Postprandial triglyceride response in normolipidemic, hyperlipidemic and obese subjects - the influence of polydextrose, a non-digestible carbohydrate

Effects of Betaine and Polydextrose on Intestinal Microbiota and Liver Ergothioneine in a High-Fat Diet-Fed Mouse Model and a Human Colonic Simulation Model

BACKGROUND/OBJECTIVES

Ergothioneine (EGT) is an effective antioxidant that animals cannot produce and has an important anti-inflammatory role in cell protection, which can help lower the risk of various diseases. In this study, we investigated the potential role of gut microbiota in the production of EGT, which was found to increase in the mouse liver after dietary supplementation with betaine (BET) or polydextrose (PDX).

METHODS

The effects of BET and PDX on the gut microbiota and tissue EGT content were investigated using a diet-induced obese mouse model and simulated fermentation in the human colon. Male C57BL/6J mice were fed a high-fat diet (HFD) for 8 weeks to induce obesity and related metabolic disorders, and for the last 4 weeks of this study, the mice continued on the same diet, supplemented with BET, PDX, or their combination. The potential function of BET and PDX in microbial EGT production was further studied in an in vitro human colon model.

RESULTS

The quantity of Bifidobacterium spp. and Bacteroidota were significantly higher in the feces of mice on diets supplemented with PDX or BET + PDX, and Enterobacteriaceae levels were significantly higher in PDX-supplemented mice than in HFD-fed mice. Untargeted metabolomic analysis of the liver revealed a significant increase in EGT in mice fed HFDs with BET or BET + PDX. Microbial analysis from samples collected from the human in vitro model showed significant changes in Neglecta timonensis, Blautia faecis, Lachnospiracea incertae sedis, Faecalibacillus, and Stenotrophomonas maltophilia species, along with an increase in microbial metabolites, namely, acetic, propionic and butyric acids, and a decrease in 2-methylbutyric acid.

CONCLUSIONS

Although PDX and BET or their combination affected microbial composition and metabolites in the human colon simulation model, the model used was not able to detect a significant change in microbiota-based EGT production and, therefore, could not explain the increase in EGT in the liver of betaine-fed mice.

Biochemical Changes in Adult Male Gamers During Prolonged Gaming: Pilot Study

BACKGROUND

Gaming has become an integrated part of life for children and adults worldwide. Previous studies on the impact of gaming on biochemical parameters have primarily addressed the acute effects of gaming. The literature is limited, and the study designs are very diverse. The parameters that have been investigated most thoroughly are blood glucose and cortisol.

OBJECTIVE

This exploratory study is the first to investigate the effects of long gaming sessions on the biochemical parameters of healthy male adults. The extensive testing allowed us to observe short-term changes (within 6 hours), long-term changes during the duration of the gaming sessions, and follow-up after 1 week to determine whether any changes were longer lasting.

METHODS

In total, 9 experienced gamers completed 2 back-to-back 18-hour gaming sessions interspersed with a 6-hour rest period. All participants adhered to a structured sleep pattern due to daytime employment or attending university. Blood, saliva, and urine samples were collected from the participants every 6 hours. Linear mixed-effect models were used to analyze the repeated-measures data accumulated during the study. A total of 51 biochemical parameters were investigated.

RESULTS

In total, 12 of the 51 biochemical parameters significantly changed during the study: alkaline phosphatase, aspartate aminotransferase, bilirubin, chloride, creatinine, glucose, hemoglobin, immature reticulocyte fraction, lactate, methemoglobin, sodium, and thrombocytes. All changes were within the normal range. The mean glucose level of the participants was 4.39 (SD 0.07) mmol/L at baseline, which increased significantly by 0.24 (SD 0.07) mmol/L per 6 hours during the first period and by 0.38 (SD 0.07) mmol/L per 6 hours in the second period (P<.001). The glucose levels during the second session increased even though the participants had little energy intake. Cortisol levels did not change significantly, although the cortisol pattern deviated from the typical circadian rhythm. During both gaming sessions, we observed increasing cortisol levels from 6 AM until noon. The participants were relatively dehydrated at the start of the study. The patients were asked to fast before the first blood sampling. Within the first 6 hours of the study, the participants rehydrated, followed by relative dehydration during the remainder of the study. This pattern was identified using the following parameters: albumin, creatinine, hemoglobin, erythrocytes, potassium, and platelets.

