Preferential fat intake of pups nursed by dams fed low fat diet during pregnancy and lactation is higher than that of pups nursed by dams fed control diet and high fat diet

To investigate the effect of dams' dietary fat type during pregnancy and lactation on fat choice of pups, three groups of dams were fed one of three diets: a low fat diet (LFD), a control diet (CTD) or a high fat diet (HFD). After weaning their pups were offered a self-selection regimen of both a fat protein diet (FPD) and a carbohydrate protein diet (CPD) for 3 wk. Although the ratio of FPD intake [FPD intake (g)/total intake (g)] by pups nursed by dams fed LFD during the self-selection period was higher than that by pups nursed by dams fed CTD and HFD, no significant difference in the ratio was observed between pups nursed by dams fed CTD and HFD. It was considered that pups nursed by dams fed CTD and HFD self-selected FPD and CPD in an adequate fat energy ratio (F ratio) compared to that of AIN-93G and AIN-93M. The ratio of FPD intake by pups of these three groups was 16-21% within the first week after weaning. Although pups nursed by dams fed CTD continued to consume the same ratio of FPD during the self-selection period, the ratio of pups nursed by dams fed LFD increased and that of pups nursed by dams fed HFD decreased. These findings indicate that: [1] pups nursed by dams fed CTD and HFD have the ability to consume FPD and CPD in an adequate F ratio, and [2] preferential fat intake of pups nursed by dams fed LFD is stronger than that of pups nursed by dams fed CTD and HFD.     

Pups of dams fed low-fat diet during pregnancy and lactation showed strong preference for high-fat diet to achieve optimal growth

To investigate the causes why pups of dams fed a low-fat high-carbohydrate diet (LFD) showed a strong preference for fat, three groups of dams were fed one of three diets during pregnancy and lactation: the LFD, a control diet (CTD) or a high-fat low-carbohydrate diet (HFD). After weaning, pups of each of the three groups were divided into two equal subgroups (Pair 1 and Pair 2), for a total of six pup subgroups. Each subgroup was placed on a two-choice diet program of the LFD and the HFD (Pair 1), or the LFD and a HFDLE (with cellulose added to maintain the same energy concentration as the LFD) (Pair 2), for 3 wk. Although the energy intake of dams fed the LFD during the nursing period was lower than that of the HFD group, no significant difference in body weight was observed among the three groups. At weaning, the body weight of pups nursed by dams fed the LFD was lower than that of the other groups. In Pair 1, the HFD intake ratio of the LFD and the HFD groups during the self-selection period was higher than that of the CTD group. In Pair 2, the HFDLE intake ratio of the LFD and the CTD groups was lower than that of the HFD group. At the end of the self-selection period, no significant difference in body weight was observed among the three groups of Pair 1. However, in Pair 2, the body weight of the LFD group was lower than that of the other groups. Therefore, it was supposed that pups of dams fed the LFD showed strong preference for the HFD containing high energy in order to achieve optimal growth.     

Fish-oil high-fat diet intake of dams after day 5 of pregnancy and during lactation guards against excessive fat consumption of their weaning pups

To investigate the influence of parental fat intake on preferential fat intake by pups after weaning, two groups of dams in study 1 were fed either a low-fat diet (LFD) or a lard high-fat diet (HFD) and those in study 2 were fed either a LFD or a fish-oil HFD after day 5 of pregnancy and during lactation. In study 1, when pups were placed on a self-selection regimen of the LFD and the lard HFD within the first week after weaning, the ratio of the lard HFD intake [lard HFD intake (g)/total intake (g)] by pups of both groups was about 70%. Although pups nursed by dams fed the lard HFD continued to eat the same ratio of the lard HFD, the ratio for pups nursed by dams fed the LFD gradually decreased to 20% in week 3 after weaning. In study 2, when pups were placed on a self-selection regimen of the LFD and the fish-oil HFD after weaning, the ratio of the fish-oil HFD intake in both groups of pups nursed by dams fed the LFD and the fish-oil HFD was about 20% for 3 wk after weaning. In studies 1 and 2, although no significant difference in dietary intake or body weight of dams and pups was observed among all groups through the experimental period, perirenal fat tissue weight of dams fed the lard HFD was higher than that of dams fed the LFD. These findings indicate that (1) fat preference of weaning pups nursed by dams fed the lard HFD is higher than that of weaning pups nursed by dams fed the LFD, and (2) intake of dam's fish-oil HFD diet guards against pups' intake of excessive fat.     

