} | 200.32 | White powder | [[File:Lauric acid.svg|136px|right]] |}
With regard to MCFAs, apart from the above listed straight chain (unbranched chain) fatty acids, side chain (branched chain) fatty acids also exist.<ref name=pmid23177536>{{cite journal | vauthors = Chang P, Terbach N, Plant N, Chen PE, Walker MC, Williams RS | title = Seizure control by ketogenic diet-associated medium chain fatty acids | journal = Neuropharmacology | volume = 69 | pages = 105–114 | date = June 2013 | pmid = 23177536 | pmc = 3625124 | doi = 10.1016/j.neuropharm.2012.11.004 }}</ref>
== Applications ==
=== Calorie restriction === A 2020 [[systematic review]] and [[meta-analysis]] by ''[[Critical Reviews in Food Science and Nutrition]]'' supported evidence that MCT decreases subsequent energy intake compared to [[long-chain triglycerides]] (LCTs). Despite this, it does not appear to affect appetite, and thus the authors stated that further research is required to elucidate the mechanism by which this occurs.<ref>{{cite journal | vauthors = Maher T, Clegg ME | title = A systematic review and meta-analysis of medium-chain triglycerides effects on acute satiety and food intake | journal = Critical Reviews in Food Science and Nutrition | volume = 61 | issue = 4 | pages = 636–648 | date = 2021 | pmid = 32212947 | doi = 10.1080/10408398.2020.1742654 | url = http://centaur.reading.ac.uk/89667/5/CRIFSAN.%20MCT%20and%20satiety%20-%20A%20systematic%20review%2010.3.20.pdf | access-date = 2021-06-24 | url-status = live | s2cid = 214683227 | archive-url = https://web.archive.org/web/20210715214001/http://centaur.reading.ac.uk/89667/5/CRIFSAN.%20MCT%20and%20satiety%20-%20A%20systematic%20review%2010.3.20.pdf | archive-date = 2021-07-15 }}</ref>
=== Dietary relevance === Molecular weight analysis<ref>{{cite journal | vauthors = Breckenridge WC, Kuksis A | title = Molecular weight distributions of milk fat triglycerides from seven species | journal = Journal of Lipid Research | volume = 8 | issue = 5 | pages = 473–478 | date = September 1967 | pmid = 6049672 | doi = 10.1016/S0022-2275(20)38904-5 | doi-access = free }}</ref> of milk from different species showed that while milk fats from all studied species were ''primarily'' composed of long-chain fatty acids (16 and 18 carbons long), approximately 10–20% of the fatty acids in milk from [[horse]]s, [[cow]]s, [[sheep]], and [[goat]]s were medium-chain fatty acids.
Some studies have shown that MCTs can help in the process of excess calorie burning, thus weight loss.<ref>{{cite journal | vauthors = St-Onge MP, Jones PJ | title = Greater rise in fat oxidation with medium-chain triglyceride consumption relative to long-chain triglyceride is associated with lower initial body weight and greater loss of subcutaneous adipose tissue | journal = International Journal of Obesity and Related Metabolic Disorders | volume = 27 | issue = 12 | pages = 1565–1571 | date = December 2003 | pmid = 12975635 | doi = 10.1038/sj.ijo.0802467 | s2cid = 21935201 | doi-access = free }}</ref><ref name="B_Martena">{{cite journal| title=Medium-chain triglycerides | vauthors = Marten B, Pfeuffer M, Schrezenmeir J |journal= International Dairy Journal |volume=16| issue=11| year=2006| pages=1374–1382 |doi=10.1016/j.idairyj.2006.06.015 |pmc=2020023}}</ref><ref>{{cite journal | vauthors = St-Onge MP, Jones PJ | title = Physiological effects of medium-chain triglycerides: potential agents in the prevention of obesity | journal = The Journal of Nutrition | volume = 132 | issue = 3 | pages = 329–332 | date = March 2002 | pmid = 11880549 | doi = 10.1093/jn/132.3.329 | doi-access = free }}</ref> MCTs are also seen as promoting fat oxidation and reduced food intake.