Monounsaturated fat-rich diet reduces body adiposity in women with obesity, but does not influence energy expenditure and substrate oxidation: a parallel randomized controlled clinical trial.

BACKGROUND: Obesity is an important and growing health problem whose treatment involves dietary changes. In this context, studying the role of macronutrients in weight loss is required in order to understand which strategies may be applied for weight loss. We aimed to evaluate the effects of diets rich in polyunsaturated (PUFAs) and monounsaturated fatty acids (MUFAs) on resting energy expenditure (REE), substrate oxidation, and weight loss in women with obesity. METHODS: Randomized, controlled, single blind, parallel-group clinical trial was conducted for 60 days. Participants (n = 32) were divided into three groups: G1= normocaloric PUFAs-rich diet (12% of total energy expenditure (TEE), 10% of n-6 and up to 2% of n-3); G2= normocaloric MUFAs-rich diet (15-20% TEE); and G3= maintenance of the usual diet. Anthropometric and metabolic variables (REE and substrate oxidation by indirect calorimetry) were evaluated. RESULTS: G2 decreased body weight (-1.92 ± 1.99 kg, P = 0.02), body mass index (BMI) (-0.69 ± 0.70 kg/m2; P = 0.02), waist circumference (WC) (-1.91 ± 1.82 cm; P = 0.02), and body fat (-1.14 ± 1.53 kg; P = 0.04). CONCLUSION: MUFAs-rich diet reduces body weight, BMI, body fat, and WC. CLINICAL TRIALS: NCT02656940. CLINICAL TRIAL REGISTRATION: Clinical Trials: NCT02656940.

A high fat to vitamin E ratio in the feed protects and improves uptake of the natural form of vitamin E in postweaning calves.

In postweaning calves, it is a challenge to maintain the plasma vitamin E level at or above the recommended level (3 µg/mL), which is linked to a good immune response. It has been unclear until now why the provision of solid feed with concentrations below 200 mg/kg feed of vitamin E is ineffective in maintaining the plasma vitamin E level of calves above the recommended plasma level postweaning. The present study was conducted to investigate if a high fat to vitamin E ratio in the concentrate could protect and improve the delivery of the natural form of vitamin E (RRR-α-tocopherol) to calves postweaning. Thirty calves were included in the experiment from 2 weeks preweaning until 2 weeks postweaning (Weeks -2, -1, 0 [weaning], 1, and 2 relative to weaning) and fed one of three concentrates in which lecithin mixture provided the fat supplement: control (77 mg/kg of vitamin E and 4.9% DM of crude fat; CONT), medium level of vitamin E supplemented (147 mg/kg of vitamin E and 7.7% DM of crude fat; MedVE) or high level of vitamin E supplemented (238 mg/kg of vitamin E and 12.4% DM of fat; HiVE). Thus, there was a comparable ratio of fat to vitamin E (520-630) in the three concentrates. During the 2 weeks postweaning, final body weight (92 ± 2 kg), average daily gain (917 ± 51 g/day) and concentrate intake (2.2 ± 0.09 kg/day; mean of treatment ± standard error) were unaffected by treatment and the interaction between treatment and week. There was an interaction between treatment and week for vitamin E intake pre- (p < 0.001) and postweaning (p < 0.001). There was an interaction between treatment and week (p < 0.001) for plasma vitamin E level postweaning, and it was 2.5, 3.1, and 3.8 µg/mL in CONT, MedVE, and HiVE, respectively, at Week 1 postweaning. In addition, plasma vitamin E levels at Week 2 postweaning were 2.6, 3.6 and 4.8 µg/mL in CONT, MidVE and HiVE respectively. The results show that 147 mg/kg of lecithin-protected vitamin E in the concentrate is needed to secure a plasma vitamin E level well above the recommended level. In addition, lecithin-protected vitamin E elevated the plasma level of triglycerides and nonesterified fatty acids.

Dietary-fat supplementation alleviates cold temperature-induced metabolic dysbiosis and barrier impairment by remodeling gut microbiota.

