Dietary Fatty Acid Composition Research Articles

Use of chia seed on regular and low-fat crackers, their antioxidant properties, and in-vitro bioaccessibility

Although having functional properties, fat is known to be adversely effective in case of high consumption. High fat consumption causes health disorders such as obesity, cardiovascular diseases and high blood pressure, insulin balance disorders and cancer. For this reason, it is important to reduce fat consumption and create food formulations rich in bioactive components. In the scope of this study, CS (Chia seed) was replaced with wheat flour 10%, 20%, and 30% (w/w) and the fat amount was decreased in 25%, 50%, 75% (w/w) ratios for formulating low-fat crackers, and the antioxidative potential of the samples was evaluated. Extractable, hydrolysable, bioaccessible phenolic fractions of samples were analyzed in terms of TEACABTS, TEACCUPRAC, TEACDPPH and Total Phenolic Content (TPC) (Folin Ciocalteu’s method). CS replacement was determined to be more effective than a fat reduction on AC and TPC results of samples. By 25, 50 and 100% fat reduction of extractable, hydrolysable and bioaccessible phenolic fractions, TEACABTS values increased respectively as 5.87%, 9.33% and 12.11%. 75% fat reduced-30% CS supplemented sample was 91.0% higher than 100% fat including-30% CS supplemented sample and 143.4% higher than the control sample in terms of TEACABTS for bioaccessible phenolic fractions. The dietary fiber, protein content and fatty acid composition are thought to be effective in the potential of CS. It is proved that CS could be expressed as a convenient pseudo-cereal for functional food formulations.

Effects of fish oil substitution by hazelnut oil on growth performance, whole‐body fatty acid composition and enzymes of intermediary metabolism of juvenile meagre ( Argyrosomus regius Asso, 1801)

The need for new alternative oil sources in the ever-increasing aquaculture of carnivorous species is imperative. We substituted fish oil (FO) with hazelnut oil (HO) in meagre diet at 20, 40, 60, 80 and 100%. Triplicate groups of 40 fish/tank juvenile meagre (ca 15 g) were used. For the reduction of FO level in meagre diet, a 40% substitution by HO is attainable without affecting growth performance. However, higher substitutions appear to have a negative effect on growth performance and feed efficiency, although daily feed intake seems to remain unaffected by the reduction in FO. No effects on whole-body protein and lipid concentration were observed for fish fed the experimental diets. Whole-body fatty acid composition reflected the dietary fatty acid composition in all dietary groups. Diets with higher than 40% levels of FO substitution significantly reduce highly unsaturated ω-3 fatty acids in the fish. Although the metabolic relationship between carbohydrate and fatty acid exploitation is extremely versatile, and thus it is difficult to reach a safe conclusion, it seems that FO substitution by HO activates fish carbohydrate, rather than fatty acids, exploitation machinery. These results support the use of HO in meagre diets up to 40% FO substitution with a future thought for more efficient use of 30% FO substitution by HO.

Dietary Supplementation With Eicosapentaenoic Acid Inhibits Plasma Cell Differentiation and Attenuates Lupus Autoimmunity.

Accumulating evidence suggests that cholesterol accumulation in leukocytes is causally associated with the development of autoimmune diseases. However, the mechanism by which fatty acid composition influences autoimmune responses remains unclear. To determine whether the fatty acid composition of diet modulates leukocyte function and the development of systemic lupus erythematosus, we examined the effect of eicosapentaenoic acid (EPA) on the pathology of lupus in drug-induced and spontaneous mouse models. We found that dietary EPA supplementation ameliorated representative lupus manifestations, including autoantibody production and immunocomplex deposition in the kidneys. A combination of lipidomic and membrane dynamics analyses revealed that EPA remodels the lipid composition and fluidity of B cell membranes, thereby preventing B cell differentiation into autoantibody-producing plasma cells. These results highlight a previously unrecognized mechanism by which fatty acid composition affects B cell differentiation into autoantibody-producing plasma cells during autoimmunity, and imply that EPA supplementation may be beneficial for therapy of lupus.

