Lymphatic absorption of structured triglycerides vs. physical mix in a rat model of fat malabsorption

Innovative applications of medium- and long-chain triacylglycerol in nutritional support: Current perspectives and future directions

As a unique structured lipid, medium- and long-chain triacylglycerol (MLCT) is characterized by the combination of medium- and long-chain fatty acids in a single triacylglycerol molecule. In recent years, MLCT, as a nutritional lipid, has gradually emerged as a research hot topic in the fields of food science and nutrition. This paper innovatively provides a comprehensive review of the current application status and development prospects of MLCT in nutritional support. First, the basic principles defining characteristics and selection basis of both enteral and parenteral nutrition are analyzed, elucidating the differences between the two modalities in terms of nutrient delivery pathway, absorption mechanisms, and physiological effects. Subsequently, the natural sources and artificial synthetic pathways of MLCT along with its metabolic behavior in vivo are elaborated. On this basis, the latest research advancements in the application of MLCT in both nutritional models are reviewed, with a particular emphasis on current research hotspots. Finally, the challenges encountered in the practical application of MLCT are discussed, and the future trajectory of MLCT as a functional lipid is predicted. In particular, the innovative potential of MLCT in functional foods, food for special medical purposes, personalized nutrition, and other aspects is emphasized, which provides beneficial ideas and directions for further research and industrial applications of MLCT.

A review on lipid inclusion in preterm formula: Characteristics, nutritional support, challenges, and future perspectives

The lack of nutrient accumulation during the last trimester and the physiological immaturity at birth make nutrition for preterm infants a significant challenge. Lipids are essential for preterm infant growth, neurodevelopment, immune function, and intestinal health. However, the inclusion of novel lipids in preterm formulas has rarely been discussed. This study discusses specific lipid recommendations for preterm infants according to authoritative legislation based on their physiological characteristics. The gaps in lipid composition, such as fatty acids, triacylglycerols, and complex lipids, between preterm formulas and human milk have been summarized. The focus of this study is mainly on the vital roles of lipids in nutritional support, including long-chain polyunsaturated fatty acids, structural lipids, milk fat global membrane ingredients, and other minor components. These lipids have potential applications in preterm formulas for improving lipid absorption, regulating lipid metabolism, and protecting against intestinal inflammation. The lipidome and microbiome can be used to provide adequately powered evidence of the effects of lipids. This study proposes nutritional strategies for preterm infants and suggests approaches to enhance their lipid quality in preterm formula.

Eicosapentaenoic Acid and Medium-Chain Triacylglycerol Structured Lipid Supplementation Improves Muscular Endurance Exercise Performance and Reduces Muscle Fatigue in Young Healthy Male

OBJECTIVE

Structured lipids containing medium-chain fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) from fish oil (EPA/MCT) and it improve overall endurance. However, their effects on local muscle endurance remain unclear. This study aimed to investigate the effects of EPA/MCT intake on muscle endurance during leg extension exercises and subsequent muscle fatigue.

METHODS

This 8-week, placebo-controlled, randomized, double-blind parallel-group trial involved 20 healthy young men. Subjects were randomly assigned to an EPA/MCT group (10 subjects) and a placebo group (PL group, 10 subjects). They consumed 4560 mg of the test food daily for 8 wk before an exercise intervention. The EPA/MCT supplement contained 600 mg of EPA, 260 mg of DHA, and 1890 mg of MCT (1110 mg of octanoic acid and 780 mg of decanoic acid). After the 8-week intervention, the subjects performed four sets of leg extension exercises at 40% of their body weight until exhaustion. The number of repetitions per set and the total repetitions across the four sets served as indicators of muscle endurance. Isometric maximum voluntary contraction (MVC), range of motion, circumference, muscle thickness, echo intensity, and muscle stiffness were measured before and after exercise to assess muscle fatigue.

RESULTS

There was no difference between the groups in the number of repetitions for sets 1-4 or in the total number of repetitions during the leg extension exercise. In the EPA/MCT group, a significant negative correlation was observed between the increase in the blood EPA/AA ratio and the rate of decrease in the number of repetitions. Additionally, the decrease in MVC after exercise was significantly smaller in the EPA/MCT group than in the PL group.

CONCLUSION

Our study results suggest that an 8-week intake of EPA/MCT can increase the blood EPA/AA ratio and improve muscle endurance performance. Additionally, EPA/MCT intake reduces muscle fatigue after exercise.

