Effect of Chlorella vulgaris on lipid metabolism in Wistar rats fed high fat diet

This study was performed to investigate effects of Chlorella vulgaris on lipid metabolism in rats fed high fat diet. Sixty 6-week-old male Wistar rats were divided into two groups; normal diet group and high fat diet group, then the rats in each group were further divided into three subgroups and fed 0%, 5% and 10% (w/w) chlorella-containing diets, respectively, and raised for 9 weeks. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity and total protein and albumin concentration were not different among groups. Serum total lipids and liver TG concentration were significantly lower in 5% and 10% chlorella groups than 0% chlorella group in high fat diet groups (p<0.05). Serum TG, serum total cholesterol, liver total lipid and liver total cholesterol concentrations were significantly lower in 10% chlorella groups than 0% chlorella group in high fat diet groups (p<0.05). Fecal total lipid, TG and total cholesterol excretions were significantly higher in 5% and 10% chlorella groups than 0% chlorella groups in normal diet and high fat diet groups, respectively (p<0.05). These results suggest that Chlorella vulgaris is effective for prevention of dyslipidemia which may be due to the modulation of lipid metabolism and increased fecal excretion of lipid.     

Dietary fat level affects tissue iron levels but not the iron regulatory gene HAMP in rats

Because dietary fats affect the regulation and use of body iron, we hypothesized that iron regulatory and transport genes may be affected by dietary fat. A model of early-stage I to II, nonalcoholic fatty liver was used in which rats were fed standard (35% energy from fat) or high-fat (71% energy from fat) liquid diets with normal iron content (STD/HF groups). In addition, intraperitoneal injections of iron dextran were given to iron-loaded (STD+/HF+ groups) and iron-deficient diets to STD−/HF− groups. Plasma osmolality, hemoglobin level, and mean corpuscular hemoglobin concentration were increased in all STD diet groups compared with all HF diet groups. Plasma iron and transferrin saturation were affected by an interaction between dietary fat and iron. They were high in the STD group (normal iron) compared with their respective HF group. Similarly, this group also showed a 4-fold increase in the messenger RNA expression of the hepatic hemochromatosis gene. Spleen iron was high in the iron-loaded STD+ group compared with all other groups. Hepatic iron and messenger RNA expression of peroxisome proliferator–activated receptor-γ, CCAAT/enhancer binding protein α, interleukin-6, and iron transport genes (transferrin receptor 2, divalent metal transporter 1 iron-responsive element, and divalent metal transporter 1 non–iron-responsive element) were increased, whereas tumor necrosis factor α was decreased in the HF diet groups. The expression of iron regulatory gene HAMP was not increased in the HF diet groups. Iron regulatory and transport genes involved in cellular and systemic iron homeostasis may be affected by the macronutrient composition of the diet.     

Lycopene supplementation suppresses oxidative stress induced by a high fat diet in gerbils

The effect of lycopene supplementation on the antioxidant system was investigated by analyzing lipid peroxide levels, glutathione contents, and antioxidant enzyme activities in Mongolian gerbils fed a high fat diet. Gerbils were fed on each experimental diet for 6 weeks; normal diet (NC), normal diet with 0.05% lycopene (NL), high fat diet (HF), and a high fat diet with 0.05% lycopene (HFL). Dietary supplementation of lycopene increased hepatic lycopene level in gerbils fed a normal or high fat diet (P < 0.05). Liver and erythrocyte concentrations of lipid peroxide increased in gerbils fed a high fat diet, whereas lycopene supplementation decreased liver and erythrocyte concentrations of lipid peroxide (P < 0.05). Hepatic total glutathione content was higher in the NL group than that in the NC group (P < 0.05). Total antioxidant status in plasma increased following lycopene supplementation compared with that of the non-lycopene supplemented groups (P < 0.05). Hepatic catalase activity increased following dietary lycopene supplementation (P < 0.05). Superoxide dismutase activity in liver remained unchanged with lycopene supplementation, but erythrocyte superoxide dismutase activity increased in NL group compared with NC group (P < 0.05). Glutathione-S-transferase activity increased in the NL group compared to NC group (P < 0.05). Liver and erythrocyte glutathione peroxidase activity increased significantly in the NL group compared to that in the HF group (P < 0.05). Liver glutathione reductase activity was higher in the NL group than that in the NC group (P < 0.05). These results suggest that lycopene supplementation may be efficient for preventing chronic diseases induced by oxidative stress related to high fat diet.     