As important components of the mammalian diet and tissues, fats are involved in a variety of biological processes in addition to providing energy. In general, the increase in basal metabolism and health risks under cold temperature conditions causes the host to need more energy to maintain body temperature and normal biological processes. The intestine and its microbiota are key components in orchestrating host metabolic homeostasis and immunity, and respond rapidly to changing environmental conditions. However, the role of dietary-fat supplementation in regulating host homeostasis of metabolism and barrier functions through gut microbiota at cold temperatures is incompletely understood. Our results showed that dietary-fat supplementation alleviated the negative effects of cold temperatures on the alpha-diversity of both ileal and colonic microbiota. Cold temperatures altered the ileal and colonic microbiota of pigs, and the extent of changes was more pronounced in the colonic microbiota. Translocation of the gut microbiota was restored after supplementation with a high-fat diet. In addition, cold temperatures exacerbated ileal mucosal damage and inflammation, and disrupted barrier function, which may be associated with decreased concentrations of butyrate and isobutyrate. Cold temperature-induced metabolic dysbiosis was manifested by altered hormone levels and upregulation of expression of multiple metabolites involved in metabolism (lipids, amino acids and minerals) and the immune response. Supplementation with a high-fat diet restored metabolic homeostasis and barrier function by improving gut-microbiota composition and increasing SCFAs concentrations in pigs. In conclusion, cold temperatures induced severe translocation of microbiota and barrier damage. These actions increased the risk of metabolic imbalance. Dietary-fat supplementation alleviated the adverse effects of cold temperatures on host metabolism by remodeling the gut microbiota.

Fat from Hermetia illucens Alters the Cecal Gut Microbiome and Lowers Hepatic Triglyceride Concentration in Comparison to Palm Oil in Obese Zucker Rats.

BACKGROUND: Palm oil (PO) is the most widely utilized plant oil for food production. Owing to the great ecologic problems associated with PO production, sustainably produced fats, such as insect fat, might be a suitable alternative. OBJECTIVES: The hypothesis was tested that fat from Hermetia illucens larvae (HF) compared with PO and soybean oil (SO) has no adverse effects on hepatic lipid metabolism, plasma metabolome, and cecal microbiome in obese Zucker rats. METHODS: Thirty male obese Zucker rats were randomly assigned to 3 groups (SO, PO, HF; n = 10 rats/group) and fed 3 different semisynthetic diets containing either SO, PO, or HF as the main fat source for 4 wk. The effects were evaluated by measurement of liver and plasma lipid concentrations, liver transcriptomics, targeted plasma metabolomics, and cecal microbiomics. RESULTS: Supplementation of HF reduced hepatic triglyceride concentration and messenger ribonucleic acid concentrations of selected genes involved in fatty acid and triglyceride synthesis in comparison to PO (P < 0.05). Pairwise comparison of the Simpson index and Jaccard index showed a higher cecal microbial α- and ß-diversity in rats fed the HF diet than in rats fed the PO diet (P = 0.015 and P = 0.027), but no difference between rats fed the diets with SO or PO. Taxonomic analysis of the cecal microbial community revealed a lower abundance of Clostridium_sensu_stricto_1 and a higher abundance of Blautia, Mucispirillum, Anaerotruncus, Harryflintia, and Peptococcus in rats supplemented with HF than in rats supplemented with PO (P < 0.05). CONCLUSIONS: HF, compared with PO, has liver lipid-lowering effects in obese Zucker rats, which may be caused by a shift in the gut microbial community. Thus, HF might serve as a sustainably produced fat alternative to PO for food production.

Effects of dietary fat, nitrate, and 3-nitrooxypropanol and their combinations on methane emission, feed intake, and milk production in dairy cows.