Medium- and Long-Chain Triacylglycerol: Preparation, Health Benefits, and Food Utilization

Medium- and long-chain triacylglycerol (MLCT) is a structured lipid with both medium- and long-chain fatty acids in one triacylglycerol molecule. Compared with long-chain triacylglycerol (LCT), which is mainly present in common edible oils, and the physical blend of medium-chain triacylglycerol with LCT (MCT/LCT), MLCT has different physicochemical properties, metabolic characteristics, and nutritional values. In this article, the recent advances in the use of MLCT in food formulations are reviewed. The natural sources and preparation of MLCT are discussed. A comprehensive summary of MLCT digestion, absorption, transport, and oxidation is provided as well as its health benefits, including reducing the risk of overweight, hypolipidemic and hypoglycemic effects, etc. The potential MLCT uses in food formulations, such as infant formulas, healthy foods for weight loss, and sports foods, are summarized. Finally, the current safety assessment and regulatory status of MLCT in food formulations are reviewed.

Synthesis of eicosapentaenoic acid-enriched medium- and long-chain triglyceride by lipase-catalyzed transesterification: a novel strategy for clinical nutrition intervention

BACKGROUND

Eicosapentaenoic acid (EPA) has been recognized as a promising nutrient to improve therapeutic efficacy for cancer patients. Nevertheless, there are certain limitations to the application of EPA due to its structural characteristics. To maximize the nutritive value of EPA, a type of medium- and long-chain triacylglycerol (MLCT) enriched with EPA was designed and synthesized using the lipase-catalyzed transesterification of medium-chain triglyceride (MCT) and EPA-enriched fish oil (FO).

RESULTS

The optimum synthesis conditions for EPA-enriched MLCT used Lipozyme RM as catalyst, and had a substrate mass ratio (MCT/EPA-enriched FO) of 3:1, lipase loading of 80 g kg^-1 , a reaction temperature of 60 °C, and a reaction time of 6 h. The MLCT content was as high as 80.79% after the transesterification reaction and the purification, and the content of MLCT containing EPA accounted for 70.21%. The distribution of EPA at the sn-2 position showed a significant increase in MLCT compared with the original substrate, from 18.89% to 26.93%. The in vitro digestion results demonstrated that MLCT had a significantly higher EPA bioaccessibility than the original substrate.

CONCLUSION

Eicosapentaenoic acid-enriched MLCT was developed. This may provide a novel strategy for clinical nutritional intervention. © 2023 Society of Chemical Industry.

Role Medium-Chain Fatty Acids in the Lipid Metabolism of Infants

Human breastmilk, the ideal food for healthy infants, naturally contains a high concentration of medium-chain fatty acids (MCFAs, about 15% of total fatty acids). MCFAs are an important energy source for infants due to their unique digestive and metabolic properties. MCFA-enriched oils are widely used in an infant formula, especially the formula produced for preterm infants. Recently, there has been a growing interest in the triglyceride structure of MCFAs in human milk, their metabolism, and their effects on infant health. This study summarized the MCFA composition and structure in both human milk and infant formula. Recent studies on the nutritional effects of MCFAs on infant gut microbiota have been reviewed. Special attention was given to the MCFAs digestion and metabolism in the infants. This paper aims to provide insights into the optimization of formulations to fulfill infant nutritional requirements.

Effect of mono- and diglycerides on the digestion and absorption of lutein in lymph fistula rats

Breast milk lutein is better absorbed by infants than lutein delivered in infant formula. Therefore, we wanted to better understand the possible absorption differences of lutein in breast milk vs. that in infant formula by determining its bioavailability after gastric administration and whether the intestinal absorption of lutein can be improved by using new delivery vehicles. Study 1 compared the intestinal uptake,and the lymphatic and portal transport of lutein in conscious lymph fistula rats. Four groups of lymph- and portal vein-cannulated rats ( n = 8-10/group) were randomized to receive via gastric tube increasing doses (10, 20, 40, or 80 mg/kg) of 20% lutein in safflower oil (SO) suspension to assess whether there was a saturable level of lutein that could be absorbed and transported in lymph. Aliquots of hourly portal blood and lymph were taken for lutein and zeaxanthin analyses. The dose-response study showed that 20 mg/kg lutein was the saturable level of lymphatic lutein absorption with no lutein detected in portal circulation at any dosage level tested. Study 2 randomized five groups of lymph fistula rats ( n = 4-9/group) to receive 20 mg/kg lutein from either lutein in SO or lutein in four different mono- and diglyceride oils (MDGs). Gastric infusion of lutein suspended in MDG (20 mg/kg) significantly improved (71-211%, P < 0.05) lymphatic lutein output 2-6 h after lipid feeding vs. lutein in SO. Lymphatic zeaxanthin (10% of the lutein fed mixture) transport in both Study 1 and Study 2 followed that of lutein. We conclude that a mixture of MDGs helps solubilize lutein and facilitate gastrointestinal micelle formation, thus improving lymphatic lutein absorption compared with triglyceride oils. NEW & NOTEWORTHY This paper describes how lutein is digested and absorbed by the gastrointestinal tract by using the conscious lymph fistula rat model. Our dose-response study showed that absorption and lymphatic transport of lutein is a saturable process with no lutein detected in portal circulation at any dosage level tested. Our paper also provides insight into how this process can be improved by modifying the typical lipid mixtures carrying the lutein.

