Table 2.
Studies examining effects of acute MCT oil supplementation on various outcomes
| Study | Participant (n, sex) | Condition | Type & dose of MCT | Exercise intervention | Result | Outcome* |
|---|---|---|---|---|---|---|
| Angus et al. (2000)9 | Elite cyclists (8, men) | MCT+CHO CHO Placebo |
(71% C8: 23% C10); 6% CHO solution w/ 4.2% MCT solution | 100-km TT | No differences were seen when including MCT in a CHO solution compared to CHO alone; however, MCT+CHO and CHO alone were significantly different from placebo. | O2 consumption = ↔ HR = ↔ RER = ↔ FO = ↔ CHOO = ↔ Lactate = ↔ Glucose = ↔ TT times = ↔ |
| Décombaz et al. (1983)24 | Healthy individuals (12, men) | MCT+caseinate CHO+caseinate |
(NS); 25 g MCT | Cycle 1-H at 60% VO2max | Ketone concentration increased when taking MCT. | RER = ↔ FO = ↔ CHOO = ↔ Lactate = ↔ Glucose = ↔ Ketones = ↑ Glycerol = ↑ |
| Goedecke et al. (1999)23 | Endurance cyclists (9, men) | MCT+CHO HMCT+CHO CHO |
(NS); 10% CHO+1.72% MCT; 10% CHO+3.44% MCT solution | Cycle 2-H at 63% VO2max followed by a 40-km TT | MCT ingestion raised ketone concentrations (BOHB) with increasing dose. | RER = ↔ FO = ↔ CHOO = ↔ Lactate = ↔ Glucose = ↔ Ketones = ↑ Glycerol = ↔ avg cycling speed = ↔ |
| Goedecke et al. (2005)25 | Endurance cyclists (8, men) | MCT+CHO CHO |
(NS); 32 g MCT+ (4.3% MCT+10% CHO solution during exercise) | Cycle 270 minutes at 50% PPO, interspersed with 75 kJ sprints at 60-minute intervals, followed by a 200-kJ TTE | Hourly sprint and TT times were significantly slower in MCT group than CHO; an increase in HR after 1-H of exercise was seen in MCT+CHO group. | O2 consumption = ↔ HR = ↑ RER = ↔ FO = ↔ CHOO = ↔ TTE = ↑ |
| Horowitz et al. (2000)26 | Endurance cyclists (7, men) | MCT+CHO CHO |
(99% C10); ~25 g MCT+0.72 g sucrose/kg | Cycle 30 minutes at 84% VO2max | An increase in ketone concentrations (BOHB) was seen in the MCT group and was greater during exercise. | O2 consumption = ↔ HR = ↔ RER = ↔ FO = ↔ CHOO = ↔ Lactate = ↔ Glucose = ↔ Ketones = ↑ Glycerol = ↔ |
| Ivy et al. (1980)27 | Well-trained individuals (10, men) | MCT LCT CHO Nothing |
(NS); 30 g MCT | Cycle at ~80 RPM (n = 6); exercise on treadmill at 70% VO2max (n = 4) | Serum ketone concentration rose only in the MCT group; effects of MCT consumption did not differ from those of CHO and LCT. | HR = ↔ RER = ↔ FO = ↔ CHOO = ↔ Glucose = ↔ Ketones = ↑ Glycerol = ↔ |
| Jeukendrup et al. (1995)28 | Endurance cyclists (8, men) | EQ MCT+CHO MCT+CHO MCT CHO |
(99% C8); 29 g MCT; EQ MCT+CHO | Cycle 180 minutes at 50% Wmax (57% VO2max) | A significant increase in lactate was seen at 180 minutes in those taking MCT alone. | RER = ↔ FO = ↑ CHOO = ↓ Lactate = ↑ Ketones = ↑ Glycerol = ↔ |
| Jeukendrup et al. (1996)10 | Elite cyclists (8, Men) | LG: MCT+CHO HG: MCT+CHO LG: CHO HG: CHO |
(99% C8); 26.6 g MCT; EQ MCT+CHO | Cycle 90 minutes at 50% Wmax | Ketone concentrations rose when taking MCT regardless of LG or HG group. | RER = ↔ FO = ↔ CHOO = ↔ Glucose = ↔ Ketones = ↑ Glycerol = ↔ |
| Jeukendrup et al. (1996)11 | Endurance trained athletes (9, men) | MCT+CHO MCT+HCHO CHO Nothing |
(99% C8); equicaloric suspension CHO+29 g MCT; 150 g CHO+29 g MCT | Cycle 180 minutes at 50% Wmax (57% VO2max) | MCT ingestion increased total ketone concentrations. | RER = ↔ FO = ↔ CHOO = ↔ Glucose = ↔ Lactate = ↔ Ketones = ↑ Glycerol = ↔ |
