Medium- And Long-chain Triacylglycerols Research Articles

Medium-chain fatty acid-containing dietary oil alleviates the depression-like behaviour in mice exposed to stress due to chronic forced swimming

Antidepressant-like effects of medium-chain fatty acid-containing dietary oil were examined by using mice forced to swim. This stress loading induced features typical for depression such as depressive symptoms and decreased the ratio of phosphorylated (p) extracellular signal-regulated kinases (ERK)1/2 to ERK1/2 in the hippocampus, demonstrating that our animal model prepared in mice was comparable to the general models using rats. Test diets containing structured medium- and long-chain triacylglycerols (MLCTs) and/or long-chain triacylglycerols (LCTs) as test oils and tap water were given freely during the stress period. Consequently, the intake of MLCTs resulted in a significant reduction in the immobility time in the forced swim test. Moreover, the ratio of pERK1/2 to ERK1/2 in the hippocampus was significantly higher in mice fed the MLCT diet than in those fed the LCT one. These results are the first evidence showing that MLCTs have a preventive effect against forced swimming-induced depression-like symptoms.

Health Benefits, Enzymatic Production, and Application of Medium‐ and Long‐Chain Triacylglycerol (MLCT) in Food Industries: A Review

Medium- and long-chain triacylglycerol (MLCT) is a modified lipid containing medium- chain (C6-C12) and long-chain fatty acids (C14-C24) in the same triacylglycerol (TAG) molecule. It can be produced either through enzymatic (with 1,3 specific or nonspecific enzyme) or chemical methods. The specialty of this structured lipid is that it is metabolized differently compared to conventional fats and oils, which can lead to a reduction of fat accumulation in the body. Therefore, it can be used for obesity management. It also contains nutritional properties that can be used to treat metabolic problems. This review will discuss on the health benefits of MLCT, its production methods especially via enzymatic processes and its applications in food industries.

Dietary intake of medium- and long-chain triacylglycerols ameliorates insulin resistance in rats fed a high-fat diet

Objective Excessive accumulation of visceral fat is strongly associated with insulin resistance. The present investigation examined the effects of dietary intake of medium- and long-chain triacylglycerols (MLCTs), which have been shown to induce significantly lower visceral fat accumulation in rats and humans, on high-fat diet–induced obesity and insulin resistance in rats. These effects were then compared with those observed in long-chain triacylglycerol (LCT)-fed rats. Methods After an 8-wk feeding of a high-fat diet, which induced severe whole-body insulin resistance, male Sprague-Dawley rats were fed a standard diet containing LCTs or MLCTs for 6 wk. After the dietary treatment, an oral glucose tolerance test was performed. Results Although body weight and total intra-abdominal fat mass did not differ between the two groups, mesenteric fat weight in the MLCT-fed group was significantly lower than that in the LCT group ( P < 0.05). The increase in plasma insulin concentrations, but not in glucose, after glucose administration (area under the curve) was significantly smaller in the MLCT group than in the LCT group ( P < 0.01) and was significantly associated with mesenteric fat weight ( P < 0.05). MLCT-fed rats had significantly higher plasma adiponectin concentrations compared with LCT rats ( P < 0.05). Adiponectin concentrations were negatively correlated with the area under the curve for plasma insulin ( P < 0.05) and tended to be inversely related to mesenteric fat weight ( P = 0.08). Conclusion These results suggest that dietary intake of MLCTs may improve insulin resistance in rats fed a high-fat diet, at least in part through increased adiponectin concentrations caused by a lower mesenteric fat mass.

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.

Relationship between textural properties and sensory qualities of cookies made from medium‐ and long‐chain triacylglycerol‐enriched margarines

This study aims to investigate the textural properties and sensory qualities of cookies made from medium- and long-chain triacylglycerol (MLCT)-enriched margarines. Margarine with formulations of MLCT:palm olein:palm stearin, 60:30:10 and 70:20:10, were selected to produce cookies. The textural properties of cookies were determined using a texture analyser. Quantitative descriptive analysis (QDA) and acceptance test were carried out to describe the attributes and to evaluate the degree of liking of cookies, respectively. Cookies made from MLCT-enriched margarines showed high values for hardness, fracturability, but also for cohesiveness and adhesiveness. Trained panelists rated the cookies made from MLCT-enriched margarines to be lower as compared to those made from commercial margarine for most of QDA attributes. However, cookies made from MOS 603010 and commercial margarines were scored similarly (P > 0.05) for all acceptance test attributes. Overall acceptability was found to be highly and negatively correlated for hardness, fracturability and cohesiveness (R(2) > 0.90). Principal component analysis showed that the taste attribute of cookies and the % solid fat content of margarine at 35 degrees C highly influenced the overall quality of the cookies. Cookies made from MLCT-enriched margarines were not successfully produced. However, the findings obtained provide new perspectives in the production of low-calorie bakery fat.