��-Lipoic acid reduced weight gain and improved the lipid profile in rats fed with high fat diet

The purpose of this study was to investigate the effects of α-lipoic acid on body weight and lipid profiles in Sprague-Dawley rats fed a high fat diet (HFD). After 4 weeks of feeding, rats on the HFD were divided into three groups by randomized block design; the first group received the high-fat-diet (n = 10), and the second group received the HFD administered with 0.25% α-lipoic acid (0.25LA), and the third group received the high-fat diet with 0.5% α-lipoic acid (0.5LA). The high fat diet with α-lipoic acid supplemented groups had significantly inhibited body weight gain, compared to that in the HFD group (P < 0.05). Organ weights of rats were also significantly reduced in liver, kidney, spleen, and visible fat tissues in rats supplemented with α-lipoic acid (P < 0.05). Significant differences in plasma lipid profiles, such as total lipids, total cholesterol, triglycerides, low-density lipoprotein, and high-density lipoprotein, were observed between the HFD and 0.5LA groups. The atherogenic index and the plasma high density lipoprotein-cholesterol/total cholesterol ratio improved significantly with α-lipoic acid supplementation in a dose-dependent manner (P < 0.05). Total hepatic cholesterol and total lipid concentration decreased significantly in high fat fed rats supplemented with α-lipoic acid in a dose-dependent manner (P < 0.05), whereas liver triglyceride content was not affected. In conclusion, α-lipoic acid supplementation had a positive effect on weight gain and plasma and liver lipid profiles in rats.     

Characteristics of nonalcoholic fatty liver disease induced in wistar rats following four different diets

BACKGROUND/OBJECTIVESThe prevalence of nonalcoholic fatty liver disease (NAFLD) has increased worldwide in parallel with overnutrition characterized by high-fat and high-carbohydrate intake. Our objective was to establish, in 16 weeks, a model of NAFLD in Wistar pathogen-free rats following four dietary types.MATERIALS/METHODSForty (6 weeks old) healthy Wistar male rats, weighing an average of 150 g were randomly divided into four groups of ten and assigned a diet with the same quantity (15 g/rat/day), but with different composition. The moderate-fat (MF) group was fed a moderate-fat diet (31.5% fat and 50% carbohydrates), the high-fat (HF) group was fed a fat-rich diet (51% fat), the high-sucrose (HS) group and the high-fructose (HFr) group were fed a carbohydrate-rich diet (61%). The carbohydrate contents of the HS group was composed of 60.3% sucrose while that of the HFr group was composed of 59.3% fructose.RESULTSAt week 16, the HF group had the highest percentage of cells enriched in fat (40%) and the highest weight and liver weight (P < 0.05). The HFr group showed significantly higher levels of serum triglycerides, alanine aminotransferase and adiponectin at week 16 as compared to week 1 (P < 0.05).CONCLUSIONSThe 15 g/rat/day diet composed of 51% fat or 61% carbohydrates enriched mainly in fructose may induce characteristics of NAFLD in rats.     

