Effect of medium-chain triglycerides supplements and walking on health-related quality of life in sedentary, healthy middle-aged, and older adults with low BMIs: a randomized, double-blind, placebo-controlled, parallel-group trial.

Introduction: To extend individuals' healthy life expectancies, the improvement of subjective health and quality of life (QOL) has been increasingly prioritized, alongside the improvement of their physical functioning. Reports have indicated that intake of medium-chain triglycerides (MCTs) benefits the physical health of older individuals requiring nursing care, and athletes, and healthy individuals. But there are few studies investigating the effects of MCTs on subjective health and QOL. The present study sought to evaluate the combined effects of 12-week MCTs supplements and moderate-intensity walking exercise on the subjective health and QOL of middle-aged and older adults aged 60-74 with low BMIs (< 24 kg/m2) and who had no exercise habits. Methods: A placebo-controlled, double-blind, parallel-group trial was conducted. Three MCTs supplement groups with different doses and fatty acid compositions were compared with a control group. The study used the SF-36v2 questionnaire to assess subjective health and health-related QOL (HRQOL). Results: The result showed significant improvements in the scores on subscales of the physical QOL, such as Physical functioning and General health, and summary scores on the mental QOL, compared to the control. Conclusion: It is estimated that the combination of continuous intake of MCTs and walking exercise may affect HRQOL and improve subjective physical and mental health in sedentary, healthy, middle-aged and older adults. Clinical trial registration: https://rctportal.niph.go.jp/s/detail/um?trial_id=UMIN000046861, UMIN000046861.

Ingestion of triglycerides containing medium- and long-chain fatty acids can increase metabolism of ingested long-chain triglycerides in overweight persons.

Introduction: Medium-chain fatty acids (MCFAs) have attracted considerable attention for preventing or improving obesity, which is a recognized risk factor for lifestyle-related diseases. Medium- and long-chain triglycerides (MLCTs) are expected to improve the metabolism of ingested long-chain triglycerides (LCTs). However, previous studies have reported mixed results. In this study, the effect of ingestion of MLCTs was evaluated on the metabolism of LCTs and compared to the ingestion of rapeseed oil (control oil). Methods: A randomized, double-blind, placebo-controlled crossover study was performed among sedentary participants with BMIs ranging from 25 below 30 kg/m2. Thirty participants were asked to ingest either 14 g of MLCTs or a control oil for 4 weeks. The metabolism of ingested LCTs was evaluated by measuring isotopically labeled carbon dioxide released by the degradation of carbon-13 (13C)-labeled LCTs. Results: Ingestion of MLCTs markedly enhanced the metabolism of ingested LCTs by comparison to the control oil. Conclusion: The findings of this study suggest that ingestion of MLCTs may enhance the metabolism of dietary LCTs through activation of ß-oxidation in liver mitochondria, which may increase the metabolic kinetics of ingested long-chain fatty acid (LCFAs). Clinical trial registration: https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000053101, identifier: UMIN000046604.

A Randomized, Double-Blind, Controlled Trial Assessing If Medium-Chain Triglycerides in Combination with Moderate-Intensity Exercise Increase Muscle Strength in Healthy Middle-Aged and Older Adults.

An adequate nutritional intake is recommended for the prevention of physical frailty and sarcopenia. In particular, medium-chain fatty acids (MCFAs) are reportedly important for muscle strength in nursing home residents. However, the effects of MCFAs on healthy adults at risk for frailty remain unknown. Hence, a randomized, placebo-controlled study was conducted to investigate the effects of 12 weeks of medium-chain triglycerides (MCTs) intake and walking on muscle mass and function in healthy, sedentary, middle-aged and older adults with a low body mass index. Three MCT intake groups with different amounts of octanoic and decanoic acid intake were compared with a control group. After 12 weeks, knee extension strength increased in all groups, with the increases in all MCT intake groups being significantly higher than those in the control group (p < 0.05). Grip strength significantly increased from baseline in the MCT 6 g/day intake group (p < 0.05). The combination of aerobic exercise and MCT intake may be effective in preventing decline in muscle strength and promoting increase in muscle strength as they can improve muscle energy production, thereby contributing to the maintenance of good health for middle-aged and older adults at high risk for frailty and sarcopenia.