The fat:carbohydrate energy ratio of the weaning diet programs later susceptibility to obesity in male sprague dawley rats

Dietary fat intake, which is high during suckling, is markedly reduced when food and drinks are introduced into the diet. We investigated whether alterations in the fat:carbohydrate (CHO) content of the weaning diet influenced the later development of adiposity and insulin sensitivity. Three groups of male rats (24/group) were fed from age 16-37 d (phase I) with weaning diets varying in their fat:CHO energy (E) ratios, 10:70 low-fat, high-CHO (LFHC); 30:50 medium-fat, medium-CHO (MFMC), and 60:30 high-fat, high-CHO (HFLC), on an isocaloric basis. Then, all groups consumed ad libitum first a low-fat diet (13% fat E) for 30 wk (phase II) and subsequently a high-fat diet (45% fat E) for another 18 wk (phase III). At the end of phase I, the group fed the HFLC diet demonstrated higher plasma glucose and insulin responses to an oral glucose tolerance test (P < 0.05), but this effect was transient and did not persist into adulthood (phases II and III). By contrast, when challenged with a high-fat diet later in life (age 35.3-53.3 wk), the LFHC group had greater gains in weight (as percent initial weight) and body fat (as absolute and percent body weight) than the other 2 groups that had been weaned with diets higher in fat (P < 0.04 for all). These results provide evidence that metabolic programming by altering the dietary fat:CHO ratio can occur during the weaning period and emphasizes the importance of the fat:CHO ratio of the complementary diet and its relation to the susceptibility to develop adiposity later in life.     

Zinc's role in rat preference for a low-fat diet in a two-choice diet program of low- and high-fat diets

To investigate the change in preference for a low-fat diet (LFD) and a high-fat diet (HFD) under disorders induced by a zinc (Zn)-deficiency, two groups of 4-wk-old male rats were fed a two-choice diet of Zn-deficient (ZnD; 0.75 mg/kg) and Zn-adequate (ZnA; 30.75 mg/kg) LFD and HFD. After 21 d, 10 rats in each of the two groups were sacrificed. The remaining ZnD rats were switched to ZnA diets for 7 d. Intakes of the LFD and the HFD were measured to determine the diet preferences of the ZnD, the ZnA and the Zn-recovered groups. Energy intake of the ZnD group was significantly lower than that of the ZnA group and showed cyclical 3- to 4-d patterns of decrease. In the ZnD group, although the LFD intake decreased parallel to the reduction in the energy intake, the HFD intake did not show the cyclical pattern of decrease. The reduced intake of the LFD in the ZnD rats was accompanied by a low carbohydrate intake and a low plasma insulin concentration. When the ZnD group recovered sufficient amounts of Zn, the energy intake was restored to normal levels and the difference in the LFD intake and the plasma insulin concentration disappeared between the ZnD and the ZnA groups. It was supposed that the specific change in the LFD intake patterns during development and recovery from Zn-deficiency might be related to Zn-mediated changes in impaired synthesis and the release of insulin from the pancreas.     

Ratio of high-fat diet intake of pups nursed by dams fed combination diet was lower than that of pups nursed by dams fed high-fat or low-fat diet

To investigate the influence of fat-feeding dams on the food choice of their pups after weaning, each of three groups of dams was fed a low-fat diet (LHD), a high-fat diet (HFD) or a two-choice diet of LFD and HFD during pregnancy and lactation. Immediately after weaning, all pups were placed on a two-choice diet program for 5 wk. The fat energy ratio (F ratio) for dams fed the two-choice diet was 31%. Although no significant differences in body weight or calorie intake were observed between these three groups of dams, liver and perirenal fat tissue weights and plasma and liver trigluceride and total-cholesterol concentrations were lower in dams fed the two-choice diet than in dams fed LHD or HFD. Both groups of pups nursed by dams fed LFD or HFD continued to eat a large amount of HFD after weaning (F ratio was over 40%). Although within first week after weaning, no significant difference in the ratio of HFD intake was observed among the three groups of pups, the ratio for pups nursed by dams fed the two-choice diet decreased after the second week. The F ratio for pups nursed by dams fed the two-choice diet was 32%. These data lead us to conclude that if dams ate more than one diet in an adequate PFC ratio, their pups would have the ability to eat adequately after weaning.     

