Medium-chain triglyceride ameliorates insulin resistance and inflammation in high fat diet-induced obese mice

BDH1 overexpression alleviates diabetic cardiomyopathy through inhibiting H3K9bhb-mediated transcriptional activation of LCN2

BACKGROUND

Diabetic cardiomyopathy (DbCM) is one of the common complications in diabetic patients, but there is no effective treatment for it up to now. Ketone bodies such as β-OHB have been widely reported to be beneficial for metabolic diseases including various diabetic complications. However, the role of ketone metabolism, especially the relevant enzymes, in the pathogenesis of DbCM is poorly understood.

METHODS AND RESULTS

In this study, we firstly observed BDH1, the rate-limiting enzyme of ketone metabolism, was markedly diminished in cardiac tissues from db/db mice and diabetic patients, as well as in H9C2 cells treated with palmitic acid. Genetic deletion of BDH1 aggravated, whereas AAV-mediated BDH1 overexpression attenuated, the diastolic dysfunction and pathogenic progression including apoptosis, fibrosis and inflammation of hearts from db/db mice. Likewise, BDH1 knockdown promoted, whereas BDH1 overexpression reversed, the palmitic acid-induced lipotoxicity in H9C2 cells. Transcriptome analysis revealed that BDH1 negatively regulated LCN2 expression and LCN2 overexpression largely abrogated BDH1 overexpression-mediated myocardial protection in vitro and in vivo. Mechanistically, BDH1 overexpression reprogrammed ketone metabolism with increased AcAc and decreased β-OHB, thereby resulting in decreased β-hydroxybutyrylation of H3K9 on promoter region of LCN2, which repressed transcription of LCN2 and ultimately inhibited NF-κB activity through weakening interaction between NF-κB and RPS3. Furthermore, oral administration of β-hydroxybutyrylation inhibitor A485 to diabetic mice mitigated the cardiac injury concurrently with decreased expression of LCN2.

CONCLUSION

Our results uncovered a novel mechanism whereby myocardial BDH1 ameliorates DbCM via epigenetic regulation of LCN2, which highlights the potential of BDH1/LCN2-based therapeutics in DbCM.

Metabolic effects of medium-chain triacylglycerol consumption are preserved in obesity

Several health-beneficial effects are associated with intake of medium-chain triacylglycerol (MCT); however, the underlying mechanisms are unknown. Furthermore, it remains uncertain whether the acute metabolic effects of MCT differ between lean individuals and individuals with obesity-and whether these effects are sustained following chronic intake. This study aimed to elucidate the postprandial physiological and metabolic effects of MCT before and after 8 days intake compared with intake of energy-matched triacylglycerol consisting of long-chain fatty acids (long-chain triacylglycerols, LCT) using a randomized cross-over design in lean individuals (n = 8) and individuals with obesity (n = 8). The study revealed that consumption of MCT increased ketogenesis and metabolic rate while lowering blood glucose levels over 5 h. The hypoglycemic action of MCT intake was accompanied by a concomitant transient increase in plasma insulin and glucagon levels. Interestingly, the effects on ketogenesis, metabolic rate, and glycemia were preserved in individuals with obesity and sustained after 8 days of daily supplementation. Lipidomic plasma analysis in lean individuals (n = 4) showed that a part of the ingested MCT bypasses the liver and enters the systemic circulation as medium-chain fatty acids (MCFAs). The findings suggest that MCFAs, along with ketone bodies from the liver, may act as signaling molecules and/or substrates in the peripheral tissues, thereby contributing to the effects of MCT intake. In summary, these findings underscore the health benefits of MCT in metabolically compromised individuals after daily supplementation. Moreover, we uncover novel aspects of MCFA biology, providing insights into how these fatty acids orchestrate physiological effects in humans.NEW & NOTEWORTHY We reveal that medium-chain triacylglycerol (MCT) intake increases postprandial ketogenesis and metabolic rate and reduces plasma glucose levels in humans. Notably, these responses persist in individuals with obesity and are maintained following chronic MCT supplementation. Some medium-chain fatty acids entered the circulation, suggesting that these, together with ketone bodies, act as signaling molecules/substrates in peripheral tissues. The findings highlight health beneficial effects of dietary MCT in individuals with obesity and reveal new insights into lipid biology.

Exploring green solvent systems and enhanced solubility of xanthone in triglyceride-based tricaprin-tricaprylin mixtures with thermodynamic insights

This study explores the use of green solvent systems by investigating the solubility and thermodynamic properties of xanthone (1) in triglyceride-based tricaprin (2) and tricaprylin (3) mixtures, aiming to replace traditional organic solvents. The solubility profile exhibited a concave trend, and the highest solubility was observed at a solute-free fraction (x2) of 0.36. The solubility exponentially increased with increasing temperature in the range from 30 °C to 75 °C. The solubility data were effectively correlated using the local composition-regular solution theory (LC-RST) model and achieved an ARDln value of 4.8 × 10-3. The model indicated strong interactions between tricaprin and tricaprylin, followed by interactions between tricaprylin and xanthone and between tricaprin and xanthone. The dissolution process of xanthone was primarily enthalpy driven. Based on the structural analysis, xanthone maintained its molecular structure after dissolution in tricaprin and tricaprylin; however, changes in crystallinity levels were observed. These findings provide insights into the use of triglycerides as solvents to improve the solubility and bioaccessibility of hydrophobic compounds such as xanthone.

Unabsorbed Fecal Fat Content Correlates with a Reduction of Immunoglobulin a Coating of Gut Bacteria in High-Lard Diet-Fed Mice

SCOPE

Immunoglobulin A (IgA) selectively coats gut bacteria and contributes to regulatory functions in gastrointestinal inflammation and glucose metabolism. Excess intake of lard leads to decrease in the IgA coating of gut bacteria, although the underlying mechanisms remain unknown. This study validates how unabsorbed fat derived from a high-lard diet in the gut affects the IgA coating of bacteria, as assessed in mouse models using three types of dietary fat (lard, medium-, and long-chain triglycerides [MLCTs], and medium-chain triglycerides [MCTs]) exhibiting different digestibilities.

METHODS AND RESULTS

C57BL/6J mice are maintained on diets containing lard, MLCTs, or MCTs at 7% or 30% w/w for 10 weeks (n = 6 per group). The fecal fatty acid concentration is measured to quantify unabsorbed fat content. The ratio of IgA-coated bacteria to total bacteria (IgA coating ratio) in the feces is measured by flow cytometry. Compared to lard-fed mice, MLCT- and MCT-fed mice exhibit lower fecal concentrations of palmitic acid, stearic acid, and oleic acid and higher IgA coating ratios at both 7% and 30% dietary fat, and these parameters exhibit significant negative correlations.

CONCLUSION

Unabsorbed fat content in the gut may result in attenuated IgA coating of bacteria in high-lard diet-fed mice.

Black soldier fly larvae oil (Hermetia illucens L.) calcium salt enhances intestinal morphology and barrier function in laying hens

This study aimed to determine the influence of black soldier fly larvae oil calcium salt (BSFLO-SCa) supplementation on performance, jejunal histomorphology and gene expression of tight junctions and inflammatory cytokines in laying hens. A total of 60 ISA Brown laying hens (40 wk of age) were divided into 3 treatment groups, including a control group fed a basal diet (T0) and basal diets supplemented with 1% (T1) and 2% (T2) of BSFLO-SCa. Each treatment group consisted of 5 replicates with 4 laying hens each. Results showed that 1% and 2% BSFLO-SCa supplementation significantly reduced (P < 0.05) feed conversion ratio (FCR), while egg weight (EW) increased (P < 0.05). The inclusion with 2% increased (P < 0.05) both egg production (HDA) and mass (EM). The addition of 1% and 2% BSFLO-SCa significantly increased (P < 0.05) villus height (VH) and villus width (VW), while crypt depth (CD) significantly increased (P < 0.05) with 2% BSFLO-SCa. The tight junction and gene expression of claudin-1 (CLDN-1), junctional adhesion molecules-2 (JAM-2), and occludin (OCLN) were significantly upregulated (P < 0.05) with 2% BSFLO-SCa. The pro-inflammatory cytokines and gene expression of interleukin-6 (IL-6) was significantly downregulated (P < 0.05) with the addition of BSFLO-SCa, while gene expression of interleukin-18 (IL-18), toll-like receptor 4 (TLR-4), and tumor necrosis factor-α (TNF-α) were downregulated with 2% BSFLO-SCa. On the other hand, the anti-inflammatory cytokines and gene expression of interleukin-13 (IL-13) and interleukin-10 (IL-10) were significantly upregulated (P < 0.05) at 2% BSFLO-SCa. In conclusion, dietary supplementation with 2% BSFLO-SCa improved productivity, intestinal morphology and integrity by upregulating tight junction-related protein of gene expression of laying hens. In addition, supplementation with BSFLO-SCa enhanced intestinal immune responses by upregulating anti-inflammatory and downregulating pro-inflammatory cytokine gene expression.