Effects of Dietary Fatty Acid Composition on Lipid Metabolism and Body Fat Accumulation in Ovariectomized Rats.

Background: Obesity is a state of excess energy storage resulting in body fat accumulation, and postmenopausal obesity is a rising issue. In this study using ovariectomized (OVX) rats, we mimicked low estrogen levels in a postmenopausal state in order to investigate the effects of different amounts and types of dietary fatty acids on body fat accumulation and body lipid metabolism. Methods: At 9 weeks of age, rats (n = 40) were given an ovariectomy, eight of which were sham-operated to serve as a control group (S). We then divided OVX rats into four different intervention groups: diet with 5% soybean oil (C), and diet with 5% (L), 15% (M), and 20% (H) (w/w) experimental oil, containing 60% monounsaturated fatty acids (MUFAs) and with a polyunsaturated/saturated fatty acid (P/S) ratio of 5. Results: After OVX, compared to the S group, the C group showed significantly higher body weight, and insulin and leptin levels. Compared to the C group, the H group had lower hepatic triglyceride level and FAS enzyme activity, and higher hepatic ACO and CPT-1 gene expressions and enzyme activities. Conclusions: An OVX leads to severe weight gain and lipid metabolism abnormalities, while according to previous studies, high fat diet may worsen the situation. However, during our experiment, we discovered that the experimental oil mixture with 60% MUFAs and P/S = 5 may ameliorate these imbalances.

Increasing dietary SFA:MUFA ratio with low levels of LC-PUFA affected lipid metabolism, tissue fatty acid profile and growth of juvenile California Yellowtail (Seriola dorsalis)

Lipids rich in saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) are among the alternative sources reported to maintain growth and tissue fatty acid composition and, in some cases, reducing the long-chain polyunsaturated fatty acids (LC-PUFA) requirements. The present works aims to investigate the effects of different SFA:MUFA ratios on growth performance, tissue fatty acid composition, and the expression of crucial genes involved in the lipid metabolism of juvenile California Yellowtail (Seriola lalandi) fed diets with increasing SFA:MUFA ratios (1.6, 1.8, and 2.0) with low LC-PUFA levels. After eight weeks, fish fed the control diet outperformed the experimental feeds with increasing SFA:MUFA ratio in terms of final weight, specific growth rate, and liver index. No differences were observed in survival, viscerosomatic index, and condition factor across dietary treatments. Whole-body, liver, and muscle tissues proximate composition was slightly affected by increasing the dietary SFA:MUFA ratio. In terms of fatty acid composition, whole-body, liver, and muscle tissues reflected the dietary fatty acid composition to most extent, except SFA (mainly 16:0) that was not proportionally deposited. LC-PUFA sparing effect was demonstrated at a low degree in this study, likely due to the low SFA:MUFA ratio or high content of dietary MUFA. Significant changes were observed in the expression of genes related to lipid metabolism. The ppara and igf1 expression were higher in fish fed the Control diet than those fed SFA:MUFA 1.6 diet. Whereas the fish from SFA:MUFA 1.6 group displayed higher cptla expression compared to fish from SFA:MUFA 2.0.

Impact of Dietary Fatty Acids on Chylous Effusion in a Mouse Model of Generalized Lymphatic Anomaly

