High Fat Diet with a High Monounsaturated Fatty Acid and Polyunsaturated/Saturated Fatty Acid Ratio Suppresses Body Fat Accumulation and Weight Gain in Obese Hamsters. Nutrients. 2017;9:1148. [PMID: 29048361 PMCID: PMC5691764 DOI: 10.3390/nu9101148]

The comparison of meat yield, quality, and flavor between small-tailed Han sheep and two crossbred sheep and the verification of related candidate genes

Introduction

In Northeast China, Dorper and Australian White rams are commonly crossbred with small-tailed Han (STH) ewes to improve the offspring's meat yield and quality. However, the differences in traits and the flavor between the crossbred sheep and STH sheep remain unclear. In addition, the candidate genes potentially influencing the meat quality in the three sheep breeds require further verification.

Methods

A total of 18 2-month-old healthy rams were raised over a period of 5 months, which included 6 STH, 6 Dorper and small-tailed Han crossbred (Do × STH), and 6 Australian white and small-tailed Han crossbred (Au × STH) offspring. The differences in slaughter, meat quality traits, fatty acid and amino acid composition in the muscular longissimus dorsi (MLD), and volatile compounds in the semitendinosus muscle were compared between the sheep breeds. The candidate genes related to intramuscular fat (IMF) content and fatty acids were validated.

Results

The results of this study revealed that the crossbred sheep had higher body weight, carcass weight, bone weight, net meat weight, and IMF content than the STH sheep (p < 0.05). The Do × STH offspring had a higher pH value (24 h), moisture content, and cooking percentage; they also had redder and brighter meat color. The content of myristate, palmitic, and margaric acids in the crossbred sheep was higher than that in the STH sheep (p < 0.05). The Do × STH offspring had the highest saturated fatty acid content (p < 0.05). The Au × STH offspring had the highest protein content (p < 0.05). The arachidonic acid and amino acid (Asp, Ala, Ile, Leu, Lys, Thr, and essential amino acid) contents were higher in the STH sheep than in the crossbred sheep (p < 0.05). The odor activity value (OAV) analysis showed that most of the aldehydes in the Au × STH offspring had higher values. The PDK4 gene expression was positively associated with the IMF content and was negatively correlated with the linoleic acid content in the Do × STH sheep (p < 0.05). The TMEM273 gene expression was positively associated with linoleic and arachidonic acid contents and was negatively correlated with oleic and palmitic acid contents in the Do × STH sheep (p < 0.05).

Discussion

The results showed the differences between the crossbred sheep and STH sheep and provided the candidate genes related to meat quality in sheep.

Association between dietary fatty acids and urinary incontinence

Background

Dietary nutrient intake contributes to urination; however, the association between dietary nutrient intake, especially that of fat, and urinary incontinence (UI) is not well understood. The most common types of UI include stress UI (SUI) and urgency UI (UUI).

Objective

To investigate the potential effect(s) of dietary fat intake on UI and explore its mechanism of action in relation to body mass index (BMI).

Methods

A cross-sectional survey of data from 15,121 individuals (20-85 years of age) from the National Health and Nutrition Examination Survey (2001-2008), a random population-based sample, was performed. Data regarding dietary nutrient intake were collected through 24 h dietary recall interviews. UI and covariate data were collected through in-person interviews. UI was assessed according to the American Urological Association Symptom Index. The odds ratio (OR) for SUI and UUI were calculated using multivariate logistic regression analysis. The mediation effect was estimated using observational mediation analysis.

Results

Higher total fat intake was positively associated with increased odds for developing UI (OR 1.44 [95% confidence interval (CI) 1.08-1.93]). Females who consumed more saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) were more likely to develop SUI. BMI partially explained the association between total fat, SFA, MUFA, and PUFA and SUI; the proportions of the mediation effect of BMI were 14.7%, 13.0%, 18.7%, and 16.3%, respectively.

Conclusions

Results of this study emphasize the key role of dietary fat intake in the prevalence of UI. Higher fat intake was positively associated with UI and BMI partially mediated the effect of fat intake on SUI.