Bitter melon (Momordica charantia) reduces adiposity,lowers serum insulin and normalizes glucose tolerance in rats fed a high fat diet

Bitter melon (BM) is known for its hypoglycemic effect but its effect on rats fed a hyperinsulinemic high fat diet has not been examined. In a dose-response (0.375, 0.75 and 1.5%) study, oral glucose tolerance was improved in rats fed a high fat (HF; 30%) diet supplemented with freeze-dried BM juice at a dose of 0.75% or higher (P < 0.05). At the highest dose, BM-supplemented rats had lower energy efficiency (P < 0.05) and tended (P = 0.10) to have less visceral fat mass. In a subsequent experiment, rats habitually fed a HF diet either continued to consume the diet or were switched to a HF+BM, low fat (LF; 7%) or LF+BM diet for 7 wk. BM was added at 0.75%. Final body weight and visceral fat mass of the two last-mentioned groups were similar to those of rats fed a LF diet for the entire duration. Rats switched to the HF+BM diet gained less weight and had less visceral fat than those fed the HF diet (P < 0.05). The addition of BM did not change apparent fat absorption. BM supplementation to the HF diet improved insulin resistance, lowered serum insulin and leptin but raised serum free fatty acid concentration (P < 0.05). This study reveals for the first time that BM reduces adiposity in rats fed a HF diet. BM appears to have multiple influences on glucose and lipid metabolism that strongly counteract the untoward effects of a high fat diet.     

Effect of coenzyme Q10 and Ardisia japonica Blume on plasma and liver lipids, platelet aggregation, and erythrocyte Na efflux channels in simvastatin-treated guinea pigs

Forty guinea pigs were divided into four groups and fed 0.04% cholesterol based control diet, plus 0.05% simvastatin, and statin plus 0.1% CoQ10 or 10% Ardisia Japonica Blume (AJB) leave powder for 4 weeks. Plasma total cholesterol levels decreased significantly in all groups fed the statin-containing diet compared with that in guinea pigs fed the control diet (P < 0.01). Plasma and liver triglycerides decreased significantly in the statin plus CoQ10 group compared with those in the control (both P < 0.05). Maximum platelet aggregation was significantly higher in the statin plus CoQ10 group than that in the other groups (P < 0.05). Na-K ATPase activity increased in the statin group and decreased in the statin plus CoQ10 group (P < 0.01). Na-K co-transport and Na passive transport decreased significantly in the control group compared with those in the other groups (both P < 0.05). Intracellular Na was highest in the statin group and lowest in the statin plus CoQ10 group and was correlated with Na-K ATPase activity. Thiobarbituric acid reactive substance production in platelet-rich plasma and liver tended to decrease in the statin plus CoQ10 group compared with those in the other groups. Plasma glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase increased significantly in the statin group compared with those in the control (P < 0.05). These result suggest that antioxidant rich AJB did not have positive effects on cardiovascular disease parameters. The statin plus CoQ10 seemed to decrease cholesterol more efficiently than that of statin alone.     

Dietary chitosan improves hypercholesterolemia in rats fed high-fat diets

The hypolipidemic mechanism of chitosan was investigated in male Sprague-Dawley rats. Animals were divided into 5 groups (n = 8): a normal fat control group, a high-fat control group (HF), a positive control group (CR), and 2 chitosan groups (CIS1 and CIS2). Chitosan was fed at the beginning (CIS1) and after 2 weeks (CIS2). A commercial diet with 5% (wt/wt) cellulose (HF), cholestyramine (CR), or chitosan (CIS1, CIS2) was fed for 6 weeks. Chitosan did not affect food intake but decreased body weight gain and significantly increased fecal fat and cholesterol excretion, reduced the lipid level in plasma and liver, increased liver hepatic and lipoprotein lipase activities compared with HF (P < .05), and tended to relieve the degenerated fatty liver tissue. No significant differences in all measurements were found between the CIS1 and CIS2 groups although the CIS1 rats exhibited lower lipid levels compared to those in the CIS2 group. The results suggest that chitosan reduced the absorption of dietary fat and cholesterol in vivo and could effectively improve hypercholesterolemia in rats.     

The effects of Momordica charantia on obesity and lipid profiles of mice fed a high-fat diet

BACKGROUND/OBJECTIVES

The present study was conducted to investigate the effects of dried Momordica charantia aqueous extracts (MCA) and ethanol extracts (MCE) on obesity and lipid profiles in mice fed a high-fat diet.