Introduction Generalized lymphatic anomalies (GLA) are complicated vessel malformations that can result in impaired lymphatic function. Potential GLA complications include lipid-rich lymph in the thoracic cavity or abdomen, respectively chylothorax and chylous ascites. To reduce the potential for chylous accumulation, GLA patients limit dietary fats. We hypothesized that dietary fatty acid composition impacts the potential for lymphatic dysfunction and chylous effusion in GLA. Methods Adipose-specific overexpression of lymphatic growth factors has demonstrated lethal chylothorax in mice. Here we utilized mice with inducible adipose overexpression of VEGF-D (Adipo-VD) to mimic GLA and tested the chylothorax incidence with a mixed high fat diet (HFD), high saturated (HSFD), or high unsaturated (HUSFD) fat diet. Lipid transport was assessed by oral triglyceride uptake and mesenteric fat analysis. Lymphatic expansion and inflammation were determined by whole mount immunofluorescence and gene expression. Body composition was assessed with by MRI. Results Oral gavage of a triglyceride bolus increased chylous effusion in all groups. HSFD resulted in a significant increase in TNF-α, IL-6, and IL-10 expression compared to HFD and HUSFD groups. HFD fed mice demonstrated a significant increase is body fat compared to HUSFD fed mice. Interestingly, the chylous effusion incidence was highest in HFD fed mice compared to either HSFD and HUSFD. Conclusion HFD results in increased chylous effusion driven particularly by a bolus lipid load in Adipo-VD mice. These findings suggest that dietary fatty acid composition, and in particularly large meal feeding, may result in increased chylothorax risk for GLA patients.

Effects of different dietary lipid resources on sperm quality and reproductive success in rainbow trout ( Oncorhynchus mykiss )

The present study evaluated the effects of dietary fish oil replacement with linseed or sesame oil on sperm quality and reproductive performance in rainbow trout (Oncorhynchus mykiss) during a 7-month feeding trial. Male (≈ 970 g) broodfish were fed three isonitrogeneous and isolipidic formulated diets containing fish oil (FO diet), linseed oil (LO diet) and sesame oil (SO diet). Commercial trout broodfish diet was fed to another group to serve as control (CD). Growth performance was not affected by diet. Slight variations in volume, pH and density were recorded in the semen produced by rainbow trout subjected to the different dietary treatments (p > 0.05). Similarly, motility and kinematic parameters were not influenced by diets (p > 0.05). However, osmolality differed in the dietary groups, with semen from SO and LO fed fish having comparatively higher values (p < 0.05). Fatty acid (FA) profile of fish spermatozoa reflected dietary FA composition. FA profile of spermatozoa showed evidence of de novo biosynthesis of eicosapentaenoic acid, docosahexaenoic acid and arachidonic acid. Dietary treatments did not significantly affect reproductive performance (fertilization, eyeing and hatching rates). This may be suggestive of the ability of male rainbow trout to synthesize HUFA in vivo to meet their reproductive needs in the event of low dietary n-3 HUFA supplementation.

Influence of dietary fatty acid composition on enzymatic activity and digestive histology in silver catfish (Rhamdia quelen)

Dietary fatty acids may influence the development of the digestive tract and initial activation of digestive enzymes in fish. The objective of this study was to evaluate the effect of the diet lipid profile on ontogeny and activity of digestive enzymes in silver catfish post larvae fed practical diets. Five diets were tested, replacing broiler liver by soybean protein concentrate (SPC) or fish meal (FM): Standard, 15SPC, 30SPC, 15FM and 30FM. The enzymatic activity of fish was analyzed from 32 Hours after fertilization (Haf). Were analysed acid protease, trypsin, chymotrypsin, lipase, amylase and maltase. The development of the digestive system was analyzed from first feeding up to 28 days by histological techniques. The enzymatic activity presented peaks for the post-larvae fed with the 15SPC diet and fish fed with diet 15FM showed best growth. The development of the digestive system did not suffer damage from the diets offered. Post-larvae fed the 30SPC diet showed reduced development of the digestive tract. The diet 15FM provide good lipid profile for silver catfish post larvae.

Influence of different dietary oil consumption on nutrient malabsorption: An animal trial using Sprague Dawley rats.