A MUFA/carotenoid-rich oil ameliorated insulin resistance by improving inflammation and oxidative stress in obese rats

Obesity is associated with low-grade inflammation and oxidative stress, leading to insulin resistance and type II diabetes. Caryocar brasiliense pulp oil (pequi oil - PO) is rich in oleic acid and carotenoids and positively implicated in regulating inflammation and oxidative stress. This study investigated PO's antioxidant and anti-inflammatory effects in a diet-induced obesity model. Male Wistar rats were allocated into three experimental groups: Control (CD), Western Diet (WD), and Western Diet, with 27% of lard switched by PO (WDP). Metabolic, inflammatory, and oxidative stress biomarkers were evaluated after 12 weeks of diet protocols in liver and adipose tissue. WDP rats gained less body mass and epididymal fat, had less hepatic fat infiltration, and were more glucose-tolerant and insulin-sensitive than WD (p < 0.05). In the liver, the WDP group had the highest non-enzymatic antioxidant capacity, SOD and GPx activities, CAT, SOD II, and HSP72 expression compared to WD (p < 0.05). Adipose tissue IL-6 and TNF were reduced, and IL-10 was increased in WDP compared to WD (p < 0.05). Our data suggest that the partial replacement of lard by PO in a Western diet prevented visceral fat accumulation and contributed to reducing inflammation in adipose tissue and liver oxidative stress, improving obesity-related insulin resistance.

Effects of Melatonin Supplementation on Lipid Metabolism and Body Fat Accumulation in Ovariectomized Rats

Postmenopausal obesity is a rising problem. Melatonin (Mel) is a hormone secreted by the pineal gland that regulates the circadian rhythms and improves obesity. In this experiment, ovariectomized (OVX) rats were used as a menopause model to explore the effects of Mel supplementation on lipid metabolism, body fat accumulation, and obesity. Nine-week-old female rats underwent an OVX surgery and were assigned to the following groups: control group (C), low-dose group (L, 10 mg/kg body weight (BW) Mel), medium-dose group (M, 20 mg/kg BW Mel), and high-dose group (H, 50 mg/kg BW Mel), administered by gavage for 8 weeks. The results showed that the OVX rats supplemented with low, medium, and high doses of Mel for 8 weeks exhibited reduced BW gain, perirenal fat mass, and gonads fat mass, and an increased serum irisin level. Low and high doses of Mel induced brite/beige adipocytes in the white adipose tissues. In addition, the messenger RNA levels of the fatty acid synthesis enzymes were significantly reduced after the high-dose Mel supplementation. Thus, Mel can reduce the hepatic fatty acid synthesis and promote the browning of white adipose tissues through irisin; thereby, improving obesity and body fat accumulation in OVX rats.

Effects of Different Vegetable Oils on the Nonalcoholic Fatty Liver Disease in C57/BL Mice

Background

Nonalcoholic fatty liver disease (NAFLD) is the most common hepatic disorder, affecting 22-28% of the adult population and more than 50% of obese people all over the world. Modulation of the fatty acids in diet as a means of prevention against nonalcoholic fatty liver disease in animal models (NAFLD) remains unclear. The treatment of NAFLD has not been described in specific guidelines so far. Thus, the justification for the study is to check modifications in macronutrients composition, fatty acids, in particular, play a significant role in the treatment of NAFLD regardless of weight loss.

Aim

To investigate different vegetable oils in prevention and progression of NAFLD in animal models.

Methods

For the experiment were used fifty C57BL/6J mice male fed with high fat and fructose diet (HFD) to induce the NAFLD status and they received different commercial vegetable oils for 16 weeks to prevent steatosis. Liver steatosis and oxidative stress parameters were analyzed using biochemical and histological methods. Fatty acids profile in the oils and in the liver samples was obtained.

Results

The high fat and fructose diet led to obesity and the vegetable oils offered were effective in maintaining body weight similar to the control group. At the end of the experiment (16 weeks), the HFHFr group had a greater body weight compared to control and treated groups (HFHFr: 44.20 ± 2.34 g/animal vs. control: 34.80 ± 3.45 g/animal; p < 0.001; HFHFr/OL: 35.40 ± 4.19 g/animal; HFHFr/C: 36.10 ± 3.92 g/animal; HFHFr/S: 36.25 ± 5.70 g/animal; p < 0.01). Furthermore, the HFD diet has caused an increase in total liver fat compared to control (p < 0.01). Among the treated groups, the animals receiving canola oil showed a reduction of hepatic and retroperitoneal fat (p < 0.05). These biochemical levels were positively correlated with the hepatic histology findings. Hepatic levels of omega-3 decreased in the olive oil and high fat diet groups compared to the control group, whereas these levels increased in the groups receiving canola and soybean oil compared to control and the high fat groups.

Conclusion

In conclusion, the commercial vegetable oils either contributed to the prevention or reduction of induced nonalcoholic fatty liver with high fat and fructose diet, especially canola oil.

The association between fatty acid intake and breast cancer based on the NHANES and Mendelian randomization study

BACKGROUND

Observational studies have examined the association between fatty acid intake and breast cancer (BC), and the association might vary depending on menopausal status, but the results remain controversial. The objective of this study was to investigate the associations between fatty acid intake and BC.

