High Fructose Corn Syrup Accelerates Kidney Disease and Mortality in Obese Mice with Metabolic Syndrome.

The presence of obesity and metabolic syndrome is strongly linked with chronic kidney disease (CKD), but the mechanisms responsible for the association are poorly understood. Here, we tested the hypothesis that mice with obesity and metabolic syndrome might have increased susceptibility to CKD from liquid high fructose corn syrup (HFCS) by favoring the absorption and utilization of fructose. We evaluated the pound mouse model of metabolic syndrome to determine if it showed baseline differences in fructose transport and metabolism and whether it was more susceptible to chronic kidney disease when administered HFCS. Pound mice have increased expression of fructose transporter (Glut5) and fructokinase (the limiting enzyme driving fructose metabolism) associated with enhanced fructose absorption. Pound mice receiving HFCS rapidly develop CKD with increased mortality rates associated with intrarenal mitochondria loss and oxidative stress. In pound mice lacking fructokinase, the effect of HFCS to cause CKD and early mortality was aborted, associated with reductions in oxidative stress and fewer mitochondria loss. Obesity and metabolic syndrome show increased susceptibility to fructose-containing sugars and increased risk for CKD and mortality. Lowering added sugar intake may be beneficial in reducing the risk for CKD in subjects with metabolic syndrome.

Neurosecretory Protein GL Accelerates Liver Steatosis in Mice Fed Medium-Fat/Medium-Fructose Diet.

Sugar consumption can readily lead to obesity and metabolic diseases such as liver steatosis. We previously demonstrated that a novel hypothalamic neuropeptide, neurosecretory protein GL (NPGL), promotes fat accumulation due to the ingestion of sugar by rats. However, differences in lipogenic efficiency of sugar types by NPGL remain unclear. The present study aimed to elucidate the obesogenic effects of NPGL on mice fed different sugars (i.e., sucrose or fructose). We overexpressed the NPGL-precursor gene (Npgl) in the hypothalamus of mice fed a medium-fat/medium-sucrose diet (MFSD) or a medium-fat/medium-fructose diet (MFFD). Food intake and body mass were measured for 28 days. Body composition and mRNA expression of lipid metabolic factors were measured at the endpoint. Npgl overexpression potently increased body mass with fat accumulation in the white adipose tissue of mice fed MFFD, although it did not markedly affect food intake. In contrast, we observed profound fat deposition in the livers of mice fed MFFD but not MFSD. In the liver, the mRNA expression of glucose and lipid metabolic factors was affected in mice fed MFFD. Hence, NPGL induced liver steatosis in mice fed a fructose-rich diet.

Metformin treatment for 8 days impacts multiple intestinal parameters in high-fat high-sucrose fed mice.

Although the mechanism of action of the antidiabetic drug metformin is still a matter of discussions, it is well accepted that the gut plays an important role. To gain more insights into the mechanisms occurring in the different regions of the intestine, adult male mice were fed a high-fat-high sucrose (HFS) diet for 8 days and treated with metformin by gavage (300 mg/day/kg body weight) during the HFS diet. Metformin counteracted HFS diet-induced overexpression of a network of genes involved in the transport of glucose and fatty acids in the different regions of the small intestine. It also induced beneficial modification of secondary bile acid profile in the caecum, with a reduction of deoxycholic acid and lithocholic acid levels and increased abundance of ursodeoxycholic acid and tauroursodeoxycholic acid, potentially leading to FRX inhibition. In parallel, metformin treatment was associated with specific changes of the microbiota composition in the lumen of the different regions of the intestine. Metformin induced a marked increase in the abundance of Akkermansia muciniphila in the lumen all along the gut and counteracted the effects of HFS diet on the abundances of some bacterial groups generally associated with metabolic disturbances (f-Lachnospiraceae, f-Petostreptococcaceae, g-Clostidium). Therefore, the present work clearly emphasises the role of all the regions of the intestinal tract in the beneficial action of the antidiabetic drug metformin in a prediabetic mouse model.