CONCLUSIONS

This study is the first of its kind, and many of the analyses in the study yielded novel results. The study was designed to emulate the behavior of gamers during the weekend and other long gaming sessions. At this point, we are not able to determine the difference between the effects of gaming and behavior during gaming. Regardless, the results of this study suggest that healthy gamers can partake in long gaming sessions, with ample amounts of unhealthy foods and little rest, without acute impacts on health.

Time-resolved concentrations of serum amino acids, one-carbon metabolites and B-vitamin biomarkers during the postprandial and fasting state: the Postprandial Metabolism in Healthy Young Adults (PoMet) Study

Metabolomics has been utilised in epidemiological studies to investigate biomarkers of nutritional status and metabolism in relation to non-communicable diseases. However, little is known about the effect of prandial status on several biomarker concentrations. Therefore, the aim of this intervention study was to investigate the effect of a standardised breakfast meal followed by food abstinence for 24 h on serum concentrations of amino acids, one-carbon metabolites and B-vitamin biomarkers. Thirty-four healthy subjects (eighteen males and sixteen females) aged 20-30 years were served a breakfast meal (∼500 kcal) after which they consumed only water for 24 h. Blood samples were drawn before and at thirteen standardised timepoints after the meal. Circulating concentrations of most amino acids and metabolites linked to one-carbon metabolism peaked within the first 3 h after the meal. The branched-chain amino acids steadily increased from 6 or 8 hours after the meal, while proline decreased in the same period. Homocysteine and cysteine concentrations immediately decreased after the meal but steadily increased from 3 and 4 hours until 24 h. FMN and riboflavin fluctuated immediately after the meal but increased from 6 h, while folate increased immediately after the meal and remained elevated during the 24 h. Our findings indicate that accurate reporting of time since last meal is crucial when investigating concentrations of certain amino acids and one-carbon metabolites. Our results suggest a need for caution when interpretating studies, which utilise such biomarkers, but do not strictly control for time since the last meal.

Blood Microbiota Profile Is Associated with the Responsiveness of Postprandial Lipemia to Platycodi radix Beverage: A Randomized Controlled Trial in Healthy Subjects

Prolonged postprandial hyperlipidemia may cause the development of cardiovascular diseases. This study explored whether postprandial triglyceride-rich lipoprotein (TRL) clearance responsiveness to Platycodi radix beverage (PR) is associated with changes in blood microbiota profiles. We conducted an 8-week randomized controlled clinical trial involving normolipidemic adults with low fruit and vegetable intakes. Participants underwent an oral fat tolerance test and 16S amplicon sequencing analysis of blood microbiota. Using the Qualitative Interaction Trees, we identified responders as those with higher baseline dietary fat intake (>38.5 g/day) and lipoprotein lipase levels (>150.6 ng/mL), who showed significant reductions in AUC for triglyceride (TG) and chylomicron-TG after the oral fat tolerance test. The LEfSe analysis showed differentially abundant blood microbiota between responders and non-responders. A penalized logistic regression algorithm was employed to predict the responsiveness to intervention on the TRL clearance based on the background characteristics, including the blood microbiome. Our findings suggest that PR intake can modulate postprandial TRL clearance in adults consuming higher fat intake over 38.5 g/day and low fruit and vegetable intake through shared links to systemic microbial signatures.

Assessing Insulin Sensitivity and Postprandial Triglyceridemic Response Phenotypes With a Mixed Macronutrient Tolerance Test

The use of meal challenge tests to assess postprandial responses in carbohydrate and fat metabolism is well established in clinical nutrition research. However, challenge meal compositions and protocols remain a variable. Here, we validated a mixed macronutrient tolerance test (MMTT), containing 56-g palm oil, 59-g sucrose, and 26-g egg white protein for the parallel determination of insulin sensitivity and postprandial triglyceridemia in clinically healthy subjects. The MMTT was administered in two study populations. In one, women with overweight/obese BMIs (n = 43) involved in an 8-week dietary intervention were administered oral glucose tolerance tests (OGTTs) and MMTTs within 2 days of each other after 0, 2, and 8 weeks of the dietary intervention. In the other, 340 men and women between 18 and 64 years of age, with BMI from 18–40 kg/m2, completed the MMTT as part of a broad nutritional phenotyping effort. Postprandial blood collected at 0, 0.5, 3, and 6 h was used to measure glucose, insulin, and clinical lipid panels. The MMTT postprandial insulin-dependent glucose disposal was evaluated by using the Matsuda Index algorithm and the 0- and 3 h blood insulin and glucose measures. The resulting MMTT insulin sensitivity index (ISIMMTT) was strongly correlated (r = 0.77, p &lt; 0.001) with the OGTT-dependent 2 h composite Matsuda index (ISIComposite), being related by the following equation: Log (ISIComposite) = [0.8751 x Log(ISIMMTT)] –0.2115. An area under the triglyceride excursion curve &gt;11.15 mg/mL h–1 calculated from the 0, 3, and 6 h blood draws established mild-to-moderate triglyceridemia in agreement with ∼20% greater prevalence of hypertriglyceridemia than fasting indications. We also demonstrated that the product of the 0 to 3 h and 3 to 6 h triglyceride rate of change as a function of the triglyceride incremental area under the curve optimally stratified subjects by postprandial response patterns. Notably, ∼2% of the population showed minimal triglyceride appearance by 6 h, while ∼25% had increasing triglycerides through 6 h. Ultimately, using three blood draws, the MMTT allowed for the simultaneous determination of insulin sensitivity and postprandial triglyceridemia in individuals without clinically diagnosed disease.

