Dietary fructose improves intestinal cell survival and nutrient absorption.

Fructose consumption is linked to the rising incidence of obesity and cancer, which are two of the leading causes of morbidity and mortality globally1,2. Dietary fructose metabolism begins at the epithelium of the small intestine, where fructose is transported by glucose transporter type 5 (GLUT5; encoded by SLC2A5) and phosphorylated by ketohexokinase to form fructose 1-phosphate, which accumulates to high levels in the cell3,4. Although this pathway has been implicated in obesity and tumour promotion, the exact mechanism that drives these pathologies in the intestine remains unclear. Here we show that dietary fructose improves the survival of intestinal cells and increases intestinal villus length in several mouse models. The increase in villus length expands the surface area of the gut and increases nutrient absorption and adiposity in mice that are fed a high-fat diet. In hypoxic intestinal cells, fructose 1-phosphate inhibits the M2 isoform of pyruvate kinase to promote cell survival5-7. Genetic ablation of ketohexokinase or stimulation of pyruvate kinase prevents villus elongation and abolishes the nutrient absorption and tumour growth that are induced by feeding mice with high-fructose corn syrup. The ability of fructose to promote cell survival through an allosteric metabolite thus provides additional insights into the excess adiposity generated by a Western diet, and a compelling explanation for the promotion of tumour growth by high-fructose corn syrup.

High fructose corn syrup alters behavioural and neurobiological responses to oxycodone in rats.

There are indications that sugars in the diet can play a role in vulnerability to opioid abuse. The current study examined a range of neuro-behavioural interactions between oxycodone (OXY) and high fructose corn syrup (HFCS). Male Sprague-Dawley rats had access to HFCS (0 or 50%) over 26 days in their home cages and were subsequently tested on place conditioning induced by 0, 0.16 and 2.5 mg/kg OXY (3 pairings of drug and saline, each 30 min), as well as on locomotor responses to 0, 0.16 and 2.5 mg/kg OXY, and in-vivo microdialysis was employed to measure dopamine (DA) levels in the nucleus accumbens (NAc) in response to 0 and 2.5 mg/kg OXY. A complex set of interactions between HFCS exposure and responses to OXY were observed: HFCS increased place preference induced by OXY, it enhanced the suppressant effect of OXY on locomotion, and it attenuated OXY-induced elevation in DA overflow in the NAc. Taken together, these findings suggest that nutrition has the potential to influence some responses to opioids which may be relevant to their abuse.

Arterial stiffness is not acutely modified by consumption of a caffeinated soft drink sweetened with high-fructose corn syrup in young healthy adults.

We tested the hypothesis that ingestion of a caffeinated soft drink sweetened with high-fructose corn syrup acutely increases arterial stiffness. In a randomized counterbalanced, crossover design, fourteen healthy adults (25 ± 3 years, 6 women) reported to the laboratory for two experimental visits where 500 ml of tap water (H2 O) or 500 ml of Mountain Dew® (a caffeinated soft drink sweetened with high-fructose corn syrup (HFCS)) were consumed. Arterial stiffness (carotid-to-femoral pulse wave velocity (cfPWV)), peripheral and central blood pressures were measured pre-consumption, 30 min post-consumption, and 120 min post-consumption. Prior to each measurement period, beat-to-beat hemodynamic measures were collected. Changes in heart rate, blood pressure, and cardiac output from pre-consumption did not differ between trials at any timepoint (p ≥ 0.06). Moreover, changes in peripheral or central blood pressures from pre-consumption did not differ between trials (p ≥ 0.84). Likewise, changes in cfPWV from pre-consumption to 30 min post-consumption (HFCS: 0.2 ± 0.3 m/s, H2 O: 0.0 ± 0.3 m/s, p = 0.34) and 120 min post-consumption (HFCS: 0.3 ± 0.4 m/s, H2 O: 0.2 ± 0.3 m/s, p = 0.77) did not differ. Changes in aortic augmentation pressure, augmentation index, augmentation index corrected to a heart rate of 75 bpm, and reflection magnitude did not differ between conditions at 30 min post- (p ≥ 0.55) or 120 min post- (p ≥ 0.18) consumption. In healthy young adults, ingesting 500 ml of a commercially available caffeinated soft drink sweetened with high-fructose corn syrup does not acutely change indices of arterial stiffness and wave reflection.