Medium-chain triglyceride-specific appetite is regulated by the β-oxidation of medium-chain fatty acids in the liver

Most studies on fat appetite have focused on long-chain triglycerides (LCTs) due to their obesogenic properties. Medium-chain triglycerides (MCTs), conversely, exhibit antiobesogenic effects; however, the regulation of MCT intake remains elusive. Here, we demonstrate that mice can distinguish between MCTs and LCTs, and the specific appetite for MCTs is governed by hepatic β-oxidation. We generated liver-specific medium-chain acyl-CoA dehydrogenase (MCAD)-deficient (MCADL-/-) mice and analyzed their preference for MCT and LCT solutions using glyceryl trioctanoate (C8-TG), glyceryl tridecanoate (C10-TG), corn oil, and lard oil in two-bottle choice tests conducted over 8 days. In addition, we used lick microstructure analyses to evaluate the palatability and appetite for MCT and LCT solutions. Finally, we measured the expression levels of genes associated with fat ingestion (Galanin, Qrfp, and Nmu) in the hypothalamus 2 h after oral gavage of fat. Compared with control mice, MCADL-/- mice exhibited a significantly reduced preference for MCT solutions, with no alteration in the preference for LCTs. Lick analysis revealed that MCADL-/- mice displayed a significantly decreased appetite for MCT solutions only while the palatability of both MCT and LCT solutions remained unaffected. Hypothalamic Galanin expression in control mice was elevated by oral gavage of C8-TG but not by LCTs, and this response was abrogated in MCADL-/- mice. In summary, our data suggest that hepatic β-oxidation is required for MCT-specific appetite but not for LCT-specific appetite. The induction of hypothalamic galanin upon MCT ingestion, dependent on hepatic β-oxidation, could be involved in the regulation of MCT-specific appetite.NEW & NOTEWORTHY Whether and how medium-chain triglyceride (MCT) intake is regulated remains unknown. Here, we showed that mice can discriminate between MCTs and LCTs. Hepatic β-oxidation participates in MCT-specific appetite, and hypothalamic galanin may be one of the factors that regulate MCT intake. Because of the antiobesity effects of MCTs, studying MCT-specific appetite may help combat obesity by promoting the intake of MCTs instead of LCTs.

A very-low carbohydrate content in a high-fat diet modifies the plasma metabolome and impacts systemic inflammation and experimental atherosclerosis

Ketogenic diets (KDs) are very high-fat low-carbohydrate diets that promote nutritional ketosis and are widely used for weight loss, although concerns about potential adverse cardiovascular effects remain. We investigated a very high-fat KD's vascular impact and plasma metabolic signature compared to a non-ketogenic high-fat diet (HFD). Apolipoprotein E deficient (ApoE -/-) mice were fed a KD (%kcal:81:1:18, fat/carbohydrate/protein), a non-ketogenic high-fat diet with half of the fat content (HFD) (%kcal:40:42:18, fat/carbohydrate/protein) for 12 weeks. Plasma samples were used to quantify the major ketone body beta-hydroxybutyrate (BHB) and several pro-inflammatory cytokines (IL-6, MCP-1, MIP-1alpha, and TNF alpha), and to targeted metabolomic profiling by mass spectrometry. In addition, aortic atherosclerotic lesions were quantified ex-vivo by magnetic resonance imaging (MRI) on a 14-tesla system. KD was atherogenic when compared to the control diet, but KD mice, when compared to the HFD group (1) had markedly higher levels of BHB and lower levels of cytokines, confirming the presence of ketosis that alleviated the well-established fat-induced systemic inflammation; (2) displayed significant changes in the plasma metabolome that included a decrease in lipophilic metabolites and an increase in hydrophilic metabolites; (3) had significantly lower levels of several atherogenic lipid metabolites, including phosphatidylcholines, cholesterol esters, sphingomyelins, and ceramides; and (4) presented significantly lower aortic plaque burden. KD was atherogenic and was associated with specific metabolic changes but alleviated the fat-induced inflammation and lessened the progression of atherosclerosis when compared to the HFD.

A high-fat diet supplemented with medium-chain triglycerides ameliorates hepatic steatosis by reducing ceramide and diacylglycerol accumulation in mice

Non-alcoholic fatty liver disease (NAFLD) is projected to be the most common chronic liver disease worldwide and is closely linked to obesity, insulin resistance and type 2 diabetes. Currently, no pharmacological treatments are available to treat NAFLD, and lifestyle modification, including dietary interventions, is the only remedy. Therefore, we conducted a study to determine whether supplementation with medium-chain triglycerides (MCTs), containing a mixture of C8 and C10 (60/40), attenuates NAFLD in obese and insulin-resistant mice. To achieve that, we fed C57BL/6 male mice a high-fat diet (HFD) for 12 weeks to induce obesity and hepatic steatosis, after which obese mice were assigned randomly either to remain on the HFD or to transition to an HFD supplemented with MCTs (HFD + MCTs) or a low-fat diet (LFD) for 6 weeks as another dietary intervention model. Another group of mice was kept on an LFD throughout the study and used as a lean control group. Obese mice that transitioned to HFD + MCTs exhibited improvement in glucose and insulin tolerance tests, and the latter improvement was independent of changes in adiposity when compared with HFD-fed mice. Additionally, supplementation with MCTs significantly reduced hepatic steatosis, improved liver enzymes and decreased hepatic expression of inflammation-related genes to levels similar to those observed in obese mice transitioned to an LFD. Importantly, HFD + MCTs markedly lowered hepatic ceramide and diacylglycerol content and prevented protein kinase C-ε translocation to the plasma membrane. Our study demonstrated that supplementation with MCTs formulated mainly from C8 and C10 effectively ameliorated NAFLD in obese mice.

Effect of Different Medium-Chain Triglycerides on Glucose Metabolism in High-Fat-Diet Induced Obese Rats

Obesity can be associated with significant metabolic disorders. Our previous study found that medium-chain triglycerides (MCTs) improved lipid metabolism in obese rats. However, scant attention has been given to exploring the impact of MCTs on glucose metabolism in obese rats. This study is designed to examine the effects and mechanisms of three distinct MCTs on glucose metabolism in obese rats. To induce obesity, Sprague-Dawley (SD) rats were fed a high-fat diet, followed by a 12-week treatment with caprylic triglyceride (CYT), capric triglyceride (CT), and lauric triglyceride (LT). The results showed that three types of MCT intervention reduced the levels of lipids (TC, TG, LDL-c, and HDL-c), hyperglycemia, insulin resistance (insulin, OGTT, HOMA-IR, and ISI), and inflammatory markers (IL-4, IL-1β, and TNF-α) in obese rats (p < 0.01), The above parameters have been minimally improved in the high-fat restoring group (HR) group. MCTs can modulate the PI3K/AKT signaling pathways to alleviate insulin resistance and improve glucose metabolism in obese rats. Furthermore, MCTs can activate peroxisome proliferator-activated receptor (PPAR) γ and reduce the phosphorylation of PPARγser237 mediated by CDK5, which can improve insulin sensitivity without lipid deposition in obese rats. Among the MCT group, CT administration performed the best in the above pathways, with the lowest blood glucose level and insulin resistance. These findings contribute to a deeper understanding of the connection between health benefits and the specific type of MCT employed.

Relationship between rumen bacterial community and milk fat in dairy cows

Introduction

Milk fat is the most variable nutrient in milk, and recent studies have shown that rumen bacteria are closely related to milk fat. However, there is limited research on the relationship between rumen bacteria and milk fatty. Fatty acids (FAs) are an important component of milk fat and are associated with various potential benefits and risks to human health.

Methods

In this experiment, forty-five healthy Holstein dairy cows with alike physiological and productive conditions were selected from medium-sized dairy farms and raised under the same feeding and management conditions. The experimental period was two weeks. During the experiment, raw milk and rumen fluid were collected, and milk components were determined. In this study, 8 high milk fat percentage (HF) dairy cows and 8 low milk fat percentage (LF) dairy cows were selected for analysis.

Results

Results showed that the milk fat percentage in HF group was significantly greater than that of the dairy cows in the LF group. 16S rRNA gene sequencing showed that the rumen bacterial abundance of HF dairy cows was significantly higher than that in LF dairy cows; at the genus level, the bacterial abundances of Prevotellaceae_UCG-001, Candidatus_Saccharimonas, Prevotellaceae_UCG-003, Ruminococcus_1, Lachnospiraceae_XPB1014_group, Lachnospiraceae_AC2044_group, probable_genus_10 and U29-B03 in HF group were significantly higher than those in the LF group. Spearman rank correlation analysis indicated that milk fat percentage was positively related to Prevotellaceae_UCG-001, Candidatus_Saccharimonas, Prevotellaceae_UCG-003, Ruminococcus_1, Lachnospiraceae_XPB1014_group, Lachnospiraceae_AC2044_group, probable_genus_10 and U29-B03. Furthermore, Prevotellaceae_UCG-001 was positively related to C14:0 iso, C15:0 iso, C18:0, Ruminococcus_1 with C18:1 t9, Lachnospiraceae_AC2044_group with C18:1 t9 and C18:1 t11, U29-B03 with C15:0 iso.

Discussion

To sum up, rumen bacteria in dairy cows are related to the variation of milk fat, and some rumen bacteria have potential effects on the deposition of certain fatty acids in raw milk.

Potential benefits of medium chain fatty acids in aging and neurodegenerative disease

Neurodegenerative diseases are a large class of neurological disorders characterized by progressive dysfunction and death of neurones. Examples include Alzheimer's disease, Parkinson's disease, frontotemporal dementia, and amyotrophic lateral sclerosis. Aging is the primary risk factor for neurodegeneration; individuals over 65 are more likely to suffer from a neurodegenerative disease, with prevalence increasing with age. As the population ages, the social and economic burden caused by these diseases will increase. Therefore, new therapies that address both aging and neurodegeneration are imperative. Ketogenic diets (KDs) are low carbohydrate, high-fat diets developed initially as an alternative treatment for epilepsy. The classic ketogenic diet provides energy via long-chain fatty acids (LCFAs); naturally occurring medium chain fatty acids (MCFAs), on the other hand, are the main components of the medium-chain triglyceride (MCT) ketogenic diet. MCT-based diets are more efficient at generating the ketone bodies that are used as a secondary energy source for neurones and astrocytes. However, ketone levels alone do not closely correlate with improved clinical symptoms. Recent findings suggest an alternative mode of action for the MCFAs, e.g., via improving mitochondrial biogenesis and glutamate receptor inhibition. MCFAs have been linked to the treatment of both aging and neurodegenerative disease via their effects on metabolism. Through action on multiple disease-related pathways, MCFAs are emerging as compounds with notable potential to promote healthy aging and ameliorate neurodegeneration. MCFAs have been shown to stimulate autophagy and restore mitochondrial function, which are found to be disrupted in aging and neurodegeneration. This review aims to provide insight into the metabolic benefits of MCFAs in neurodegenerative disease and healthy aging. We will discuss the use of MCFAs to combat dysregulation of autophagy and mitochondrial function in the context of "normal" aging, Parkinson's disease, amyotrophic lateral sclerosis and Alzheimer's disease.