<ref name=Clegg>{{cite journal | vauthors = Clegg ME | title = Medium-chain triglycerides are advantageous in promoting weight loss although not beneficial to exercise performance | journal = International Journal of Food Sciences and Nutrition | volume = 61 | issue = 7 | pages = 653–679 | date = November 2010 | pmid = 20367215 | doi = 10.3109/09637481003702114 | s2cid = 6128370 }}</ref> MCTs have been recommended by some endurance athletes and the [[bodybuilding]] community.<ref>{{cite book |author1=Talbott, Shawn M. |author2=Hughes, Kerry |year=2006 |title=The Health Professional's Guide to Dietary Supplements |publisher=Lippincott Williams & Wilkins |pages=[https://books.google.com/books?id=hV2_TdmoDo8C&pg=PA60 60–63] |isbn=978-0781746724}}</ref> While health benefits from MCTs seem to occur, a link to improved exercise performance is inconclusive.<ref name=Clegg /> A number of studies back the use of MCT oil as a weight loss supplement, but these claims are not without conflict, as about an equal number found inconclusive results.<ref>{{cite journal | vauthors = Rego Costa AC, Rosado EL, Soares-Mota M | title = Influence of the dietary intake of medium chain triglycerides on body composition, energy expenditure and satiety: a systematic review | journal = Nutricion Hospitalaria | volume = 27 | issue = 1 | pages = 103–108 | year = 2012 | pmid = 22566308 | doi = 10.3305/nh.2012.27.1.5369 }}</ref>
===Pharmaceutical relevance===
MCTs can be used in solutions, liquid suspensions and lipid-based drug delivery systems for emulsions, self-emulsifying drug delivery systems,<ref>{{cite journal | vauthors = Banov D, Liu Y, Ip K, Shan A, Vu C, Zdoryk O, Bassani AS, Carvalho M | title = Analysis of the Physical Characteristics of an Anhydrous Vehicle for Compounded Pediatric Oral Liquids | journal = Pharmaceutics | volume = 15 | issue = 11 | pages = 2642 | date = November 2023 | pmid = 38004620 | pmc = 10674891 | doi = 10.3390/pharmaceutics15112642 | doi-access = free }}</ref> creams, ointments, gels and foams as well as suppositories. MCTs are also suitable for use as solvent and liquid oily lubricant in soft gels. Brand names of pharma-grade MCT include Kollisolv MCT 70.<ref>{{Cite web |title=Kollisolv MCT 70 |url=https://pharma.basf.com/products/kollisolv-mct-70 |access-date=2021-04-27 |website=pharmaceutical.basf.com |language=en}}</ref>
=== Medical relevance === MCTs passively diffuse from the [[GI tract]] to the [[hepatic portal system]] (longer fatty acids are absorbed into the [[lymphatic system]]) without requirement for modification like [[long-chain fatty acids]] or very-long-chain fatty acids. In addition, MCTs do not require [[bile salt]]s for absorption. Patients who have [[malnutrition]], [[malabsorption]] or particular [[fatty-acid metabolism disorder]]s are treated with MCTs because MCTs do not require energy for absorption, use, or storage.