The Increasing Use of Interesterified Lipids in the Food Supply and Their Effects on Health Parameters

A variety of modified fats that provide different functionalities are used in processed foods to optimize product characteristics and nutrient composition. Partial hydrogenation results in the formation of trans FAs (TFAs) and was one of the most widely used modification processes of fats and oils. However, the negative effects of commercially produced TFAs on serum lipoproteins and risk for cardiovascular disease resulted in the Institute of Medicine and the 2010 US Dietary Guidelines for Americans both recommending that TFA intake be as low as possible. After its tentative 2013 determination that use of partially hydrogenated oils is not generally regarded as safe, the FDA released its final determination of the same in 2015. Many food technologists have turned to interesterified fat as a replacement. Interesterification rearranges FAs within and between a triglyceride molecule by use of either a chemical catalyst or an enzyme. Although there is clear utility of interesterified fats for retaining functional properties of food, the nutrition and health implications of long-term interesterified fat consumption are less well understood. The Technical Committee on Dietary Lipids of the North American Branch of the International Life Sciences Institute sponsored a workshop to discuss the health effects of interesterified fats, identify research needs, and outline considerations for the design of future studies. The consensus was that although interesterified fat production is a feasible and economically viable solution for replacing dietary TFAs, outstanding questions must be answered regarding the effects of interesterification on modifying certain aspects of lipid and glucose metabolism, inflammatory responses, hemostatic parameters, and satiety.

The optimal lipid formulation in enteral feeding in critical illness: clinical update and review of the literature

Suitable and timely early enteral nutrition is paramount to providing optimal patient care for the critically ill. Lipids serve many essential roles throughout the human body, and are important components of most enteral formulations. This paper reviews lipid structure, function, and optimal utility for this macronutrient in enteral feeds. The use of omega-3 fatty acids has become common in critical care formulations, and their clinical efficacy is outlined separately. Available evidence is reviewed, and future directions are discussed.

Enzyme replacement therapy for pancreatic insufficiency: present and future

Pancreatic enzyme replacement therapy is currently the mainstay of treatment for nutrient malabsorption secondary to pancreatic insufficiency. This treatment is safe and has few side effects. Data demonstrate efficacy in reducing steatorrhea and fat malabsorption. Effective therapy has been limited by the ability to replicate the physiologic process of enzyme delivery to the appropriate site, in general the duodenum, at the appropriate time. The challenges include enzyme destruction in the stomach, lack of adequate mixing with the chyme in the duodenum, and failing to deliver and activate at the appropriate time. Treatment is begun when clinically significant malabsorption occurs resulting in steatorrhea and weight loss. Treatment failure is addressed in a sequential fashion. Current research is aimed at studying new enzymes and delivery systems to improve the efficiency of action in the duodenum along with developing better means to monitor therapy.

Effect of a fish oil-containing beverage on changes in plasma lipid fatty acids in patients with malabsorption

BACKGROUND

The aim of this pilot study was to assess tolerance of a beverage containing ω-3 fatty acids (fish oil) in patients with malabsorption receiving chronic parenteral nutrition (PN). The authors wanted to determine whether fish oil could be absorbed and incorporated into plasma fatty acids and reduce markers of inflammation.

METHODS

This was a small intervention study in home-dwelling PN-dependent patients with chronic malabsorption. Ten patients were provided a drink containing 1.5 g of fish oil per day for 12 weeks. Baseline and post-supplement serum fatty acid profiles were compared.

RESULTS

Five of 10 patients withdrew from the study because of GI side effects, principally worsened diarrhea, associated with the supplement. Modest increases were found in 20:5ω-3, 22:5ω-3, and 22:6ω-3 levels in both phospholipids and triglycerides in plasma (all P < .05). In phospholipids, a reduced arachidonic acid level was seen (P = .02). These changes were not sufficient to effect improvements in serum tumor necrosis factor-alpha (TNFα), soluble TNF receptor, C-reactive protein, or interleukin-6.

CONCLUSIONS

Some patients with severe malabsorption can absorb oral ω-3 fatty acid supplements and incorporate these fatty acids into serum phospholipids and triglycerides. However, side effects are very common, and no anti-inflammatory effect was found, presumably related to the modest level of fatty acid change.