Effect of Continuous Ingestion of 2 g of Medium-Chain Triglycerides on Substrate Metabolism during Low-Intensity Physical Activity.

Increasing fat burning during physical activity is thought to be an effective strategy for maintaining health and preventing lifestyle-related diseases, such as obesity and diabetes. In recent years, medium-chain triglycerides (MCTs) have gained attention as a dietary component for increasing fat-burning. However, this fat-burning effect has been unclear in people with high body mass index (BMI). Therefore, we aimed to clarify the effects of 2 g of daily ingestion of MCTs over 2 weeks on substrate oxidation during low-intensity physical activity in sedentary (i.e., with no exercise habit) subjects with a BMI from 25 (kg/m2) to less than 30, which is classified as obese in Japan. A placebo-controlled, randomized, double-blind, crossover study with a 2-week washout period was conducted. The rate of fat oxidation as well as the respiratory exchange ratio (RER) during exercise (with a cycle ergometer at a 20-watt load) were measured with a human calorimeter. MCTs ingestion significantly increased fat oxidation during physical activity and decreased RER compared to long-chain triglycerides ingestion. In conclusion, we suggest that daily ingestion of 2 g of MCTs for 2 weeks increases fat burning during daily physical activities in sedentary persons with a BMI ranging from 25 to less than 30.

Short-Term Ingestion of Medium-Chain Triglycerides Could Enhance Postprandial Consumption of Ingested Fat in Individuals with a Body Mass Index from 25 to Less than 30: A Randomized, Placebo-Controlled, Double-Blind Crossover Study.

The elimination of obesity is essential to maintaining good health. Medium-chain triglycerides (MCTs) inhibit fat accumulation. However, studies examining energy expenditure and fat oxidation with continuous ingestion of MCTs show little association with the elimination of obesity. In this study, we conducted a randomized, double-blind crossover clinical trial to investigate the effects of continuous ingestion of MCTs on postprandial energy expenditure and ingested long-chain triglycerides (LCTs) oxidation. A daily 2 g of MCTs were ingested for two weeks by sedentary participants with a body mass index (BMI) from 25 (kg/m2) to less than 30. Ingestion of a meal containing MCTs and isotopic carbon-13-labeled (13C) LCTs increased energy expenditure and consumption of diet-derived LCTs, as determined by postprandial 13C carbon dioxide excretion, compared to canola oil as the placebo control. These results indicate that continuous ingestion of MCTs could enhance postprandial degradation of diet-derived fat and energy expenditure in sedentary, overweight individuals.

Effect of Ingestion of Medium-Chain Triglycerides on Substrate Oxidation during Aerobic Exercise Could Depend on Sex Difference in Middle-Aged Sedentary Persons.

Fat oxidation (FAO) during aerobic exercise and whole-body FAO via lipid intake are thought to be important for the maintenance of health, such as the prevention of type 2 diabetes and obesity in sedentary persons in their 40s and 50s. Medium-chain triglycerides (MCTs) ingestion has been attracting attention. However, the effects of difference of sex and the composition of medium-chain fatty acids (MCFAs) are unclear, so we examined the effects of these factors on FAO during aerobic exercise. We conducted a randomized, double-blind, placebo-controlled, 3-arm, within-participants crossover trial. FAO during low- to moderate-intensity exercise was compared when octanoate-rich MCTs (C8R), decanoate-rich MCTs (C10R), or carbohydrate (control) was ingested. Three 2-week interventions were separated by two 2-week washout periods. An increase of FAO during exercise after the C8R diet was found in males, but not in females. An increase of carbohydrate oxidation (CAO) and oxygen uptake during exercise after the C10R diet was found in females, but not in males. In a pooled estimate of the effect of MCTs (C8R and C10R) in women and men, FAO increased during exercise. In conclusion, short-term ingestion of MCTs by middle-aged sedentary persons could increase FAO during aerobic exercise compared to carbohydrate ingestion, but the enhancing effect of MCTs on substrate utilization and oxygen uptake might vary, depending on sex and the composition of MCFAs.