Clinical Trial Registration

[https://clinicaltrials.gov/], identifier [NCT02298725; NCT02367287].

Decreased Efficiency of Very-Low-Density Lipoprotein Lipolysis Is Linked to Both Hypertriglyceridemia and Hypercholesterolemia, but It Can Be Counteracted by High-Density Lipoprotein

Impaired triglyceride-rich lipoprotein plasma catabolism is considered the most important factor for hypertriglyceridemia development. The aim of this study was to evaluate the impact of hypercholesterolemia and hypertriglyceridemia on the efficiency of lipoprotein lipase (LPL)-mediated very-low-density lipoprotein (VLDL)-triglyceride lipolysis and the role of high-density lipoprotein (HDL) in this process. Subjects with no history of cardiovascular disease (CVD) and untreated with lipid-lowering agents were recruited into the study and divided into normolipidemic, hypercholesterolemic, and hyperlipidemic groups. VLDL was isolated from serum and incubated with LPL in the absence or presence of HDL. For the hypercholesterolemic and hyperlipidemic groups, a significantly lower percentage of hydrolyzed VLDL-triglyceride was achieved compared to the normolipidemic group (p < 0.01). HDL enhanced the lipolysis efficiency in the hypercholesterolemic and hyperlipidemic groups on average by ~7% (p < 0.001). The lowest electrophoretic mobility of the VLDL remnants indicating the most effective lipolysis was obtained in the normolipidemic group (p < 0.05). HDL presence significantly reduced the electrophoretic mobility of the VLDL remnants for the hypercholesterolemic and hyperlipidemic groups (p < 0.05). The results of our study indicate that VLDL obtained from hypercholesterolemic and hyperlipidemic subjects are more resistant to lipolysis and are additional evidence of the need for early implementation of hypocholesterolemic treatment, already in asymptomatic CVD subjects.

Postprandial lipaemia following consumption of a meal enriched with medium chain saturated and/or long chain omega-3 polyunsaturated fatty acids. A randomised cross-over study

BACKGROUND & AIMS

Postprandial lipaemic response has emerged as a risk factor for cardiovascular disease. Dietary fats such as medium-chain saturated fatty acids (MCSFA) and long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) are known to reduce postprandial lipaemic responses. The combination of the two could potentially have complementary and/or synergistic effects for optimising cardiovascular health. This study aims to investigate the effects of MCSFA (coconut oil) with or without LCn-3PUFA (fish oil) inclusion in the test meal on postprandial blood lipids in healthy adults.

METHODS

In a randomised, double-blinded, placebo-controlled, 2 × 2 factorial cross-over study, participants (n = 15) were randomised to receive four standardised isocaloric test meals. Test meals include: placebo [PL, containing no fish oil (0 g EPA & DHA) or coconut oil (0 g MCSFA)], fish oil [FO, 6 g fish oil (3.85 g EPA & DHA), containing no coconut oil (0 g MCSFA)], coconut oil [CO, 18.65 g coconut oil (15 g MCSFA), containing no fish oil (0 g EPA & DHA)] and coconut oil + fish oil [COFO, 18.65 g coconut oil (15 g MCSFA) + 6 g fish oil (3.85 g EPA & DHA)]; all providing a total fat content of 33.5 g. Participants received all four treatments on four separate test days with at least 3 days washout in between. Blood parameters were measured by finger pricks at 7 timepoints between 0 and 300min. The primary outcome of this study was the change in postprandial triglycerides (TG) concentrations with secondary outcomes as total cholesterol, high-density lipoprotein cholesterol and blood glucose concentrations.