Impact of High-Sucrose Diet on the mRNA Levels for Elongases and Desaturases and Estimated Protein Activity in Rat Adipose Tissue.

Fatty acids (FAs) present in the adipose tissue (AT) can be modified by elongases and desaturases. These enzymes are regulated by different factors including nutrients. The aim of the study was to evaluate the impact of high-sucrose diet (HSD; 68% sucrose) on the levels of mRNAs for elongases (Elovl2, Elovl5, Elovl6) and desaturases (Fads1, Fads2, Scd) and on the activity of the corresponding proteins in the rat AT. Male Wistar rats were randomized into two study groups: fed with an HSD and with a standard diet (ST). The mRNA levels were determined by a semi-quantitative reverse transcription-PCR. FA composition was analyzed by gas chromatography, and FA ratios were used to estimate the activity of the enzymes. In the HSD rats, the levels of Elovl5, Elovl6, Fads1, and Scd mRNAs were higher, while the level of Fads2 mRNA was lower than in the ST group. Higher levels of Elovl5 and Elovl6 mRNAs corresponded to higher relative activities of these enzymes, while downregulation of the Fads2 mRNA was associated with the lower activity of this desaturase. In contrast, an increase in the level of Scd mRNA was accompanied by a decrease in the enzyme activity. Less monounsaturated FAs were detected in the AT of HSD rats than in the ST group. The composition of individual FAs differed between the groups. This study supports the notion that the regulation of mRNA levels and activity of both elongases and desaturases play an important role in managing the AT lipid composition in response to changes in the dietary status.

High sucrose diet attenuates oxidative stress, inflammation and liver injury in thioacetamide-induced liver cirrhosis.

AIMS: Liver cirrhosis is the main chronic liver disease and is considered a catabolic disease. Cirrhotic patients have a low energy intake and high energy expenditure at rest, leading to metabolic disorders. Malnutrition is associated with complications of cirrhosis and has been shown that a nutritional intervention with increase of energy intake improves the survival of cirrhotic patients. Therefore, our aim was to evaluate the effect of a high sucrose diet in the liver of animals with cirrhosis induced by thioacetamide and investigate the mechanism involved. MAIN METHODS: Male Wistar rats were divided into three groups: Control; Thioacetamide; and Thioacetamide + high sucrose diet. The thioacetamide was administrated (100 mg kg-1) intraperitoneally and the sucrose was offered in drinking water (300 g L-1). KEY FINDINGS: The administration of thioacetamide was associated with fibrosis and inflammatory infiltrate in the liver and increased levels of transaminases enzymes. The high sucrose diet promoted a reduction of theses parameters in cirrhotic rats. The malnutrition observed in cirrhotic rats was attenuated by the high sucrose diet shown by the improvements in weight loss, subcutaneous fat, and caloric intake. The high sucrose diet also attenuated the oxidative stress present in the liver of animals with thioacetamide-induced cirrhosis. SIGNIFICANCE: The high sucrose diet had anti-inflammatory and anti-oxidant effects in the liver of animals with thioacetamide-induced cirrhosis. In addition, the high sucrose diet also improved malnutrition and catabolism present in cirrhosis. Thus, a high sucrose diet may be a therapeutic option for cirrhotic patients in a catabolic state.

Sweet Taste Antagonist Lactisole Administered in Combination with Sucrose, But Not Glucose, Increases Energy Intake and Decreases Peripheral Serotonin in Male Subjects.

