BACKGROUND: We have previously demonstrated that dietary saturated fatty acids (SFA), when compared to polyunsaturated fatty acids (PUFA), are preferentially partitioned into oxidation pathways. However, it remains unclear if this preferential handling is maintained when hepatocellular metabolism is shifted toward fatty acid (FA) esterification and away from oxidation, such as when hepatic de novo lipogenesis (DNL) is upregulated.
OBJECTIVE: To investigate whether an acute upregulation of hepatic DNL influences dietary FA partitioning into oxidation pathways.
METHODS: 20 healthy volunteers (11 females) underwent a fasting baseline visit followed by two study days, 2-weeks apart. Prior to each study day, participants consumed an isocaloric high-carbohydrate diet (to upregulate hepatic DNL) for 3-days. On the two study days, participants consumed an identical standardised test meal that contained either [U13C]palmitate or [U13C]linoleate, in random order, to trace the fate of dietary FA. Blood and breath samples were collected over a 6h postprandial period and 13C enrichment in breath CO2 and plasma lipid fractions were measured using gas-chromatography-combustion-isotope ratio mass spectrometry.
RESULTS: Compared to the baseline visit, fasting plasma triglyceride concentrations and markers of hepatic DNL, the lipogenic and stearyl-CoA desaturase indices, were significantly (p < 0.05) increased after consumption of the high-carbohydrate diet. Appearance of 13C in expired CO2 and tracer recovery were significantly (p < 0.05) higher after consumption of the meal containing [U13C]linoleate compared to [U13C]palmitate (5.1 ± 0.5% vs. 3.7 ± 0.4%), respectively. Incorporation of 13C into the plasma triglyceride and non-esterified fatty acid pool was significantly (p < 0.001) greater for [U13C]palmitate compared to [U13C]linoleate.
CONCLUSIONS: Dietary PUFA compared to SFA appear to be preferentially partitioned into oxidation pathways during an acute upregulation of hepatic DNL, thus consumption of a PUFA-enriched diet may help mitigate intrahepatic triglyceride accumulation in individuals at risk of cardiometabolic disease.

The intestinal barrier system protects the human body from harmful factors, by continuously renewing the intestinal epithelium, tight junctions and enteric microbes. However, dietary fat can harm the intestinal epithelial barrier enhancing gut permeability. In recent years, Apolipoprotein A-I has attracted much attention because of its anti-inflammatory properties. Numerous studies have demonstrated that Apolipoprotein A-I can regulate mucosal immune cells, inhibit the progression of inflammation, promote epithelial proliferation and repair, and maintain physical barrier function; it can also regulate angiogenesis, thereby improving local circulation. This article is intended to elucidate the mechanism by which Apolipoprotein A-I improves intestinal barrier damage caused by dietary fat and to review the role of Apolipoprotein A-I in maintaining intestinal homeostasis.

Fatty acid desaturase (FADS1) variant-rs174550 strongly regulates polyunsaturated fatty acid (PUFA) biosynthesis. Additionally, the FADS1 has been shown to be related to mitochondrial function. Thus, we investigated whether changes in mitochondrial function are associated with the genetic variation in FADS1 (rs174550) in human adipocytes isolated from individuals consuming diets enriched with either dietary alpha-linolenic (ALA) or linoleic acid (LA). Two cohorts of men homozygous for the genotype of FADS1 (rs174550) were studied: FADSDIET2 dietary intervention study with ALA- and LA-enriched diets and Kuopio Obesity Surgery study (KOBS), respectively. We could demonstrate that differentiated human adipose-derived stromal cells from subjects with the TT genotype had higher mitochondrial metabolism compared with subjects with the CC genotype of FADS1-rs174550 in the FADSDIET2. Responses to PUFA-enriched diets differed between the genotypes of FADS1-rs174550, showing that ALA, but not LA, -enriched diet stimulated mitochondrial metabolism more in subjects with the CC genotype when compared with subjects with the TT genotype. ALA, but not LA, proportion in plasma phospholipid fraction correlated positively with adipose tissue mitochondrial-DNA amount in subjects with the CC genotype of FADS1-rs174550 in the KOBS. These findings demonstrate that the FADS1-rs174550 is associated with modification in mitochondrial function in human adipocytes. Additionally, subjects with the CC genotype, when compared with the TT genotype, benefit more from the ALA-enriched diet, leading to enhanced energy metabolism in human adipocytes. Altogether, the FADS1-rs174550 could be a genetic marker to identify subjects who are most suitable to receive dietary PUFA supplementation, establishing also a personalized therapeutic strategy to improve mitochondrial function in metabolic diseases.