METHODS

The National Health and Nutrition Examination Survey (NHANES) 1999-2016 was used in the study, and stratified analysis by menopausal status was performed. Logistic regression models were used to evaluate the associations between BC and intake of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs), adjusting for covariates. Three two-sample Mendelian randomization (MR) methods-inverse variance weighted (IVW), weighted median, and Mendelian randomization-Egger (MR-Egger) regression-were applied to further verify the associations between intake of fatty acids and BC.

RESULTS

Higher intake of MUFAs was associated with lower risk of BC in premenopausal women: ORs (95 %CI): 0.325 (0.110, 0.964). IVW showed that increased intake of MUFAs was associated with a reduced risk of BC: 0.997 (0.995, 1.000), p = 0.024. No associations between BC and SFAs, MUFAs or PUFAs were found in postmenopausal women or in the overall population.

CONCLUSIONS

Increasing intake of MUFAs might reduce the risk of BC in premenopausal women. The protective effect of MUFAs on BC was also supported by MR study.

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.

Effect of Trilobatin from Lithocarpus polystachyus Rehd on Gut Microbiota of Obese Rats Induced by a High-Fat Diet

Trilobatin was identified as the primary bioactive component in the Lithocarpus polystachyus Rehd (LPR) leaves. This study explored the antiobesity effect of trilobatin from LPR leaves and its influence on gut microbiota in obese rats. Results showed that trilobatin could significantly reduce body and liver weight gain induced by a high-fat diet, and the accumulation of perirenal fat, epididymal fat, and brown fat of SD (Male Sprague–Dawley) obese rats in a dose-independent manner. Short-chain fatty acids (SCFAs) concentrations increased, especially the concentration of butyrate. Trilobatin supplementation could significantly increase the relative abundance of Lactobacillus, Prevotella, CF231, Bacteroides, and Oscillospira, and decrease greatly the abundance of Blautia, Allobaculum, Phascolarctobacterium, and Coprococcus, resulting in an increase of the ratio of Bacteroidetes to Firmicutes (except the genera of Lactobacillus and Oscillospira). The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway predicted by the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) indicated the different relative metabolic pathways after trilobatin supplementation. This study may reveal the contribution of gut microbiota to the antiobesity effect of trilobatin from LPR leaves and predict the potential regulatory mechanism for obesity induced by a high-fat diet.

Diet-induced rodent models of obesity-related metabolic disorders-A guide to a translational perspective

Diet is a critical element determining human health and diseases, and unbalanced food habits are major risk factors for the development of obesity and related metabolic disorders. Despite technological and pharmacological advances, as well as intensification of awareness campaigns, the prevalence of metabolic disorders worldwide is still increasing. Thus, novel therapeutic approaches with increased efficacy are urgently required, which often depends on cellular and molecular investigations using robust animal models. In the absence of perfect rodent models, those induced by excessive consumption of fat and sugars better replicate the key aspects that are the root causes of human metabolic diseases. However, the results obtained using these models cannot be directly compared, particularly because of the use of different dietary protocols, and animal species and strains, among other confounding factors. This review article revisits diet-induced models of obesity and related metabolic disorders, namely, metabolic syndrome, prediabetes, diabetes and nonalcoholic fatty liver disease. A critical analysis focused on the main pathophysiological features of rodent models, as opposed to the criteria defined for humans, is provided as a practical guide with a translational perspective for the establishment of animal models of obesity-related metabolic diseases.

Anti-inflammatory and anti-oxidant effects of aloe vera in rats with non-alcoholic steatohepatitis

BACKGROUND

Aloe vera exerts several biological activities, such as, anti-inflammatory, antioxidant, and antimicrobial effects. It was recently shown to reduce insulin resistance and triglyceride level. We hypothesized that aloe vera would have beneficial effects in alleviating non-alcoholic steatohepatitis (NASH) in rats.

AIM

To examine the therapeutic effects of aloe vera in NASH rats.

METHODS

All rats were randomly divided into 3 groups (n = 6 in each group). Rats in the control group were fed ad libitum with a standard diet for 8 wk. Rats in the NASH group were fed ad libitum with a high-fat high-fructose diet (HFHFD) for 8 wk. Rats in the aloe vera group were fed ad libitum with a HFHFD and aloe vera in dimethylsulfoxide (50 mg/kg) by gavage daily for 8 wk. Liver samples were collected at the end of the treatment period.