Knowledge regarding the involvement of sweetness perception on energy intake is scarce. Here, the impact of glucose and sucrose sweetness, beyond their caloric load, on subsequent food intake and biomarkers of satiation was evaluated by co-administration of the sweet taste receptor inhibitor lactisole. A total of 27 healthy, male subjects received solutions of either 10% glucose w/o 60 ppm lactisole or 10% sucrose w/o 60 ppm lactisole. Subsequent food intake from a standardized breakfast was evaluated 2 h after receiving the respective test solution. Changes in postprandial plasma concentrations of cholecystokinin, ghrelin, and serotonin were determined over a period of 120 min, as was the body temperature. Administration of lactisole to the sucrose solution increased the energy intake from the subsequent standardized breakfast by 12.9 ± 5.8% (p = 0.04), led to a decreased Δ AUC of the body core temperature by 46 ± 20% (p = 0.01), and time-dependently reduced Δ serotonin plasma concentrations (-16.9 ± 6.06 ng/mL vs. -0.56 ± 3.7 ng/mL after sucrose administration, p = 0.03). The present study shows that lactisole increases energy intake and decreases plasma serotonin concentrations as well as body core temperature induced by sucrose, but not glucose. This finding may be associated with the different binding affinities of sucrose and glucose to the sweet taste receptor.

High sucrose diet induces morphological, structural and functional impairments in the renal tubules of Drosophila melanogaster: A model for studying type-2 diabetes mediated renal tubular dysfunction.

Continuous feeding of high dietary sugar is strongly associated with type 2 diabetes (T2D) and its secondary complications. Diabetic nephropathy (DN) is a major secondary complication that leads to glomerular and renal tubular dysfunction. The present study is aimed to investigate the effects of chronic exposure of high sugar diet (HSD) on renal tubules. Malpighian tubules (MTs), a renal organ of Drosophila, were used as a model in the study. Feeding of HSD develops T2D condition in Drosophila. The MTs showed structural abnormalities in 20 days of HSD fed flies. Impaired insulin signaling, oxidative stress, enhanced levels of AGE-RAGE and induction of apoptosis were observed in the MTs of these flies. Further, altered expression of transporters, enhanced uric acid level and reduced fluid secretion rate confirmed the impaired function of MTs in these flies. RNA-seq and RT-PCR analyses in the MTs of HSD fed-and control-flies revealed the altered expression of candidate genes that regulate several important pathways including extracellular matrix (ECM), advanced glycation end products-receptor for advanced glycation end products (AGE-RAGE), transforming growth factor ß (TGF-ß), galactose, starch and sucrose metabolism that are well known mediators of renal tubular dysfunction in DN patients. Disruption of insulin signaling in the MTs also causes renal tubular dysfunction similar to HSD fed flies. Overall, the study suggests that phenotypes observed in the MTs of HSD fed flies recapitulate several hallmarks of renal tubular dysfunction in DN patients. Therefore, we conclude that MTs of HSD fed flies may be used for deciphering the underlying mechanisms of T2D mediated renal tubular dysfunction.

Comparable Exogenous Carbohydrate Oxidation from Lactose or Sucrose during Exercise.

PURPOSE: Ingesting readily oxidized carbohydrates (CHO) such as sucrose during exercise can improve endurance performance. Whether lactose can be utilized as a fuel source during exercise is unknown. The purpose of this study was to investigate the metabolic response to lactose ingestion during exercise, compared with sucrose or water. METHODS: Eleven participants (age, 22 ± 4 yr; V[Combining Dot Above]O2peak, 50.9 ± 4.7 mL·min·kg) cycled at 50% Wmax for 150 min on five occasions. Participants ingested CHO beverages (lactose or sucrose; 48 g·h, 0.8 g·min) or water throughout exercise. Total substrate and exogenous CHO oxidation was estimated using indirect calorimetry and stable isotope techniques (naturally high C-abundance CHO ingestion). Naturally low C-abundance CHO trials were conducted to correct background shifts in breath CO2 production. Venous blood samples were taken to determine plasma glucose, lactate, and nonesterified fatty acid concentrations. RESULTS: Mean exogenous CHO oxidation rates were comparable with lactose (0.56 ± 0.19 g·min) and sucrose (0.61 ± 0.10 g·min; P = 0.49) ingestion. Endogenous CHO oxidation contributed less to energy expenditure in lactose (38% ± 14%) versus water (50% ± 11%, P = 0.01) and sucrose (50% ± 7%, P ≤ 0.05). Fat oxidation was higher in lactose (42% ± 8%) than in sucrose (28% ± 6%; P ≤ 0.01); CHO conditions were lower than water (50% ± 11%; P ≤ 0.05). Plasma glucose was higher in lactose and sucrose than in water (P ≤ 0.01); plasma lactate was higher in sucrose than in water (P ≤ 0.01); plasma nonesterified fatty acids were higher in water than in sucrose (P ≤ 0.01). CONCLUSIONS: Lactose and sucrose exhibited similar exogenous CHO oxidation rates during exercise at moderate ingestion rates. Compared with sucrose ingestion, lactose resulted in higher fat and lower endogenous CHO oxidation.