In the present study, the influences of five typical dietary oils (i.e., palm oil, PO; leaf lard oil, LO; rapeseed oil, RO; sunflower oil, SO; and linseed oil, LN) consumption on the nutrients malabsorption were studied using adult male Sprague Dawley rats. Results suggested that the C16:0 (24.534±2.26% to 54.269±1.28%) and C18:0 (18.433±4.421% to 36.455±3.316%) were the dominant fatty acids in fecal samples in different groups. After 6-week intervention by different dietary oils, the fecal moisture and water soluble protein content in PO group, the reducing sugar content in PO, LO, and RO groups were significantly increased compared with those in the control group (p<.05). Moreover, the Na, K, and Fe contents in LO group were all the highest among the all groups. These effects were probably due to the different fatty acids composition as illustrated in the correlation analysis results. The different effects were probably due to their distinct fatty acids composition as illustrated in the correlation analysis results. Results further indicated that the different dietary oils treatment, especially for the PO (SFAs, 43.17±0.98%) and LO (SFAs, 36.44±0.65%), increased the upstream inflammatory cytokine expression level in the Toll-like receptor signal pathway (i.e., TLR4 and MyD88), enhancing the gut permeability. This resulted in significant increase of serum lipopolysaccharide (LPS) levels (p<.05), which was closely connected with different metabolic diseases. The present study may provide basic understandings about different dietary oil enteral nutrition and their effects on gut health. PRACTICAL APPLICATIONS: The PO, LO, RO, SO, and LN are the five of the most typical dietary lipids in Asia countries, especially in China. They are the natural edible oils which are rich in C16:0, C18:0, C18:1, C18:2ω6, and C18:3ω3, respectively. The present study indicated that the different dietary lipid consumption may result in different dietary nutrients malabsorption, which are related with the dietary lipid fatty acid composition.

Influence of Genetic Selection for Growth and Broodstock Diet n-3 LC-PUFA Levels on Reproductive Performance of Gilthead Seabream, Sparus aurata.

Simple SummaryGilthead seabream (GSB) broodstock were genetically selected based on their growth trait either high growth (HG) or low growth (LG) to evaluate the reproductive performance of these both traits under either fish oil (FO) or vegetable oil (VO) based diets feeding regime. The egg and larval quality were significantly improved by the broodstock selected for HG trait fed under FO based diet. This indicates that broodstock selected with HG trait has positive influence on the improving sperm, egg and larval quality in gilthead seabream.Genetic selection in gilthead seabream (GSB), Sparus aurata, has been undertaken to improve the growth, feed efficiency, fillet quality, skeletal deformities and disease resistance, but no study is available to delineate the effect of genetic selection for growth trait on GSB reproductive performance under mass spawning condition. In this study, high growth (HG) or low growth (LG) GSB broodstock were selected to evaluate the sex steroid hormones, sperm, egg quality and reproductive performance under different feeding regime of commercial diet or experimental broodstock diet containing either fish oil (FO) or vegetable oil (VO) based diet. Under commercial diet feeding phase, broodstock selected for either high growth or low growth did not show any significant changes in the egg production per kg female whereas egg viability percentage was positively (p = 0.014) improved by the high growth trait broodstock group. The experimental diet feeding results revealed that both growth trait and dietary fatty acid composition influenced the reproductive performance of GSB broodstock. In the experimental diet feeding phase, we observed high growth trait GSB males produced a higher number of sperm cells (p < 0.001) and also showed a higher sperm motility (p = 0.048) percentage. The viable egg and larval production per spawn per kg female were significantly improved by the broodstock selected for high growth trait and fed with fish oil-based diet. This present study results signifies that gilthead seabream broodstock selected on growth trait could have positive role in improvement of sperm and egg quality to produce viable progeny.

Dietary soybean oil aggravates the adverse effects of low salinity on intestinal health in juvenile mud crab Scylla paramamosain