THERMAL AND VISCOSITY PROPERTIES OF MEDIUM‐ AND LONG‐CHAIN TRIACYLGLYCEROL BLENDS

ABSTRACT The physical properties of medium‐ and long‐chain triacylglycerol (MLCT) blends were characterized in this study. Blending MLCT oil with either palm olein or soybean oil changed the distribution of fatty acid groups, the crystallization and melting behavior of oil samples, and oil cloudiness. The crystallization and melting curves of both palm olein‐ and soybean‐based MLCT blends showed that the peaks shift to different transition temperatures depending on the percent of MLCT oil added. Viscosity analysis revealed that the oil viscosity was dependent on the temperature and triacylglycerol composition of the oil samples. Blending MLCT oil with either 50% palm olein or 50% soybean oil could assist in preventing crystal growth for the first 8 h of storage at 5 and 0C, respectively. PRACTICAL APPLICATIONSIn this study, the physical properties of medium‐ and long‐chain triacylglycerols (MLCTs) and MLCT‐blended oils were determined. Under an appropriate dietary regime, consumption of MLCT has been shown to reduce body weight and blood hypertriglyceridemic. Knowledge about the viscosity of MLCT and MLCT‐blended oils is important for process design and the transportation of fats and oils products. Moreover, this study attempted to produce clear MLCT‐blended oil as there is an important consideration for oil sold in plastic containers or glass bottles to be crystal clear. The findings from this study provide useful information for the application of MLCT‐blended oils in various food products such as frying oil.

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.

Physicochemical Properties and Sensory Attributes of Medium- and Long-Chain Triacylglycerols (MLCT)-Enriched Bakery Shortening

Six binary formulations of medium- and long-chain triacylglycerols (MLCT) fat and palm stearin and four ternary formulations of MLCT fat, palm stearin, and palm olein were produced. MLCT fat and palm stearin were mixed in ranges of 40–90% with 10% increments (w/w), while for the ternary formulations, 10% and 20% palm olein were substituted to palm stearin in MS 46 and MS 55 formulations. The solid fat content (SFC) by pulsed nuclear magnetic resonance and heating profiles using differential scanning calorimeter of these formulations were determined. Results obtained from SFC and heating profiles found that all the formulations melted completely at 55 °C. The high complete melting temperature is due to the stearic acid content in MLCT fat. Generally, increasing % MLCT fat (40–90%) in the formulations lowers the SFC curves at the measured temperatures (0–60 °C). The binary samples of MS 73, MS 82, and MS 91 showed SFC between 15% and 25% at room temperature (25 °C), which indicated that these formulations were suitable for shortening production. As the production cost of MLCT fat is high (approximately USD 3/kg), an attempt to reduce the proportion of MLCT fat in the shortening formulations was done by developing the ternary formulations. Shortenings formulated with 40:40:20 (MSO 442), 50:40:10 (MSO 541), and 50:30:20 (MSO 532) of MLCT fat/palm stearin/palm olein formulations had similar SFC% at 25 °C, and they were subsequently chosen to produce shortening. Using multivariate analysis, taste attribute showed positively and highly correlated to the melting temperature and SFC at 25 °C of the MLCT-enriched shortenings. In acceptance test, high correlation (R 2 = 0.98) was only found on cakes made from MSO 442 and MSO 541 shortenings. Both untrained and trained panelists rated the Madeira cakes made from MSO 532 shortening the highest for overall acceptability.