Consummatory, Feeding Microstructural, and Metabolic Effects Induced by Limiting Access to Either a High-Sucrose or a High-Fat Diet.

BACKGROUND: Binge eating disorder (BED) is characterized by recurrent binge eating episodes consisting of rapid consumption of excessive amounts of highly palatable, energy-dense food within discrete periods of time. The aim of this study was to test the consummatory, food microstructural, and metabolic effects of a one hour limited access to either a high-sucrose diet (HSD) or a high-fat diet (HFD) in an operant rat model of binge-like eating. METHODS: Female rats were subject to a binge-like eating procedure in which a HSD, a HFD, or a standard chow diet were provided in a fixed ratio 1 (FR1) operant schedule of reinforcement. RESULTS: Limiting access to either a HSD or a HFD promoted binge-like eating as compared to the control chow diet. However, binge-like eating of HSD, but not HFD, was based on a true increase in the amount of food consumed, an increased eating rate, and a decrease in the intake of the home-cage standard chow, altogether suggesting an increase in palatability. Moreover, while HSD rats consumed overall less energy than HFD rats, the former were more energy efficient and gained more body weight than the latter. CONCLUSIONS: These results provide information on how the quality of food can deeply influence the behavioral and metabolic outcomes of binge-like eating.

Effects of the amount and type of carbohydrates used in type 2 diabetes diets in animal models: A systematic review.

Type 2 diabetes mellitus (T2DM) is among the most prevalent diseases in the world, affecting over 420 million people. The disease is marked by a poor metabolic effect of insulin leading to chronic hyperglycaemia, which can result in microvascular complications. It is widely known that postprandial glycaemia is reliant on the total carbohydrate content of a meal. However, the importance of the amount and the source of these carbohydrates remains controversial due to mechanisms other than insulin secretion. Oxidative stress, inflammation, pyruvate production and the quality of the intestinal microbiota, resulting in plasma lipopolysaccharides and short-chain fatty acids production, play an important role in blood sugar control and consequently in type 2 diabetes. Thus, we systematically reviewed the preclinical evidences on the impact of the amount and type of carbohydrate found in different diets and its influence on blood glucose levels in diabetic animals. We used a comprehensive and structured search in biomedical databases Medline (PubMed), Scopus and Web of Science, recovering and analyzing 27 original studies. Results showed that sucrose-rich diets deteriorated diabetic condition in animal models regardless of the total dietary carbohydrate content. On the other hand, fiber, particularly resistant starch, improved blood glucose parameters through direct and indirect mechanisms, such as delayed gastric emptying and improved gut microbiota. All studies used rodents as animal models and male animals were preferred over females. Improvements in T2DM parameters in animal models were more closely related to the type of dietary carbohydrate than to its content on a diet, i. e., resistant starch seems to be the most beneficial source for maintaining normoglycemia. Results show that current literature is at high risk of bias due to neglecting experimental methods.

SHR-Zbtb16 minimal congenic strain reveals nutrigenetic interaction between Zbtb16 and high-sucrose diet.