Effects of a low-fat diet compared with those of a high-monounsaturated fat diet on body weight, plasma lipids and lipoproteins, and glycemic control in type 2 diabetes

BACKGROUND: An important therapeutic goal for patients with type 2 diabetes is weight loss, which improves metabolic abnormalities. Ad libitum low-fat diets cause weight loss in nondiabetic populations. Compared with diets higher in monounsaturated fat, however, eucaloric low-fat diets may increase plasma triacylglycerol concentrations and worsen glycemic control in persons with type 2 diabetes. OBJECTIVE: We investigated whether, in type 2 diabetes patients, an ad libitum low-fat diet would cause greater weight loss than would a high-monounsaturated fat diet and would do this without increasing plasma triacylglycerol concentrations or worsening glycemic control. DESIGN: Eleven patients with type 2 diabetes were randomly assigned to receive an ad libitum low-fat, high-carbohydrate diet or a high-monounsaturated fat diet, each for 6 wk. The diets offered contained 125% of the estimated energy requirement to allow self-selection of food quantity. The response variables were body weight; fasting plasma lipid, lipoprotein, glucose, glycated hemoglobin A(1c), and fructosamine concentrations; insulin sensitivity; and glucose disposal. RESULTS: Body weight decreased significantly (1.53 kg; P < 0.001) only with the low-fat diet. Plasma total, LDL-, and HDL-cholesterol concentrations tended to decrease during both diets. There were no interaction effects between diet and the lipid profile response over time. Plasma triacylglycerol concentrations, glycemic control, and insulin sensitivity did not differ significantly between the 2 diets. CONCLUSION: Contrary to expectations, the ad libitum, low-fat, high-fiber diet promoted weight loss in patients with type 2 diabetes without causing unfavorable alterations in plasma lipids or glycemic control.     

Resistance to dietary hyperphagia in juvenile rats

Adult rats (12 wk of age) fed a wet, high starch diet consumed more energy, gained more weight, and had more carcass fat than rats fed the same diet in a dry form. In contrast, juvenile rats (3.5 wk of age) did not consume more energy, gain more weight, or become fatter when fed the wet, high starch diet than when fed the same diet in dry form. Although rats of both age groups fed high fat diets consumed more energy than rats fed high starch diets, the effect of the high fat diets was much smaller in juvenile than in adult rats. The level of dietary protein (20 vs. 8%) in the diets did not interact with diet type, but juvenile rats fed low protein diets gained less weight than juvenile rats fed standard protein diets. Additional experiments showed that juvenile rats fed a 20% protein diet were capable of increasing fluid intake and energy intake when given sweetened water or insulin, respectively. Thus, low susceptibility to dietary hyperphagia in juvenile rats cannot be explained by assuming that juvenile rats already eat as much as they can. These data are consistent with the possibility that developmental changes in taste responsiveness may contribute to this effect of age.     

Whole-body fat oxidation rate and plasma triacylglycerol concentrations in men consuming an ad libitum high-carbohydrate or low-carbohydrate diet

BACKGROUND: High-carbohydrate diets may increase plasma triacylglycerol concentrations either by increasing production of triacylglycerols or by reducing their clearance. OBJECTIVE: We assessed whether the changes in plasma triacylglycerol concentrations induced by dietary interventions were associated with the changes in whole-body fat oxidation rates. DESIGN: In a parallel study, 37 healthy male subjects [body mass index (in kg/m(2)): 28 +/- 5, age: 34 +/- 11 y (x +/- SD)] consumed an ad libitum high-carbohydrate (60% of energy; n = 19) or low-carbohydrate (46% of energy), high-fat (41% of energy, 23% as monounsaturated fatty acids; n = 18) diet for 7 wk. The following variables were measured before and after the dietary interventions: 1) plasma triacylglycerols before and 2, 4, 6, and 8 h after a meal (containing 40% of daily energy needs and 41% fat); 2) indirect calorimetry throughout the 8-h test; and 3) postheparin plasma lipoprotein lipase (phLPL) activity at time 8 h of the test. RESULTS: The diets induced changes in 1) body weight: -2.5 +/- 2.8 kg (P < 0.01) and -1.7 +/- 3.1 kg (P < 0.05) and 2) fasting plasma triacylglycerols: 0.0 +/- 0.4 mmol/L (NS) and -0.3 +/- 0.3 mmol/L (P < 0.05) for the high-carbohydrate and the low-carbohydrate diets, respectively. In normoinsulinemic subjects (fasting insulin < 100 pmol/L), dietary changes in postprandial triacylglycerols were significantly predicted by changes in phLPL, body weight, respiratory quotient (or fat oxidation), and the type of diet (stepwise multiple linear regression). CONCLUSION: Postprandial plasma triacylglycerol concentrations may depend at least partly on fat oxidation, body weight, and LPL activity.     