Background and Objectives: The trends in metabolic dysfunction-associated steatotic liver disease (MASLD) and related metabolic dysfunctions in Japan are unknown. Thus, we aimed to clarify these trends before the novel coronavirus disease 2019 pandemic in Japan. Materials and Methods: We included Japanese individuals aged 25-79 years who underwent health examinations at our center. We analyzed anthropometry, lifestyle-related disease, and nutritional intake in relation to MASLD trends from 2010-2019. Results: The prevalence of MASLD increased in all ages and body mass index (BMI) classes, reaching 30.3% in males and 16.1% in females, with MASLD accounting for 75% of steatotic liver cases and more than half of all type 2 diabetes mellitus (T2DM) and high waist circumference (HWC) cases. The increase in the prevalence of MASLD was thought to be largely attributable to an increase in that of the incidence of steatotic liver itself, and there was no increase in the prevalence of other factors, such as overweight, T2DM, hypertension, and dyslipidemia. The prevalence of glucose metabolic disorders (GMDs) and hypertension decreased. National nutritional data showed an increase in energy intake, total fat, saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids, which correlated with a decrease in GMDs. Salt intake also decreased, which correlated with hypertension. The MASLD group had a higher prevalence of all related metabolic factors than the non-MASLD group, especially HWC, T2DM, and hyperlipidemia. Conclusions: The prevalence of MASLD increased with that of steatotic liver, regardless of age or BMI. A relationship between increased dietary fat, increased steatotic liver, and decreased GMDs was suggested.

The pulmonary system represents a unique lipidomic environment as it contains cellular membrane bound lipid species and a specialized reservoir of lipids in the airway epithelial lining fluid. As a major initial point of defense, airway lipids react to inhaled contaminants such as volatile organic compounds, oxides of nitrogen, or ozone (O3), creating lipokine signaling that is crucial for both the initiation and resolution of inflammation within the lung. Dietary modulation of eicosanoids has gained increased attention in recent years for improvements to cardiovascular health. The current study sought to examine how dietary supplementation with eicosanoid precursors (i.e., oils rich in saturated or polyunsaturated fatty acids) might alter the lung lipid composition and subsequently modify the inflammatory response to ozone inhalation. Our study demonstrated that mice fed a diet high in saturated fatty acids resulted in diet-specific changes to lung lipid profiles and increased cellular recruitment to the lung following ozone inhalation. Bioinformatic analysis revealed an ozone-dependent upregulation of several lipid species, including phosphoserine 37:5. Pathway analysis of lipid species revealed the process of lateral diffusion of lipids within membranes to be significantly altered due to ozone exposure. These results show promising data for influencing pulmonary lipidomic profiles via diet, which may provide a pragmatic therapeutic approach to protect against lung inflammation and damage following pulmonary insult.