RESULTS

TG area under the curve (AUC) (mmol/L/min) was significantly lower for FO (383.67, p = 0.0125) and COFO (299.12, p = 0.0186) in comparison to PL (409.17) only. TG incremental area under the curve (iAUC) (mmol/L/min) was significantly lower with COFO (59.67) in comparison to CO (99.86), (p = 0.0480). Compared to PL, the change in absolute TG concentrations (mmol/L) from baseline to post TG peak time (180min) after FO were significantly less at 240min (0.39 vs 0.15), 270min (0.2 vs 0.1), and 300min (0.28 vs 0.06), and after COFO was significantly less at 300min (0.28 vs 0.16) (p < 0.05). No significant differences in postprandial AUC and iAUC for any other blood parameters were reported.

CONCLUSIONS

Our study demonstrated that LCn-3PUFA with or without MCSFA but not MCSFA alone are effective in reducing postprandial TG in healthy individuals.

Acute whole apple consumption did not influence postprandial lipaemia: a randomised crossover trial

Whole apples are a source of pectin and polyphenols, both of which show potential to modulate postprandial lipaemia (PPL). The present study aimed to explore the effects of whole apple consumption on PPL, as a risk factor for CVD, in generally healthy but overweight and obese adults. A randomised, crossover acute meal trial was conducted with seventeen women and nine men (mean BMI of 34·1 (sem0·2) kg/m2). Blood samples were collected for 6 h after participants consumed an oral fat tolerance test meal that provided 1 g fat/kg body weight and 1500 mg acetaminophen per meal for estimating gastric emptying, with and without three whole raw Gala apples (approximately 200 g). Plasma TAG (with peak postprandial concentration as the primary outcome), apoB48, chylomicron-rich fraction particle size and fatty acid composition, glucose, insulin and acetaminophen were analysed. Differences between with and without apples were identified by ANCOVA. Apple consumption did not alter postprandial TAG response, chylomicron properties, glucose or acetaminophen (P> 0·05), but did lead to a higher apoB48 peak concentration and exaggerated insulin between 20 and 180 min (P< 0·05). Overall, as a complex food matrix, apples did not modulate postprandial TAG when consumed with a high-fat meal in overweight and obese adults, but did stimulate insulin secretion, potentially contributing to an increased TAG-rich lipoprotein production.

Effect of dietary supplementation with brewer's yeast hydrolysate on growth performance, faecal microbial counts, diarrhoea score, blood profile, rectal temperature in weanling pigs challenged with lipopolysaccharide

The objective of this study was to determine the effects of brewer's yeast hydrolysate (BYH) supplementation on growth performance, blood profile, diarrhoea score, faecal microbial and rectal temperature in lipopolysaccharide (LPS) challenged in weanling pigs. A total of 40 cross-bred weanling pigs [(Yorkshire × Landrace) × Duroc] with an average body weight of 8.15 ± 0.87 kg were used in a 6 weeks experiment. Pigs were randomly allotted to the following four dietary treatments (five pigs/two replicate/treatment) according to their initial body weight and gender. Treatments were as follows: CON, basal diet + Saline injection; NC, basal diet + LPS challenge; PC1, basal diet + 1.0% BYH + saline injection; and PC2, basal diet + 1.0% BYH + LPS challenge. Our results demonstrated pig fed diets with BYH had higher (p < .05) average daily feed intake (ADFI) during week 2-4 as well as gain:feed (G:F) during the whole experimental period than pigs fed diets without BYH. At the end of experiment, faecal Escherichia coli counts in pigs with an LPS injection tended to increase (p = .08). Meanwhile, the rectal temperature concentration of IgM and lymphocyte percentage in pigs with an LPS injection increase (p = .05) at 6 and 12 hr. In conclusion, the supplementation of 1.0% BYH can improve ADFI and G:F, as well as may reduce the diarrhoea in weanling pigs.