MATERIALS/METHODS

Forty two ICR mice were randomly divided into six groups. The normal group was fed a basal diet, and other groups were fed a 45% high-fat diet (HFD) for 7 weeks. The normal and HFD groups were also orally administered distilled water each day for 7 weeks. The remaining groups received Momordica charantia extract (0.5 or 1.0 g/kg/day MCA, and 0.5 or 1.0 g/kg/day MCE). In order to measure the anti-obesity and lipid profile improvement effects, body and visceral tissue weight, lipid profiles, plasma insulin levels, hepatic malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity were measured.

RESULTS

Both MCA and MCE significantly decreased body and visceral tissue weight relative to those of the HFD group (P < 0.05). Additionally high doses of MCE and MCA significantly reduced the plasmatic insulin levels compared to the HFD groups (P < 0.05) to concentrations comparable to those found in the normal group. MCA and MCE supplementation also significantly modulated the lipid profiles in plasma, liver, and feces compared to mice fed the HFD (P < 0.05). Furthermore MCA and MCE significantly increased hepatic SOD activity, and reduced MDA generation in the liver of the HFD mice (P < 0.05).

CONCLUSIONS

Results from the present study suggest that Momordica charantia extracts have anti-obesity effects and the ability to modulate lipid prolife of mice fed a HFD by suppressing body weight gain, visceral tissue weight, plasma and hepatic lipid concentrations, and lipid peroxidation along with increasing lipid metabolism.     

Effects of green tea or Sasa quelpaertensis bamboo leaves on plasma and liver lipids, erythrocyte Na efflux, and platelet aggregation in ovariectomized rats

This study was conducted to investigate the effects of Sasa quelpaertensis bamboo and green tea on plasma and liver lipids, platelet aggregation, and erythrocyte membrane Na channels in ovariectomized (OVX) rats. Thirty female rats were OVX, and ten female rats were sham-operated at the age of 6 weeks. The rats were divided into four groups at the age of 10 weeks and fed the experiment diets: sham-control, OVX-control, OVX-bamboo leaves (10%), or OVX-green tea leaves (10%) for four weeks. Final body weight increased significantly in the OVX groups compared with that in the sham-control, whereas body weight in the OVX-green tea group decreased significantly compared with that in the OVX-control (P < 0.01). High density lipoprotein (HDL)-cholesterol level decreased in all OVX groups compared with that in the sham-control rats (P < 0.05) but without a difference in plasma total cholesterol. Plasma triglycerides in the OVX-green tea group were significantly lower than those in the sham-control or OVX-control group (P < 0.05). Liver triglycerides increased significantly in the OVX-control compared with those in the sham-control (P < 0.01) but decreased significantly in the OVX-green tea group compared with those in the OVX-control or OVX-bamboo group (P < 0.01). Platelet aggregation in both maximum and initial slope tended to be lower in all OVX rats compared with that in the sham-control rats but was not significantly different. Na-K ATPase tended to increase and Na-K cotransport tended to decrease following ovariectomy. Na-K ATPase decreased significantly in the OVX-green tea group compared with that in the OVX-control group (P < 0.01), and Na-K cotransport increased significantly in the OVX-bamboo and OVX-green tea groups compared with that in the OVX-control (P < 0.05). Femoral bone mineral density tended to be lower in OVX rats than that in the sham-control, whereas the green tea and bamboo leaves groups recovered bone density to some extent. The results show that ovariectomy caused an increase in body weight and liver triglycerides, and that green tea was effective for lowering body weight and triglycerides in OVX rats. Ovariectomy induced an increase in Na efflux via Na-K ATPase and a decrease in Na efflux via Na-K cotransport. Furthermore, consumption of green tea and bamboo leaves affected Na efflux channels, controlling electrolyte and body water balance.     