Both prenatal and postnatal excessive consumption of dietary sucrose or fructose was shown to be detrimental to health and contributing to pathogenesis of metabolic syndrome. Our knowledge of genetic determinants of individual sensitivity to sucrose-driven metabolic effects is limited. In this study, we have tested the hypothesis that a variation of metabolic syndrome-related gene, Zbtb16 (Zinc Finger and BTB Domain Containing 16 will affect the reaction to high-sucrose diet (HSD) content in "matched" nutritional exposition settings, i.e. maternal HSD with re-exposition to HSD in adulthood vs. standard diet. We compared metabolic profiles of adult males of spontaneously hypertensive rats (SHR) and a single-gene, minimal congenic strain SHR-Zbtb16 fed either standard diet or exposed to HSD prenatally throughout gestation and nursing and again at the age of 6 months for the period of 14 days. HSD exposition led to increased adiposity in both strains and decrease of glucose tolerance and cholesterol (Ch) concentrations in majority of low-density lipoprotein (LDL) particle classes and in very large and large high-density lipoprotein (HDL) in SHR-Zbtb16 male offspring. There was a similar pattern of HSD-induced increase of triacylglycerols in chylomicrons and very low-density lipoprotein (VLDL) of both strains, though the increase of (triacylglycerol) TAG content was clearly more pronounced in SHR. We observed significant STRAIN*DIET interactions for the smallest LDL particles as their TAG content decreased in SHR-Zbtb16 and did not change in SHR in response to HSD. In summary, we provide evidence of nutrigenetic interaction between Zbtb16 and HSD in context of pathogenesis of metabolic syndrome.

Grandmother's Diet Matters: Early Life Programming with Sucrose Influences Metabolic and Lipid Parameters in Second Generation of Rats.

Early life exposure to certain environmental stimuli is related to the development of alternative phenotypes in mammals. A number of these phenotypes are related to an increased risk of disease later in life, creating a massive healthcare burden. With recent focus on the determination of underlying causes of common metabolic disorders, parental nutrition is of great interest, mainly due to a global shift towards a Western-type diet. Recent studies focusing on the increase of food or macronutrient intake don't always consider the source of these nutrients as an important factor. In our study, we concentrate on the effects of high-sucrose diet, which provides carbohydrates in form of sucrose as opposed to starch in standard diet, fed in pregnancy and lactation in two subsequent generations of spontaneously hypertensive rats (SHR) and congenic SHR-Zbtb16 rats. Maternal sucrose intake increased fasting glycaemia in SHR female offspring in adulthood and increased their chow consumption in gravidity. High-sucrose diet fed to the maternal grandmother increased brown fat weight and HDL cholesterol levels in adult male offspring of both strains, i.e., the grandsons. Fasting glycaemia was however decreased only in SHR offspring. In conclusion, we show the second-generation effects of maternal exposition to a high-sucrose diet, some modulated to a certain extent by variation in the Zbtb16 gene.

Association of sugar-sweetened drinks with caries in 10- and 15-year-olds.

BACKGROUND: Sugar-sweetened drinks (SSDs) are known to be cariogenic, but this association has not been well investigated in population-based repeated cross-sectional studies in recent years. Therefore, this study examined whether SSD intake is associated with higher caries experience in 10- and 15-year-olds. METHODS: The study sample included participants from the Munich study centre of two birth cohorts with data on non-cavitated caries lesions (NCCL/S), caries experience (DMF/S index), overall caries burden (DMF + NCCL/S) and SSD intake. In total, 915 and 996 children were included from the 10- and 15-year follow-ups, respectively. Intake (g/day) of SSDs, comprising cola, lemonade, ice-tea, sport/energy drinks, fruit squashes and nectars, was calculated from food frequency questionnaires. For analyses, the SSD intake was converted into portions (250 ml/day). Multiple logistic regression and prospective analysis models were performed to test associations between SSD intake and various definitions of caries, adjusting for sex, parental education, body mass index (BMI) categories, study cohort, plaque-affected sextants, mode of SSD consumption, energy content of SSDs, and total energy intake. RESULTS: The mean overall caries burden at 10 and 15 years of age was 1.81 (SD: 2.71) and 6.04 (SD: 8.13), respectively. The average consumption of SSDs at the 10- and 15-year follow-ups was 0.48 (SD: 0.85) and 0.83 (SD 1.40) portions/day, respectively. After adjusting for confounders, in 10-year-olds, SSD intake was significantly associated with higher caries experience based on the indices DMF/S (adjusted odds ratio: 1.29; 95% CI: 1.06-1.57), NCCL/S (1.24; 1.03-1.49) and DMF + NCCL/S (1.27; 1.05-1.55). At the 15-year follow-up, SSD consumption was significantly associated with increased DMF/S index (1.12; 1.01-1.25) only. Prospective model associating 10-year SSD intake with 15-year caries experience was not significant. CONCLUSIONS: SSD intake significantly increases the caries burden in 10-year-olds, with attenuated effects in 15-year-olds. To prevent caries, SSD consumption should be reduced, especially in children and adolescents.