This systematic review assesses the knowledge, attitudes, and behaviors (KAB) surrounding dietary fat intake among people with type 2 diabetes mellitus (T2DM) and healthcare professionals. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, four databases were searched to identify studies published between 1995 and 2023 reporting people with T2DM or healthcare professionals that measured KAB towards dietary fat. This work was registered at PROSPERO (CRD42020140247). Twenty-four studies were included. Studies assessed knowledge of people with T2DM and reported poor nutrition knowledge regarding the health effect of fat consumption. Two opposing attitudes towards dietary fat was reported: (1) dietary fat should be limited, (2) promoted dietary fat intake through a low-carbohydrate diet. Participants reported behaviors of limiting fat intake, including trimming visible fat or choosing lower-fat alternatives. Total fat intake ranged between 10 and 66% of participants\' total energy intake, while saturated fat intake ranged between 10 and 17%. People with T2DM reported poor knowledge of dietary fats in particular, and they were frequently unable to identify high-fat food. Attitudes towards dietary fat were heterogenous, and regarding behaviors, saturated fat intake was higher than recommended. Future studies should assess the KAB of people with T2DM based on dietary fat subtypes.

UNASSIGNED: Different types of dietary fat may influence memory and cognitive functions. This study aimed to investigate the association between dietary fat intake and transient global amnesia (TGA).
UNASSIGNED: This case-control study was conducted using Persian Sabzevar cohort data on 258 individuals with TGA and 520 individuals without amnesia in Sabzevar Iran. The food frequency questionnaire (FFQ) was used to assess the intake of dietary fats of the participants. All study participants were screened for TGA by a neurologist and their status was determined based on the diagnostic symptoms defined by the Kaplan and Hodges criteria.
UNASSIGNED: There was an inverse association between the risk of TGA and dietary intake of alpha-linolenic acid (ALA) (OR = 0.94, CI95%:0.88-0.99, P = 0.01). Also, a positive association was observed between TGA and dietary intake of n-6 fatty acids (OR = 1.18, CI 95%: 1.04-1.33, P = 0.01). The results remained significant after adjustment for age, sex, education, job, marital status, physical activity, BMI, and calorie intake.
UNASSIGNED: Omega-3 fatty acids may have beneficial effects; however, omega-6 fatty acids may have adverse effects on the risk of amnesia. Further longitudinal studies are warranted.

Vegetable fat blends are commonly used as fat sources in milk replacers (MR) for calves, but their composition differs considerably from that of bovine milk fat. The aim of this study was to investigate the serum lipid profile of pre-weaned calves fed twice-daily MR containing 30% fat (% DM). Upon arrival, 30 male Holstein-Friesian calves (BW = 45.6 ± 4.0 kg, age = 2.29 ± 0.8 d) were randomly assigned to 2 experimental diets (n = 15 per treatment): one MR was derived from either vegetable fats (VG; 80% rapeseed and 20% coconut fats) or animal fats (AN; 65% Packer\'s lard and 35% dairy cream). The 2 MR formulas contained 30% fat, 24% CP, and 36% lactose. Calves were housed indoors in individual pens with ad libitum access to chopped straw and water. Daily milk allowances were 6.0 L from d 1 to 5, 7.0 L from d 6 to 9, and 8.0 L from d 10 to 35, divided into 2 equal meals and prepared at 13.5% solids. An untargeted liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) method was employed to analyze the lipid profiles in the serum of calves sampled from the jugular vein at 35 d of age. In total, 594 lipids were characterized, comprising 25 different lipid classes. Principal component analysis (PCA) showed significant separation between VG and AN, indicating different lipid profiles in the serum. An orthogonal partial least squares discriminant analysis (OPLS-DA) classification model was used to further validate the distinction between the 2 treatment groups. The model exhibited a robust class separation and high predictive accuracy. Using a Volcano plot (fold change threshold ≥1.5 and false discovery rate ≤0.05), it was observed that calves fed AN had higher levels of 39 lipid species in serum than calves fed VG, whereas 171 lipid species were lower in the AN group. Lipid classes, such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), sphingomyelin (SM), triglycerides (TG), lysophosphatidylcholine (LPC), and lysophosphatidylethanolamine (LPE), were different. In particular, PC and PE were observed at lower levels in calves fed AN, possibly indicating shifts in cell membrane characteristics, intracellular signaling, and liver functions. In addition, a decrease in certain triglyceride (TG) species was observed in calves fed AN, including a decrease in TG species such as TG 36:0 and TG 38:0, possibly related to variations in the content of certain fatty acids (FA) within the AN MR, such as C10:0, C12:0, C14:0, and C18:0 compared with the VG MR. Calves fed AN had lower levels of LPC and LPE, and lyso-phosphatidylinositol (LPI), SM, and phosphatidylinositol (PI) species than calves fed VG, suggesting shifts in lipoprotein and lipid metabolic pathways. In conclusion, these results deepen the understanding of how lipid sources in MR can modulate the serum lipidome profiles of dairy calves.