Effects of Dietary Glucose and Fructose on Copper, Iron, and Zinc Metabolism Parameters in Humans.

Alterations of transition metal levels have been associated with obesity, hepatic steatosis, and metabolic syndrome in humans. Studies in animals indicate an association between dietary sugars and copper metabolism. Our group has conducted a study in which young adults consumed beverages sweetened with glucose, fructose, high fructose corn syrup (HFCS), or aspartame for two weeks and has reported that consumption of both fructose- and HFCS-sweetened beverages increased cardiovascular disease risk factors. Baseline and intervention serum samples from 107 participants of this study were measured for copper metabolism (copper, ceruloplasmin ferroxidase activity, ceruloplasmin protein), zinc levels, and iron metabolism (iron, ferritin, and transferrin) parameters. Fructose and/or glucose consumption were associated with decreased ceruloplasmin ferroxidase activity and serum copper and zinc concentrations. Ceruloplasmin protein levels did not change in response to intervention. The changes in copper concentrations were correlated with zinc, but not with iron. The decreases in copper, ceruloplasmin ferroxidase activity, ferritin, and transferrin were inversely associated with the increases in metabolic risk factors associated with sugar consumption, specifically, apolipoprotein CIII, triglycerides, or post-meal glucose, insulin, and lactate responses. These findings are the first evidence that consumption of sugar-sweetened beverages can alter clinical parameters of transition metal metabolism in healthy subjects.

The effect of high fructose corn syrup on the plasma insulin and leptin concentration, body weight gain and fat accumulation in rat.

BACKGROUND: Studies on the effects of high fructose corn syrup (HFCS) on the metabolism are scarce and their results are inconsistent. OBJECTIVES: The aim of this research was to examine in an animal model the effect of replacing sucrose with HFCS-55 on the levels of glucose, insulin and leptin, and on the consumption of feed, body weight gain and fat storage. MATERIAL AND METHODS: The experiment was carried out on 30 Wistar male rats aged 5 months, fed 3 different diets, containing whole grains (group I), 10% sucrose (group II) and 10% HFCS (group III). RESULTS: It was found that the amount of daily energy intake was similar for all the groups of animals. There was no difference in fasting glucose and insulin level and homeostatic model assessment for insulin resistance (HOMA-IR) index. The higher leptin level was determined in blood plasma of the animal fed a feed with sucrose (group 2) compared to group 1 and group 3 (360 ng/mL vs 263 and 230 ng/mL, respectively). Despite the similar amounts of consumed energy, the animals fed with modified feeds achieved higher weight gain and the effect of HFCS-55 was similar to the effect of sucrose. CONCLUSIONS: The obtained results indicate similar metabolic effects of HFCS-55 and sucrose in feed, at the level of 11% dietary energy value, on the energy intake, body weight gain and periorgan adipose tissue accumulation in rats. The results suggest that accusations against HFCS as the major dietary contributor to overweight and obesity are unfounded, and the total elimination of HFCS from the diet seems to be unnecessary. The modified feeds (containing both sucrose and HFCS) produced greater absolute weight gain and weight gain per kilojoule consumed compared to standard feeds. This may indicate not just a basic thermodynamic consequence of consuming more energy, but a change in the metabolic efficiency when consuming a diet with simple sugars and refined carbohydrates.

Assessing the effect of sugar type and form of its intake on selected parameters of carbohydrate-lipid metabolism and plasma atherogenic indices in rats