A Medium Chain Fatty Acid, 6-hydroxyhexanoic acid (6-HHA), Protects Against Obesity and Insulin Resistance

Obesity, a worldwide health problem, increases the risk for developing metabolic diseases such as insulin resistance and diabetes. It is well recognized that obesity-associated chronic inflammation plays a key role in the pathogenesis of systemic metabolic dysfunction. Previously, we revealed an anti-inflammatory role for spent culture supernatants isolated from the oral commensal bacterial species Streptococcus gordonii (Sg-SCS). Here, we identified that 6-hydroxyhexanoic acid (6-HHA), a medium chain fatty acid (MCFA), is the one of the key components of Sg-SCS . We found that treatment of 6-HHA in mice fed a high-fat diet (HFD) significantly reduced HFD-mediated weight gain which was largely attributed to a decrease in fat mass. Systemically, 6-HHA improves obesity-associated glucose intolerance and insulin resistance. Furthermore, administration of 6-HHA suppressed obesity-associated systemic inflammation and dyslipidemia. At the cellular level, treatment of 6-HHA ameliorated aberrant inflammatory and metabolic transcriptomic signatures in white adipose tissue of mice with diet-induced obesity (HFD). Mechanistically, we found that 6-HHA suppressed adipocyte-proinflammatory cytokine production and lipolysis, the latter through Gαi-mediated signaling. This work provides direct evidence for the anti-obesity effects of a novel MCFA, which could be a new therapeutic treatment for combating obesity.

KEY POINTS

Hydroxyhexanoic medium chain fatty acids (MCFAs) are dietary and bacterial-derived energy sources, however, the outcomes of using MCFAs in treating metabolic disorders are diverse and complex. The MCFA 6-hydroxyhexanoic acid (6-HHA) is a metabolite secreted by the oral bacterial commensal species Streptococcus gordonii; here we investigated its role in modulating high-fat diet (HFD)-induced metabolic dysfunction. In a murine model of obesity, we found 6-HHA-mediated improvement of diet-mediated adiposity, insulin resistance and inflammation were in part due to actions on white adipose tissue (WAT).6-HHA suppressed proinflammatory cytokine production and lipolysis through Gi-mediated signaling in differentiated white adipocytes.

Anti-Inflammatory Activity of Black Soldier Fly Oil Associated with Modulation of TLR Signaling: A Metabolomic Approach

Dietary intervention in the treatment of ulcerative colitis involves, among other things, modifications in fatty acid content and/or profile. For example, replacing saturated long chain fatty acids with medium chain fatty acids (MCFAs) has been reported to ameliorate inflammation. The Black Soldier Fly Larvae's (BSFL) oil is considered a sustainable dietary ingredient rich in the MCFA C12:0; however, its effect on inflammatory-related conditions has not been studied until now. Thus, the present study aimed to investigate the anti-inflammatory activity of BSFL oil in comparison to C12:0 using TLR4- or TLR2-activated THP-1 and J774A.1 cell lines and to assess its putative protective effect against dextran sulfate sodium (DSS)-induced acute colitis in mice. BSFL oil and C12:0 suppressed proinflammatory cytokines release in LPS-stimulated macrophages; however, only BSFL oil exerted anti-inflammatory activity in Pam3CSK4-stimulated macrophages. Transcriptome analysis provided insight into the possible role of BSFL oil in immunometabolism switch, involving mTOR signaling and an increase in PPAR target genes promoting fatty acid oxidation, exhibiting a discrepant mode of action compared to C12:0 treatment, which mainly affected cholesterol biosynthesis pathways. Additionally, we identified anti-inflammatory eicosanoids, oxylipins, and isoprenoids in the BSFL oil that may contribute to an orchestrated anti-inflammatory response. In vivo, a BSFL oil-enriched diet (20%) ameliorated the clinical signs of colitis, as indicated by improved body weight recovery, reduced colon shortening, reduced splenomegaly, and an earlier phase of secretory IgA response. These results indicate the novel beneficial use of BSFL oil as a modulator of inflammation.

The Role of a Ketogenic Diet in the Treatment of Dementia in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) shares a common molecular mechanism and underlying pathology with dementia, and studies indicate that dementia is widespread in people with T2DM. Currently, T2DM-induced cognitive impairment is characterized by altered insulin and cerebral glucose metabolism, leading to a shorter life span. Increasing evidence indicates that nutritional and metabolic treatments can possibly alleviate these issues, as there is a lack of efficient preventative and treatment methods. The ketogenic diet (KD) is a very high-fat, low-carbohydrate diet that induces ketosis in the body by producing a fasting-like effect, and neurons in the aged brain are protected from damage by ketone bodies. Moreover, the creation of ketone bodies may improve brain neuronal function, decrease inflammatory expression and reactive oxygen species (ROS) production, and restore neuronal metabolism. As a result, the KD has drawn attention as a potential treatment for neurological diseases, such as T2DM-induced dementia. This review aims to examine the role of the KD in the prevention of dementia risk in T2DM patients and to outline specific aspects of the neuroprotective effects of the KD, providing a rationale for the implementation of dietary interventions as a therapeutic strategy for T2DM-induced dementia in the future.

Associations between dietary fatty acid patterns and cognitive function in the Hispanic Community Health Study/Study of Latinos

Our objective was to quantify the cross-sectional associations between dietary fatty acid (DFA) patterns and cognitive function among Hispanic/Latino adults. This study included data from 8942 participants of the Hispanic Community Health Study/Study of Latinos, a population-based cohort study (weighted age 56·2 years and proportion female 55·2 %). The National Cancer Institute method was used to estimate dietary intake from two 24-h recalls. We derived DFA patterns using principal component analysis with twenty-six fatty acid and total plant and animal MUFA input variables. Global cognitive function was calculated as the average z-score of four neurocognitive tests. Survey linear regression models included multiple potential confounders such as age, sex, education, depressive symptoms, physical activity, energy intake and CVD. DFA patterns were characterised by the consumption of long-chain SFA, animal-based MUFA and trans-fatty acids (factor 1); short to medium-chain SFA (factor 2); very-long-chain n-3 PUFA (factor 3); very-long-chain SFA and plant-based MUFA and PUFA (factor 4). Factor 2 was associated with greater scores for global cognitive function (β = 0·037 (sd 0·012)) and the Digit Symbol Substitution (DSS) (β = 0·56 (sd 0·17)), Brief Spanish English Verbal Learning-Sum (B-SEVLT) (β = 0·23 (sd 0·11)) and B-SEVLT-Recall (β = 0·11 (sd 0·05)) tests (P < 0·05 for all). Factors 1 (β = 0·04 (sd 0·01)) and 4 (β = 0·70 (sd 0·18)) were associated with the DSS test (P < 0·05 for all). The consumption of short to medium-chain SFA may be associated with higher cognitive function among US-residing Hispanic/Latino adults. Prospective studies are necessary to confirm these findings.

Effects of supplemental octanoate on hepatic lipid metabolism, serum biochemical indexes, antioxidant capacity and inflammation-related genes expression of large yellow croaker (Larimichthys crocea) fed with high soybean oil diet

Dietary high soybean oil (SO) levels might cause hepatic lipid deposition, induce oxidative stress and inflammatory response in aquatic animals, while octanoate (OCT) is beneficial to metabolism and health in mammals. However, the effect of OCT has been studied rarely in aquatic animals. In this study, a 10-week feeding trial was conducted to investigate the effect of supplemental OCT on hepatic lipid metabolism, serum biochemical indexes, antioxidant capacity and inflammatory response of large yellow croaker (Larimichthys crocea) fed with high SO levels diet. The negative control diet contained 7% fish oil (FO), while the positive control diet contained 7% SO. The other four experimental diets were supplemented with 0.7, 2.1, 6.3 and 18.9 g/kg sodium octanoate (OCT) based on the positive control diet. Results showed that OCT supplementation effectively reduced the hepatic crude lipid, triglyceride (TG), total cholesterol (TC) and non-esterified free fatty acids contents, and alleviated lipid accumulation caused by the SO diet. Meanwhile, OCT supplementation decreased the serum TG, TC, alanine transaminase, aspartate transaminase and low-density lipoprotein cholesterol levels, increased the serum high-density lipoprotein cholesterol level, improved the serum lipid profiles and alleviated hepatic injury. Furthermore, with the supplementation of OCT, the mRNA expression of genes related to lipogenesis (acc1, scd1, fas, srebp1, dgat1 and cebpα) and fatty acid (FA) transport (fabp3, fatp and cd36) were down-regulated, while the mRNA expression of genes related to lipolysis (atgl, hsl and lpl) and FA β-oxidation (cpt1 and mcad) were up-regulated. Besides that, dietary OCT increased the total antioxidant capacity, activities of peroxidase, catalase and superoxide dismutase and the content of reduced glutathione, decreased the content of 8-hydroxy-deoxyguanosine and malondialdehyde and relieved hepatic oxidative stress. Supplementation of 0.7 and 2.1 g/kg OCT down-regulated the mRNA expression of genes related to pro-inflammatory cytokines (tnfα, il1β and ifnγ), and suppressed hepatic inflammatory response. In conclusion, supplementation with 0.7-2.1 g/kg OCT could reduce hepatic lipid accumulation, relieve oxidative stress and regulate inflammatory response in large yellow croaker fed the diet with high SO levels, providing a new way to alleviate the hepatic fat deposition in aquatic animals.