Salinity is one of the important factors affecting the physiological state of crustaceans in marine environments. Lipid plays major roles in energy supply and is main sources of essential fatty acids for membrane integrity, which is critical in adaptations to changes in salinity. Here we evaluated the effects of salinity (medium, 23 ppt and low, 4 ppt) and dietary lipid source (fish oil, FO and soybean oil, SO) on intestinal health of the marine crustacean mud crab Scylla paramamosain. The results indicated that low salinity and dietary SO (LSO group) significantly affected intestinal histomorphology, with a significant decrease of intestinal fold height and width as well as down-regulation of intestinal mRNA levels of tight junction genes compared to crab reared at medium salinity and fed FO diets (MFO group). Crabs reared at low salinity and fed SO showed an increased inflammatory response in intestine, which stimulated a physiological detoxification response together with apoptosis compared to crab in the MFO group. Low salinity and SO diets also could be responsible for multiply the pathogenic bacteria of Photobacterium and inhibit the beneficial bacteria of Firmicutes and Rhodobacteraceae in intestine, and act on a crucial impact on the development of intestinal microbial barrier disorders. The results of microbial function predictive analysis also support these inferences. The findings of the present study demonstrated that soybean oil as the main dietary lipid source could exacerbate the adverse effects of low salinity on intestinal health of mud crab, and provided evidence suggesting that dietary lipid source and fatty acid composition may play vital roles in intestinal health and the process of adaptation to environmental salinity in marine crustaceans.

Composition of Dietary Fatty Acids and Health Risks in Japanese Youths.

In the overall composition of dietary fatty acids (FAs), the quantity of each FA is interrelated with that of others. We examined the associations between dietary FA composition and cardiometabolic risk in Japanese youths. Risk factors (anthropometric characteristics, serum lipid and liver enzyme levels, and blood pressure) were measured in 5485 junior-high-school students. Dietary intake was assessed using a food frequency questionnaire. The mean saturated FA (SFA), monounsaturated FA (MUFA), omega-6 polyunsaturated FAs (PUFAs), and omega-3 PUFAs intake were 9.6%E, 10.3%E, 6.3%E, and 1.1%E, respectively. In compositional regression analysis controlled for confounders, a high intake of omega-6 PUFAs relative to others was associated with low low-density-lipoprotein cholesterol levels (LDL-C; p = 0.003), and relative SFA intake was associated with high levels of gamma-glutamyl transpeptidase (p = 0.019). Relative omega-3 PUFAs intake was associated with low blood pressure (p = 0.005–0.034) but had unfavorable effects on adiposity and alanine transaminase. Substitutional models showed similar results for omega-6 PUFAs on LDL-C, but MUFA had inconsistent effects on risk factors. The results from the compositional data analysis were consistent with previous studies and clinical practice/knowledge. Focusing on increasing omega-6 PUFAs in Japanese youths could have favorable consequences in the long term.

Modulation of hepatic miRNA expression in Atlantic salmon (Salmo salar) by family background and dietary fatty acid composition.

This study finds significant differences in hepatic fatty acid composition between four groups of Atlantic salmon (Salmo salar) consisting of offspring from families selected for high and low capacities to express the delta 6 desaturase isomer b and fed diets with 10% or 75% fish oil. The results demonstrated that hepatic lipid metabolism was affected by experimental conditions (diet/family). The fatty acid composition in the four groups mirrored the differences in dietary composition, but it was also associated with the family groups. Small RNA sequencing followed by RT‐qPCR identified 12 differentially expressed microRNAs (DE miRNAs), with expression associated with family groups (miR‐146 family members, miR‐200b, miR‐214, miR‐221, miR‐125, miR‐135, miR‐137, miR_nov_1), diets (miR‐203, miR‐462) or both conditions. All the conserved DE miRNAs have been reported as associated with lipid metabolism in other vertebrates. In silico predictions revealed 37 lipid metabolism pathway genes, including desaturases, transcription factors and key enzymes in the synthesis pathways as putative targets (e.g., srebp‐1 and 2, Δ6fad_b and c, hmdh, elovl4 and 5b, cdc42). RT‐qPCR analysis of selected target genes showed expression changes that were associated with diet and with family groups (d5fad, d6fad_a, srebp‐1). There was a reciprocal difference in the abundance of ssa‐miR‐203a‐3p and srebp‐1 in one group comparison, whereas other predicted targets did not reveal any evidence of being negatively regulated by degradation. More experimental studies are needed to validate and fully understand the predicted interactions and how the DE miRNAs may participate in the regulation of hepatic lipid metabolism.