Resveratrol up-regulates hepatic uncoupling protein 2 and prevents development of nonalcoholic fatty liver disease in rats fed a high-fat diet

Obesity is associated with a markedly increased risk of nonalcoholic fatty liver disease. The anti-inflammatory polyphenol resveratrol possess promising properties in preventing this metabolic condition by dampening the pathological inflammatory reaction in the hepatic tissue. However, in the current study, we hypothesize that the beneficial effect of resveratrol is not solely attributable to its anti-inflammatory potential. Eight-week-old male Wistar rats were randomly distributed into 3 groups of 12 animals each: control diet (C), high-fat diet (HF), and HF supplemented with 100 mg resveratrol daily (HFR). After 8 weeks of dietary treatment, the rats were euthanized and relevant tissues were prepared for subsequent analysis. Resveratrol prevented the high fat–induced steatosis assessed by semiquantitative grading, which furthermore corresponded with a complete normalization of the hepatic triglyceride content (P < .001), despite no change in total body fat. In HFR, the hepatic uncoupling protein 2 expression was significantly increased by 76% and 298% as compared with HF and C, respectively. Moreover, the hepatic mitochondria content in HFR was significantly higher as compared with both C and HF (P < .001 and P = .004, respectively). We found no signs of hepatic inflammation, hereby demonstrating that resveratrol protects against fatty liver disease independently of its proposed anti-inflammatory potential. Our data might indicate that an increased number of mitochondria and, particularly, an increase in hepatic uncoupling protein 2 expression are involved in normalizing the hepatic fat content due to resveratrol supplementation in rodents fed a high-fat diet.     

Sex Differences in Early Programming by Maternal High Fat Diet Induced-Obesity and Fish Oil Supplementation in Mice

Pre-pregnancy obesity is a contributing factor for impairments in offspring metabolic health. Interventional strategies during pregnancy are a potential approach to alleviate and/or prevent obesity and obesity related metabolic alterations in the offspring. Fish oil (FO), rich in omega-3 polyunsaturated fatty acids (n-3 PUFAs) exerts metabolic health benefits. However, the role of FO in early life remains still unknown. Hence, this study objective was to determine the effect of FO supplementation in mice from pre-pregnancy through lactation, and to study the post-natal metabolic health effects in gonadal fat and liver of offspring fed high fat (HF) diet with or without FO. Female C57BL6J mice aged 4–5 weeks were fed a HF (45% fat) diet supplemented with or without FO (30 g/kg of diet) and low fat (LF; 10% fat) pre-pregnancy through lactation. After weaning, offspring (male and female) from HF or FO dams either continued the same diet (HF-HF and FO-FO) or switched to the other diet (HF-FO and FO-HF) for 13 weeks, creating four groups of treatment, and LF-LF was used as a control group. Serum, gonadal fat and liver tissue were collected at termination for metabolic analyses. Offspring of both sexes fed HF with or without fish oil gained (p < 0.05) more weight post weaning, compared to LF-LF-fed mice. All the female offspring groups supplemented with FO had reduced body weight compared to the respective male groups. Further, FO-FO supplementation in both sexes (p < 0.05) improved glucose clearance and insulin sensitivity compared to HF-HF. All FO-FO fed mice had significantly reduced adipocyte size compared to HF-HF group in both male and females. Inflammation, measured by mRNA levels of monocyte chemoattractant protein 1 (Mcp1), was reduced (p < 0.05) with FO supplementation in both sexes in gonadal fat and in the liver. Markers of fatty acid synthesis, fatty acid synthase (Fasn) showed no sex specific differences in gonadal fat and liver of mice supplemented with HF. Female mice had lower liver triglycerides than male counterparts. Supplementation of FO in mice improved metabolic health of offspring by lowering markers of lipid synthesis and inflammation.     