Enhancement of Fat Oxidation during Submaximal Exercise in Sedentary Persons: Variations by Medium-Chain Fatty Acid Composition and Age Group.

Previous studies in recreational and trained athletes aged mostly in their 20s have reported that short-term ingestion of medium-chain triacylglycerols (MCT) enhances fat oxidation (FAO) during submaximal exercise. However, whether the FAO-enhancing effect of MCT with a different composition of medium-chain fatty acids (MCFA) occurs in older sedentary persons is unclear. The present study investigated the effect of MCT ingestion with different proportions of MCFA in sedentary participants in their 40's and 50's. Participants ingested 0 g of MCT (control), 6 g of octanoic acid-rich MCT (OAR), or 6 g of decanoic acid-rich MCT (DAR) for 14 days separated by a 14-day washout period in random order. Cumulative FAO (Fcv ) during submaximal, fixed, and incremental exercise was evaluated at workload from 20 W to the appearance of a ventilation threshold (VT). During the 20 W fixed-load exercise, Fcv was significantly (p < 0.05) higher in the OAR than in the control. At appearance of VT, intervention effect of power output was significantly higher in the OAR and DAR than in the control. In a subgroup analysis by age, intervention effects of maximal FAO rate and oxygen uptake in the upper age subgroup were higher in the OAR and DAR than in the control. In a pooled analysis with age subgroup and diet, the integrated pooled estimate of Fcv during submaximal exercise was significantly higher in 6 g of MCT ingestion than 0 g ingestion. Our data show that the effect of MCT might differ depending on the age group and the proportion of MCFA, while MCT could enhance FAO during submaximal exercise.

Medium-chain Triglycerides with Maltodextrin Increase Fat Oxidation during Moderate-intensity Exercise and Extend the Duration of Subsequent High-intensity Exercise.

Medium-chain triglycerides (MCT) are useful for increasing fat utilization during exercise. The highest rate of fat oxidation during submaximal exercise tends to precede the lactate threshold in untrained adults. In our previous study, blood lactate concentration was more than 4 mmol/L (onset of blood lactate) in recreational athletes during exercise at a workload corresponding to 60% peak O2 uptake (Vï½¥o2), which was below ventilation threshold. In the present study, we investigated the effect of 2 week of ingestion of food containing 6 g MCT on substrate oxidation during moderate-intensity (50% peak Vï½¥o2) exercise and high-intensity (70% peak Vï½¥o2) exercise in recreational athletes. For comparison, two experimental trials were conducted after participants had been administered isoenergic test foods (MCT-supplemented food with mainly maltodextrin-containing carbohydrate (MCT + CHO) or CHO) for 2 weeks, with a washout period between trials. Participants were instructed to perform cycle ergometer exercise at a workload corresponding to 50% peak Vï½¥o2 for 40 min followed by a workload corresponding to 70% peak Vï½¥o2 until exhaustion. Fat oxidation was significantly increased in the MCT + CHO trial (13.3 ± 2.7 g/40 min, mean ± SD, p < 0.05) during moderate-intensity exercise and the duration was extended significantly (23.5 ± 19.4 min, p < 0.05) during subsequent high-intensity exercise, compared with that observed in the CHO trial (fat oxidation; 11.7 ± 2.8 g/40 min, duration; 17.6 ± 16.1 min). In conclusion, continuous ingestion of 6 g MCT with maltodextrin could increase fat oxidation during moderate-intensity exercise and extend the duration of subsequent high-intensity exercise in recreational athletes, compared with the ingestion of isoenergic maltodextrin alone.