High-fat diet action on adiposity,inflammation, and insulin sensitivity depends on the control low-fat diet

Animal studies using a high-fat diet (HFD) have studied the effects of lipid overconsumption by comparing a defined HFD either with a natural-ingredient chow diet or with a defined low-fat diet (LFD), despite the dramatic differences between these control diets. We hypothesized that these differences in the control diet could modify the conclusions regarding the effects that an increase of fat in the diet has on several metabolic parameters. For 11 weeks, C57bl6/J mice were fed a low-fat chow diet (8% energy from fat), a typical semisynthetic LFD (12%), or a semisynthetic HFD (sy-HF) (40%). Conclusions about the effect of sy-HF on body weight gain, subcutaneous adipose tissue, insulin sensitivity, and adipose tissue inflammation were modified according to the control LFD. Conversely, conclusions about epididymal and retroperitoneal adipose tissue; fat intake effects on liver and muscular lipids, cholesterol, free fatty acids, and markers of low-grade inflammation; and of adipose tissue macrophage infiltration were the same regardless of the use of low-fat chow diet or semisynthetic LFD. For some physiological outcomes, conflicting conclusions were even reached about the effects of increased fat intake according to the chosen low-fat control. Some deleterious effects of sy-HF may not be explained by lipid overconsumption but rather by the overall quality of ingredients in a semisynthetic diet. According to the control LFD chosen, conclusions on the lipid-related effects of HFDs must be formulated with great care because some end points are profoundly affected by the ingredient composition of the diet rather than by fat content.     

Effects of meal frequency and high-fibre rye-bread diet on glucose and lipid metabolism and ileal excretion of energy and sterols in ileostomy subjects

OBJECTIVE: To investigate the effect of a rye, high-fibre diet (HFD) vs a wheat, low-fibre diet (LFD), meal frequency, nibbling (Nib, seven times a day) or ordinary (Ord, three times a day), and their combined effects on blood glucose, insulin, lipids, urinary C-peptide and ileal excretion of energy, cholesterol and bile acids in humans. DESIGN: LFD period with Nib or Ord meal frequency followed by an HFD diet with Nib or Ord meal frequency in randomized, crossover design. SETTING: Outpatients of ileostomy volunteers were called for an investigation in research word. SUBJECTS: A total of 10 subjects (two female subjects, age 34 and 51 y; eight males, mean age 54.4 y, range 43-65 y) participated in the experiment. All subjects were proctocolectomized for ulcerative colitis (mean 16.0 y, range 8-29 y before the study). INTERVENTION: In total, 10 ileostomy subjects started with LFD for 2 weeks, the first week on either Nib (five subjects) or Ord (five subjects) and the second week on the other meal frequencies, in a crossover design, followed by a wash-out week, and continued with HFD period for 2 weeks in the same meal frequency manner. All foods consumed in both Nib or Ord regimens were identical and a high-fibre rye bread was used in the HFD period and a low-fibre wheat bread in the LFD period. MAIN OUTCOME MEASURES: Day-profiles of blood glucose, insulin and lipids, blood lipids before and after dietary intervention, and excretion of steroids in the effluents and C-peptide in the urine. RESULTS: During the Nib regimen, plasma glucose and insulin peaks were lower at the end of the day with HFD compared with LFD. Urinary C-peptide excretion was significantly higher in the day-time on LFD compared with HFD (LFD-Ord vs HFD-Ord, P < 0.01; LFD-Nib vs HFD-Nib, P < 0.01). Plasma free-cholesterol, total cholesterol, triglycerides and phospholipids were significantly higher (P < 0.05) after LFD than after HFD with the Nib regimen. A higher excretion of energy (P < 0.05) and chenodeoxycholic acid (P < 0.05) were observed with HFD compared with LFD regardless of meal frequency. A higher daily excretion of cholic acid, total bile acids, cholesterol, net cholesterol and net sterols (P < 0.05) was observed on HFD compared with LFD with the Nib regimen. CONCLUSIONS: An HFD decreased insulin secretion measured as a decreased excretion of C-peptide in urine and as decreased plasma insulin peaks at the end of the day during a Nib regimen. The smoother glycaemic responses at the end of the day during a Nib regimen may be a consequence of a second meal phenomenon, possibly related to the nature of dietary fibre complex.     