Background: Over the past 50 years, the average consumption of sugar worldwide has tripled, also the type of consumed sugar has changed. Due to high price of sucrose and its technological disadvantages, high fructose corn syrup (HFCS) has become one of the most commonly used substitutes. Objective: The aim of the study was to compare, on the animal model, the effect of sugar type (sucrose vs high fructose corn syrup 55% of fructose) and the sugar form (solid vs fluid and solid) on the chosen parameters of carbohydrate-lipid metabolism. Material and methods: The experiment was carried out on 40 Wistar male rats aged 5 months, fed four isocaloric diets, containing: group I (SUC 15%) fodder with 15% sucrose, group II (HFCS 15%) fodder with 15% HFCS-55%, group III (SUC 7.5%+7.5%) ­ 7.5% sucrose in solid fodder and 7.5% sucrose water solution, group IV (HFCS 7.5%+7.5%) ­ 7.5% HFCS-55% in solid fodder and 7.5% HFCS water solution. Results: The effect of HFCS-55 on the parameters of carbohydrate and lipid metabolism was not equivalent of the effect of sucrose. Dietary use of HFCS-55 instead of sucrose causes adverse changes in blood parameters of carbohydrate and lipid metabolism, particularly when provided in beverages, as at comparable weight gains to that of sucrose. More intense changes, manifesting in increased blood levels of glucose, triglycerides and uric acid, as well as increased liver fat content, were observed at simultaneous intake of sweeteners in solid foods and fluids, even with less sugar consumption, compared to solid food only. Conclusions: Dietary use of HFCS-55 causes adverse changes in blood parameters of carbohydrate and lipid metabolism, as at comparable weight gains to that of sucrose. But liquid form of sugar intake is more important insulin resistance and cardiovascular disease risk factor than the sugar type.

Effect of blueberry extract, carriers, and combinations on the growth rate of probiotic and pathogenic bacteria.

The blueberry is recognised as a source of phenolic compounds that have beneficial effects on human health; however, they possess low bioavailability and can be degraded by gastrointestinal conditions. Encapsulation has been widely used to mitigate these disadvantages; Gum Arabic (GA) and Corn Syrup Solids (CSS) are common carriers used in this technique. The aim of this study was to evaluate the effect of Blueberry Extract (BE), carriers and their mixtures on the kinetic growth and maximal growth rate of probiotics and pathogenic bacteria. Kinetics were performed in MRS medium with and without a carbon source through Optical Density (OD) measurements and fitting these to the logistic model to compare the maximal growth rates (µmax) of the microorganisms. Each food component and its mixtures exert a different influence on the µmax of the bacteria studied (p < 0.05). This knowledge is important to improve the design of additives and functional foods.

The effect of maternal intake of sucrose or high-fructose corn syrup (HFCS)-55 during gestation and lactation on lipogenic gene expression in rat offspring at 3 and 12 weeks of age.

Perinatal exposure to sucrose or high-fructose corn syrup-55 (HFCS-55) in rats has previously been associated with altered hepatic fat content and composition post-weaning, although the effects on hepatic metabolism are unknown. The current study aimed to determine the sex-specific effects of maternal consumption of sucrose or HFCS-55 on the expression of hepatic lipogenic genes in the offspring. Liver samples were collected from offspring of albino Wistar rats provided with ad libitum access to either water (control), 10% sucrose or 10% HFCS-55 solution during pregnancy and lactation at 3 weeks (control n=16, sucrose n=22, HFCS-55 n=16) and 12 weeks (control n=16, sucrose n=10, HFCS-55 n=16) of age. Hepatic expression of the transcription factors such as carbohydrate response element-binding protein, sterol regulatory element-binding protein-1c and downstream genes was determined by quantitative real-time PCR. Sucrose-exposed offspring had higher hepatic SREBP-1c messenger RNA expression compared with control and HFCS-55 groups at both 3 weeks (P=0.01) and 12 weeks (P=0.03) of age. There were no differences in the expression of other hepatic lipogenic genes between groups at either 3 or 12 weeks. Thus, perinatal exposure to sucrose may be more detrimental to offspring hepatic metabolism compared with HFCS-55, independent of sex, and it will be important to evaluate the longer-term effects of perinatal sucrose exposure in future studies.

Neonatal intake of oleanolic acid attenuates the subsequent development of high fructose diet-induced non-alcoholic fatty liver disease in rats.

Dietary manipulations during the early postnatal period are associated with the development of metabolic disorders including non-alcoholic fatty liver disease (NAFLD) or long-term protection against metabolic dysfunction. We investigated the potential hepatoprotective effects of neonatal administration of oleanolic acid (OA), a phytochemical, on the subsequent development in adulthood, of dietary fructose-induced NAFLD. Male and female suckling rats (n=112) were gavaged with; distilled water (DW), OA (60 mg/kg), high fructose solution (HF; 20% w/v) and OA+HF (OAHF) for 7 days. The rats were weaned onto normal rat chow on day 21 up to day 55. From day 56, half of the rats in each treatment group were continued on plain water or HF as drinking fluid for 8 weeks. Hepatic lipid accumulation and hepatic histomorphometry were then determined. Fructose consumption in adulthood following neonatal fructose intake (HF+F) caused a 47-49% increase in hepatic lipid content of both male and female rats (P<0.05). However, fructose administered in adulthood only, caused a significant increase (P<0.05) in liver lipid content in females only. NAFLD activity scores for inflammation and steatosis were higher in the fructose-fed rats compared with other groups (P<0.05). Steatosis, low-grade inflammation and fibrosis were observed in rats that received HF+F. NAFLD area fraction for fibrosis was three times higher in rats that received fructose neonatally and in adulthood compared with the rats in the negative control group (P<0.05). Treatment with OA during a critical window of developmental plasticity in rats prevented the development of fructose-induced NAFLD.