The objective of the present study was to investigate the effect of individual and combined use of dietary fat, nitrate, and 3-nitrooxypropanol (3-NOP) on dairy cows' enteric methane (CH4) emission and production performance. Twenty-four primiparous and 24 multiparous Danish Holstein cows (111 ± 44.6 d in milk; mean ± standard deviation) were included in an incomplete 8 × 8 Latin square design with six 21-d periods. Dietary treatments were organized in a 2 × 2 × 2 factorial arrangement aiming for 2 levels of FAT (30 or 63 g of crude fat/kg of dry matter [DM]; LF or HF, respectively), 2 levels of NITRATE (0 or 10 g of nitrate/kg of DM; UREA or NIT, respectively), and 2 levels of 3-NOP (0 or 80 mg/kg DM; BLANK or NOP, respectively). Treatments were included in ad libitum-fed partial mixed rations in bins that automatically measured feed intake and eating behavior. Additional concentrate was offered as bait in GreenFeed units used for measurement of gas emission. For total DM intake (DMI), a FAT × NITRATE interaction showed that DMI, across parities and levels of 3-NOP, was unaffected by separate fat supplementation, but reduced by nitrate with 4.6% and synergistically decreased (significant 2-way interaction) with 13.0% when fat and nitrate were combined. Additionally, 3-NOP decreased DMI by 13.4% and the combination of 3-NOP with fat and nitrate decreased DMI in an additive way (no significant 3-way interaction). The decreasing effects on DMI were more pronounced in multiparous cows than in primiparous cows. For treatments with largest reductions in DMI, eating behavior was altered toward more frequent, but smaller meals, a slower eating rate and increased attempts to visit unassigned feed bins. Energy-corrected milk (ECM) yield increased by 6.3% with fat supplementation, whereas ECM yield did not differ among diets including nitrate (FAT × NITRATE interaction). Cows supplemented with 3-NOP had 9.0% lower ECM yield than cows fed no 3-NOP. Based on three 2-way interactions including FAT, NITRATE, and 3-NOP, the combined use of the additives resulted in antagonistic effects on CH4 reduction. A 6% to 7% reduction in CH4 yield (CH4/kg of DMI) could be ascribed to the effect of fat, a 12% to 13% reduction could be ascribed to the effect of nitrate and an 18% to 23% reduction could be ascribed to the effect of 3-NOP. Hence, no combinations of additives resulted in CH4 yield-reductions that were greater than what was obtained by separate supplementation of the most potent additive within the combination. The CH4 yield reduction potential of additives was similar between parities. Increased apparent total-tract digestibility of organic matter (OM) in cows fed combinations including nitrate or 3-NOP was a result of a NITRATE × 3-NOP interaction. Apparent total-tract digestibility of OM was also increased by fat supplementation. These increases reflected observed decreases in DMI. In conclusion, combined use of fat, nitrate, and 3-NOP in all combinations did not result in CH4 reductions that were greater than separate supplementation of the most potent additive within the combination (3-NOP > nitrate > fat). Additionally, separate supplementation of some additives and combined use of all additives reduced DMI.

Impact of various high fat diets on gene expression and the microbiome across the mouse intestines.

High fat diets (HFDs) have been linked to several diseases including obesity, diabetes, fatty liver, inflammatory bowel disease (IBD) and colon cancer. In this study, we examined the impact on intestinal gene expression of three isocaloric HFDs that differed only in their fatty acid composition-coconut oil (saturated fats), conventional soybean oil (polyunsaturated fats) and a genetically modified soybean oil (monounsaturated fats). Four functionally distinct segments of the mouse intestinal tract were analyzed using RNA-seq-duodenum, jejunum, terminal ileum and proximal colon. We found considerable dysregulation of genes in multiple tissues with the different diets, including those encoding nuclear receptors and genes involved in xenobiotic and drug metabolism, epithelial barrier function, IBD and colon cancer as well as genes associated with the microbiome and COVID-19. Network analysis shows that genes involved in metabolism tend to be upregulated by the HFDs while genes related to the immune system are downregulated; neurotransmitter signaling was also dysregulated by the HFDs. Genomic sequencing also revealed a microbiome altered by the HFDs. This study highlights the potential impact of different HFDs on gut health with implications for the organism as a whole and will serve as a reference for gene expression along the length of the intestines.

Reducing Dietary Polyunsaturated to Saturated Fatty Acids Ratio Improves Lipid and Glucose Metabolism in Obese Zucker Rats.

We investigated the influence of varying dietary polyunsaturated fatty acid (PUFA)/saturated fatty acids (SFA) ratios on insulin resistance (IR), fatty acid metabolism, N-acylethanolamine (NAE) bioactive metabolite levels, and mitochondrial function in lean and obese Zucker rats in a model designed to study obesity and IR from overnutrition. We provided diets with 7% fat (w/w), with either a low PUFA/SFA ratio of 0.48, predominantly comprising palmitic acid (PA), (diet-PA), or the standard AIN-93G diet with a high PUFA/SFA ratio of 3.66 (control, diet-C) over eight weeks. In obese rats on diet-PA versus diet-C, there were reductions in plasma triglycerides, cholesterol, glucose, insulin concentrations and improved muscle mitochondrial function, inflammatory markers and increased muscle N-oleoylethanolamine (OEA), a bioactive lipid that modulates lipid metabolism and metabolic flexibility. Elevated palmitic acid levels were found exclusively in obese rats, regardless of their diet, implying an endogenous production through de novo lipogenesis rather than from a dietary origin. In conclusion, a reduced dietary PUFA/SFA ratio positively influenced glucose and lipid metabolism without affecting long-term PA tissue concentrations. This likely occurs due to an increase in OEA biosynthesis, improving metabolic flexibility in obese rats. Our results hint at a pivotal role for balanced dietary PA in countering the effects of overnutrition-induced obesity.