The change in conjugated linoleic acid concentration in blood of Japanese fed a conjugated linoleic acid diet.

Conjugated linoleic acid (CLA) is a collective term used for fatty acids with a conjugated double bond that are geometrical and positional isomers of linoleic acid. Anti-obesity and anti-cancer properties, an immunopotentiation effect, and promotion of bone formation by CLA have been shown in cell culture and animal studies. A mixture of 9c11t- and 10t12c-CLA is now used as a health food supplement after testing in clinical trials. These trials focused on improvement of lipid metabolism by CLA, whereas few studies have examined absorption and metabolism of CLA in humans. In addition, there is no report concerning absorption and metabolism of CLA in Japanese. This study was designed to examine CLA concentration in blood, the elimination rate of CLA, and metabolic differences between 9c11t-CLA and 10t12c-CLA in blood in Japanese who ingested CLA (about 2 g/d, equal weights of 9c11t-CLA and 10t12c-CLA) for 3 wk. Blood samples were collected 1 wk before the 3-wk period, on the first and last days of the period, and 1 wk after the end of the period, and the CLA concentration and distribution in blood were investigated. The CLA concentration in blood was significantly increased by CLA ingestion and reached 36 µmol/L. The CLA concentration in blood one week after the intake period was significantly lower than that at the end of CLA intake. The 10t12c-CLA level in plasma decreased faster than that of 9c11t-CLA. This suggests faster metabolism (fatty acid ß oxidation) of 10t12c-CLA compared with 9c11t-CLA.

Medium- and long-chain triacylglycerols reduce body fat and blood triacylglycerols in hypertriacylglycerolemic, overweight but not obese, Chinese individuals.

In contrast to the consumption of long-chain triacylglycerols (LCT), consumption of medium- and long-chain triacylglycerols (MLCT) reduces the body fat and blood triacylglycerols (TAG) level in hypertriacylglycerolemic Chinese individuals. These responses may be affected by BMI because of obesity-induced insulin resistance. We aimed to compare the effects of consuming MLCT or LCT on reducing body fat and blood TAG level in hypertriacylglycerolemic Chinese subjects with different ranges of BMI. Employing a double-blind, randomized and controlled protocol, 101 hypertriacylglycerolemic subjects (including 67 men and 34 women) were randomly allocated to ingest 25-30 g/day MLCT or LCT oil as the only cooking oil for 8 consecutive weeks. Anthropometric measurements of body weight, BMI, body fat, WC, HC, blood biochemical variables, and subcutaneous fat area and visceral fat area in the abdomen were measured at week 0 and 8. As compared to subjects with BMI 24-28 kg/m(2) in the LCT group, corresponding subjects in the MLCT group showed significantly greater decrease in body weight, BMI, body fat, WC, ratio of WC to HC, total fat area and subcutaneous fat area in the abdomen, as well as blood TAG and LDL-C levels at week 8. Based upon our results, consumption of MLCT oil may reduce body weight, body fat, and blood TAG and LDL-C levels in overweight hypertriacylglycerolemic Chinese subjects but may not induce these changes in normal or obese hypertriacylglycerolemic subjects.

A good response to oil with medium- and long-chain fatty acids in body fat and blood lipid profiles of male hypertriglyceridemic subjects.