Manipulation of fatty acid composition in a high-fat meal does not result in differential alterations in appetite or food intake in normal weight females: A single-blind randomized crossover study

A behavioral concept that generates a path to obesity is eating in the absence of hunger (EAH). One strategy that may be effective in preventing EAH is the manipulation of dietary fatty acid (FA) composition. However, it remains unclear which FA has the greatest impact on both appetite and EAH. Therefore, the purpose of this study was to examine the effect of different dietary FA compositions (monounsaturated, MUFA; polyunsaturated, PUFA; saturated, SFA) on subjective ratings of appetite and subsequent ad libitum eating after a 3 h postprandial period. Sixteen apparently healthy normal weight females between ages 18–40 completed this randomized, single-blind, crossover study. Participants consumed a HF meal (65% energy from fat) rich in SFA, MUFA, and PUFA with an energy content corresponding to 35% of their measured resting metabolic rate on three separate occasions. Visual analog scales were collected while fasted and every 30 min for 3 h during a postprandial period to measure feelings of hunger, fullness, and desire to eat (DTE). Participants were provided an ad libitum buffet meal 3 h after the HF meal. There were no statistically significant differences for ratings of hunger, fullness, or DTE across conditions. Further, there was no significant difference in energy intake during the ad libitum lunch. We conclude that the manipulation of FA composition in a HF meal does not differentially affect appetite sensations or subsequent energy intake.

Interplay between dietary lipids and cadmium exposure in rainbow trout liver: Influence on fatty acid metabolism, metal accumulation and stress response

The present study aimed at investigating interactive effects between dietary lipids and both short- and long-term exposures to a low, environmentally realistic, cadmium (Cd) concentration. Juvenile rainbow trout were fed four isolipidic diets (31.7 g/kg) enriched in either linoleic acid (LA, 18:2n-6), alpha-linolenic acid (ALA, 18:3n-3), eicosapentaenoic acid (EPA, 20:5n-3) or docosahexaenoic acid (DHA, 22:6n-3). From the 4th week of this 10-week experiment, the lipid level of the diet was increased (120.0 g/kg) and half of the fish fed each diet were aqueously exposed to Cd (0.3 μg/L) while the other half were not exposed to Cd (control). Fish were sampled and their liver was harvested for fatty acid profile, hepatic Cd and calcium concentrations, total glutathione level and gene expression assessment, either (i) after 4 weeks of feeding and 24 h of Cd contamination (day 29) (short-term Cd exposure) or (ii) after 10 weeks of feeding and 6 weeks of Cd contamination (day 70) (long-term Cd exposure). We found that both dietary lipids and Cd exposure influenced fatty acid homeostasis and metabolism. The hepatic fatty acid profile mostly reflected that of the diet (e.g. n-3/n-6 ratio) with some differences, including selective retention of specific long chain polyunsaturated fatty acids (LC-PUFAs) like DHA and active biotransformation of dietary LA and ALA into LC-PUFAs. Cd effects on hepatic fatty acid profiles were influenced by the duration of the exposure and the nutritional status of the fish. The effects of diet and Cd exposure on the fatty acid profiles were only sparsely explained by variation of the expression pattern of genes involved in fatty acid metabolism. The biological responses to Cd were also influenced by dietary lipids. Fish fed the ALA-enriched diet seemed to be the least affected by the Cd exposure, as they showed a higher detoxifying ability against Cd with an early upregulation of protective metallothionein a (MTa) and apoptosis regulator BCL2-Like1 (BCLx) genes, an increased long-term phospholipid synthesis and turnover and fatty acid bioconversion efficiency, as well as a lower long-term accumulation of Cd in their liver. In contrast, fish fed the EPA-enriched diet seemed to be the most sensitive to a long-term Cd exposure, with an impaired growth performance and a decreased antioxidant capacity (lower glutathione level). Our results highlight that low, environmentally realistic aqueous concentrations of Cd can affect biological response in fish and that these effects are influenced by the dietary fatty acid composition.