Systematic Review and Quantitative Data Synthesis of Peripheral Blood Mononuclear Cell Transcriptomics Reveals Consensus Gene Expression Changes in Response to a High Fat Meal.

SCOPE: Metabolic flexibility is essential for a healthy response to a high fat meal, and is assessed by measuring postprandial changes in blood markers including peripheral blood mononuclear cells (PBMCs; lymphocytes and monocytes). However, there is no clear consensus on postprandial gene expression and protein changes in these cells. METHOD AND RESULTS: The study systematically reviews the literature reporting transcriptional and proteomic changes in PBMCs after consumption of a high fat meal. After re-analysis of the raw data to ensure equivalence between studies, ≈85 genes are significantly changed (defined as in the same direction in ≥3 studies) with about half involved in four processes: inflammation/oxidative stress, GTP metabolism, apoptosis, and lipid localization/transport. For meals consisting predominantly of unsaturated fatty acids (UFA), notable additional processes are phosphorylation and glucocorticoid response. For saturated fatty acids (SFA), genes related to migration/angiogenesis and platelet aggregation are also changed. CONCLUSION: Despite differences in study design, common gene changes are identified in PBMCs following a high fat meal. These common genes and processes will facilitate definition of the postprandial transcriptome as part of the overall postcibalome, linking all molecules and processes that change in the blood after a meal.

Effect of exogenous bile salts supplementation on the performance and hepatic lipid metabolism of aged laying hens.

Bile acids (BA), a series of hydroxylated steroids secreted by the liver, are involved in the digestion and absorption of dietary fats. In the present study, the effect of exogenous BAs on the performance and liver lipid metabolism of laying hens was investigated. Three hundred and sixty 50-wk-old Hy-line Brown hens were randomly allocated into three groups and subjected to one of the following treatments: fed with the basal diet (control, Con), the basal diet supplemented with 0.1 g/kg (0.1 g/kg BAs), or 0.2 g/kg (0.2 g/kg BAs) porcine BAs. Laying performance, egg quality, and blood parameters were measured during the 8-wk experimental period. The expression of genes related to hepatic lipid metabolism was determined at the end of experiment. The results showed that BAs treatments had no influence (P > 0.05) on laying rate, egg weight, and feed efficiency. BAs treatment, however, significantly decreased mortality of hens (P = 0.006). BAs treatment showed a transient negative influence on eggshell quality at week 4 but not at week 8. The yolk color on week 8 was increased by BAs treatments (P < 0.0001) compared to control. The duodenum index showed a tendency to be increased (P = 0.053) and jejunum index were increased (P = 0.007) by BAs treatment. Compared to control, BAs treatments decreased lipid droplet content (P < 0.0001) and TG content (P = 0.002) of liver. Fatty acid synthase activity was also decreased as an effect of BAs dietary supplementation. Compared to the control group, 0.1 g/kg BAs treatment increased (P < 0.05) the mRNA expression of genes Farnesoid X receptor (FXR) (P = 0.042), cytochrome P450 family 7 subfamily A member 1 (CYP7A1) (P = 0.002), and cytochrome P450 family 8 subfamily B member 1 (CYP8B1) (P = 0.017), fatty acid synthase (FAS) (P = 0.020), acetyl-CoA carboxylase (ACC) (P = 0.032), sterol regulatory element binding protein-1c (SREBP-1c) (P = 0.037), proliferator-activated receptor gamma (PPARγ) (P = 0.002), apolipoprotein B (APO-B) (P = 0.020), and very low density lipoprotein receptor (VLDLR) (P = 0.024). In conclusion, the addition of exogenous BAs reduces lipid accumulation in liver. BA supplementation reduces the mortality of hens and improves egg yolk color, with no unfavorable effect on laying performance. The result suggests that suppressed FAS activity is involved in the reduced hepatic lipid accumulation by BAs treatment.