A double blind clinical trial was carried out to clarify the effects of oil with medium- and long-chain triglyceride (MLCT) on body fat and blood lipid profiles in hypertriglyceridemic subjects. One-hundred-and-twelve subjects were enrolled and divided into two groups; those that consumed MLCT oil and those that consumed long-chain triglyceride (LCT) oil for 8 weeks. All subjects were requested to consume 25-30 g of the oils daily and maintain a fixed level of energy intake and exercise. Anthropometric and blood biochemical parameters were measured when the study was initiated and completed. The LCT group consisted of 50 subjects (34 men and 16 women), while the MLCT group consisted of 51 subjects (33 men and 18 women) who completed the study. Larger decreases in body weight, body mass index, waist circumference, body fat, total fat area and subcutaneous fat area in the abdomen and serum triglycerides, low-density lipoprotein cholesterol, apolipoprotein B, C2, C3 and E were observed in male subjects in the MLCT group than those in the LCT group. However, no significant differences in these parameters between the female subjects in the two groups were observed. Data from this study indicate that consumption of medium-and long-chain triglycerides can reduce body weight and body fat and improve blood lipid profiles in male hypertriglyceridemic subjects.

Chinese hypertriglycerideamic subjects of different ages responded differently to consuming oil with medium- and long-chain fatty acids.

Two groups of Chinese hypertriacylglycerolemic subjects were recruited and randomized to medium- and long-chain triacylglycerols (MLCT) oil or long-chain triacylglycerols (LCT) oil. Two subgroups were divided by age at less or more 60 years in both groups. Both oils were consumed at 25-30 g daily for 8 weeks. Anthropometry, blood biochemicals, and computed tomography (CT) scanning were done at the initial and final times. In subjects of age less than 60 years on MLCT, the body weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-hip ratio (WHR), body fat, total fat area, and subcutaneous fat area were significantly lower than those of the initial values, and the change values in these indicators and visceral fat area lowered significantly as compared with those on LCT. The levels of apoB, apoA2, apoC2, and apoC3 decreased significantly, and the change in values in the levels of triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), apoA1, apoB, apoA2, apoC2, apoC3 were significantly lower on MLCT of age under 60 years as compared with those on LCT.

Effect of ingestion of medium-chain triacylglycerols on moderate- and high-intensity exercise in recreational athletes.

Medium-chain triacylglycerols (MCT) are known to hydrolyze readily and completely to fatty acids and to be metabolized more easily by beta-oxidation than long-chain triacylglycerols (LCT). Therefore, we investigated the effect of 2 wk of ingestion of food containing a small amount (6 g) of MCT on energy metabolism during moderate-intensity exercise and high-intensity exercise in recreational athletes. For comparison, the subjects were administered food containing MCT or LCT for 14 d, and were instructed to perform cycle ergometer exercise at a workload corresponding to 60% peak O(2) uptake (VO(2)) for 40 min followed by a workload corresponding to 80% peak VO(2) until exhaustion. Blood lactate concentration, VO(2), VCO(2), and rating of perceived exertion (RPE) were measured at rest and during exercise. The exercise time to exhaustion at a workload corresponding to 80% peak VO(2) was significantly (p<0.05) longer in the MCT trial (10.2+/-7.6 min; mean+/-SD) than in the LCT trial (5.8+/-3.3 min). Blood lactate concentration and RPE during exercise were significantly (p<0.05) lower after ingestion of MCT-containing food. Fat oxidation rate was higher and carbohydrate oxidation rate was lower during exercise in the MCT trial than in the LCT trial, but the differences were not significant. These results indicate that the ingestion of MCT-containing food may suppress utilization of carbohydrate for energy production because of increased utilization of fatty acids for generating energy. In conclusion, our data suggest that short-term ingestion of food containing a small amount of MCT suppresses the increase in blood lactate concentration and RPE during moderate-intensity exercise and extends the duration of subsequent high-intensity exercise, at levels higher than those achieved by ingestion of LCT-containing food.

Combined intervention of medium-chain triacylglycerol diet and exercise reduces body fat mass and enhances energy expenditure in rats.