| Jeukendrup et al. (1998)12 | Endurance cyclists (7, men) | MCT+CHO MCT CHO Water |
(99% C8); 85 g MCT; 85 g MCT+170 g CHO | Cycle 2-H at 60% VO2max followed by a 15-minute TT | TT times increased, and avg work rate was lower when consuming MCT; mean HR was lower when taking MCT alone; RER was lower during 2nd hour of exercise when consuming MCT alone. | HR = ↓ RER = ↓ FO = ↔ CHOO = ↔ Lactate = ↔ Glucose = ↓ Ketones = ↑ Glycerol = ↔ avg work rate = ↓ TT times = ↑ |
| Massicotte et al. (1992)13 | Healthy individuals (6, men) | MCT CHO Water |
(NS); 25 g MCT | Cycle 2-H between 62%–68% VO2max | MCT ingestion increased endogenous fat oxidation rate from 0–60 minutes of exercise and at 0–120 minutes of exercise; ketone concentrations were higher when taking MCT. | RER = ↔ FO = ↑ CHOO = ↔ Glucose = ↔ Ketones = ↑ |
| Van Zyl et al. (1996)15 | Endurance cyclists (6, men) | MCT+CHO MCT CHO |
(NS); 4.3% MCT emulsion; 4.3% MCT+10% CHO | Cycle 2-H at 60% VO2max followed by a 40-km TT | MCT+CHO showed faster 40-km TT+avg cycling speed; MCT alone had slowest TT+cycle speed; ketone concentration was higher in MCT alone, but MCT+CHO produced had a significant increase; MCT+ CHO and MCT alone showed decreased lactate and CHO concentrations. | CHOO = ↓ Lactate = ↓ Glucose = ↔ Ketones = ↑ Glycerol = ↑ TT times = ↓ avg cycling speed = ↑ |
| Vistisen et al. (2003)16 | Endurance cyclists (7, men) | MLM+CHO CHO |
(Pure C8+LCT mixture) | Cycle 3-H at 55% VO2max followed by 800-kJ TTE | RER was lower during the first hour of cycling; however, after 2-H, no differences were seen. | RER = ↓ Lactate = ↔ Glucose = ↔ TTE = ↔ RPE = ↔ |
| Chronic Use | ||||||
| Misell et al. (2001)29 | Endurance runners (12, men) | MCT LCT |
(6% < C8: 67% C8: 23% C10: 4% > C10); 30 g MCT | VO2max; 30 minutes later, run on treadmill for 30 minutes at 85% VO2max followed by a reduction to 75% VO2max until exhaustion | RER was significantly different at 15 minutes of exercise; however, there were no differences before 15 minutes. | O2 consumption = ↔ RER = ↔ Lactate = ↔ Glucose = ↔ Glycerol = ↔ Ketones = ↔ Body weight = ↔ TT times = ↔ |
| Ööpik et al. (2001)30 | Endurance runners (7, men) | MCT LCT |
(NS); ~35 g MCT | VO2max; TTE measured when running at a range of 73.2%–85.5% (80.3% ± 4.6%) of VO2max | MCT ingestion caused an increase in ketone concentration. | Hematocrit = ↔ Hemoglobin = ↔ Lactate = ↔ Glucose = ↔ Glycerol = ↑ Ketones = ↑ TTE = ↔ |
*Outcome symbol: ↔, no significant difference; ↑, a significant increase (P<0.05); ↓, a significant decrease (P<0.05).
MCT, medium-chain triglyceride; CHO, carbohydrate; TT, time trial; HR, heart rate; RER, respiratory exchange ratio; FO, fat oxidation; CHOO, carbohydrate oxidation; NS, not specified; VO2max, maximal oxygen consumption; HMCT, high medium-chain triglyceride; BOHB, beta-hydroxy-butyrate; avg, average; PPO, peak power output; TTE, time to exhaustion; LCT, long-chain triglyceride; RPM, rotations per minute; EQ, equicaloric; Wmax, maximum wattage; LG, low glycogen; HG, high glycogen; MLM, mixture of medium-chain and long-chain triglycerides; RPE, rate of perceived exertion.