Association of dietary fatty acids and the incidence risk of cardiovascular disease in adults: the Tehran Lipid and Glucose Prospective Study

BackgroundConsidering the inconsistent available findings regarding the cardioprotective effect of dietary fatty acid composition, we prospectively examined the feasible association between the dietary fatty acids and the cardiovascular disease (CVD) incidence in framework of the population-based Tehran Lipid and Glucose Study.MethodsA total of 2369 participants (19–70 years, 43.5% men) without CVD at baseline (2006–2008) were included and followed-up for 6.7 years. Fatty acids’ dietary intake was estimated using a 168-item semi-quantitative food frequency questionnaire. The CVD incidence risk across tertiles of dietary fatty acids was predicted via Cox proportional hazards regression models.ResultsThe average age and body mass index of the included population were 38.5 ± 13.3 years and 26.6 ± 4.8 kg/m2 at baseline. Over 6.7 years of follow-up, 79 cases of CVD were detected. The risk of CVD was lower in upper tertile of monounsaturated fatty acids, oleic acid, and docosahexaenoic acid + eicosapentaenoic acid among the tertiles. No significant associations were found between total fat, saturated and polyunsaturated fatty acids’ intake, and CVD.ConclusionsOur results suggest that the dietary fatty acid composition might affect the incidence risk of CVD within the Iranian population.

Dietary fatty acids modulate cortisol concentrations and social dominance during social confrontations in adolescent male guinea pigs

The hypothalamic-pituitary-adrenal (HPA)-axis and related glucocorticoid concentrations regulate physiology and behavior, which can be modulated by nutritional conditions, particularly by the dietary fatty acid composition. Omega-3 polyunsaturated fatty acids (PUFAs) have been shown to promote hypothalamic-pituitary-adrenal (HPA)-axis functions, whereas saturated fatty acids (SFAs) in general produce adverse effects and even increase baseline glucocorticoid concentrations. Glucocorticoids (e.g. cortisol) were further documented to modulate the establishment of dominance relationships, while the involvement of dietary fatty acids remains understudied. This study focused on different effects of PUFAs and SFAs on cortisol concentrations and social dominance in male guinea pigs. Three groups of animals were maintained on diets high in PUFAs (10 % w/w walnut oil), SFAs (10 % w/w coconut fat), or on an untreated control diet starting already prenatally. During adolescence, at an age of 60, 90, and 120 days, each individual's saliva cortisol concentrations and hierarchy index (calculated by initiated and received agonistic behavior) were measured during basal group housing conditions and stressful social confrontations with unfamiliar individuals of the other groups. SFA males showed highest baseline cortisol concentrations, lowest cortisol responses to social confrontations, and became subdominant. PUFA and control males showed significant cortisol responses. However, while control males became dominant during social confrontations, the hierarchy index in PUFA males decreased with age. Individual hierarchy indices during consecutive social confrontations revealed a high consistency. The findings presented here indicate that dietary fatty acids differently affect HPA-axis functions and social dominance but the underlying mechanisms remain to be determined.

The Beneficial Effects of Apical Sodium-Dependent Bile Acid Transporter Inactivation Depend on Dietary Fat Composition.

ScopeThe apical sodium‐dependent bile acid transporter (ASBT, SLC10A2) is important in the enterohepatic cycling of bile acids and thereby in the intestinal absorption of lipids. ASBT inhibition has been shown to improve aspects of the metabolic syndrome, but the underlying mechanisms have remained unclear. Here, the effect of ASBT inhibition on the uptake of specific fatty acids and its consequences for diet‐induced obesity and non‐alcoholic fatty liver disease (NAFLD) are investigated.MethodsIntestinal fat absorption is determined in mice receiving an ASBT inhibitor and in Asbt−/− mice. Metabolic disease development is determined in Asbt−/− mice receiving a low‐fat control diet (LFD) or high‐fat diet (HFD) rich in saturated fatty acids (SFAs) or PUFAs.ResultsBoth ASBT inhibition and Asbt gene inactivation reduce total fat absorption, particularly of SFAs. Asbt gene inactivation lowers bodyweight gain, improves insulin sensitivity, and decreases the NAFLD activity score upon feeding a HFD rich in SFAs, but not in PUFAs.ConclusionsThe beneficial metabolic effects of ASBT inactivation on diet‐induced obesity depend on decreased intestinal absorption of SFAs, and thus on the dietary fatty acid composition. These findings highlight the importance of dietary fatty acid composition in the therapeutic effects of ASBT inhibition.