Previous studies indicated that a medium-chain triacylglycerol (MCT) diet could inhibit body fat accumulation. It is also well established that exercise can reduce fat mass. However, the effects of a combination of MCT diet and exercise on reduction of fat mass have not been studied. Here we examined whether MCT diet and exercise intervention exert cooperative effects on body composition. Rats were assigned to 4 groups: 1. LCT diet, control (LCT-C); 2. MCT diet, control (MCT-C); 3. LCT diet, exercise (LCT-E); 4. MCT diet, exercise (MCT-E). After the 6-wk intervention, visceral fat mass was measured by CT scan and dissection, and energy expenditure was estimated for 24 h. The value of the visceral fat mass showed a significant correlation between CT scan and dissection (r=0.995, p<0.001). Visceral fat mass in the MCT-C group was lower than that in the LCT-C group. Furthermore, the fat-lowering effects were greater in the MCT-E group than that in either intervention alone. Thus significant effects of the MCT diet and exercise on the reduction of visceral fat mass were observed. Energy expenditure was significantly higher in the MCT-E group than in the other groups. Our present findings suggest that combined intervention of MCT diet and exercise has an additive effect on reduction of visceral and subcutaneous fat accumulation, and that this effect may be partially related to increased energy expenditure. However, future studies are necessary to define the relationship between energy expenditure and fat mass accumulation.

Research on the nutritional characteristics of medium-chain fatty acids.

Medium-chain fatty acids (MCFA) have attracted attention as part of a healthy diet, because they are absorbed and transported directly into the liver via the portal vein, metabolized rapidly by beta-oxidation, and increase diet-induced thermogenesis. Because medium-chain triacylglycerols (MCT) containing only MCFA has a few weak points as frying oils, we have developed medium- and long-chain triacylglycerols (MLCT). MLCT is produced by lipase-catalyzed enzymatic transesterification. Recently, long-term clinical trials have demonstrated that MLCT and MCT result in less body fat-deposition. MLCT oil (Trade name: Healthy Resseta) is safe and can be substitute for common edible vegetable oils. Healthy Resseta has been approved as FOSHU (Food for Specified Health Use), by the Ministry of Health, Labour and Welfare of Japan in December 2002 for use as a cooking oil with a suppressing effect on body fat accumulation. Healthy Resseta is widely sold in Japan.

Dietary medium- and long-chain triacylglycerols accelerate diet-induced thermogenesis in humans.

This study investigated the effects of a liquid meal containing medium- and long-chain triacylglycerols (MLCT) on diet-induced thermogenesis (DIT) and was conducted in double-blind cross-over manner. Twenty subjects participated in this examination. The subjects consumed the liquid meal, which was made with 14 g of canola oil (LCT, long-chain triacylglycerols) or MLCT containing about 12% medium-chain fatty acids (MCFA). Oxygen consumption and carbon dioxide production were measured by indirect calorimetry. Resting energy expenditure (REE) was determined based on there parameters, applying the equation of Weir. Increase in DIT after ingesting the liquid meal with MLCT during 6h was significantly greater than with LCT (P<0.05). The results suggest that the substitution of MLCT for cooking oil is useful to control body weigh and fat in subjects.

Effect of dietary medium- and long-chain triacylglycerols (MLCT) on accumulation of body fat in healthy humans.

We investigated whether a structured medium- and long-chain triacylglycerols (MLCT) diet could decrease accumulation of body fat in healthy humans. The study was conducted under a double-blind randomized design. Ninety-three subjects participated in this study. However, 10 subjects could not consume the specified meal, and one subject wished to opt out. Consequently, the study included 82 subjects. The experimental subjects consumed the test bread, which was made with 14 g of MLCT containing 1.7 g MCFA, daily at breakfast during the study period of 12 weeks, and the control subjects consumed bread made with long-chain triacylglycerols (LCT). All subjects consumed the same standard packaged meals. Body composition parameters were body weight, total body fat and abdominal fat, and blood analyses included serum cholesterol, triacylglycerols and phospholipids. Significant decreases of body weight, the amount of body fat, subcutaneous and visceral fat were noted in the MLCT group as compared with those of the LCT group for 12 weeks (P<0.05). Furthermore, a significant decrease in serum total cholesterol was noted in the MLCT group as compared with that of the LCT group at 8 weeks (P<0.05). However, other serum parameters were not different between the MLCT and LCT groups. The results suggest that the daily intake of MLCT diet could result in a reduction in body weight and in accumulation of body fat, and, moreover, it could reduce serum total cholesterol.