Effects of the Novel LaPLa-Enriched Medium- and Long-Chain Triacylglycerols on Body Weight, Glycolipid Metabolism, and Gut Microbiota Composition in High Fat Diet-Fed C57BL/6J Mice

The roles of medium- and long-chain triacylglycerols (MLCT) on health benefits under high fat diet (HFD) conditions remain in dispute. This study was conducted to investigate the effects of novel LaPLa-rich MLCT on the glycolipid metabolism and gut microbiota in HFD-fed mice when pork fat is half replaced with MLCT and palm stearin (PS). The results showed that although MLCT could increase the body weight in the mouse model, it can improve the energy utilization, regulate the glucose and lipid metabolism, and inhibit the occurrence of inflammation. Furthermore, 16S rRNA gene sequencing of gut microbiota indicated that PS and MLCT affected the overall structure of the gut microbiota to a varying extent and specifically changed the abundance of some operational taxonomic units (OTUs). Moreover, several OTUs belonging to the genera Dorea, Streptococcus, and g_Eryipelotrichaceae had a high correlation with obesity and obesity-related metabolic disorders of the host. Therefore, it can be seen that this new MLCT has different properties and functions from the previous traditional MLCT, and it can better combine the advantages of MLCT, lauric acid, and sn-2 palmitate, as well as the advantages of health function and metabolism. In summary, this study explored the effects of LaPLa-enriched lipids on glycolipid metabolism in mice, providing theoretical support for future studies on the efficacy of different types of conjugated lipids, intending to apply them to industrial production and subsequent development of related products.

Dietary additive octyl and decyl glycerate modulates metabolism and inflammation under different dietary patterns with the contribution of the gut microbiota

Octyl and decyl glycerate (ODG), a medium-chain triglyceride (MCT), is widely used as a food additive. Medium-chain monoglycerides, such as glycerol monolaurate and glycerol monocaprylate, were found to change the composition of the gut microbiota and influence glucose and lipid metabolism and inflammation. However, whether ODG influences the gut microbiota and whether the alteration in the gut microbiota contributes to the metabolic phenotype remain unknown. Under a normal-chow diet, mice were treated with or without different dosages of ODG (150, 800, 1600 mg kg^-1) for 22 weeks. All doses of ODG significantly decreased the ratio of HDL to LDL cholesterol, improved the inflammation and insulin resistance, and increased the α-diversity of the gut microbiota and the abundance of Bifidobacterium and Turicibacter. Under a high-fat diet, mice were treated with or without 1600 mg kg^-1 ODG for 16 weeks. The results demonstrated that ODG significantly alleviated the increase in the ratio of HDL to LDL cholesterol, insulin resistance, and inflammation caused by HFD. The expression of related genes was consistent with the above observations. ODG also altered the composition of the gut microbiota and increased the Bifidobacterium abundance under HFD. Our findings indicated that ODG similarly improved glucose metabolism and inflammation but exhibited differential effects on lipid metabolism under different dietary patterns. Furthermore, changes in the gut microbiota caused by ODG supplementation might contribute to the alteration in glucose and lipid metabolism and inflammation, which might be influenced by dietary patterns.

Ca:Mg ratio, medium-chain fatty acids, and the gut microbiome

BACKGROUND & AIMS

Ketogenic medium-chain fatty acids (MCFAs) with profound health benefits are commonly found in dairy products, palm kernel oil and coconut oil. We hypothesize that magnesium (Mg) supplementation leads to enhanced gut microbial production of MCFAs and, in turn, increased circulating MCFAs levels.

METHODS

We tested this hypothesis in the Personalized Prevention of Colorectal Cancer Trial (PPCCT) (NCT01105169), a double-blind 2 × 2 factorial randomized controlled trial enrolling 240 participants. Six 24-h dietary recalls were performed for all participants at the baseline and during the intervention period. Based on the baseline 24-h dietary recalls, the Mg treatment used a personalized dose of Mg supplementation that would reduce the calcium (Ca): Mg intake ratio to around 2.3. We measured plasma MCFAs, sugars, ketone bodies and tricarboxylic acid cycle (TCA cycle) metabolites using the Metabolon's global Precision Metabolomics™ LC-MS platform. Whole-genome shotgun metagenomics (WGS) sequencing was performed to assess microbiota in stool samples, rectal swabs, and rectal biopsies.

RESULTS

Personalized Mg treatment (mean dose 205.58 mg/day with a range from 77.25 to 389.55 mg/day) significantly increased the plasma levels of C7:0, C8:0, and combined C7:0 and C8:0 by 18.45%, 25.28%, and 24.20%, respectively, compared to 14.15%, 10.12%, and 12.62% decreases in the placebo arm. The effects remain significant after adjusting for age, sex, race and baseline level (P = 0.0126, P = 0.0162, and P = 0.0031, respectively) and FDR correction at 0.05 (q = 0.0324 for both C7:0 and C8:0). Mg treatment significantly reduced the plasma level of sucrose compared to the placebo arm (P = 0.0036 for multivariable-adjusted and P = 0.0216 for additional FDR correction model) whereas alterations in daily intakes of sucrose, fructose, glucose, maltose and C8:0 from baseline to the end of trial did not differ between two arms. Mediation analysis showed that combined C7:0 and C8:0 partially mediated the effects of Mg treatment on total and individual ketone bodies (P for indirect effect = 0.0045, 0.0043, and 0.03, respectively). The changes in plasma levels of C7:0 and C8:0 were significantly and positively correlated with the alterations in stool microbiome α diversity (r = 0.51, p = 0.0023 and r = 0.34, p = 0.0497, respectively) as well as in stool abundance for the signatures of MCFAs-related microbiota with acyl-ACP thioesterase gene producing C7:0 (r = 0.46, p = 0.0067) and C8:0 (r = 0.49, p = 0.003), respectively, following Mg treatment.

CONCLUSIONS

Optimizing Ca:Mg intake ratios to around 2.3 through 12-week personalized Mg supplementation leads to increased circulating levels of MCFAs (i.e. C7:0 and C8:0), which is attributed to enhanced production from gut microbial fermentation and, maybe, sucrose consumption.

Individual SFA intake and risk of overweight/obesity: findings from a population-based nationwide cohort study

The relationship between SFA consumption and the risk of overweight/obesity remains unclear. Epidemiological evidence is lacking among Chinese population. This study aimed to investigate the association between individual dietary SFA intake and the risk of overweight/obesity in Chinese adults. Data from 8465 adults with BMI < 24 kg/m² at entry in the China Health and Nutrition Survey (1989-2011) were analysed. Three-day 24-h dietary records were used to collect dietary data. Cox proportional hazards regression models were constructed to estimate hazard ratios (HR) and 95 % CI for the risk of developing overweight or obesity. A total of 3171 incident cases of overweight/obesity were identified (1649 for women and 1522 for men) during a median of 11 years of follow-up. Compared with the lowest category, the intake of total SFA (TSFA) showed no significant association with the risk of overweight/obesity. However, an increased risk of overweight/obesity was observed with a higher intake of medium chain SFA (MCSFA) (P_trend = 0·004), especially decanoic acid (10:0) (HR was 1·25 (95 % CI 1·10, 1·42) comparing the highest category with the reference group; P_trend < 0·001), whereas an inverse relationship was observed for hexanoic acid (6:0) consumption; compared with non-consumers, 6:0 intake was associated with 32 % lower risk of overweight/obesity (HR: 0·68 (95 % CI 0·56, 0·84); P_trend < 0·001). Overall, the intake of subtypes of MCSFA but not TSFA was associated with the risk of overweight/obesity. Increasing hexanoic acid (6:0) and limiting decanoic acid (10:0) consumption may be protective for overweight/obesity among Chinese population.

The Storage Conditions of High-Fat Diet Are the Key Factors for Diet-Induced Obesity and Liver Damage

The diet-induced obesity (DIO) mouse model has been widely used for obesity studies. The effects of storage conditions on the composition of nutrients in high-fat diets (HFDs) and their impact on metabolic homeostasis have not been systemically investigated. In the current study, we tested the effects of HFDs stored under different conditions and found that mice fed a HFD stored in the fridge (HFD^fri) gained less weight than those fed HFDs stored in the freezer (HFD^fre). Further analysis revealed that changes in the relative abundance of medium-chain triglyceride (MCT) in the HFD^fri, which have much lower intestinal absorption rates, contributed to the body weight differences. In contrast, exacerbated liver damage and elevated levels of unfolded protein response (UPR) was observed in the mice fed by HFD^fri. Depletion of the UPR-regulated gene Nnmt alleviated liver damage via the inhibition of the integrated stress response (ISR). Our study, for the first time, provides evidence that HFD storage conditions can have a significant impact on both body weight changes and liver damage in the DIO model.