Effects of ��-lipoic acid and L-carnosine supplementation on antioxidant activities and lipid profiles in rats

α-Lipoic acid and L-carnosine are powerful antioxidants and are often used as a health supplement and as an ergogenic aid. The objective of this study was to investigate the effects of α-lipoic acid and/or L-carnosine supplementation on antioxidant activity in serum, skin, and liver of rats and blood lipid profiles for 6 weeks. Four treatment groups received diets containing regular rat chow diet (control, CON), 0.5% α-lipoic acid (ALA), 0.25% α-lipoic acid + 0.25% L-carnosine (ALA + LC), or 0.5% L-carnosine (LC). Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and lipid peroxidation products, malondialdehyde (MDA) concentrations, were analyzed in serum, skin, and liver. Blood lipid profiles were measured, including triglycerides (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL-C). Skin and liver SOD activities of the ALA and LC groups were higher than those of the CON group (P < 0.05), but serum SOD activity was higher only in the LC group compared to that in the CON group (P < 0.05). Additionally, only liver GSH-Px activity in the LC group was higher than that of the CON and the other groups. Serum and skin MDA levels in the ALA and LC groups were lower than those in the CON group (P < 0.05). Serum TG and TC in the ALA and ALA + LC groups were lower than those in the CON and LC groups (P < 0.05). The HDL-C level in the LC group was higher than that in any other group (P < 0.05). LDL-C level was lower in the ALA + LC and LC groups than that in the CON group (P < 0.05). Thus, α-lipoic acid and L-carnosine supplementation increased antioxidant activity, decreased lipid peroxidation in the serum, liver, and skin of rats and positively modified blood lipid profiles.     

牛磺酸与高脂膳对二甲基苯蒽诱发大鼠乳癌的影响

目的 :　探讨牛磺酸和 /或高脂饲料对二甲基苯蒽 ( DMBA)诱发大鼠乳腺癌的影响 ,初步探讨其可能的机制。方法 :　初断乳雌性 SD大鼠 1 0 1只 ,随机分为牛磺酸组 ( Tau)、牛磺酸 +高脂组 ( TH)、高脂组 ( HF)和对照组 ( CL) ,于 6w龄灌胃给予 DMBA后 ,分别饲以不同饲料。实验期 2 6w,实验结束时处死全部动物 ,检查肿瘤发生情况并进行血清抗氧化、血脂及免疫学指标检测。结果 :　Tau组乳腺肿瘤发生率低于 HF组而与 CL组差异未见显著性 ;平均瘤重 Tau组低于 CL组和 HF组 ;各组肿瘤平均潜伏期未见明显差异。与 CL组比较 ,Tau组血清 SOD、GSH- Px活力增高 ,LDL- C、MDA含量下降 ;HF组可见 GSH- Px活力和抗体生成能力下降 ,血清 TC升高 ;而添加了 Tau的高脂饲料组 ( TH)则仅出现了 GSH- Px活力的下降。结论 :　膳食中补充 5 %牛磺酸对诱发肿瘤的生长具有一定的抑制作用 ,并在一定程度上对抗高脂膳食的促癌作用。该作用可能是通过调节免疫功能、增强抗氧化能力及调节脂代谢等多种途径实现的     

Effects of cranberry powder on biomarkers of oxidative stress and glucose control in db/db mice

Increased oxidative stress in obese diabetes may have causal effects on diabetic complications, including dyslipidemia. Lipopolysccharides (LPS) along with an atherogenic diet have been found to increase oxidative stress and insulin resistance. Cranberry has been recognized as having beneficial effects on diseases related to oxidative stress. Therefore, we employed obese diabetic animals treated with an atherogenic diet and LPS, with the aim of examining the effects of cranberry powder (CP) on diabetic related metabolic conditions, including lipid profiles, serum insulin and glucose, and biomarkers of oxidative stress. Forty C57BL/KsJ-db/db mice were divided into the following five groups: normal diet + saline, atherogenic diet + saline, atherogenic diet + LPS, atherogenic diet + 5% CP + LPS, and atherogenic diet + 10% CP + LPS. Consumption of an atherogenic diet resulted in elevation of serum total cholesterol and atherogenic index (AI) and reduction of high density lipoprotein (HDL)-cholesterol. However, with 10% CP, the increase in mean HDL-cholesterol level was close to that of the group with a normal diet, whereas AI was maintained at a higher level than that of the group with a normal diet. LPS induced elevated serum insulin level was lowered by greater than 60% with CP (P < 0.05), and mean serum glucose level was reduced by approximately 19% with 5% CP (P > 0.05). Mean activity of liver cytosolic glutathione peroxidase was significantly increased by LPS injection, however it was reduced back to the value without LPS when the diet was fortified with 10% CP (P < 0.05). In groups with CP, a reduction in mean levels of serum protein carbonyl tended to occur in a dose dependent manner. Particularly with 10% CP, a reduction of approximately 89% was observed (P > 0.05). Overall results suggest that fortification of the atherogenic diet with CP may have potential health benefits for obese diabetes with high oxidative stress, by modulation of physical conditions, including some biomarkers of oxidative stress.     