Dietary nutrient balance shapes phenotypic traits of Drosophila melanogaster in interaction with gut microbiota.

The dietary nutrient composition can affect insects' phenotypes by modulating their physiology. Furthermore, diet can affect gut microbiota composition and abundance, with indirect consequences for the host. In this study, we reared Drosophila melanogaster on five different diets; three with balanced sugar:yeast ratio, but with increasing caloric content (2:2, 8:8, 16:16, in weight %), and two with imbalanced sugar:yeast ratio, either with low sugar and high yeast content (2:16) or vice-versa (16:2). In each of these diets, we compared flies with conventional vs. artificially altered gut microbiota with antibiotics that reduced the bacterial load. The antibiotic treatment also had the surprising effect of increasing the amount of live yeast associated with the flies. We characterized flies from these ten treatments (5 diets × 2 microbiota) in terms of development, body mass, food preference, body reserves, metabolic rate and a range of stress tolerance traits (heat, cold, starvation and desiccation tolerance). Diets, and to a lesser extent antibiotic treatment, affected development rate, weight, and cold tolerance of adult flies. Other traits such as energy reserves, metabolic rate, food preference, or starvation tolerance were affected by diet alone. When detected, the effect of antibiotic treatment was stronger in yeast-poor diets, suggesting that gut bacterial community might help to counterbalance nutritional deficiencies. These results show that changes in dietary factors lead to a global re-organization of fly's physiology and development while the manipulation of gut microorganisms had minor effects that were mainly seen in case of protein restriction.

Circadian rhythm-dependent induction of hepatic lipogenic gene expression in rats fed a high-sucrose diet.

Metabolic syndrome has become a global health challenge and was recently reported to be positively correlated with increased sucrose consumption. Mechanistic analyses of excess sucrose-induced progression of metabolic syndrome have been focused mainly on abnormal hepatic lipogenesis, and the exact contribution of excess sucrose to metabolic disorders remains controversial. Considering that carbohydrate and lipid metabolisms exhibit clear circadian rhythms, here we investigated the possible contribution of diurnal oscillations to responses of hepatic lipid metabolism to excess sucrose. We found that excess sucrose dose-dependently promotes fatty liver and hyperlipidemia in in rats fed a high-sucrose diet (HSD). We observed that excess sucrose enhances the oscillation amplitudes of the expression of clock genes along with the levels of hepatic lipid and carbohydrate metabolism-related mRNAs that increase lipogenesis. We did not observe similar changes in the levels of the transcription factors regulating the expression of these genes. This suggested that the excess sucrose-induced, circadian rhythm-dependent amplification of lipogenesis is post-transcriptionally regulated via the stability of metabolic gene transcripts. Of note, our findings also provide evidence that fructose causes some of the HSD-induced, circadian rhythm-dependent alterations in lipogenic gene expression. Our discovery of HSD-induced circadian rhythm-dependent alterations in lipogenesis at the post-transcriptional level may inform future studies investigating the complex relationships among sucrose uptake, circadian rhythm, and metabolic enzyme expression. Our findings could contribute to the design of chrono-nutritional interventions to prevent or manage the development of fatty liver and hyperlipidemia in sucrose-induced metabolic syndrome.