Intestinal disease is one of the earliest manifestations of cystic fibrosis (CF) in children and is closely tied to deficits in growth and nutrition, both of which are directly linked to future mortality. Patients are treated aggressively with pancreatic enzyme replacement therapy and a high-fat diet to circumvent fat malabsorption, but this does not reverse growth and nutritional defects. We hypothesized that defects in chylomicron production could explain why CF body weights and nutrition are so resistant to clinical treatments. We used gold standard intestinal lipid absorption and metabolism approaches, including mouse mesenteric lymph cannulation, in vivo chylomicron secretion kinetics, transmission electron microscopy, small intestinal organoids, and chylomicron metabolism assays to test this hypothesis. In mice expressing the G542X mutation in cystic fibrosis transmembrane conductance regulator (CFTR-/- mice), we find that defective FFA trafficking across the epithelium into enterocytes drives a chylomicron formation defect. Furthermore, G542X mice secrete small, triglyceride-poor chylomicrons into the lymph and blood. These defective chylomicrons are cleared into extraintestinal tissues at ∼10-fold faster than WT chylomicrons. This defect in FFA absorption resulting in dysfunctional chylomicrons cannot be explained by steatorrhea or pancreatic insufficiency and is maintained in primary small intestinal organoids treated with micellar lipids. These studies suggest that the ultrahigh-fat diet that most people with CF are counselled to follow may instead make steatorrhea and malabsorption defects worse by overloading the absorptive capacity of the CF small intestine.

Increasing evidence hints that DNA hypermethylation may mediate the pathogenic response to cardiovascular risk factors. Here, we tested a corollary of that hypothesis, that is, that the DNA methyltransferase inhibitor decitabine (Dec) ameliorates the metabolic profile of mice fed a moderately high-animal fat and protein diet (HAFPD), a proxy of cardiovascular risk-associated Western-type diet. HAFPD-fed mice were exposed to Dec or vehicle for eight weeks (8W set, 4-32/group). To assess any memory of past exposure to Dec, we surveyed a second mice set treated as 8W but HAFPD-fed for further eight weeks without any Dec (16W set, 4-20/group). In 8W, Dec markedly reduced HAFPD-induced body weight gain in females, but marginally in males. Characterization of females revealed that Dec augmented skeletal muscle lipid content, while decreasing liver fat content and increasing plasma nonesterified fatty acids, adipose insulin resistance, and-although marginally-whole blood acylcarnitines, compared to HAFPD alone. Skeletal muscle mitochondrial DNA copy number was higher in 8W mice exposed to HAFPD and Dec, or in 16W mice fed HAFPD only, relative to 8W mice fed HAFPD only, but Dec induced a transcriptional profile indicative of ameliorated mitochondrial function. Memory of past Dec exposure was tissue-specific and sensitive to both duration of exposure to HAFPD and age. In conclusion, Dec redirected HAFPD-induced lipid accumulation toward the skeletal muscle, likely due to augmented mitochondrial functionality and increased lipid demand. As caveat, Dec induced adipose insulin resistance. Our findings may help identifying strategies for prevention and treatment of lipid dysmetabolism.