Examining the Effect of Consuming C8 Medium-Chain Triglyceride Oil for 14 Days on Markers of NLRP3 Activation in Healthy Humans

Chronic, low-grade inflammation is associated with the development of numerous diseases and is mediated in part by overactivation of the NLRP3 inflammasome. The ketone body beta-hydroxybutyrate (βHB) suppresses the NLRP3 inflammasome and alters intracellular signalling pathways in vitro and in animal models; however, this effect has not yet been shown in vivo in humans. The purpose of this single-arm pilot trial was to determine if consuming 15 mL of C₈ medium-chain triglyceride (trioctanoin; MCT) oil, which induces mild elevation of βHB, twice daily (30 mL total) for 14 days would suppress markers of NLRP3 inflammasome activation in young, healthy humans while following their habitual diet. Consuming a single dose of 15 mL of C₈ MCT oil significantly raised blood βHB from fasting at 60 minutes and 120 minutes post ingestion (both P < 0.05). However, consumption of C₈ MCT oil for 14 days did not impact markers of monocyte NLRP3 inflammasome activation compared to baseline. Specifically, caspase-1 activation and secretion of its downstream product interleukin (IL)-1β were unchanged following 14 days of C₈ MCT oil supplementation when measured in unstimulated and LPS-stimulated whole blood cultures (all P > 0.05). Acetylation of histone H3 on the lysine residue 9 was unchanged (P < 0.05) and acetylation of lysine residue 14 was decreased (P < 0.05) following 14 days of supplementation. Thus, adding twice daily C₈ MCT oil supplementation to the habitual diet of young, healthy humans does not appear to suppress NLRP3 inflammasome activation.

Medium chain triglycerides (MCT): State-of-the-art on chemistry, synthesis, health benefits and applications in food industry

Medium chain triglycerides (MCT) are esters of fatty acids with 6 to 12 carbon atom chains. Naturally, they occur in various sources; their composition and bioactivity are source and extraction process-linked. The molecular size of MCT oil permits unique metabolic pathways and energy production rates, making MCT oil a high-value functional food. This review details the common sources of MCT oil, presenting critical information on the various approaches for MCT oil extraction or synthesis. Apart from conventional techniques, non-thermal processing methods that show promising prospects are analyzed. The biological effects of MCT oil are summarized, and the range of need-driven modification approaches are elaborated. A section is devoted to highlighting the recent trends in the application of MCT oil for food, nutraceuticals, and allied applications. While much is debated about the role of MCT oil in human health and wellness, there is limited information on daily requirements, impact on specific population groups, and effects of long-term consumption. Nonetheless, several studies have been conducted and continue to identify the most effective methods for MCT oil extraction, processing, handling, and storage. A knowledge gap exists and future research must focus on technology packages for scalability and sustainability.

Is a Ketogenic Diet Superior to a High-Fat, High-Cholesterol Diet Regarding Testicular Function and Spermatogenesis?

The study aimed to determine effects of a ketogenic diet on metabolic dysfunction, testicular antioxidant capacity, apoptosis, inflammation, and spermatogenesis in a high-fat and high-cholesterol diet-induced obese mice model. Forty-two male C57BL/6 mice were fed either a normal diet (NC group) or a high-fat and high-cholesterol (HFC) diet (HFC group) for 16 weeks, and mice from the HFC group were later randomly divided into two groups: the first were maintained on the original HFC diet, and the second were fed a medium-chain triacylglycerol (MCT)-based ketogenic diet for 8 weeks (KD group). A poor semen quality was observed in the HFC group, but this was eliminated by the ketogenic diet. Both the HFC and KD groups exhibited enhanced apoptosis protein expressions in testis tissue, including caspase 3 and cleaved PARP, and higher inflammation protein expressions, including TNF-α and NF-κB. However, the KD group exhibited a statistically-significant reduction in lipid peroxidation and an increased glutathione peroxidase level as compared with the HFC group. The HFC diet induced obesity in mice, which developed body weight gain, abnormal relative organ weights, metabolic dysfunction, and liver injury. Overall, the results showed that a ketogenic diet attenuated oxidative stress and improved the semen quality reduced by the HFC diet.

Activation of G protein-coupled receptors by ketone bodies: Clinical implication of the ketogenic diet in metabolic disorders

Ketogenesis takes place in hepatocyte mitochondria where acetyl-CoA derived from fatty acid catabolism is converted to ketone bodies (KB), namely β-hydroxybutyrate (β-OHB), acetoacetate and acetone. KB represent important alternative energy sources under metabolic stress conditions. Ketogenic diets (KDs) are low-carbohydrate, fat-rich eating strategies which have been widely proposed as valid nutritional interventions in several metabolic disorders due to its substantial efficacy in weight loss achievement. Carbohydrate restriction during KD forces the use of FFA, which are subsequently transformed into KB in hepatocytes to provide energy, leading to a significant increase in ketone levels known as "nutritional ketosis". The recent discovery of KB as ligands of G protein-coupled receptors (GPCR) - cellular transducers implicated in a wide range of body functions - has aroused a great interest in understanding whether some of the clinical effects associated to KD consumption might be mediated by the ketone/GPCR axis. Specifically, anti-inflammatory effects associated to KD regimen are presumably due to GPR109A-mediated inhibition of NLRP3 inflammasome by β-OHB, whilst lipid profile amelioration by KDs could be ascribed to the actions of acetoacetate via GPR43 and of β-OHB via GPR109A on lipolysis. Thus, this review will focus on the effects of KD-induced nutritional ketosis potentially mediated by specific GPCRs in metabolic and endocrinological disorders. To discriminate the effects of ketone bodies per se, independently of weight loss, only studies comparing ketogenic vs isocaloric non-ketogenic diets will be considered as well as short-term tolerability and safety of KDs.

Enzymatic synthesis of capric acid-rich structured lipids and their effects on mice with high-fat diet-induced obesity

The objective of this study was to produce structured lipids (SLs) by enzymatic acidolysis using Rhizopus oryzae lipase covalently immobilized in a low-cost material. Grape seed oil was used to synthesize SLs containing the medium-chain fatty acid (C10:0) capric acid. SL synthesis led to 38.8% medium-chain fatty acid incorporation with 5 reuses of the enzymatic derivative. The reaction conditions for the synthesis of MLM-TAGs (triacylglycerols with one long- and two medium-chain acyl residues) were at a molar ratio of fatty acid:oil of 3:1, performed at 40 °C and lipase immobilized load of 5% (w/w). The in vivo effects of SLs were studied in Swiss mice fed premade diets: control (C) diet, high-fat diet (HFD) with 100% lipid content as lard, HFD with 50% lipid content as grape seed oil (HG) or HFD with 50% lipid content as capric acid-containing SLs produced from grape seed oil (HG-MCT). Mice from HG and HG-MCT groups had decreases in body weight gain and reductions in the weights of white adipose tissues. In addition, HG and HG-MCT mice had low plasma levels of glucose and total cholesterol, and improvements in the glucose tolerance. HG and HG-MCT diets have remarkable antioxidant properties, since low plasma levels of TBARS (thiobarbituric acid reactive substances, biomarkers of lipid peroxidation) were found in mice fed these diets. Interestingly, TBARS levels in HG-MCT mice were further decreased than values of HG mice. Mice fed HG and HG-MCT diets also showed preservation in the activity of the antioxidant enzyme paraoxonase 1. Both HG and HG-MCT diets promoted reduction of IL-6 and IL-10 production by splenocytes. The capric acid-containing SLs produced from grape seed oil emerges as a functional oil capable to mitigate obesity complications resulting from oxidative stress and inflammation.

Bioactive Lipids and Their Derivatives in Biomedical Applications

Lipids, which along with carbohydrates and proteins are among the most important nutrients for the living organism, have a variety of biological functions that can be applied widely in biomedicine. A fatty acid, the most fundamental biological lipid, may be classified by length of its aliphatic chain, and the short-, medium-, and long-chain fatty acids and each have distinct biological activities with therapeutic relevance. For example, short-chain fatty acids have immune regulatory activities and could be useful against autoimmune disease; medium-chain fatty acids generate ketogenic metabolites and may be used to control seizure; and some metabolites oxidized from long-chain fatty acids could be used to treat metabolic disorders. Glycerolipids play important roles in pathological environments, such as those of cancers or metabolic disorders, and thus are regarded as a potential therapeutic target. Phospholipids represent the main building unit of the plasma membrane of cells, and play key roles in cellular signaling. Due to their physical properties, glycerophospholipids are frequently used as pharmaceutical ingredients, in addition to being potential novel drug targets for treating disease. Sphingolipids, which comprise another component of the plasma membrane, have their own distinct biological functions and have been investigated in nanotechnological applications such as drug delivery systems. Saccharolipids, which are derived from bacteria, have endotoxin effects that stimulate the immune system. Chemically modified saccharolipids might be useful for cancer immunotherapy or as vaccine adjuvants. This review will address the important biological function of several key lipids and offer critical insights into their potential therapeutic applications.

Ketogenic diet with medium-chain triglycerides restores skeletal muscle function and pathology in a rat model of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is an intractable genetic disease associated with progressive skeletal muscle weakness and degeneration. Recently, it was reported that intraperitoneal injections of ketone bodies partially ameliorated muscular dystrophy by increasing satellite cell (SC) proliferation. Here, we evaluated whether a ketogenic diet (KD) with medium-chain triglycerides (MCT-KD) could alter genetically mutated DMD in model rats. We found that the MCT-KD significantly increased muscle strength and fiber diameter in these rats. The MCT-KD significantly suppressed the key features of DMD, namely, muscle necrosis, inflammation, and subsequent fibrosis. Immunocytochemical analysis revealed that the MCT-KD promoted the proliferation of muscle SCs, suggesting enhanced muscle regeneration. The muscle strength of DMD model rats fed with MCT-KD was significantly improved even at the age of 9 months. Our findings suggested that the MCT-KD ameliorates muscular dystrophy by inhibiting myonecrosis and promoting the proliferation of muscle SCs. As far as we can ascertain, this is the first study to apply a functional diet as therapy for DMD in experimental animals. Further studies are needed to elucidate the underlying mechanisms of the MCT-KD-induced improvement of DMD.