Fermentation characteristics of resistant starch, arabinoxylan, and β-glucan and their effects on the gut microbial ecology of pigs: A review

Dietary fibers (DF) contain an abundant amount of energy, although the mammalian genome does not encode most of the enzymes required to degrade them. However, a mutual dependence is developed between the host and symbiotic microbes, which has the potential to extract the energy present in these DF. Dietary fibers escape digestion in the foregut and are fermented in the hindgut, producing short-chain fatty acids (SCFA) that alter the microbial ecology in the gastrointestinal tract (GIT) of pigs. Most of the carbohydrates are fermented in the proximal part, allowing protein fermentation in the distal part, resulting in colonic diseases. The structures of resistant starch (RS), arabinoxylan (AX), and β-glucan (βG) are complex; hence, makes their way into the hindgut where these are fermented and provide energy substrates for the colonic epithelial cells. Different microbes have different preferences of binding to different substrates. The RS, AX and βG act as a unique substrate for the microbes and modify the relative composition of the gut microbial community. The granule dimension and surface area of each substrate are different, which influences the penetration capacity of microbes. Arabinose and xylan are 2 different hemicelluloses, but arabinose is substituted on the xylan backbone and occurs in the form of AX. Fermentation of xylan produces butyrate primarily in the small intestine, whereas arabinose produces butyrate in the large intestine. Types of RS and forms of βG also exert beneficial effects by producing different metabolites and modulating the intestinal microbiota. Therefore, it is important to have information of different types of RS, AX and βG and their roles in microbial modulation to get the optimum benefits of fiber fermentation in the gut. This review provides relevant information on the similarities and differences that exist in the way RS, AX, and βG are fermented, and their positive and negative effects on SCFA production and gut microbial ecology of pigs. These insights will help nutritionists to develop dietary strategies that can modulate specific SCFA production and promote beneficial microbiota in the GIT of swine.

Effect of Acute Ingestion of Green Tea Extract and Lemon Juice on Oxidative Stress and Lipid Profile in Pigs Fed a High-Fat Diet

Green tea and its catechins have been shown to ameliorate high fat diet-induced oxidative stress and hyperlipidemia. However, low bioavailability of catechins limits their therapeutic potential. Lemon juice (LJ) has been suggested to enhance the bioavailability of catechins in vitro. This study investigated the antioxidative and hypolipidemic efficacy of a single dose of green tea extract (GTE) or GTE plus LJ (GTE + LJ) in high-fat diet fed pigs. Sixteen pigs ingested a single dose of GTE (190 mg/kg/day) or GTE + LJ (0.75 mL/kg/day) mixed with low-fat (LF; 5% fat) or high-fat (HF; 22% fat) diets and blood samples were collected for 24 h. Plasma catechin level peaked at two hours, and gradually returned to baseline after six hours following the intake. The addition of LJ significantly increased plasma catechin level. The diet containing GTE did not lower plasma cholesterol and triacylglycerol (TG) concentrations, superoxide dismutase (SOD) and catalase activity, or malondialdehyde concentration in 24 h in HF-fed pigs. Addition of a single dose of LJ, however, significantly decreased plasma TG level in LF groups but did not cause further changes on any other markers compared to the GTE alone. Our findings indicate limited effect of a single meal containing GTE on plasma antioxidant enzymes, lipid profile, and lipid peroxidation in pigs and no significant synergistic/additive action of adding LJ to GTE within 24 h in pigs. A study with a longer treatment period is warranted to further understand the potential role of GTE in reducing HF diet-induced oxidative stress and the possible synergistic role of LJ.

Ingestion of Lycosome L-tug Formulation of Dark Chocolate Ameliorates Postprandial Hyperlipidemia and Hyperglycemia in Healthy Volunteers

Twenty-eight healthy middle-aged volunteers (40-60 years old) with equal gender representation were randomized into 3 study groups to investigate the changes in postprandial glucose and lipids after ingestion of different formulations of dark chocolate (DC). The volunteers from the first group were requested to ingest 100 g of regular DC whereas the individuals from the third group were given 100 g of highly bioavailable lycosome formulated L-tug formulation of DC containing 23.3 mg of lycopene. A second group received a 23.3 mg lycopene capsule, a tomato-derived antioxidant carotenoid as a matching control. Serum specimens were obtained following 30 minutes as well as 1, 2, and 3 hours after study products intake. Ingestion of L-tug DC was accompanied by the reduced postprandial hyperglycemia with maximum difference seen at 3^rd hour of the study and reduction of average AUC_Gluc values by 20% (P<0.05) as compared to regular DC. Moreover, ingestion of L-tug DC was accompanied by a statistically significantly reduced median concentration for postprandial triglycerides (to 390.7 mg⁎hr/dL; 5/95%% CIs: 363.2/405.7 versus regular DC value of 439.5mg⁎hr/dL and a lower range of confidence intervals - 5/95%CIs: 394.0/475.1). A similar tendency was observed in changes of total cholesterol concentration. Ingestion of L-tug DC completely abolished total cholesterol increase seen in volunteers at 3^rd hour of postprandial period following intake of the control DC. Ingestion of lycopene alone did not cause any changes in postprandial changes of glucose or serum lipids. The observed postprandial changes can be related to the 56.2 % increase in serum lycopene level which was observed after ingestion of L-tug DC only. Higher serum lycopene levels following the ingestion of L-tug DC resulted in a corresponding increase in serum antioxidant capacity and reduction of oxidized LDL as well as a decline in malonic dialdehyde concentration in the serum of volunteers.