Fatty liver hemorrhagic syndrome is one of the most common diseases in laying hens and is a metabolic disease characterized by disorders of lipid metabolism in the liver, manifested by fatty liver degeneration and varying degrees of hemorrhage, which often occurs in caged hens in good condition and with high egg production rates. Bile acids (BA), a group of hydroxylated steroids synthesized from cholesterol in the liver, play an important role in lipid metabolism. This study aimed to examine the effects of dietary addition of different levels of BAs on the production performance and liver fat metabolism of 50-wk-old Hy-line Brown hens. The result indicates that the addition of exogenous BAs reduces lipid accumulation in liver. BAs supplementation reduces the mortality of hens and improves egg yolk color, with no other unfavorable side effects on laying performance. The results of the present study suggest that suppressed fatty acid synthase activity is involved in the reduced hepatic lipid accumulation as an effect of BAs dietary supplementation.

Impact of saturated compared with unsaturated dietary fat on insulin sensitivity, pancreatic ß-cell function and glucose tolerance: a systematic review and meta-analysis of randomized, controlled trials.

BACKGROUND: The impact of the dietary fat type on type 2 diabetes (T2D) remains unclear. OBJECTIVES: We aimed to evaluate the effects of replacing dietary saturated fatty acids (SFA) with mono- or poly-unsaturated fatty acids (MUFA and PUFA, respectively) on insulin sensitivity, pancreatic ß-cell function, and glucose tolerance, as surrogate endpoints for T2D. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials that replaced ≥5% of total energy intake provided by SFA with MUFA or PUFA and reported indexes of insulin sensitivity, ß-cell function, and/or glucose tolerance. We searched MEDLINE, Scopus, and the Cochrane Library (CENTRAL) up to 9 January, 2023. Eligible interventions had to be isocaloric, with no significant difference in other macronutrients. Data were synthesized using random-effects model meta-analysis. RESULTS: Of 6355 records identified, 10 parallel and 20 crossover trials with 1586 participants were included. The mean age of the participants was 42 years, 47% were male, mean body mass index (BMI; in kg/m2) was 26.8, median baseline fasting glucose was 5.13 mmol/L, and the median duration of interventions was 5 weeks. Replacing SFA with MUFA or PUFA had no significant effects on insulin sensitivity [standardized mean difference (SMD) SFA compared with MUFA: 0.01, 95% confidence interval (CI): -0.06 to 0.09, I2 = 0% and SMD SFA compared with PUFA: 0, 95% CI: -0.15 to 0.14, I2 = 0%]. Replacing SFA with MUFA did not significantly impact the ß-cell function, evaluated by the disposition index (mean difference: -12, 95% CI: -158 to 133, I2=0%). Evidence on glucose tolerance (SFA compared with MUFA or PUFA) and on ß-cell function when SFA were replaced with PUFA was scant. CONCLUSIONS: Short-term substitution of saturated with unsaturated fat does not significantly affect insulin sensitivity nor ß-cell function (the latter in the SFA compared with MUFA comparison). Future studies are needed to elucidate longer term effects of dietary fat saturation on glucose homeostasis. This trial was registered at PROSPERO as CRD42020178382.

Fatty acid composition of cholesterol esters reflects dietary fat intake after dietary interventions in a multinational population.

BACKGROUND: The effects of different dietary fatty acids (FA) on cardiovascular risk still needs clarification. Plasma lipids composition may be a biomarker of FA dietary intake. PURPOSE: To evaluate in a composite population the relationships between changes in dietary fat intake and changes in FA levels in serum cholesterol esters. METHODS: In a multinational, parallel-design, dietary intervention (KANWU study), dietary intakes (3-day food record) and FA composition of serum cholesterol esters (gas-liquid chromatography) were evaluated at baseline and after 3 months in 162 healthy individuals, randomly assigned to a diet containing a high proportion of saturated (SFA) or monounsaturated (MUFA) fat, with a second random assignment to fish oil or placebo supplements. RESULTS: Main differences in serum lipid composition after the two diets included saturated (especially myristic, C14:0, and pentadecanoic, C15:0) and monounsaturated (oleic acid, C18:1 n-9) FA. C14:0 and C15:0 were related to SFA intake, while C18:1 n-9 was associated with MUFA intake. Fish oil supplementation induced a marked increase in eicosapentaenoic (C20:5 n-3) and docosahexaenoic (C22:6 n-3) acids. After the 3-month intervention, Δ-9 desaturase activity, calculated as palmitoleic acid/palmitic acid (C16:1/C16:0) ratio, was more reduced after the MUFA (0.31±0.10 vs 0.25±0.09, p<0.0001) than SFA diet (0.31±0.09 vs 0.29±0.08, p=0.006), with a statistically significant difference between the two groups (p<0.0001). CONCLUSIONS: This study shows that serum cholesterol ester FA composition can be used during randomized controlled trials as an objective indicator of adherence to experimental diets based on saturated and monounsaturated fat modifications, as well as fish oil supplementation.