Adaptation of skeletal muscle characteristics to a high-fat diet in rats with different intra-abdominal-obesity susceptibilities

The purpose of the present study was to investigate the relationship between intra-abdominal-obesity susceptibility and the adaptation of skeletal muscle metabolic and histochemical characteristics when fed a high-fat diet (HFD) for a short period of time. Twenty-four male Wistar rats were fed a HFD (39.7% calories of fat) for 5 wk. After the 5-wk dietary period, the rats were sacrificed and divided into intra-abdominal-obesity-prone (OP) or obesity-resistant (OR) groups according to the total intra-abdominal fat pads (epididymal, mesenteric, and perirenal) weights. A superficial portion of the Muscle (M.) gastrocnemius tissue obtained from 2 groups before and after feeding the HFD were analyzed to determine their hexokinase (HK), (beta-hydroxyacyl CoA dehydrogenase (beta-HAD), and citrate synthase (CS) activities. Muscle fiber composition and capillary density were examined in the deep portion of the M. gastrocnemius, soleus, and extensor digitorum longus (EDL) gained after the HFD. While the OP group had more intra-abdominal fat pads and a heavier final body weight than the OR group, there was no significant difference in the energy intake between the two. Due to the HFD, the OP group showed significant increases in beta-HAD and CS activities, while the OR group did not. Change of beta-HAD activity by HFD in the OP group was significantly greater than that in the OR group. The ratio of fat oxidation, expressed as beta-HAD/CS, significantly increased in the OP group, but not in the OR group. No differences were found in either the muscle fiber composition or capillarization. These results suggest that intra-abdominal-obesity-susceptive rats may have a higher adaptation degree in muscle oxidative enzyme activities as characteristic in the early stage of intra-abdominal adipose accumulation.     

Effects of high-fat diet intake on glucose uptake in central and peripheral tissues of non-obese rats

We previously demonstrated that plasma glucose concentration was higher while plasma insulin concentration was lower in rats fed a high-fat diet. In the present study, we examined the effects of high-fat diet on glucose uptake in central and peripheral tissues in non-obese rats. Forty male Sprague-Dawley rats were fed high- or low-fat diets for 4 wk. Body weight and body fat accumulation were not different between the two diet groups after 4 wk. Glucose uptake in the skeletal muscles and adipose tissues, estimated by the 2-deoxy-D-glucose method, was lower in the rats fed the high-fat diet than that in the rats fed the low-fat diet, whereas uptake in the liver and pancreas did not differ between the two groups. Glucose uptake in the hypothalamus and cortex was higher in the high-fat diet group as compared with that in the low-fat diet group. These results suggest that increased plasma glucose levels in rats fed the high-fat diet were caused by a decrease in glucose uptake in the skeletal muscles and adipose tissues. Reduced plasma insulin level in the high fat diet group with no difference in glucose uptake in the pancreas may be due to increased sympathetic activity in the pancreas resulting from the increased glucose uptake in the brain regions involved in autonomic functions.     

Dietary intake of medium- and long-chain triacylglycerols ameliorates insulin resistance in rats fed a high-fat diet

Objective

Excessive accumulation of visceral fat is strongly associated with insulin resistance. The present investigation examined the effects of dietary intake of medium- and long-chain triacylglycerols (MLCTs), which have been shown to induce significantly lower visceral fat accumulation in rats and humans, on high-fat diet-induced obesity and insulin resistance in rats. These effects were then compared with those observed in long-chain triacylglycerol (LCT)-fed rats.