Prolonged monitoring of postprandial lipid metabolism after a western meal rich in linoleic acid and carbohydrates

Today, awareness has been raised regarding high consumption of n-6 polyunsaturated fatty acids (PUFA) in western diets. A comprehensive analysis of total and individual postprandial fatty acids profiles would provide insights into metabolic turnover and related health effects. After an overnight fast, 9 healthy adults consumed a mixed meal comprising 97 g carbohydrate and 45 g fat, of which 26.4 g was linoleic acid (LA). Nonesterified fatty acids (NEFA), phospholipid fatty acids (PL-FA) and triacylglycerol fatty acids (TG-FA) were monitored in plasma samples, at baseline and hourly over a 7-h postprandial period. Total TG-FA concentration peaked at 2 h after the meal and steadily decreased thereafter. LA from TG18:2n-6 and behenic acid from TG22:0 showed the highest response among TG-FA, with a biphasic response detected for the former. PL-FA exhibited no change. Total NEFA initially decreased to nadir at 1 h, then increased to peak at 7 h. The individual NEFA showed the same response curve except LA and some very-long-chain saturated fatty acids (VLCSFA, ≥20 carbon chain length) that markedly increased shortly after the meal intake. The similarities and dissimilarities in lipid profiles between study subjects at different time points were visualized using nonmetric multi-dimensional scaling. Overall, the results indicate that postprandial levels of LA and VLCSFA, either as NEFA or TG, were most affected by the test meal, which might provide an explanation for the health effects of this dietary lifestyle characterized by high intake of mixed meals rich in n-6 PUFA.

High-Fat Diet, Betaine, and Polydextrose Induce Changes in Adipose Tissue Inflammation and Metabolism in C57BL/6J Mice

SCOPE

High-fat diets are a likely cause of low-grade inflammation and obesity-related pathologies. This study measures the effects of a high-fat diet, in combination with two dietary supplements-betaine and polydextrose-on metabolism and inflammation in the adipose tissue of diet-induced obese mice.

METHODS AND RESULTS

Forty male C57BL/6J mice are fed a high-fat diet for 8 weeks and compared with low-fat-diet-fed control animals (n = 10). For the last 4 weeks, the high-fat-diet-fed animals are supplemented with 1% betaine, 3.33% polydextrose, their combination, or plain water. Fat depots from subcutaneous and visceral adipose tissue are analyzed for inflammatory markers and nontargeted metabolomics by quantitative PCR and LC-QTOF-MS. The high-fat diet significantly increases adipose tissue inflammation in both fat depots. By metabolic profiling, clear differences are noted between low-fat-diet and high-fat-diet groups with regard to the levels of several metabolite species-primarily carnitines, lipids, and amino acids. Dietary betaine mitigates the high-fat-diet-induced IL-6 expression and significantly increases betaine and butyrobetaine levels in adipose tissue.

CONCLUSIONS

The high-fat diet induces patent changes in carnitine and lipid metabolism in adipose tissue. Betaine supplementation elevates the levels of betaine and its derivatives and certain carnitine species, as reported in muscle and liver, and moderately reduces inflammation.

Hypertriglyceridemia and omega-3 fatty acids: Their often overlooked role in cardiovascular disease prevention

AIMS

This review aims to describe the pathogenic role of triglycerides in cardiometabolic risk, and the potential role of omega-3 fatty acids in the management of hypertriglyceridemia and cardiovascular disease.

DATA SYNTHESIS

In epidemiological studies, hypertriglyceridemia correlates with an increased risk of cardiovascular disease, even after adjustment for low density lipoprotein cholesterol (LDL-C) levels. This has been further supported by Mendelian randomization studies where triglyceride-raising common single nucleotide polymorphisms confer an increased risk of developing cardiovascular disease. Although guidelines vary in their definition of hypertriglyceridemia, they consistently define a normal triglyceride level as <150 mg/dL (or <1.7 mmol/L). For patients with moderately elevated triglyceride levels, LDL-C remains the primary target for treatment in both European and US guidelines. However, since any triglyceride level in excess of normal increases the risk of cardiovascular disease, even in patients with optimally managed LDL-C levels, triglycerides are an important secondary target in both assessment and treatment. Dietary changes are a key element of first-line lifestyle intervention, but pharmacological treatment including omega-3 fatty acids may be indicated in people with persistently high triglyceride levels. Moreover, in patients with pre-existing cardiovascular disease, omega-3 supplements significantly reduce the risk of sudden death, cardiac death and myocardial infarction and are generally well tolerated.