Medium-chain triglycerides are generally considered a good biologically inert source of energy that the [[human body]] finds reasonably easy to metabolize. They have potentially beneficial attributes in protein metabolism, but may be contraindicated in some situations due to a reported tendency to induce [[ketogenesis]] and [[metabolic acidosis]].<ref>{{cite journal | vauthors = Wanten GJ, Naber AH | title = Cellular and physiological effects of medium-chain triglycerides | journal = Mini Reviews in Medicinal Chemistry | volume = 4 | issue = 8 | pages = 847–857 | date = October 2004 | pmid = 15544546 | doi = 10.2174/1389557043403503 }}</ref> However, there is other evidence demonstrating no risk of ketoacidosis or ketonemia with MCTs at levels associated with normal consumption,<ref name="B_Martena" /> and that the moderately elevated blood ketones can be an effective treatment for [[epilepsy]].<ref name=pmid23177536/>
Due to their ability to be absorbed rapidly by the body, medium-chain triglycerides have found use in the treatment of a variety of malabsorption ailments. MCT supplementation with a [[low-fat diet]] has been described as the cornerstone of treatment for [[Waldmann disease]].<ref>{{cite journal | vauthors = Vignes S, Bellanger J | title = Primary intestinal lymphangiectasia (Waldmann's disease) | journal = Orphanet Journal of Rare Diseases | volume = 3 | pages = 5 | date = February 2008 | pmid = 18294365 | pmc = 2288596 | doi = 10.1186/1750-1172-3-5 | doi-access = free | type = Free full text }}</ref> MCTs are an ingredient in some specialised [[parenteral nutrition]]al emulsions in some countries.<ref>{{cite journal | vauthors = Waitzberg DL, Torrinhas RS, Jacintho TM | title = New parenteral lipid emulsions for clinical use | journal = Journal of Parenteral and Enteral Nutrition | volume = 30 | issue = 4 | pages = 351–367 | date = July–August 2006 | pmid = 16804134 | doi = 10.1177/0148607106030004351 | s2cid = 24109426 }}</ref><ref>{{cite journal | vauthors = Krohn K, Koletzko B | title = Parenteral lipid emulsions in paediatrics | journal = Current Opinion in Clinical Nutrition and Metabolic Care | volume = 9 | issue = 3 | pages = 319–323 | date = May 2006 | pmid = 16607135 | doi = 10.1097/01.mco.0000222118.76536.ad | s2cid = 27961868 }}</ref> Studies have also shown promising results for epilepsy through the use of [[ketogenic diet]]ing.<ref name=pmid23177536/><ref>{{cite journal | vauthors = Neal EG, Cross JH | title = Efficacy of dietary treatments for epilepsy | journal = Journal of Human Nutrition and Dietetics | volume = 23 | issue = 2 | pages = 113���119 | date = April 2010 | pmid = 20487176 | doi = 10.1111/j.1365-277X.2010.01043.x }}</ref><ref>{{cite journal | vauthors = Liu YM | title = Medium-chain triglyceride (MCT) ketogenic therapy | journal = Epilepsia | volume = 49 Suppl 8 | pages = 33–36 | date = November 2008 | pmid = 19049583 | doi = 10.1111/j.1528-1167.2008.01830.x | doi-access = free }}</ref>
Orally ingested medium chain triglycerides would be very rapidly degraded by first-pass metabolism by being taken up in the liver via the [[portal vein]], and are quickly metabolized via [[coenzyme A]] intermediates through [[β-oxidation]] and the [[citric acid cycle]] to produce [[carbon dioxide]], [[acetate]] and [[ketone bodies]].<ref name=pmid23177536/> Whether the ketones [[β-hydroxybutyrate]] and [[acetone]] have direct antiseizure activity is unclear.<ref>{{cite journal | vauthors = Chang P, Augustin K, Boddum K, Williams S, Sun M, Terschak JA, Hardege JD, Chen PE, Walker MC, Williams RS | title = Seizure control by decanoic acid through direct AMPA receptor inhibition | journal = Brain | volume = 139 | issue = Pt 2 | pages = 431–443 | date = February 2016 | pmid = 26608744 | pmc = 4805082 | doi = 10.1093/brain/awv325 }}</ref><ref>{{cite journal | vauthors = Viggiano A, Pilla R, Arnold P, Monda M, D'Agostino D, Coppola G | title = Anticonvulsant properties of an oral ketone ester in a pentylenetetrazole-model of seizure | journal = Brain Research | volume = 1618 | pages = 50–54 | date = August 2015 | pmid = 26026798 | doi = 10.1016/j.brainres.2015.05.023 }}</ref><ref>{{cite journal | vauthors = Rho JM, Anderson GD, Donevan SD, White HS | title = Acetoacetate, acetone, and dibenzylamine (a contaminant in l-(+)-beta-hydroxybutyrate) exhibit direct anticonvulsant actions in vivo | journal = Epilepsia | volume = 43 | issue = 4 | pages = 358–361 | date = April 2002 | pmid = 11952765 | doi = 10.1046/j.1528-1157.2002.47901.x | s2cid = 31196417 }}</ref><ref>{{cite journal | vauthors = Ma W, Berg J, Yellen G | title = Ketogenic diet metabolites reduce firing in central neurons by opening K(ATP) channels | journal = The Journal of Neuroscience | volume = 27 | issue = 14 | pages = 3618–3625 | date = April 2007 | pmid = 17409226 | pmc = 6672398 | doi = 10.1523/JNEUROSCI.0132-07.2007 }}</ref>
=== Technical uses === MCTs are bland compared to other fats and do not generate off-notes (dissonant tastes) as quickly as LCTs. They are also more [[chemical polarity|polar]] than LCTs. Because of these attributes, they are widely used as carrier oils or solvents for flavours and oral medicines and vitamins.<ref>{{cite book | vauthors = Akoh CC |title=Handbook of Functional Lipids |publisher=Taylor & Francis |location=Washington, DC |year=2006 |isbn=978-0849321627 }}</ref>
== See also == {{Portal|Food|Chemistry}} * [[List of carboxylic acids]]<!--Relevant because MCFAs are carboxylic.--> * [[Ketogenic diet]] * [[List of saturated fatty acids]]<!--Relevant because MCFAs are saturated.-->
== References == {{reflist}}
== Further reading == {{refbegin|30em}} * {{cite journal | vauthors = Aoyama T, Nosaka N, Kasai M | title = Research on the nutritional characteristics of medium-chain fatty acids | journal = The Journal of Medical Investigation | volume = 54 | issue = 3–4 | pages = 385–388 | date = August 2007 | pmid = 17878693 | doi = 10.2152/jmi.54.385 | s2cid = 905470 | doi-access = free }} * {{cite journal | vauthors = Babayan VK | title = Medium chain triglycerides and structured lipids | journal = Lipids | volume = 22 | issue = 6 | pages = 417–420 | date = June 1987 | pmid = 3112486 | doi = 10.1007/BF02537271 | s2cid = 3942399 }} * {{cite journal | vauthors = Bach AC, Babayan VK | title = Medium-chain triglycerides: an update | journal = The American Journal of Clinical Nutrition | volume = 36 | issue = 5 | pages = 950–962 | date = November 1982 | pmid = 6814231 | doi = 10.1093/ajcn/36.5.950 }} * {{cite journal | vauthors = Hayasaka K, Numakura C, Toyota K, Kakizaki S, Watanabe H, Haga H, Takahashi H, Takahashi Y, Kaneko M, Yamakawa M, Nunoi H, Kato T, Ueno Y, Mori M | title = Medium-chain triglyceride supplementation under a low-carbohydrate formula is a promising therapy for adult-onset type II citrullinemia | journal = Molecular Genetics and Metabolism Reports | volume = 1 | pages = 42–50 | date = 2014 | pmid = 27896073 | pmc = 5121258 | doi = 10.1016/j.ymgmr.2013.12.002 }} * {{cite journal | vauthors = Heydinger JA, Nakhasi DK |year=1996 |title=Medium Chain Triacylglycerols |journal=Journal of Food Lipids |volume=3 |issue=4 |pages=251–257 |doi=10.1111/j.1745-4522.1996.tb00072.x}} * {{cite journal | vauthors = Kaunitz H | title = Medium chain triglycerides (MCT) in aging and arteriosclerosis | journal = Journal of Environmental Pathology, Toxicology and Oncology | volume = 6 | issue = 3–4 | pages = 115–121 | year = 1986 | pmid = 3519928 }} * {{cite journal | vauthors = Labarthe F, Gélinas R, Des Rosiers C | title = Medium-chain fatty acids as metabolic therapy in cardiac disease | journal = Cardiovascular Drugs and Therapy | volume = 22 | issue = 2 | pages = 97–106 | date = April 2008 | pmid = 18253821 | doi = 10.1007/s10557-008-6084-0 | s2cid = 25297875 }} * {{cite journal | vauthors = Nagao K, Yanagita T | title = Medium-chain fatty acids: functional lipids for the prevention and treatment of the metabolic syndrome | journal = Pharmacological Research | volume = 61 | issue = 3 | pages = 208–212 | date = March 2010 | pmid = 19931617 | doi = 10.1016/j.phrs.2009.11.007 }} {{refend}}
{{DEFAULTSORT:Medium-Chain Triglycerides}} [[Category:Triglycerides]] [[Category:Medical food]]