Lauric Triglyceride Ameliorates High-Fat-Diet-Induced Obesity in Rats by Reducing Lipogenesis and Increasing Lipolysis and β-Oxidation

Medium-chain triglycerides (MCTs) are found in limited foods. In these medium-chain oil resources, the abundance of lauric acid (LA) is the highest among medium-chain fatty acids (MCFAs), and its effects on lipid metabolism in obese rats have not been well-studied. This study aimed to determine the anti-obesity effects and mechanisms of lauric triglyceride (LT) in Sprague Dawley (SD) rats. LA and glycerin were used to synthesize LT, then LT was used to treat obese rats for 12 weeks. The results showed that LT significantly reduced the body weight, body mass index, and Lee's index in obese rats. The mRNA expression levels of the anorexic neuropeptide POMC in the hypothalamus between the LT group and the other groups were not different, while the gene expression levels of the orexigenic neuropeptides NPY and AGRP decreased significantly in the LT group. Except serum cholesterol, LT improved the serum triglyceride metabolism in the obese rats and reduced adipocyte and hepatic lipid deposition. Moreover, LT inhibited the expression of lipogenesis-related genes and proteins (SREBP-1c, ACC1, and FASN) and increased the expression of lipolysis (ATGL, HSL, and LPL) and β-oxidation (PPARα, CPT-1a, and PCG-1α) related genes and proteins in the white fat and liver. Furthermore, LT increased the mRNA expression of mitochondrial-biosynthesis-related genes (SIRT1, NRF1, and TFAM) in the liver. The results indicated that LT ameliorates diet-induced obesity in rats.

The effect of a 6-month ketogenic medium-chain triglyceride supplement on plasma cardiometabolic and inflammatory markers in mild cognitive impairment

INTRODUCTION

Mild cognitive impairment (MCI) is often accompanied by metabolic abnormalities and inflammation that might play a role in the development of cognitive impairment. The use of ketogenic medium-chain triglycerides (kMCT) to improve cognition in this population has shown promising results but remains controversial because of the potentially detrimental effect of elevated intake of saturated fatty acids on cardiovascular (CV) health and perhaps inflammatory processes. The primary aim of this secondary data analysis report is to describe changes in cardiometabolic markers and peripheral inflammation during a 6-month kMCT intervention in MCI.

METHODS

Thirty-nine participants with MCI completed the intervention of 30 g/day of either a kMCT drink or calorie-matched placebo (high-oleic acid) for 6 months. Plasma concentrations of cardiometabolic and inflammatory markers were collected before (fasting state) and after the intervention (2 h following the last drink).

RESULTS

A mixed model ANOVA analysis revealed a time by group interaction for ketones (P < 0.001), plasma 8:0 and 10:0 acids (both P < 0.001) and IL-8 (P = 0.002) with follow up comparison revealing a significant increase in the kMCT group (+48%, P = 0.005), (+3,800 and +4,900%, both P < 0.001) and (+147%, P < 0.001) respectively. A main effect of time was observed for insulin (P = 0.004), triglycerides (P = 0.011) and non-esterified fatty acids (P = 0.036).

CONCLUSION

Under these study conditions, 30 g/d of kMCT taken for six months and up to 2-hour before post-intervention testing had minimal effect on an extensive profile of circulating cardiometabolic and inflammatory markers as compared to a placebo calorie-matched drink. Our results support the safety kMCT supplementation in individuals with MCI. The clinical significance of the observed increase in circulating IL-8 levels is presently unknown and awaits future studies.

The ameliorative effect of Lactobacillus plantarum Y44 oral administration on inflammation and lipid metabolism in obese mice fed with a high fat diet

In our previous studies, Lactobacillus plantarum Y44 showed antioxidant activity and favorable gastric and intestinal transit tolerance. The purpose of this study is to determine whether L. plantarum Y44 could ameliorate intestinal inflammation and lipid metabolism disorder in obese mice fed with a high-fat diet. L. plantarum Y44 was administered by gavage to the mice fed with a high-fat diet for 12 weeks. The mice fed with a high fat diet only showed sustainably elevated body weight, liver lipid metabolism disorder, intestinal inflammation and a lower short chain fatty acid content in feces. Oral administration of L. plantarum Y44 regulated lipid metabolism disorder by inhibiting the expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) in the liver of obese mice, reducing the contents of total cholesterol (TC), triacylglycerols (TG), low density lipoprotein cholesterol (LDL-c), alanine aminotransferase (ALT), and aspartate transaminase (AST) and increasing the content of high-density lipoprotein cholesterol (HDL-c) in the serum of obese mice. Oral administration of L. plantarum Y44 up-regulated the expression of colon tight junction protein such as claudin-1 and occludin, down-regulated p38 and phospho-p38 levels and reduced serum interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α). Oral administration of L. plantarum Y44 increased Muribaculaceae, Rikenellaceae, and Lactobacillaceae levels, reduced the Firmicutes/Bacteroidetes ratio, and Desulfovibrionaceae and Proteobacteria levels in obese mice. Oral administration of L. plantarum Y44 also enhanced the contents of propionic acid, butyric acid, butanoicacid-3-methyl, pentanoic acid and acetic acid in the feces of the obese mice. Correlation analysis of Spearman revealed a significant correlation between changes in intestinal microflora and obesity-related symptoms. L. plantarum Y44 ameliorated intestinal inflammation and lipid metabolism disorders by modulating gut microbiota.

Stability comparison of four lipases and catalytic mechanism during the synthesis of 1,3-di-oleic-2-medium chain triacylglycerols in a trace water-in-oil system: Experimental analyses and computational simulations

In the present study, a kind of structured lipids, namely 1,3-di-oleic-2-medium chain (OMO) triacylglycerols, were synthesized through lipase-catalyzed reactions using coconut oil and rapeseed acid as materials in a trace water-in-oil system. Experimental analysis and computational simulations were undertaken to compare the stability of four lipases including Lipozyme RMIM, Lipozyme TLIM, Novozym 435, and Aspergillus oryzae immobilized lipase (AOIM), and illustrate catalytic mechanism of Novozym 435 during the synthesis of OMO. Fourier transform infrared and molecular dynamics simulation results demonstrated that a decrease in ordered structure (α-helix and β-sheet) led to a reduction in enzyme activity. Compared with Lipozyme RMIM and Novozym 435, Lipozyme TLIM and AOIM exhibited better stability due to a short-chain lid in TLIM, which covers activity sites, and hydrogen bonds formed between activity center of AOIM and water. Among four lipases, AOIM exhibited best catalytic performance: a OMO yield of 30.7% at 3 hr and a good stability of long term (48 hr). Density functional theory results demonstrated that specifically, during the synthesis of OMO triacylglycerol, the addition of Novozym 435 (derived from Candida antarctica lipase B, CALB) substantially lowered reaction barriers (64.4 KJ/mol with CALB vs. 332.7 KJ/mol with no lipase), aiding in the generation of OMO because of the formations of transitional tetrahedral intermediates. A trace water-in-oil system was a green and efficient alternative for lipase-catalyzed production of OMO, and this study provided crucial insights into the stability/instability and catalytic mechanisms of lipase in the synthesis of structured lipids. PRACTICAL APPLICATIONS: We compared the stability of Lipozyme RMIM, Lipozyme 435, Lipozyme TLIM, and AOIM during the synthesis of the OMO triacylglycerols in a trace water-in-oil system, where exhibited a high catalytic activity of lipase in water-oil interface. AOIM had the highest stability and showed the best catalytic performance due to the formation of hydrogen bonds. Besides, for the first time, the transition tetrahedral structure was revealed in the enzymatic synthesis of medium- and long-chain triacylglycerols. This study provides a rational approach to compare lipase stability and a possible hint to choose appropriate enzyme in a specific catalytic condition.

New perspective toward nutritional support for malnourished cancer patients: Role of lipids

To improve the difficulties related to malnutrition, nutritional support has become an essential part of multidisciplinary comprehensive treatment for cancer. Lipids are essential nutrient source for the human body, and nowadays in clinical practices, it has a positive interventional effect on patients suffering from cancer. However, contribution of lipids in nutritional support of cancer patients is still poorly understood. Moreover, the sensory and physicochemical properties of lipids can severely restrict their applications in lipid-rich formula foods. In this review article, for the first time, we have presented a summary of the existing studies which were related to the associations between different lipids and improved malnutrition in cancer patients and discussed possible mechanisms. Subsequently, we discussed the challenges and effective solutions during processing of lipids into formula foods. Further, by considering existing problems in current lipid nutritional support, we proposed a novel method for the treatment of malnutrition, including developing individualized lipid nutrition for different patients depending on the individual's genotype and enterotype. Nonetheless, this review study provides a new direction for future research on nutritional support and the development of lipid-rich formula foods for cancer patients, and probably will help to improve the efficacy of lipids in the treatment of cancer malnutrition.

Medium chain triglyceride and medium-and long chain triglyceride: metabolism, production, health impacts and its applications - a review

Structured lipid is a type of modified form of lipid that is "fabricated" with the purpose to improve the nutritional and functional properties of conventional fats and oils derived from animal and plant sources. Such healthier choice of lipid received escalating attention from the public for its capability to manage the rising prevalence of metabolic syndrome. Of which, medium-chain triacylglycerol (MCT) and medium-and long-chain triacylglycerol (MLCT) are the few examples of the "new generation" custom-made healthful lipids which are mainly composed of medium chain fatty acid (MCFA). MCT is made up exclusively of MCFA whereas MLCT contains a mixture of MCFA and long chain fatty acid (LCFA), respectively. Attributed by the unique metabolism of MCFA which is rapidly metabolized by the body, MCFA and MCT showed to acquire multiple physiological and functional properties in managing and reversing certain health disorders. Several chemically or enzymatically oils and fats modification processes catalyzed by a biological or chemical catalyst such as acidolysis, interesterification and esterification are adopted to synthesis MCT and MLCT. With their purported health benefits, MCT and MLCT are widely being used as nutraceutical in food and pharmaceutical sectors. This article aims to provide a comprehensive review on MCT and MLCT, with an emphasis on the basic understanding of its structures, properties, unique metabolism; the current status of the touted health benefits; latest routes of production; its up-to-date applications in the different food systems; relevant patents filed and its drawbacks.