Consumption of medium- and long-chain triacylglycerols decreases body fat and blood triglyceride in Chinese hypertriglyceridemic subjects

To investigate the effects of medium- and long-chain triacylglycerol (MLCT) on blood triglyceride (TG) in Chinese hypertriglyceridemic subjects. A double-blind controlled clinical trial was carried out, in which 112 subjects with hypertriglyceridemia were randomly divided into two dietary oil groups: (1) long-chain triacylglycerol (LCT) and (2) MLCT. All subjects were requested to ingest fixed energy and to continue their normal activity levels, and to consume LCT or MLCT oil at 25-30 g daily during the study period. Anthropometric measurements of body weight, body mass index (BMI), body fat, body fat percentage, waist and hip circumference (WC and HC), areas of subcutaneous and visceral fat by computed tomography scanning and blood biochemical markers were measured at the beginning and end of the study. There were 50 and 51 subjects left in LCT and MLCT groups, respectively. There were no significant differences in daily intake of energy, protein, fat and carbohydrate, as well as the daily physical activity between the two groups during the study. After 8 weeks, MLCT group showed a significant decrease in body weight, BMI, WC, HC, ratio of WC and HC, body fat, body fat percentage and subcutaneous fat when compared with the initial values. The decrease in body weight, BMI, WC, body fat and subcutaneous and visceral fat was significantly greater in MLCT group than that in the LCT group. Furthermore, the serum concentrations of TG in MLCT group were significantly lower than those in the LCT group. Consumption of MLCT may reduce body weight, body fat and blood TG in hypertriglyceridemic subjects under an appropriate dietary regime.

Oxidative stability of palm‐ and soybean‐based medium‐ and long‐chain triacylglycerol (MLCT) oil blends

AbstractBACKGROUND: Medium‐ and long‐chain triacylglyerols (MLCT) enzymatically esterified using Lipozyme RM IM lipase has very low oxidative stability as it does not contain any antioxidants. The aim of this work was to study the ability of various antioxidants to increase the oxidative stability of palm‐ and soybean‐based MLCT blends which assist to bring up the oxidative stability of both MLCT blends. In this study, the effectiveness of rosemary extracts, sage extracts, tert‐butylhydroquinone (TBHQ) and mixtures of tert‐butyl‐4‐hydroxyanisole (BHA) and tert‐butyl‐p‐hydroxytoluene (BHT) in protecting against oxidation of various MLCT blends was investigated.RESULTS: Blending of MLCT oil with either palm olein or soybean oil improved its smoke point values and oxidative stability. TBHQ addition to both palm‐ and soybean‐based MLCT blends increased oxidative stability. Combination of BHA and BHT showed no significant improvement (P &gt; 0.05) in ability to protect blends from oxidation compared to natural antioxidants such as sage or rosemary extracts.CONCLUSION: Blended oils with 500 g kg−1 MLCT and 500 g kg−1 palm olein (MP5) were the most suitable for use at high temperature based on the fatty acid composition of the MLCT blends, which subsequently had an effect on thermal oxidative stability. In general, addition of either natural or synthetic antioxidant assisted in improving the antioxidative strength of both MLCT blends. MLCT blends with added TBHQ showed the highest thermal oxidative stability among the antioxidants used. Copyright © 2008 Society of Chemical Industry

Rheological properties, oxidative stability and sensory evaluation of enzymatically synthesized medium‐ and long‐chain triacylglycerol‐based salad dressings

AbstractThe rheological properties of various oil‐based salad dressings were investigated. The shear rate‐shear stress study based on Power Law's model indicated pseudoplastic fluid behaviors of dressings prepared in this study. Soybean‐ and medium‐ and long‐chain triacylglycerols (MLCT)‐based dressings treated with different antioxidants showed similar rheological behaviors based on the changes in the storage modulus, loss modulus, viscosity profile and loss tangent in the frequency, amplitude and temperature sweep study. The time‐dependent study revealed similar thixotrophic properties between soybean‐ and MLCT‐based dressings. Addition of synthetic or natural antioxidants reduced the rate of oil deterioration in oil‐in‐water emulsion as a function of time. No significant differences (p &gt;0.05) in hydrolytic reaction of all dressing systems were observed throughout the 3 months of storage at 20 °C. Quantitative descriptive analysis using trained panelists revealed no significant differences (p &gt;0.05) either in salad oils or salad dressings except for MLCT‐based oils/dressings treated with oleoresin sage extracts, which showed darker and stronger odor intensity than other oil systems. Nevertheless, the overall quality of the physical appearance and organoleptic acceptability showed no significant differences (p &gt;0.05) in all systems, indicating that MLCT‐based blends can be used as healthy functional oils to replace soybean oil in food dressing applications.