Methods

After an 8-wk feeding of a high-fat diet, which induced severe whole-body insulin resistance, male Sprague-Dawley rats were fed a standard diet containing LCTs or MLCTs for 6 wk. After the dietary treatment, an oral glucose tolerance test was performed.

Results

Although body weight and total intra-abdominal fat mass did not differ between the two groups, mesenteric fat weight in the MLCT-fed group was significantly lower than that in the LCT group (P < 0.05). The increase in plasma insulin concentrations, but not in glucose, after glucose administration (area under the curve) was significantly smaller in the MLCT group than in the LCT group (P < 0.01) and was significantly associated with mesenteric fat weight (P < 0.05). MLCT-fed rats had significantly higher plasma adiponectin concentrations compared with LCT rats (P < 0.05). Adiponectin concentrations were negatively correlated with the area under the curve for plasma insulin (P < 0.05) and tended to be inversely related to mesenteric fat weight (P = 0.08).

Conclusion

These results suggest that dietary intake of MLCTs may improve insulin resistance in rats fed a high-fat diet, at least in part through increased adiponectin concentrations caused by a lower mesenteric fat mass.     

Effect of oat bran on plasma cholesterol and bile acid excretion in nine subjects with ileostomies.

A higher excretion of dry matter, fat, nitrogen, energy, and total bile acids in ileal effluents; a lower plasma low-density-lipoprotein (LDL) and total cholesterols (12.1% and 9.0% lower respectively); but no change in plasma high-density-lipoprotein (HDL) cholesterol or apolipoproteins A-I and B were observed in nine subjects with ileostomies when they consumed an oat-bran, bread-based, high-fiber diet (HFD) as compared with a wheat-flour, bread-based, low-fiber diet (LFD) for 3 wk with a crossover design. Of the nine subjects only the subjects with a low daily excretion of bile acids had an elevated excretion of total bile acids during the HFD compared with the LFD. Total cholesterol, LDL cholesterol, and apolipoprotein B in plasma also decreased by 11.3%, 15.3%, and 10.7%, respectively, after consumption of the HFD for 3 wk.     

Dietary chickpeas reverse visceral adiposity, dyslipidaemia and insulin resistance in rats induced by a chronic high-fat diet

The improved effects of dietary chickpeas on visceral adiposity, dyslipidaemia and insulin resistance were examined. Rats were fed a normal-fat diet (NFD), a high-fat diet (HFD) or a high-fat plus chickpea diet (HFD+CP) for 8 months. The epididymal fat pad weight v. total body weight of rats was higher in the HFD group (0.032 (sd 0.0042) g/g) than in the NFD group (0.015 (sd 0.0064) g/g) and smaller in the HFD+CP group (0.023 (sd 0.0072) g/g) compared with the HFD group (P < 0.05). Chickpea treatment also induced a favourable plasma lipid profile reflecting decreased TAG, LDL-cholesterol (LDL-C) and LDL-C:HDL-cholesterol levels (P < 0.05). HFD-fed rats had higher TAG concentration in muscle and liver, whereas the addition of chickpeas to the HFD drastically lowered TAG concentration (muscle, 39 %; liver, 23 %). The activities of lipoprotein lipase (LPL) in epididymal adipose tissue and hepatic TAG lipase in liver recorded a 40 and 23 % increase respectively in HFD rats compared with those in NFD rats; dietary chickpeas completely normalised the levels. Furthermore, chickpea-treated obese rats also showed a markedly lower leptin and LPL mRNA content in epididymal adipose tissue. An insulin tolerance test, oral glucose tolerance test and insulin-releasing test showed that chickpeas significantly improved insulin resistance, and prevented postprandial hyperglycaemia and hyperinsulinaemia induced by the chronic HFD. The present findings provide a rational basis for the consumption of chickpeas as a functional food ingredient, which may be beneficial for correcting dyslipidaemia and preventing diabetes.     