A mixture of the Salacia reticulata (Kotala himbutu) aqueous extract and cyclodextrin reduces the accumulation of visceral fat mass in mice and rats with high-fat diet-induced obesity

The effects of a mixture of the Salacia reticulata (Kotala himbutu) aqueous extract and cyclodextrin (SRCD) on the development of obesity were examined. We studied the effects of SRCD on the elevation of plasma triacylglycerol levels induced by oral administration of a high-fat (HF) liquid diet to male Sprague-Dawley rats. The plasma triacylglycerol concentration was significantly lower in the SRCD-treated rats than in the control rats 4 h after HF diet administration (P<0.05). In a study of female C57BL/6 mice that consumed a solid HF diet containing 0, 0.2 or 0.5% SRCD ad libitum for 8 wk, the increases in body weight and visceral fat mass were less in those fed the diet supplemented with 0.5% SRCD than in those fed the HF diet (P<0.05). In male Sprague-Dawley rats fed a solid HF diet with or without 0.2% SRCD and restricted in energy intake to that of rats fed a normal diet for 35 d, the increases in body weight and visceral fat mass were smaller in the SRCD-supplemented rats (P<0.05). In addition, the energy efficiency and the plasma leptin and adiponectin concentrations were lower in the mice and rats that were administered SRCD than in those fed the HF diet alone (P<0.05). The inhibitory effects of SRCD on HF diet-induced obesity may be attributable to the inhibition of carbohydrate and lipid absorption from the small intestine. Therefore, SRCD may suppress the accumulation of visceral fat and the glucose intolerance that accompany this type of obesity.     

Insulin insensitivity is rapidly reversed in rats by reducing dietary fat from 40 to 30% of energy.

The objective of this study was to determine the effect of reducing dietary fat content from 40 to 30% of total energy on body composition and insulin sensitivity in rats. Female Sprague-Dawley rats were fed either a control diet (30% energy as fat) or a high fat diet (40% energy as fat) for 10 wk. In vivo glucose tolerance tests indicated that both basal and glucose-stimulated insulin concentrations were elevated in rats fed the high fat diet. Two groups of rats offered the high fat diet were then fed the control diet (HF,C) and two that had received the high fat diet were then fed a diet (30% energy as fat) containing a fat-mimetic carbohydrate (HF,M). Two groups continued to receive the high fat diet and two groups continued to receive the control diet. Rats were killed 1 and 2 wk after the diet switch. In vivo glucose tolerance tests indicated that insulin sensitivity was corrected in HF,C and HF,M rats after 3 d. Body fat content was greater in rats fed the high fat diet and remained high after 7 d of consuming either diet with 30% of energy from fat. There was no effect of diet on liver fatty acid utilization or on diaphragm glucose oxidation. Adipocytes from all treatment groups were insulin resistant, possibly due to feeding status or age of the rats. The results of this study suggest that a moderate reduction in fat intake, from 40 to 30% of energy, can produce a rapid improvement of insulin sensitivity in insulin-insensitive rats, independent of changes in body fat content and irrespective of the means used to reduce dietary fat content.