Deep Frying Performance of Enzymatically Synthesized Palm-Based Medium- and Long-Chain Triacylglycerols (MLCT) Oil Blends

The main aim of this work was to assess the frying strength of the enzymatically synthesized palm-based medium- and long-chain triacylglycerols (MLCT) oil with the aid of different antioxidants under deep-frying conditions. Palm-based MLCT oil in the presence of synthetic or natural antioxidants showed significantly better (P 0.05) in the saturated/unsaturated fatty acids ratio across frying periods indicated good oxidative stability of the palm-based MLCT oil. Due to the polarity of medium- and long-chain triacylglycerols in palm-based MLCT oil, total polar compounds determination may not be a suitable oil quality measures. Sensory evaluation of fried chips showed no significant differences (P > 0.05) between chips fried in RBD palm olein and palm-based MLCT oil over the 3-month storage period.

Enzymatic Synthesis of Medium- and Long-Chain Triacylglycerols (MLCT): Optimization of Process Parameters Using Response Surface Methodology

The main objective of this study was to understand the effects and relationship amongst four factors, which are reaction temperature, reaction time, enzyme load, and substrate mole ratio with the purpose of producing healthy functional cooking oil for long-term dietary treatment. Lipozyme RM IM lipase-catalyzed esterification of medium- and long-chain triacylglycerols (MLCT) from glycerol and mixtures of capric and oleic acid was optimized using response surface methodology (RSM) with a five-level, four-factorial design. Reaction temperature, reaction time, and substrate mole ratio strongly affected MLCT synthesis (P < 0.01). However, enzyme load did not have a significant (P > 0.01) effect on MLCT yield. Comparison between predicted and experimental value from central composite rotatable design optimization procedures revealed good correlation, implying that the reduced cubic polynomial model with backward elimination statistically expressed the percent MLCT yield obtained. The optimum MLCT yield was 59.76% by using 10 wt% enzyme load, reaction temperature of 70°C, reaction time of 14 h, and substrate mole ratio of 3.5:1. Experiments to confirm the predicted results using the optimal parameters showed an MLCT yield of 56.35% (n = 2). The choice on the types of fatty acids used in MLCT optimization work greatly influenced the physical and chemical properties of MLCT oil produced. The refined MLCT oil characteristics study showed this oil is suitable to be used for cooking/frying purposes as a high-value added product.

The application of medium-chain fatty acids: edible oil with a suppressing effect on body fat accumulation.

The bulk of fatty acids found in our diets consists of long-chain fatty acids (LCFA), which are molecules containing 12 or more carbon atoms. In contrast, medium-chain fatty acids (MCFA) are composed of 8-10 carbon atoms, and are found in palm kernel oil, among other types of foods. MCFA have attracted attention as being part of a healthy diet, because they are absorbed directly into the portal vein, transported rapidly to the liver for beta-oxidation, and thus increase diet-induced thermogenesis. In contrast, long-chain triacylglycerols are absorbed via the intestinal lymphatic ducts and transported by chylomicrons through the thoracic duct into the systemic circulation. Because medium-chain triacylglycerols (MCT) containing solely MCFA have a few disadvantages when used for deep frying, we have developed a new kind of triacylglycerol product: medium- and long-chain triacylglycerol (MLCT). MLCT is produced by lipase-catalyzed enzymatic transesterification. Long-term clinical trials have demonstrated that MLCT and MCT result in less body fat accumulation in humans. MLCT oil has been approved as FOSHU (Food for Specified Health Use) for use as cooking oil with a suppressing effect on body fat accumulation.

Medium‐chain fatty acids – Nutritional function and application to cooking oil

AbstractMedium‐chain fatty acids, which are saturated fatty acids composed of 8–10 carbons, have unique nutritional characteristics different from those of long‐chain fatty acids. Medium‐chain triacylglycerol (MCT) is more readily digested and absorbed than long‐chain triacylglycerol (LCT), and easily utilized as energy. The use of MCT as an edible oil is limited because it has a low smoking point and easily foams during deep‐frying like lauric acid does. Medium‐ and long‐chain triacylglycerol (MLCT) prepared by transesterification between MCT and LCT has a higher smoking point and reduced foaming property. MLCT oil has been shown to result in less body fat accumulation in animal and human studies. It has been approved as a food for specified health use (FOSHU) and widely sold in Japan as a cooking oil less likely to lead to body fat 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.