Indirect Chronic Effects of an Oleuropein-Rich Olive Leaf Extract on Sucrase-Isomaltase In Vitro and In Vivo.

Consumption of dietary bioactives is an avenue to enhancing the effective healthiness of diets by attenuating the glycaemic response. The intestinal brush border enzyme sucrase-isomaltase (SI) is the sole enzyme hydrolysing consumed sucrose, and we previously showed the acute effects of olive leaf extract (OLE) on sucrase activity when given together with sugars both in vitro and in vivo. Here we tested whether OLE could affect sucrase expression when pre-incubated chronically, a "priming" effect not dependent on competitive interaction with SI, in both a cell model and a human intervention. Using differentiated Caco-2/TC7 cells, long-term pre-treatment with oleuropein-rich olive leaf extract (OLE) lowered SI mRNA, surface protein and activity, and attenuated subsequent sucrose hydrolysis. Based on these results, a randomised, double-blinded, placebo-controlled, crossover pilot study was conducted. OLE (50 mg oleuropein) was consumed in capsule form 3 times a day for 1 week by 11 healthy young women followed by an oral sucrose tolerance test in the absence of OLE. However this treatment, compared to placebo, did not induce a change in post-prandial blood glucose maximum concentration (Glcmax), time to reach Glcmax and incremental area under the curve. These results indicate that changes in SI mRNA, protein and activity in an intestinal cell model by OLE are not sufficient under these conditions to induce a functional effect in vivo in healthy volunteers.

Impact of dietary sucrose on adiposity and glucose homeostasis in C57BL/6J mice depends on mode of ingestion: liquid or solid.

OBJECTIVE: Although it is widely accepted that obesity results from an imbalance of energy intake and expenditure, the mechanisms underlying this process and effective strategies for prevention and treatment are unclear. Growing evidence suggests excess consumption of sugar may play an important role, yet we showed previously in mice that consuming up to 30% of calories as sucrose in the diet had no impact on weight regulation. Since in humans consumption of sugar-sweetened beverages has been widely implicated, we investigated whether the mode of ingestion (solid or liquid) had different impacts on body weight regulation and glucose homeostasis. METHODS: Dietary sucrose was delivered in solid (as part of a standard pelleted rodent chow) and liquid (in drinking water) to C57BL/6 mice for 8 weeks. Body weight, body composition, energy intake and expenditure were monitored, as well as glucose and insulin tolerance tests. Expression of sweet taste receptors on the tongue, and glycogen and fat contents of the liver were also measured. RESULTS: Consumption of sucrose-sweetened water, but not equivalent levels of solid sucrose, led to body fat gain in C57BL/6 mice. Glucose intolerance was positively correlated to body fatness, rather than sucrose intake. CONCLUSIONS: Our data support the suggestion that consumption of liquid sucrose may be an important contributor to dysregulation of body weight and related metabolic syndromes.

Impacts of high-sucrose diet on circadian rhythms in the small intestine of rats.

Excessive sucrose intake, known as fructose toxicity, leads to fatty liver, hyperlipidemia, and metabolic syndrome. Circadian disorders also contribute to metabolic syndrome. Here, we investigated the effect of excessive sucrose intake on circadian rhythms of the small intestine, the main location of sucrose absorption, to elucidate a mechanism of sucrose-induced abnormal lipid metabolism. Male Wistar rats were fed control starch or high-sucrose diets for 4 weeks. High-sucrose diet-induced fatty liver and hypertriglyceridemia in rats. Amplitudes of PER1/2 expression oscillations in the small intestine were reduced by excessive sucrose, while gene expression of GLUT5 and gluconeogenic enzymes was enhanced. These changes would contribute to interfering in lipid homeostasis as well as adaptive responses to control fructose toxicity in rats.