Distribution of blood glucose and prevalence of diabetes among centenarians and oldest-old in China: based on the China Hainan Centenarian Cohort Study and China Hainan Oldest-old Cohort Study

OBJECTIVE

There was little data on the distribution of blood glucose levels and diabetes prevalence for centenarians and the oldest-old. The aim of this study is to analyzed the distribution of blood glucose and diabetes prevalence for centenarians and oldest-old in China: Based on the China Hainan Centenarian Cohort Study (CHCCS) and China Hainan Oldest-old Cohort Study (CHOCS).

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

A total of 1002 centenarians and 798 oldest-old were enrolled from 18 cities and counties in Hainan Province (one of the longevity provinces) from 2016-2018.

MEASURES

The fasting blood glucose was tested and prevalence of diabetes was calculated.

RESULTS

The average age of centenarians was 102.77 ± 2.55 years old, 82.0% were women. The average age of the oldest-old was 84.99 ± 4.01 years old, 59.9% were women. The average blood glucose of centenarians was 5.12 ± 1.44 and 4.80 ± 1.27 mmol/L, and more than 70% were between 3.00 mmol/L and 5.99 mmol/L. There was no statistical difference between different genders and age groups. A total of 9.5% of centenarians had diabetes and 8.1% had IFG. A total of 11.4% of the oldest-old had diabetes and 4.4% had IFG. Abdominal obesity and TG levels may be associated with diabetes prevalence. The corresponding ORs were 1.517(1.083-2.125) and 1.473(1.089-1.943) respectively of abdominal obesity among centenarians and the oldest-old respectively, and corresponding ORs 1.182(1.081-1.316) and 1.162(1.009-1.699) respectively of abdominal obesity among centenarians and the oldest-old respectively CONCLUSIONS AND IMPLICATIONS: In summary, the results based on CHCCS with the largest sample among centenarians and CHOCS showed that the blood glucose level and the prevalence of diabetes were at a lower level than those of adults or younger elderly. The results provide new evidence for target level of blood glucose control in those older elderly.

Implicating the effect of ketogenic diet as a preventive measure to obesity and diabetes mellitus

Obesity and diabetes are the two major metabolic complications linked with bad eating habits and the sedentary (lazy) lifestyle. In the worst-case situation, metabolic problems are a causative factor for numerous other conditions. There is also an increased demand to control the emergence of such diseases. Dietary and lifestyle improvements contribute to their leadership at an elevated level. The present review, therefore, recommends the use of the ketogenic diet (KD) in obesity and diabetes treatment. The KD involves a diet that replaces glucose sugar with ketone bodies and is effective in numerous diseases, such as metabolic disorders, epileptic seizures, autosomal dominant polycystic disease of the kidney, cancers, peripheral neuropathy, and skeletal muscle atrophy. A lot of high profile pathways are available for KD action, including sustaining the metabolic actions on glucose sugar, suppressing insulin-like growth factor-1 (IGF1) and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathways, altering homeostasis of the systemic ketone bodies, contributing to lowering diabetic hyperketonemia, and others. The KD regulates the level of glucose sugar and insulin and can thus claim to be an effective diabetes approach. Thus, a stopgap between obesity and diabetes treatment can also be evidenced by KD.

Understanding Dietary Intervention-Mediated Epigenetic Modifications in Metabolic Diseases

The global prevalence of metabolic disorders, such as obesity, diabetes and fatty liver disease, is dramatically increasing. Both genetic and environmental factors are well-known contributors to the development of these diseases and therefore, the study of epigenetics can provide additional mechanistic insight. Dietary interventions, including caloric restriction, intermittent fasting or time-restricted feeding, have shown promising improvements in patients' overall metabolic profiles (i.e., reduced body weight, improved glucose homeostasis), and an increasing number of studies have associated these beneficial effects with epigenetic alterations. In this article, we review epigenetic changes involved in both metabolic diseases and dietary interventions in primary metabolic tissues (i.e., adipose, liver, and pancreas) in hopes of elucidating potential biomarkers and therapeutic targets for disease prevention and treatment.

Consumption of Interesterified Medium- and Long-Chain Triacylglycerols Improves Lipid Metabolism and Reduces Inflammation in High-Fat Diet-Induced Obese Rats

Medium- and long-chain triacylglycerols (MLCTs) were synthesized from rapeseed oil (RO), one kind of commonly used edible long-chain triacylglycerols (TGs), and then delivered to high-fat diet (HFD)-induced obese rats. Compared with RO, MLCT consumption exhibited more potent effects on reducing body and tissue weight gains, plasma TG, and total cholesterol (TC) levels and on improving hepatic TG, TC, fatty acid synthase, acetyl-CoA carboxylase, and lipoprteinlipase contents. Meanwhile, lower amounts of tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1, and endotoxin in plasma, lower levels of interleukin-6 and TNF-α, and higher levels of interleukin-10 in both livers and white adipose tissues were detected in MLCT-fed rats. MLCT intake also remarkably suppressed the size of adipocytes and the number of macrophages. In conclusion, our study suggested that the interesterified MLCT was more efficacious in improving the lipid metabolism and inflammation in HFD-induced obese rats than RO.

Dietary substitution of soybean oil with coconut oil in the absence of dietary antibiotics supports growth performance and immune function in nursery and grower pigs

Background

We hypothesized that supplementation of nursery and grower pig diets with coconut oil in the absence of antibiotics would yield maintenance of glucose homeostasis, growth performance, and immune function similar to what is achieved with nursery and grower pig diets containing antibiotics. Pigs received the same base treatment diets from d24 (weaning) to d71 of age and had blood and fecal samples collected on d24, d31, d45 and d71 for measurement of whole blood glucose, serum insulin, cortisol and cytokines, and fecal microbiome. Pigs had weekly weights and daily feed consumption measured throughout the study. Animals were euthanized at d71 and subcutaneous fat and ileal contents were collected for assessment for fatty acids and microbiome, respectively. Diet treatments consisted of 2% soybean oil plus antibiotics (ABX; n = 22), 2% soybean oil without antibiotics (NABX; n = 22), and 2% coconut oil without antibiotics (COC; n = 22). Statistical analysis examined the effect of diet within each timepoint using a repeated measures ANOVA.

Results

Pigs fed COC diet had decreased serum insulin levels, maintained feed intake, feed conversion and weight gain, and, based on serum cytokines and fecal microbiome, were immunologically similar to ABX-fed pigs. However, NABX-fed pigs performed similarly to the ABX-fed pigs in all parameters except for serum cytokines. Additionally, there was no difference in the incidence of diarrhea between any of the diet treatments.

Conclusions

This study demonstrates that dietary antibiotics are not necessary to maintain growth performance in nursery and grower pigs. However, dietary antibiotics appear to modulate circulating cytokine levels. Dietary coconut oil is neither harmful nor helpful to growth performance or immune function in nursery and grower pigs but does modulate serum insulin levels. Therefore, while coconut oil fed at 2% by weight is a suitable substitute for dietary antibiotics, this study suggests that no substitute for dietary antibiotics is needed at all.

Effects of dietary glycerol monolaurate on productive performance, egg quality, serum biochemical indices, and intestinal morphology of laying hens

Glycerol monolaurate (GML) has been widely used as an effective antibacterial emulsifier in the food industry. A total of 360 44-week-old Hy-Line brown laying hens were randomly distributed into four groups each with six replicates of 15 birds, and fed with corn-soybean-meal-based diets supplemented with 0, 0.15, 0.30, and 0.45 g/kg GML, respectively. Our results showed that 0.15, 0.30, and 0.45 g/kg GML treatments significantly decreased feed conversion ratios (FCRs) by 2.65%, 7.08%, and 3.54%, respectively, and significantly increased the laying rates and average egg weights. For egg quality, GML drastically increased albumen height and Haugh units, and enhanced yolk color. Notably, GML increased the concentrations of polyunsaturated and monounsaturated fatty acids and reduced the concentration of total saturated fatty acids in the yolk. The albumen composition was also significantly modified, with an increase of 1.02% in total protein content, and increased contents of His (4.55%) and Glu (2.02%) under the 0.30 g/kg GML treatment. Additionally, GML treatments had positive effects on the lipid metabolism of laying hens, including lowering the serum triglyceride and total cholesterol levels and reducing fat deposition in abdominal adipose tissue. Intestinal morphology was also improved by GML treatment, with increased villus length and villus height to crypt depth ratio. Our data demonstrated that GML supplementation of laying hens could have beneficial effects on both their productivity and physiological properties, which indicates the potential application of GML as a functional feed additive and gives us a new insight into this traditional food additive.