CONCLUSIONS

Targeting resistant hypertriglyceridemia should be considered as a part of clinical management of cardiovascular risk. Omega-3 fatty acids may represent a valuable resource to this aim.

Effects of isolated soluble fiber supplementation on body weight, glycemia, and insulinemia in adults with overweight and obesity: a systematic review and meta-analysis of randomized controlled trials

Background: There is strong epidemiologic evidence that dietary fiber intake is protective against overweight and obesity; however, results of intervention studies have been mixed. Soluble fiber beneficially affects metabolism, and fiber supplementation may be a feasible approach to improve body composition and glycemia in adults with overweight and obesity.Objective: We evaluated randomized controlled trials (RCTs) of isolated soluble fiber supplementation in overweight and obese adults on outcomes related to weight management [body mass index (BMI; in kg/m²), body weight, percentage of body fat, and waist circumference] and glucose and insulin metabolism (homeostasis model assessment of insulin resistance and fasting insulin) through a systematic review and meta-analysis.Design: We searched PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature and Cochrane Library databases. Eligible studies were RCTs that compared isolated soluble fiber with placebo treatments without energy-restriction protocols. Random-effects models were used to estimate pooled effect sizes and 95% CIs. Meta-regressions were performed to assess outcomes in relation to the intervention duration, fiber dose, and fiber type. Publication bias was assessed via Begg's and Egger's tests and funnel plot inspection.Results: Findings from 12 RCTs (n = 609 participants) from 2 to 17 wk of duration are summarized in this review. Soluble fiber supplementation reduced BMI by 0.84 (95% CI: -1.35, -0.32; P = 0.001), body weight by 2.52 kg (95% CI: -4.25, -0.79 kg; P = 0.004), body fat by 0.41% (95% CI: -0.58%, -0.24%; P < 0.001), fasting glucose by 0.17 mmol/L (95% CI: -0.28, -0.06 mmol/L; P = 0.002), and fasting insulin by 15.88 pmol/L (95% CI: -29.05, -2.71 pmol/L; P = 0.02) compared with the effects of placebo treatments. No publication bias was identified. Considerable between-study heterogeneity was observed for most outcomes.Conclusions: Isolated soluble fiber supplementation improves anthropometric and metabolic outcomes in overweight and obese adults, thereby indicating that supplementation may improve fiber intake and health in these individuals. However, the interpretation of these findings warrants caution because of the considerable between-study heterogeneity. This trial was registered at clinicaltrials.gov as NCT03003897.

Small HDL subclasses become cholesterol-poor during postprandial period after a fat diet intake in subjects with high triglyceridemia increases

BACKGROUND

Postprandial triglyceridemia may transitory affect the structure of HDL subclasses and probably their antiatherogenic properties but little is known in this field. We analyzed the HDL subclasses lipid content along postprandial period.

METHODS

Fifteen metabolic syndrome (MS) patients and 15 healthy controls were enrolled. HDL were isolated from plasma samples obtained at fasting and every 2-h up to 8-h, after a 75-g fat meal. Cholesterol (C), triglycerides (TAG), and phospholipid (Ph) plasma concentrations of five HDL subclasses were determined by densitometry of electrophoresis gels enzymatically stained.

RESULTS

The increase of postprandial triglyceridemia expressed as the incremental area under the curve (iAUC) was twice in MS patients than in controls. Only large HDL2b-TAG were higher in MS than controls at 4, 6 and 8h after meal intake, whereas cholesterol of HDL2a, 3a and 3b were lower at 8h. HDL size distribution shifted towards large HDL and HDL3a-, 3b- and 3c-subclasses had a lower content of cholesterol (estimated by the C-to-Ph ratio) in subjects whose iAUC>289.5mgh/dl (n=15) in comparison with those subjects with iAUC below this cutoff point (n=15), independently of the MS status and fasting TAG. Triglycerides content of HDL subclasses changed only discreetly along the postprandial period, whereas paraoxonase-1 remained unchanged.