RESULTS

Hepatic malondialdehyde (MDA) levels increased significantly in the NASH group as compared with the control group (377 ± 77 nmol/mg vs 129 ± 51 nmol/mg protein, respectively, P < 0.001). Glutathione (GSH) levels were significantly lower in the NASH group than the control group (9 ± 2 nmol/mg vs 24 ± 8 nmol/mg protein, respectively, P = 0.001). The expression of interleukin-18 (IL-18), nuclear factor-kappa β, and caspase-3 increased, while peroxisome proliferator-activated receptor gamma decreased in the NASH group compared with the controls. Following aloe vera administration, MDA levels decreased (199 ± 35 nmol/mg protein) and GSH increased (18 ± 4 nmol/mg protein) markedly. Steatosis, hepatocyte ballooning, lobular inflammation and increased hepatocyte apoptosis were observed in the NASH group. Aloe vera treatment attenuated these changes in liver histology.

CONCLUSION

Aloe vera attenuated oxidative stress, hepatic inflammation and hepatocyte apoptosis, thus improving liver pathology in rats with NASH.

The Effects of Diets Enriched in Monounsaturated Oleic Acid on the Management and Prevention of Obesity: a Systematic Review of Human Intervention Studies

Obesity is associated with an increased risk of several major noncommunicable diseases, and is an important public health concern globally. Dietary fat content is a major contributor to the increase in global obesity rates. Changes in dietary habits, such as the quality of fatty acids in the diet, are proposed to prevent obesity and its metabolic complications. In recent years, a number of studies have found that oleic acid (OA), the most common MUFA in daily nutrition, has protective effects against human disease. Importantly, there is emerging evidence indicating the beneficial effects of OA in regulating body weight. Accordingly, the objective of this systematic review was to investigate the effects of diets enriched in monounsaturated OA on the management and prevention of obesity, emphasizing possible mechanisms of action of OA in energy homeostasis. Searches were performed in PubMed/MEDLINE, ScienceDirect, Scopus, ProQuest, and Google Scholar databases for clinical trials that examined the effects of diets rich in OA on obesity. Of 821 full-text articles assessed, 28 clinical trials were included in the present study. According to the studies examined in this review, diets enriched in OA can influence fat balance, body weight, and possibly energy expenditure. Importantly, abdominal fat and central obesity can be reduced following consumption of high-OA-containing meals. Mechanistically, OA-rich diets can be involved in the regulation of food intake, body mass, and energy expenditure by stimulating AMP-activated protein kinase signaling. Other proposed mechanisms include the prevention of the nucleotide-binding oligomerization domain-like receptor 3/caspase-1 inflammasome pathway, the induction of oleoylethanolamide synthesis, and possibly the downregulation of stearoyl-CoA desaturase 1 activity. In summary, current findings lend support to advice not restricting consumption of OA-rich meals so as to maintain a healthy body weight.

Gut Microbiota and Metabolome Response of Decaisnea insignis Seed Oil on Metabolism Disorder Induced by Excess Alcohol Consumption

This study investigated the modulatory effects of Decaisnea insignis seed oil (DISO), which was rich in palmitoleic acid (55.25%), palmitic acid (12.25%), and oleic acid (28.74%), on alcohol-induced metabolism disorder in mice. Fifty mice were orally administered with 38% alcohol (0.4 mL/day) and without or with DISO (3, 6, and 12 g/kg) for consecutive 12 weeks. DISO inhibited the alcohol-induced weight loss and liver function abnormality (p < 0.01) and shifted the profiles of cecal microbiome: elevating the abundance of Lactobacillus, Ruminoccoceae_UCG_004 (p < 0.05) and decreasing abundance of Parabacteroides (p < 0.05). This treatment also regulated metabolome response of amino acid and lipid metabolism in cecal content: upregulating 5-hydroxyindole-3-acetic acid (p < 0.05), 6-hydroxynicotinic acid, 5-methoxytryptamine, nicotinamide, and nicotinic acid (p < 0.1) and downregulating androsterone, tryptophan, and indole-3-acetamide (p < 0.05). DISO protected against alcoholic liver injury and gut microbiota dysbiosis by enriching the relative abundance of Lactobacillus, which was positively associated with the improvement of intestinal permeability and tryptophan metabolism.