The association of dietary and plasma fatty acid composition with FTO gene expression in human visceral and subcutaneous adipose tissues.

The human obesity susceptibility gene, FTO, associates with body mass and obesity in humans through regulation of energy expenditure and intake. We aimed to determine how fatty acids in plasma and in diet associate with FTO gene expression in subcutaneous and visceral adipose tissues. In this study, 97 participants aged ≥ 18years were selected from patients admitted to the hospital for abdominal surgeries. Habitual dietary intake of participants was collected using a valid and reliable food frequency questionnaire (FFQ), from which the intake of fatty acids was quantified. Plasma fatty acids were assessed by gas-liquid chromatography. The mRNA expression of the FTO gene in visceral and subcutaneous adipose tissues obtained by biopsy was measured by Real-Time Quantitative Reverse Transcription PCR. Standardized β-coefficients were calculated by multivariable linear regression. After adjusting for age, homeostasis model insulin resistance index (HOMA-IR), and body mass index, total fatty acid intake was significantly associated with FTO gene expression in visceral (STZβ = 0.208, P = 0.037) and subcutaneous (STZβ = 0.236, P = 0.020) adipose tissues. Dietary intake of monounsaturated fatty acid (MUFA) and polyunsaturated fatty acids (PUFA) had positive significant associations with the expression of FTO in visceral (STZβ = 0.227, P = 0.023; STZβ = 0.346, P < 0.001, respectively) and subcutaneous (STZβ = 0.227, P = 0.026; STZβ = 0.274, P = 0.006, respectively) adipose tissues. There were no associations between plasma fatty acids and FTO mRNA expression in either subcutaneous or visceral adipose tissues. The weak association of dietary total fatty acids, MUFA, and PUFA with FTO gene expression in both adipose tissues may highlight the importance of dietary fatty acids composition along with total fat intake in relation to FTO gene expression.

Body composition, not dietary fatty acid composition, explains metabolic responses following a high-fat meal in premenopausal normal-weight women: a single-blind, randomised, crossover study.

The aim of this study was to examine the effect of three different fatty acid (FA)-rich meals enriched in either SFA, MUFA or PUFA on postprandial metabolic responses in premenopausal, normal-weight women. For this randomised, single-blind, crossover study, three high-fat (HF) meals rich in either SFA, MUFA or PUFA (65 % energy from fat; 35 % of participants' total daily energy needs) were tested. For each visit, anthropometrics and RMR were measured following a 12-15 h fast. Then, participants consumed one of the HF meals, and respiratory gases were collected using indirect calorimetry for 3 h postprandially. Energy expenditure (EE) following a SFA-rich meal was significantly higher than a MUFA-rich meal (P = 0·04; η2 = 0·19), but SFA was not significantly different from PUFA. There was a trend towards significance in EE between PUFA and MUFA (P = 0·06). After adjusting for fat-free mass (FFM), there were no longer condition or time effects for EE, although FFM remained a significant predictor (P = 0·005; η2 = 0·45). There were no significant differences between conditions for dietary-induced thermogenesis or substrate oxidation. The relationship between fat mass (FM) and both total fat oxidation (r 0·62; P = 0·025) and total change in RER following a MUFA-rich meal was observed (r -0·55; P = 0·05). In conclusion, weight loss through increases in EE may be best achieved by increasing FFM rather than selection of FA type. Further, a relationship exists between FM and fat oxidation following a MUFA-rich meal, most likely due to an unidentified mechanism.