Safety evaluation of a medium- and long-chain triacylglycerol oil produced from medium-chain triacylglycerols and edible vegetable oil

To reduce the incorporation of dietary lipids into adipose tissue, modified fats and oils have been developed, such as medium-chain triacylglycerols (MCT). Typical dietary lipids from vegetable oils, termed long-chain triacylglycerols (LCT), are degraded by salivary, intestinal and pancreatic lipases into two fatty acids and a monoacyl glycerol; whereas, MCT are degraded by the same enzymes into three fatty acids and the simple glycerol backbone. Medium-chain fatty acids (MCFA) are readily absorbed from the small intestine directly into the bloodstream and transported to the liver for hepatic metabolism, while long-chain fatty acids (LCFA) are incorporated into chylomicrons and enter the lymphatic system. MCFA are readily broken down to carbon dioxide and two-carbon fragments, while LCFA are re-esterified to triacylglycerols and either metabolized for energy or stored in adipose tissue. Therefore, consumption of MCT decreases the incorporation of fatty acids into adipose tissue. However, MCT have technological disadvantages precluding their use in many food applications. A possible resolution is the manufacture and use of a triacylglycerol containing both LCT and MCT, termed medium- and long-chain triacylglycerol (MLCT). This manuscript describes studies performed for the safety evaluation of a MLCT oil enzymatically produced from MCT and edible vegetable oil (containing LCT), by a transesterification process. The approximate fatty acid composition of this MLCT consists of caprylic acid (9.7%), capric acid (3.3%), palmitic acid (3.8%), stearic acid (1.7%), oleic acid (51.2%), linoleic acid (18.4%), linolenic acid (9.0%), and other fatty acids (2.9%). The approximate percentages of long (L) and medium (M) fatty acids in the triacylglyerols are as follows: L, L, L (55.1%), L, L, M (35.2%), L, M, M (9.1%), and M, M, M (0.6%). The studies included: (1) acute study in rats (LD 50 > 5000 mg/kg); (2) 6 week repeat-dose safety study via dietary administration to rats (NOAEL of 3500 mg/kg/day), (3) in vitro genotoxicity studies using Salmonella typhimurium and Escherichia coli (negative at 5000 mg/plate), and (4) a four-week, placebo-controlled, double blind, human clinical trial utilizing 20 test subjects (no effects at 42 g MLCT/day). These data are corroborated by other studies published in the peer-reviewed literature on analogous MLCTs.

Effect of Randomly Interesterified Triacylglycerols Containing Medium- and Long-Chain Fatty Acids on Energy Expenditure and Hepatic Fatty Acid Metabolism in Rats

In our previous studies, medium- and long-chain triacylglycerols (MLCT), randomly interesterified triacylglycerols containing medium-chain and long-chain fatty acids in the same glycerol molecule, significantly reduced body fat accumulation in humans and rats. To clarify mechanism(s) for this effect of MLCT, we measured energy expenditure and hepatic fatty acid metabolism in rats by comparison with long-chain triacylglycerols (LCT) or medium-chain triacylglycerols (MCT). MLCT, compared with LCT, showed significantly lower body fat accumulation, higher 24-h energy expenditure and acyl-CoA dehydrogenase activity measured using octanoyl-CoA as a substrate, and similar lipogenic activity. MCT, compared with LCT, showed significantly higher energy expenditure, but fat accumulation was comparable. Additionally, MCT exhibited significantly higher lipogenic activity than the other oils. These data suggest that enhancement of energy expenditure and medium-chain fatty acids (MCFA) oxidation without activating de novo lipogenesis are responsible at least for the lower body fat accumulation in rats fed MLCT. The activation of hepatic lipogenesis by excessive intake of MCFA might counteract their preventive effects on body fat accumulation.

Effects of structured medium- and long-chain triacylglycerols in diets with various levels of fat on body fat accumulation in rats.

The effects of structured medium- and long-chain triacylglycerols (MLCT) in diets containing 50-200 g fat/kg on body fat accumulation were compared with those of long-chain triacylglycerols (LCT) in rats. In rats fed ad libitum, weights of intra-abdominal adipose tissues and carcass fat contents were significantly smaller (P<0.05) in rats fed the 150-200 g MLCT/kg diet than in rats fed 150-200 g LCT/kg diet. Serum and liver triacylglycerol contents were significantly greater (P<0.05) in rats fed 200 g MLCT/kg diet, as were hepatic capacities of citrate synthase and cytochrome oxidase (P<0.05). The effects of MLCT on body fat were also examined in adult rats fed a limited amount of food (approximately 50 % of ad libitum intake). Reduction of body fat deposition during the food restriction was the same between in LCT and MLCT groups. These results suggest that accumulation of body fat was less efficient during long-term feeding of MLCT than LCT in rats fed high-fat diets ad libitum. The effect of MLCT on body fat might be influenced by the dietary fat content or by energy sufficiency.