Intermittent fasting combined with exercise training reduces body mass and alleviates hypothalamic disorders induced by high-fat diet intake.

High-fat diet consumption causes hypothalamic inflammation, dysregulating the leptin pathway, which, in turn, compromises the modulation of hypothalamic neuronal activities and predisposes obesity development. Intermittent fasting (IF) and exercise training (ET) have been demonstrated as efficient interventions to modulate hypothalamic inflammation and neuronal activity. However, no studies have evaluated whether combining these interventions could induce better results in reestablishing hypothalamic homeostasis disrupted by high-fat diet intake. The 8-week-old male C57BL/6 mice were randomly assigned into 2 groups: sedentary mice fed a standard diet (CT), and sedentary mice fed a high-fat diet (HF). After 8 weeks of an HF diet, part of the HF group (now 16 weeks old) was randomly subjected to different interventions for 6 weeks: HF-IF = HF diet mice submitted to IF; HF-T = HF diet mice submitted to ET; HF-IFT = HF diet mice submitted to IF and ET. All interventions decreased the body weight gain induced by high-fat diet intake, associated with reduced calorie consumption in week 14. Only the HF-IFT group presented improved serum insulin, leptin, resistin, and Tnf-alpha levels concomitantly with decreased hypothalamic inflammation. The HF-IFT group also demonstrated increased Pomc mRNA expression associated with enhanced pSTAT3 expression in the hypothalamic arcuate and ventromedial hypothalamic nuclei. Our data indicate that the beneficial effects of the combination of IF and ET on energy homeostasis are associated with increased leptin sensitivity in the hypothalamic arcuate nucleus and ventromedial hypothalamic nucleus, which is likely due to an improvement in hypothalamic inflammatory pathways in these nuclei.

Interleukin-18 Is a Potential Biomarker Linking Dietary Fatty Acid Quality and Insulin Resistance: Results from a Cross-Sectional Study in Northern Italy.

Dietary lipids are pivotal in modulating metabolic inflammation. Among the inflammatory mediators characterizing metabolic inflammation, interleukin 18 (IL-18) has been consistently associated with obesity and insulin resistance. This study aims to evaluate whether the quality of lipid intake impacts upon IL-18 plasma levels and the implications on insulin resistance computed by the homeostatic model assessment for insulin resistance (HOMA-IR). Using a cross-sectional design, this study confirmed that IL-18 correlated positively with insulin resistance and individuals with a HOMA-IR ≥ 2.5 displayed higher circulating IL-18 levels compared with their insulin-sensitive counterparts. In terms of the effect of the quality of dietary lipids on IL-18 circulating levels, the ratio between monounsaturated, omega-3, polyunsaturated and saturated fatty acids as well as the intake of eicosapentaenoic and docosahexaenoic acids correlated negatively with IL-18. Despite this, IL-18 circulating levels, but not dietary fatty acid quality, predicted insulin resistance. Nevertheless, the ratio between omega 3 and saturated fatty acids was a predictor of IL-18 plasma levels. Thus, the downregulation of IL-18 may underpin, at least partially, the beneficial metabolic effects of substituting omega 3 for saturated fatty acids with this cytokine potentially representing a biomarker linking dietary lipids and metabolic outcomes.

Dietary fatty acids differentially affect secretion of pro-inflammatory cytokines in human THP-1 monocytes.

Monocytes are a major population of circulating immune cells that play a crucial role in producing pro-inflammatory cytokines in the body. The actions of monocytes are known to be influenced by the combinations and concentrations of certain fatty acids (FAs) in blood and dietary fats. However, systemic comparisons of the effects of FAs on cytokine secretion by monocytes have not be performed. In this study, we compared how six saturated FAs (SFAs), two monounsaturated FAs (MUFAs), and seven polyunsaturated FAs (PUFAs) modulate human THP-1 monocyte secretion of TNF, IL-1ß, and IL-6 in the absence or presence of lipopolysaccharide. SFAs generally stimulated resting THP-1 cells to secrete pro-inflammatory cytokines, with stearic acid being the most potent species. In contrast, MUFAs and PUFAs inhibited lipopolysaccharide-induced secretion of pro-inflammatory cytokines. Interestingly, the inhibitory potentials of MUFAs and PUFAs followed U-shaped (TNF and IL-1ß) or inverted U-shaped (IL-6) dose-response curves. Among the MUFAs and PUFAs that were analyzed, docosahexaenoic acid (C22:6 n-3) exhibited the largest number of double bonds and was found to be the most potent anti-inflammatory compound. Together, our findings reveal that the chemical compositions and concentrations of dietary FAs are key factors in the intricate regulation of monocyte-mediated inflammation.