Long-term intake of rice improves insulin sensitivity in mice fed a high-fat diet

ObjectiveThe aim of this study was to evaluate the effects of rice as a carbohydrate source and its molecular mechanisms on insulin resistance induced by a high-fat diet (HFD).MethodsC57 BL/6 J mice were divided into three groups and were fed a low-fat diet (LFD); a HFD (with 18% fat, 0.5% cholesterol, 51.5% w/w cornstarch and sucrose); or a HFD with rice (HFD-CR, with 18% fat, 0.5% cholesterol and 51.5% w/w rice powder) for 12 wk. In the HFD-CR diet, cooked rice powder was substituted for cornstarch and sucrose in the HFD as a carbohydrate source.ResultsHFD-CR–fed mice had significantly lower body weight, blood glucose, insulin and leptin levels and ameliorated glucose responses with decreased homeostasis model assessment-insulin resistance compared with HFD-fed mice. Hepatic mRNA levels of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase were down-regulated in the HFD-CR group. The hypertrophied islet size and the decreased pancreatic mRNA expression of glucose transporter 2 in the HFD group were normalized with cooked rice consumption. Rice promoted glucose uptake by activating AMP-activated protein kinase and downstream glucose transporter 4 in the skeletal muscle.ConclusionRice consumption as a carbohydrate source might potentiate improvements in glucose uptake via AMP-activated protein kinase activation and glucose transporter 4 expression in the skeletal muscles, thereby improving insulin sensitivity.     

A very low-fat diet is not associated with improved lipoprotein profiles in men with a predominance of large, low-density lipoproteins

BACKGROUND: We found previously that men with a predominance of large LDL particles (phenotype A) consuming high-fat diets (40-46% fat) show less lipoprotein benefits of low-fat diets (20-24% fat) than do men with a high-risk lipoprotein profile characterized by a predominance of small LDL (phenotype B). Furthermore, one-third of men with phenotype A consuming a high-fat diet converted to phenotype B with a low-fat diet. OBJECTIVE: We investigated effects of further reduction in dietary fat in men with persistence of LDL subclass phenotype A during both high- and low-fat diets. DESIGN: Thirty-eight men who had shown phenotype A after 4-6 wk of both high- and low-fat diets consumed for 10 d a 10%-fat diet (2.7% saturates) with replacement of fat with carbohydrate and no change in cholesterol content or ratio of polyunsaturates to saturates. RESULTS: In 26 men, phenotype A persisted (stable A group) whereas 12 converted to phenotype B (change group). LDL cholesterol did not differ from previous values for 20-24%-fat diets in either group, whereas in the change group there were higher concentrations of triacylglycerol and apolipoprotein B; greater mass of HDL, large LDL-I, small LDL-III and LDL-IV, and HDL3; lower concentrations of HDL cholesterol, apolipoprotein A-I; and lower mass of large LDL-I and HDL2. CONCLUSIONS: There is no apparent lipoprotein benefit of reduction in dietary fat from 20-24% to 10% in men with large LDL particles: LDL-cholesterol concentration was not reduced, and in a subset of subjects there was a shift to small LDL along with increased triacylglycerol and reduced HDL-cholesterol concentrations.     

Comparisons of glucose and lipid metabolism in rats fed diacylglycerol and triacylglycerol oils

The effects of dietary 1,3-diacylglycerol-rich oil (DG oil) on biochemical findings related to glucose and lipid metabolisms were investigated in comparison with triacylglycerol oil (TG oil) in normal rats. Young (7 wk-old) and old (8 mo-old) rats were fed a synthetic diet containing 10% (by weight) DC or TG oil for 1, 4, 8, or 12 wk. The body weights, epididymal and perirenal adipose tissue weights, and feed efficiency were not significantly different in the dietary oil groups during any feeding period. The plasma and liver triacylglycerol concentrations were not different in the dietary groups, except that the plasma triacylglycerol concentrations were rather lower only in the portal vein of rats fed DG oil. The plasma glucose and free fatty acid concentrations were significantly higher in rats fed DG oil as compared to TG oil. In the old rats fed DG oil for 8 wk, the fasted plasma glucose and insulin concentrations were elevated and glucose intolerance was observed. The insulin receptor expression was not different due to dietary oil, but was markedly reduced with aging. Thus, the anti-obesity and lipid-lowering effects of dietary DG oil were not found. Moreover, it appeared that the glucose intolerance might be induced by dietary DG oil, particularly in the old rats.