Adlay Bran Oil Suppresses Hepatic Gluconeogenesis and Attenuates Hyperlipidemia in Type 2 Diabetes Rats

This study aimed to examine the antidiabetic effects of various concentrations of adlay bran oil (ABO) in high fat diet and streptozotocin-induced diabetic rats. Dietary supplementation with 10% ABO for 4 weeks effectively decreased the blood triacylglycerol, glucose, and total cholesterol levels in diabetic rats, although body weight remained the same. The mRNA and protein expressions of hepatic glucose transporter 2 (GLUT-2) and phosphoenolpyruvate carboxykinase (PEPCK) were increased and that of glucokinase (GCK) were decreased in diabetic rats. However, 10% ABO treatment reduced the mRNA and protein expressions of GLUT-2 and PEPCK and elevated the expression of hepatic GCK in diabetic rats. Thus, ABO enhanced hepatic glucose metabolism to decrease blood glucose in diabetic rats. In addition, 10% ABO supplementation increased the expression of phosphorylated protein kinase B (Akt) relative to the total Akt levels in the muscles of diabetic rats, indicating enhanced insulin sensitivity. The results indicate that ABO displays a potential for improving hyperlipidemia and hyperglycemia in diabetes by enhancing insulin sensitivity and hepatic glucose metabolism.

A high-fat diet increases body fat mass and up-regulates expression of genes related to adipogenesis and inflammation in a genetically lean pig

Because of their physiological similarity to humans, pigs provide an excellent model for the study of obesity. This study evaluated diet-induced adiposity in genetically lean pigs and found that body weight and energy intake did not differ between controls and pigs fed the high-fat (HF) diet for three months. However, fat mass percentage, adipocyte size, concentrations of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), insulin, and leptin in plasma were significantly higher in HF pigs than in controls. The HF diet increased the expression in backfat tissue of genes responsible for cholesterol synthesis such as Insig-1 and Insig-2. Lipid metabolism-related genes including sterol regulatory element binding protein 1c (SREBP-1c), fatty acid synthase 1 (FASN1), diacylglycerol O-acyltransferase 2 (DGAT2), and fatty acid binding protein 4 (FABP4) were significantly up-regulated in backfat tissue, while the expression of proliferator-activated receptor-α (PPAR-α) and carnitine palmitoyl transferase 2 (CPT2), both involved in fatty acid oxidation, was reduced. In liver tissue, HF feeding significantly elevated the expression of SREBP-1c, FASN1, DGAT2, and hepatocyte nuclear factor-4α (HNF-4α) mRNAs. Microarray analysis further showed that the HF diet had a significant effect on the expression of 576 genes. Among these, 108 genes were related to 21 pathways, with 20 genes involved in adiposity deposition and 26 related to immune response. Our results suggest that an HF diet can induce genetically lean pigs into obesity with body fat mass expansion and adipose-related inflammation.

Dietary Fat, but Not Protein or Carbohydrate, Regulates Energy Intake and Causes Adiposity in Mice

The impacts of different macronutrients on body weight regulation remain unresolved, with different studies suggesting increased dietary fat, increased carbohydrates (particularly sugars), or reduced protein may all stimulate overconsumption and drive obesity. We exposed C57BL/6 mice to 29 different diets varying from 8.3% to 80% fat, 10% to 80% carbohydrate, 5% to 30% protein, and 5% to 30% sucrose. Only increased dietary fat content was associated with elevated energy intake and adiposity. This response was associated with increased gene expression in the 5-HT receptors, and the dopamine and opioid signaling pathways in the hypothalamus. We replicated the core findings in four other mouse strains (DBA/2, BALB/c, FVB, and C3H). Mice regulate their food consumption primarily to meet an energy rather than a protein target, but this system can be over-ridden by hedonic factors linked to fat, but not sucrose, consumption.

Effect of Locally Manufactured Niger Seed Oil on Lipid Profile Compared to Imported Palm and Sunflower Oils on Rat Models

Background

Different types of dietary lipids have been shown to affect lipid metabolism and lipid profile differently.

Objective

This study aims to assess the effect of local niger seed oil on serum lipid profile compared to palm oil and sunflower oil in rats.

Methods

The effect of the 15% plant oils on serum lipid profile, body weight gain percentage, and feed efficiency ratio was assessed after 8 weeks of experimental period.

Results and Conclusion

The 15% niger seed oil showed decrease and increase in the level of lipid profile as compared to rats fed with 15% palm oil and sunflower oil (except Triacylglycerol), respectively. The 15% niger seed oil showed significant decrease and increase in body weight gain percentage as compared to the 15% palm oil and 15% sunflower oil, respectively. The feed efficiency ratio was significantly higher and lower in the 15% niger seed oil compared to rats fed with 15% sunflower oil and control group and the palm oil fed rats, respectively. The current study concluded that consumption of locally manufactured niger seed oil decreased the blood lipid profiles, body weight gain percentage, and feed efficiency ratio as compared to palm oil. Utilization of oils containing more unsaturated fatty acids like niger seed oil is recommended to reduce the risk of developing cardiovascular disease.