Impact of in-feed sodium butyrate or sodium heptanoate protected with medium-chain fatty acids on gut health in weaned piglets challenged with Escherichia coli F4. Arch Anim Nutr 2020;74:271-295. [PMID: 32108496 DOI: 10.1080/1745039x.2020.1726719]

Short and medium-chain fatty acids (SCFA and MCFA, respectively) are commonly used as feed additives in piglets to promote health and prevent post-weaning diarrhoea. Considering that the mechanism and site of action of these fatty acids can differ, a combined supplementation could result in a synergistic action. Considering this, it was aimed to assess the potential of two new in-feed additives based on butyrate or heptanoate, protected with sodium salts of MCFA from coconut distillates, against enterotoxigenic Escherichia coli (ETEC) F4⁺ using an experimental disease model. Two independent trials were performed in 48 early-weaned piglets fed a control diet (CTR) or a diet supplemented with MCFA-protected sodium butyrate (BUT+; Trial 1) or sodium heptanoate (HPT+; Trial 2). After 1 week of adaptation, piglets were challenged with a single oral inoculum of ETEC F4⁺ (minimum 1.4 · 10⁹ cfu). One animal per pen was euthanised on days 4 and 8 post-inoculation (PI) and the following variables assessed: growth performance, clinical signs, gut fermentation, intestinal morphology, inflammatory mediators, pathogen excretion and colon microbiota. None of the additives recovered growth performance or reduced diarrhoea when compared to the respective negative controls. However, both elicited different responses against ETEC F4⁺. The BUT+ additive did not lead to reduce E. coli F4 colonisation but enterobacterial counts and goblet cell numbers in the ileum were increased on day 8 PI and this followed higher serum TNF-α concentrations on day 4 PI. The Firmicutes:Bacteroidetes ratio was nevertheless increased. Findings in the HPT+ treatment trial included fewer animals featuring E. coli F4 in the colon and reduced Enterobacteriaceae (determined by 16S RNA sequencing) on day 4 PI. In addition, while goblet cell numbers were lower on day 8 PI, total SCFA levels were reduced in the colon. Results indicate the efficacy of MCFA-protected heptanoate against ETEC F4⁺ and emphasise the potential trophic effect of MCFA-protected butyrate on the intestinal epithelium likely reinforcing the gut barrier.

A Neural basis for Octanoic acid regulation of energy balance

Objectives

Nutrient sensing by hypothalamic neurons is critical for the regulation of food intake and energy expenditure. We aimed to identify long- and medium-chain fatty acid species transported into the brain, their effects on energy balance, and the mechanisms by which they regulate activity of hypothalamic neurons.

Methods

Simultaneous blood and cerebrospinal fluid (CSF) sampling was undertaken in rats and metabolic analyses using radiolabeled fatty acid tracers were performed on mice. Electrophysiological recording techniques were used to investigate signaling mechanisms underlying fatty acid-induced changes in activity of pro-opiomelanocortin (POMC) neurons.

Results

Medium-chain fatty acid (MCFA) octanoic acid (C8:0), unlike long-chain fatty acids, was rapidly transported into the hypothalamus of mice and almost exclusively oxidized, causing rapid, transient reductions in food intake and increased energy expenditure. Octanoic acid differentially regulates the excitability of POMC neurons, activating these neurons directly via GPR40 and inducing inhibition via an indirect non-synaptic, purine, and adenosine receptor-dependent mechanism.

Conclusions

MCFA octanoic acid is a central signaling nutrient that targets POMC neurons via distinct direct and indirect signal transduction pathways to instigate changes in energy status. These results could explain the beneficial health effects that accompany MCFA consumption.

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Octanoic acid (C8:0) is rapidly transported from blood to the cerebrospinal fluid.

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Octanoic acid rapidly reduces food intake and increases energy expenditure.

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Octanoic acid targets POMC neurons through direct and indirect signaling pathways.

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Activation of POMC neurons occurs directly through GPR40.

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Inhibition occurs through a nonsynaptic, purine and adenosine receptor-dependent mechanism.

Efficacy of medium-chain fatty acid salts distilled from coconut oil against two enteric pathogen challenges in weanling piglets

BACKGROUND

The search for alternatives to antibiotics in pig production has increased the interest in natural resources with antimicrobial properties, such as medium-chain fatty acids (MCFA) as in-feed additives. This study evaluated the potential of a novel blend of MCFA salts (DIC) from distilled coconut oil with a lauric acid content to reduce enteropathogens and control intestinal diseases around weaning. Two experimental disease models were implemented in early-weaned piglets, consisting of two oral challenges: Salmonella Typhimurium (1.2 × 108 CFU) or enterotoxigenic Escherichia coli (ETEC) F4 (1.5 × 109 CFU). The parameters assessed were: animal performance, clinical signs, pathogen excretion, intestinal fermentation, immune-inflammatory response, and intestinal morphology.

RESULTS

The Salmonella challenge promoted an acute course of diarrhea, with most of the parameters responding to the challenge, whereas the ETEC F4 challenge promoted a mild clinical course. A consistent antipathogenic effect of DIC was observed in both trials in the hindgut, with reductions in Salmonella spp. plate counts in the cecum (P = 0.03) on d 8 post-inoculation (PI) (Salmonella trial), and of enterobacteria and total coliform counts in the ileum and colon (P < 0.10) on d 8 PI (ETEC F4 trial). When analyzing the entire colonic microbiota (16S rRNA gene sequencing), this additive tended (P = 0.13) to reduce the Firmicutes/Bacteroidetes ratio and enriched Fibrobacteres after the Salmonella challenge. In the ETEC F4 challenge, DIC prompted structural changes in the ecosystem with increases in Dialister, and a trend (P = 0.14) to increase the Veillonellaceae family. Other parameters such as the intestinal fermentation products or serum pro-inflammatory mediators were not modified by DIC supplementation, nor were the histological parameters. Only the intraepithelial lymphocyte (IEL) counts were lowered by DIC in animals challenged with Salmonella (P = 0.07). With ETEC F4, the IEL counts were higher with DIC on d 8 PI (P = 0.08).

CONCLUSIONS

This study confirms the potential activity of this MCFA salts mixture to reduce intestinal colonization by opportunistic pathogens such as Salmonella or E. coli and its ability to modulate colonic microbiota. These changes could explain to some extent the local immune cell response at the ileal level.

Effects of medium chain triglycerides on body fat distribution and adipocytokine levels in children with acute lymphoblastic leukemia under chemotherapy

Glucocorticoids used to treat acute lymphoblastic leukemia (ALL) are associated with cytotoxicity and obesity. The aim of the study was to investigate the effects of high-proportion medium chain triglyceride (MCT) on body fat distribution and levels of leptin and adiponectin during chemotherapy of children with ALL.New-onset ALL children treated at the Guangzhou Women and Children's Medical Center between March 2016 and March 2017 were enrolled. Children were divided into the MCT and control groups. For the MCT group, high-proportion MCT nutrition preparation was added to the diet, while no MCT was added for the control group. The MCT group was further divided into subgroups A and B based on the amount of supplement. Waist circumference, hip circumference, waist-to-hip ratio, bone marrow concentrations of leptin and adiponectin, and leptin-to-adiponectin ratio were measured before and on days 19 and 46 of chemotherapy. Body weight and body mass index (BMI) were measured on admission and discharge.Waist circumference in the control group increased by day 46 (P = .047), but did not change in the MCT group. The BMI of the children in the control group was higher than those in the MCT group on admission (P = .003), but not different at discharge. No significant differences in hip circumference, leptin levels, adiponectin levels, and body weight were observed between the 2 groups.This preliminary study suggests that short-term supplementation of high-proportion MCT nutrition preparation may help reduce the centripetal distribution of adipose induced by the application of glucocorticoids in children with ALL. This will have to be confirmed in future studies.

Medium-chain triglyceride diet stimulates less GIP secretion and suppresses body weight and fat mass gain compared with long-chain triglyceride diet

Gastric inhibitory polypeptide (GIP) is an incretin secreted from enteroendocrine K cells and potentiates insulin secretion from pancreatic β-cells. GIP also enhances long-chain triglyceride (LCT) diet-induced obesity and insulin resistance. Long-term intake of medium-chain triglyceride (MCT) diet is known to induce less body weight and fat mass gain than that of LCT diet. However, the effect of MCT diet feeding on GIP secretion and the effect of GIP on body weight and fat mass under MCT diet-feeding condition are unknown. In this study, we evaluated the effect of single MCT oil administration on GIP secretion and compared the effect of long-term MCT and LCT diet on body weight and fat mass gain in wild-type (WT) and GIP-knockout (GIP KO) mice. Single administration of LCT oil induced GIP secretion but that of MCT oil did not in WT mice. Long-term intake of LCT diet induced GIP hypersecretion and significant body weight and fat mass gain compared with that of control fat (CF) diet in WT mice. In contrast, MCT diet did not induce GIP hypersecretion, and MCT diet-fed mice showed smaller increase in body weight and fat mass gain compared with CF diet-fed mice. In GIP KO mice, body weight and fat mass were markedly attenuated in LCT diet-fed mice but not in MCT diet-fed mice. Our results suggest that long-term intake of MCT diet stimulates less GIP secretion and suppresses body weight and fat mass gain compared with that of LCT diet.

[Mechanisms of ketogenic diet action]

The paper considers the necessity of using ketogenic diet and its efficacy in epilepsy. Direct and indirect effects of ketones on brain cells and molecular mechanisms of their action are discussed in detail.

Medium-chain triglyceride reinforce the hepatic damage caused by fructose intake in mice

We aimed to investigate the effects of medium-chain triglyceride oil on the high fructose diet-provoked hepatic abnormalities in mice. We used C57bl/6 mice of 3-months-old divided into four groups for 12 weeks: control (C), control with MCT (C-MCT), fructose (F), and fructose with MCT (F-MCT). We investigated food and water intake, body mass, blood pressure, glucose tolerance, plasma and liver biochemistry, hepatic protein and gene expression. There were no changes in body mass, food intake and glucose tolerance among the groups. The F group presented increased water intake and blood pressure associated with hepatic steatosis and elevated de novo lipogenesis, beta-oxidation, mitochondrial biogenesis and inflammation in the liver. Surprisingly, the C-MCT group also showed hepatic steatosis and inflammation in the liver, and the F-MCT group had no exacerbations of fructose-induced abnormalities, showing marked hepatic steatosis, lipogenesis de novo and hepatic inflammation. The MCT oil groups also presented increased beta-oxidation and mitochondrial biogenesis. In conclusion, MCT oil showed detrimental hepatic effects and should be used with caution, especially in the presence of hepatic alterations.