Effect of medium-chain triglycerides on the postprandial triglyceride concentration in healthy men.

This study compared the serum lipid concentrations after a single dose of medium-chain triglycerides (MCT) or long-chain triglycerides (LCT) between individuals grouped according to the body mass index (BMI). Twenty-five males participated as volunteers, the test diet containing 10 g of MCT or LCT. Blood samples were collected up to 6 h after the intake of a test diets. The LCT diet resulted in significantly greater increases in areas under the curves (AUCs) for serum and chylomicron triglyceride in the BMI > or = 23 kg/m2 group than those in the BMI < 23 kg/m2 group. The magnitude of response after intake of the MCT diet by the BMI > or = 23 kg/m2 group was significantly lower than that after the LCT diet. These results suggest that, in subjects with BMI > or = 23 kg/m2, the intake of MCT is preferable to that of LCT for maintaining postprandial triglyceride at a low concentration.

Effects of margarine containing medium-chain triacylglycerols on body fat reduction in humans.

We found previously that the ingestion of margarine containing medium-chain triacylglycerols (MCT) resulted in a significant increase in postprandial thermogenesis when compared with long-chain triacylglycerols (LCT). Diets that included margarine containing MCT and LCT were compared for 12 weeks in 73 subjects to investigate the effects on body weight, body fat, areas of subcutaneous and visceral fat, serum total cholesterols, triglycerides, lipoproteins, plasma glucose, serum insulin, total ketone bodies, and the activities of aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltranspeptidase. We conducted a double-blind, controlled study and used blended rapeseed oil and soybean oil (LCT) as a comparison. Two groups ingested 2100-2400 kcal/day of energy, 65-73 g/day of total fat, and 14 g/day of test margarine (5 g/day of MCT or LCT). The subjects on the MCT diet demonstrated significant decreases in body fat weight (- 3.8 +/- 2.4 kg vs - 2.4 +/- 1.7 kg; MCT vs LCT, mean +/- SD), subcutaneous fat (- 38.2 +/- 29.9 cm(2) vs - 22.6 +/- 19.3 cm(2)), and visceral fat (- 12.2 +/- 11.2 cm(2) vs - 1.6 +/- 12.8 cm(2)) after 12 weeks. There were no clinical differences in measured blood parameters. We suggest that the postprandial increase in thermogenesis and control of postprandial triglyceride levels may explain these results.

Effects of dietary medium-chain triacylglycerols on serum lipoproteins and biochemical parameters in healthy men.

The objective of this study was to investigate effects of dietary medium-chain triacylglycerols (MCTs) on serum lipid levels, liver function, and hepatic fat accumulations in healthy men. Eleven subjects consumed 2200-2600 kcal daily, of which 70-80 g was fat; the fat included 40 g of MCTs or else 40 g of long-chain triacylglycerols (blended vegetable oil). The diet was followed for 4 weeks in this controlled double-blind study. At the end of the experiment, significant differences were not found in the concentrations of serum total cholesterol, very low density lipoprotein cholesterol, low density lipoprotein cholesterol, and high density lipoprotein cholesterol between the groups. Serum triglycerol levels were not significantly different in the groups. Adverse effects from ingestion of MCTs on liver functions, the liver-to-spleen ratio on computed tomography (an index of fatty liver), or results of blood tests were not seen. The results suggest that the long-term effects of dietary MCTs on serum cholesterol were similar to those of unsaturated fatty acids found abundantly in vegetable oil, and that consumption of MCTs in the amount of 40 g/day for a month does not cause liver fat accumulation or liver dysfunction.