Polyunsaturated fatty acids-rich dietary lipid prevents high fat diet-induced obesity in mice.

Diet is the primary factor affecting host nutrition and metabolism, with excess food intake, especially high-calorie diets, such as high-fat and high-sugar diets, causing an increased risk of obesity and related disorders. Obesity alters the gut microbial composition and reduces microbial diversity and causes changes in specific bacterial taxa. Dietary lipids can alter the gut microbial composition in obese mice. However, the regulation of gut microbiota and host energy homeostasis by different polyunsaturated fatty acids (PUFAs) in dietary lipids remains unknown. Here, we demonstrated that different PUFAs in dietary lipids improved host metabolism in high-fat diet (HFD)-induced obesity in mice. The intake of the different PUFA-enriched dietary lipids improved metabolism in HFD-induced obesity by regulating glucose tolerance and inhibiting colonic inflammation. Moreover, the gut microbial compositions were different among HFD and modified PUFA-enriched HFD-fed mice. Thus, we have identified a new mechanism underlying the function of different PUFAs in dietary lipids in regulating host energy homeostasis in obese conditions. Our findings shed light on the prevention and treatment of metabolic disorders by targeting the gut microbiota.

Effects of pork fat and linseed oil as additives on gel quality of fish cake.

Pork fat (PF) is a necessary ingredient in making traditional fish cakes (TFCs), which contains saturated fatty acids with potential health concerns. While linseed oil (LO) containing α-linolenic acid is a potential nutrient-enhancing fat substitute. In this study, the effect of pork fat and linseed oil level on gel quality, sensory characteristics, microstructure, and protein conformation of TFCs were characterized. Results showed that the TFCs with 30% pork fat (wt/wt) had the highest gel strength. Additionally, sensory evaluation determined that TFCs with 30% pork fat scored the best by a sensory panel with high gel strength, water-holding capacity, and fresh and sweet taste. The gel strength, chewiness, and hardness of nutrient-enriched fish cakes with 20% linseed oil replaced for pork fat were higher than that only with pork fat (wt/wt) without changing in tenderness and elasticity. Visual results showed that the network was uniform at a moderate level of linseed oil addition (20% LO/PF replacement ratio). The results of this study provided technical guidelines for standardizing the TFC manufacture processes, and useful insight for the development of fish cakes with reduced animal fat content for additional health benefits for consumers.

Saturated Fatty Acids Consumed in Smoothies Increase Glucose and Metabolic Load Index in Young Adults Compared to Polyunsaturated Omega-3-Fatty Acids.

Introduction: Chronic diets high in saturated fat (SF) and omega-6-fatty acids (O6FAs) elevate fasting triglycerides (TRGs) and glucose (GLU). Postprandial TRGs, GLU, and Metabolic Load Index (MLI) are better predictors of disease risk compared to fasting levels alone. Conversely, diets high in omega-3 fatty acids (O3FAs) may be cardioprotective. Unfortunately, many existing postprandial studies are not standardized to body weight and given in an amount individuals would typically consume in their daily lives; the MLI is not calculated, and varying types of fat content are not examined. Therefore, we sought to determine whether SF, O3FAs, or O6FAs altered postprandial TRGs, GLU, and MLI from a standardized mixed meal. Methods: Fifteen individuals (6 M and 9 F) visited the laboratory three times, separated by at least 48 h, to consume HFM smoothies with varying FA composition (SF, high O6FAs, and high O3FAs). The smoothies were standardized to 12 kcal/kg body weight, 63% total fat, and 0.72 g/kg sugar. TRGs and GLU were collected at baseline and at 2 h and 4 h postprandially; the MLI was calculated by summing the TRG and GLU responses at each time point. Results: There was a significant increase in TRGs across time points (p < 0.001). For TRGs, there was a trend toward a significant interaction between smoothie type and time (p = 0.06) due to the increase in TRGs in the SF compared to the O3FA smoothie. There was an increase in postprandial GLU that varied across smoothie types (p = 0.036). Taken together, the MLI was elevated in the SF smoothie compared to the O3FAs at 2 h (p = 0.041). Conclusion: A SF smoothie in the morning elevated the metabolic load compared to an O3FA smoothie. Mechanisms of action in the competing clearance of TRGs and GLU warrant further investigation.