CONCLUSIONS

A high postprandial triglyceridemia conditions the shift of HDL size distribution towards large particles and the decrease of cholesterol in HDL3 subclasses. These data demonstrate that postprandial hypertriglyceridemia contributes to a transitory hypoalphalipoproteinemia that may increase the risk of cardiovascular disease.

Epigenome-wide association study of triglyceride postprandial responses to a high-fat dietary challenge

Postprandial lipemia (PPL), the increased plasma TG concentration after consuming a high-fat meal, is an independent risk factor for CVD. Individual responses to a meal high in fat vary greatly, depending on genetic and lifestyle factors. However, only a few loci have been associated with TG-PPL response. Heritable epigenomic changes may be significant contributors to the unexplained inter-individual PPL variability. We conducted an epigenome-wide association study on 979 subjects with DNA methylation measured from CD4⁺ T cells, who were challenged with a high-fat meal as a part of the Genetics of Lipid Lowering Drugs and Diet Network study. Eight methylation sites encompassing five genes, LPP, CPT1A, APOA5, SREBF1, and ABCG1, were significantly associated with PPL response at an epigenome-wide level (P < 1.1 × 10⁻⁷), but no methylation site reached epigenome-wide significance after adjusting for baseline TG levels. Higher methylation at LPP, APOA5, SREBF1, and ABCG1, and lower methylation at CPT1A methylation were correlated with an increased TG-PPL response. These PPL-associated methylation sites, also correlated with fasting TG, account for a substantially greater amount of phenotypic variance (14.9%) in PPL and fasting TG (16.3%) when compared with the genetic contribution of loci identified by our previous genome-wide association study (4.5%). In summary, the epigenome is a large contributor to the variation in PPL, and this has the potential to be used to modulate PPL and reduce CVD.

Increasing dietary oat fibre decreases the permeability of intestinal mucus

This study investigates the influence of the dietary fibre β-glucan on nutrient composition and mucus permeability. Pigs were fed a standard diet or a diet containing twice the β-glucan content for 3 days (n = 5 per group), followed by the collection of small intestinal mucus and tissue samples. Samples of the consumed diets were subjected to in vitro digestion to determine β-glucan release, nutrient profile and assessment of mucus permeability. In vitro digestion of the diets indicated that 90% of the β-glucan was released in the proximal small intestine. Measurements of intestinal mucus showed a reduction in permeability to 100 nm latex beads and also lipid from the digested enhanced β-glucan diet. The data from this study show for the first time that reducing mass transfer of bile and lipid through the intestinal mucus layer may be one way in which this decrease in bile reabsorption by soluble fibre is enabled.

Independent and Combined Effects of Lactitol, Polydextrose, and Bacteroides thetaiotaomicron on Postprandial Metabolism and Body Weight in Rats Fed a High-Fat Diet

Obesity is related to the consumption of energy-dense foods in addition to changes in the microbiome where a higher abundance of gut Bacteroidetes can be found in lean subjects or after weight loss. Lactitol, a sweet-tasting sugar alcohol, is a common sugar-replacement in foods. Polydextrose (PDX), a highly branched glucose polymer, is known to reduce energy intake. Here, we test if the combined effects of lactitol or PDX in combination with Bacteroides species will have a beneficial metabolic response in rats fed a high-fat (HF) diet. A total of 175 male Wistar rats were fed either a LF or HF diet. Bacteroides thetaiotaomicron (10¹⁰ bacteria/animal/day) was orally administered with or without lactitol (1.6−2 g/animal/day) or PDX (2 g/animal/day) for 8 days. Postprandial blood samples, cecal digesta, and feces were collected on the last day. Measurements included: body weight, feed consumption, cecal short-chain fatty acids, fecal dry matter and heat value, blood glucose, insulin, triglyceride, and satiety hormone concentrations. Lactitol and PDX decreased the mean body weight when administered with B. thetaiotaomicron or when lactitol was administered alone. Levels of postprandial plasma triglycerides declined with lactitol and PDX when administered with B. thetaiotaomicron. For intestinal hormone release, lactitol – alone or with B. thetaiotaomicron – increased the release of gastrointestinal peptide tyrosine tyrosine (PYY) as well as the area under the curve (AUC) measured for PYY (0–8 h). In addition, levels of insulin AUC (0–8 h) decreased in the lactitol and PDX-supplemented groups. Lactitol and PDX may both provide additional means to regulate postprandial metabolism and weight management, whereas the addition of B. thetaiotaomicron in the tested doses had only minor effects on the measured parameters.