Continuous feeding of a combined high-fat and high-sucrose diet, rather than an individual high-fat or high-sucrose diet, rapidly enhances the glucagon-like peptide-1 secretory response to meal ingestion in diet-induced obese rats.

OBJECTIVES: Glucagon-like peptide-1 (GLP-1) is secreted by enteroendocrine L-cells in response to nutrient ingestion. To date, GLP-1 secretion in diet-induced obesity is not well characterized. We aimed to examine GLP-1 secretion in response to meal ingestion during the progression of diet-induced obesity and determinewhether a combined high-fat and high-sucrose (HFS) diet, an individual high-fat (HiFat), or a high-sucrose (HiSuc) diet affect adaptive changes in the postprandial GLP-1 response. METHODS: Rats were fed a control, HiFat diet (30% weight), HiSuc diet (40% weight), or HFS (30% fat and 40% sucrose) diet for 5 wk. Meal tolerance tests were conducted to determine postprandial glucose, insulin, and GLP-1 responses to standard (control) diet ingestion every 2 wk. RESULTS: After 5 wk, body weight gain of the HiFat (232.3 ± 7.8 g; P = 0.021) and HFS groups (228.0 ± 7.8; P = 0.039), but not the HiSuc group (220.3 ± 7.9; P = 0.244), were significantly higher than that of the control group (200.7 ± 5.4 g). In meal tolerance tests after 2 wk, GLP-1 concentration was significantly elevated in the HFS group only (17.2 ± 2.6 pM; P < 0.001) in response to meal ingestions, but the HiFat group (16.6 ± 3.7 pM; P = 0.156) had a similar response as the HFS group. After 4 wk, GLP-1 concentrations were similarly elevated at 15min in the HFS (14.1 ± 4.4; P = 0.010), HiFat (13.2 ± 2.0; P < 0.001), and HiSuc (13.0 ± 3.3; P = 0.016) groups, but the HFS (9.8 ± 1.0; P = 0.019) and HiFat (8.3 ± 1.5; P = 0.010) groups also had significant elevation at 30min. CONCLUSIONS: These results demonstrate that the continuous ingestion of excessive fat and sucrose rapidly enhances the GLP-1 secretory response to luminal nutrients, and the HiFat diet may have a potent effect compared with the HiSuc diet on GLP-1 secretory responses. The increment of postprandial GLP-1 and insulinsecretion may have a role in normalizing postprandial glycaemia and slowing the establishment of glucose intolerance.

A free-choice high-fat, high-sucrose diet induces hyperphagia, obesity, and cardiovascular dysfunction in female cycling and pregnant rats.

The main objective of these studies was to characterize metabolic, body composition, and cardiovascular responses to a free-choice high-fat, high-sucrose diet in female cycling and pregnant rats. In the nonpregnant state, female Sprague-Dawley rats offered a 3-wk free-choice high-fat, high-sucrose diet had greater energy intake, adiposity, serum leptin, and triglyceride concentrations compared with rats fed with standard chow and developed glucose intolerance. In addition, choice-diet-fed rats had larger cardiac ventricular weights, smaller kidney and pancreas weights, and higher blood pressure than chow-fed rats, but they did not exhibit resistance artery endothelial dysfunction. When the free-choice diet continued throughout pregnancy, rats remained hyperphagic, hyperleptinemic, and obese. Choice pregnant rats exhibited uterine artery endothelial dysfunction and had smaller fetuses compared with chow pregnant rats. Pregnancy normalized mean arterial blood pressure and pancreas weights in choice rats. These studies are the first to provide a comprehensive evaluation of free-choice high-fat, high-sucrose diet on metabolic and cardiovascular functions in female rats, extending the previous studies in males to female cycling and pregnant rodents. Free-choice diet may provide a new model of preconceptual maternal obesity to study the role of increased energy intake, individual food components, and preexisting maternal obesity on maternal and offspring physiological responses during pregnancy and after birth.