Fructose impairs fat oxidation: Implications for the mechanism of western diet-induced NAFLD.

Increased fructose intake from sugar-sweetened beverages and highly processed sweets is a well-recognized risk factor for the development of obesity and its complications. Fructose strongly supports lipogenesis on a normal chow diet by providing both, a substrate for lipid synthesis and activation of lipogenic transcription factors. However, the negative health consequences of dietary sugar are best observed with the concomitant intake of a HFD. Indeed, the most commonly used obesogenic research diets, such as "Western diet", contain both fructose and a high amount of fat. In spite of its common use, how the combined intake of fructose and fat synergistically supports development of metabolic complications is not fully elucidated. Here we present the preponderance of evidence that fructose consumption decreases oxidation of dietary fat in human and animal studies. We provide a detailed review of the mitochondrial ß-oxidation pathway. Fructose affects hepatic activation of fatty acyl-CoAs, decreases acylcarnitine production and impairs the carnitine shuttle. Mechanistically, fructose suppresses transcriptional activity of PPARα and its target CPT1α, the rate limiting enzyme of acylcarnitine production. These effects of fructose may be, in part, mediated by protein acetylation. Acetylation of PGC1α, a co-activator of PPARα and acetylation of CPT1α, in part, account for fructose-impaired acylcarnitine production. Interestingly, metabolic effects of fructose in the liver can be largely overcome by carnitine supplementation. In summary, fructose decreases oxidation of dietary fat in the liver, in part, by impairing acylcarnitine production, offering one explanation for the synergistic effects of these nutrients on the development of metabolic complications, such as NAFLD.

Effects of palm olein and palm stearin on cecal and fecal microbiota of C57BL/6J mice under low and high fat intakes.

This work aimed to study the effects of dietary lipid composition and content on cecal and fecal microbiota of mice fed the following diets for 8 weeks: palm olein (PO)-based low-fat diet, PO-based high-fat diet, palm stearin (PS)-based low-fat diet, and PS-based high-fat diet. Increasing the dietary PS level favored the growth of Firmicutes over Bacteroidetes in the cecum and feces. In addition, it significantly elevated the total lipid (p < 0.01) and bile acid content (p < 0.01) in feces, resulting in the enrichment of fat-degrading and bile-acid tolerant genera within the families Ruminococcaceae and Lachnospiraceae. Although increasing the PO intake also caused obesity in mice, it did not affect the microbial structure. When fat intake is constant, only at a high-fat level can PS (vs PO) induce the above-mentioned microbial shifts. These results highlighted the combined roles of lipid quality and quantity on the gut microbiota.

Effects of fat sources on liver characteristics and intestinal morphometry in an early-life animal model. / Efectos de fuentes de grasa sobre características del hígado y la morfometría intestinal en un modelo animal a temprana edad.

Motivation for the study. There is little evidence on whether the consumption of fat sources containing different proportions of fatty acids has an effect on the characteristics of the liver and small intestine at an early age. Main findings. We found that the intake of fat sources containing unsaturated fatty acids contributes to maintaining the characteristics of both organs; whereas, consumption of sources containing saturated fatty acids favors inflammation in the liver and small intestine. Implications. The consumption of quinoa oil constitutes an alternative to protect these noble organs in an animal model at an early age. We aimed to determine the effect of the consumption of three sources of fatty acids on the relative weight, macroscopic and microscopic characteristics of the liver, and intestinal morphometry in an early-life animal model. Seventy-six randomly distributed chicks received one of the diets (T1: 97.0% basal diet (BD) + 3.0% inert material, T2: 97.0% BD + 3.0% partially hydrogenated vegetable shortening, T3: 97.0% BD + 3.0% quinoa oil, and T4: 97.0% BD + 3.0% fish oil) until the seventh day of life; samples were then extracted in order to be analyzed. We found that the animals that consumed quinoa oil (T3) or fish oil (T4) had favorable results associated to lower liver weight and better absorption of nutrients at intestinal level due to higher values in the hair length and crypt depth ratio, in comparison to partially hydrogenated vegetable shortening (T2). In conclusion, quinoa oil constitutes a healthy option for consumption and an alternative source to fish oil.