Plasma fatty acid ethanolamides are associated with postprandial triglycerides, ApoCIII, and ApoE in humans consuming a high-fructose corn syrup-sweetened beverage.

Epidemiological and clinical research studies have provided ample evidence demonstrating that consumption of sugar-sweetened beverages increases risk factors involved in the development of obesity, Type 2 diabetes, and cardiovascular disease (CVD). Our previous study demonstrated that when compared with aspartame (Asp), 2 wk of high-fructose corn syrup (HFCS)-sweetened beverages provided at 25% of daily energy requirement was associated with increased body weight, postprandial (pp) triglycerides (TG), and fasting and pp CVD risk factors in young adults. The fatty acid ethanolamide, anandamide (AEA), and the monoacylglycerol, 2-arachidonoyl- sn-glycerol (2-AG), are two primary endocannabinoids (ECs) that play a role in regulating food intake, increasing adipose storage, and regulating lipid metabolism. Therefore, we measured plasma concentrations of ECs and their analogs, oleoylethanolamide (OEA), docosahexaenoyl ethanolamide (DHEA), and docosahexaenoyl glycerol (DHG), in participants from our previous study who consumed HFCS- or Asp-sweetened beverages to determine associations with weight gain and CVD risk factors. Two-week exposure to either HFCS- or Asp-sweetened beverages resulted in significant differences in the changes in fasting levels of OEA and DHEA between groups after the testing period. Subjects who consumed Asp, but not HFCS, displayed a reduction in AEA, OEA, and DHEA after the testing period. In contrast, there were significant positive relationships between AEA, OEA, and DHEA vs. ppTG, ppApoCIII, and ppApoE in those consuming HFCS, but not in those consuming Asp. Our findings reveal previously unknown associations between circulating ECs and EC-related molecules with markers of lipid metabolism and CVD risk after HFCS consumption.

Maternal dietary free or bound fructose diversely influence developmental programming of lipogenesis.

BACKGROUND: Maternal dietary choices throughout preconception, pregnancy, and lactation irreversibly affect the development of fetal tissues and organs, known as fetal programming. Recommendations tend to emphasize reducing added sugars. However, the impact of maternal dietary free or bound fructose in added sugars on developmental programming of lipogenesis is unknown. METHODS: Virgin Sprague-Dawley rats were randomly divided into five groups. Rats were given feed and plain water (control) or water containing maltodextrin (vehicle), fructose, high-fructose corn syrup (HFCS) containing 55% fructose, sucrose (20% w/v) for 12 weeks before mating and throughout the pregnancy and lactation periods. Body weight, water, and feed intake were measured throughout the study. At the end of the lactation period, blood was drawn to determine the fasting levels of glucose, insulin, triglycerides, and non-esterified fatty acids (NEFA) in blood. Triglycerides and acetyl Co-A Carboxylase-1 (ACC1) levels in livers were analyzed, and insulin resistance was calculated. RESULTS: The energy intake of dams in the HFCS group was higher than in the fructose group, while weight gain was less in the HFCS group than in the fructose group. HFCS resulted in greater insulin resistance in dams, whereas free fructose had a robust effect on the fetal programming of insulin resistance. Free fructose and HFCS in the maternal diet increased blood and liver triglycerides and NEFA content in pups. Furthermore, fructose and HFCS exposure increased phosphorylated ACC1 as compared to maltodextrin and control, indicating greater fatty acid synthesis in pups and dams. CONCLUSION: Different types of added sugar in the maternal diet have different metabolic effects on the developmental programming of lipogenesis. Consequently, high fructose intake via processed foods may increase the risk for chronic diseases, and free fructose might contribute to developmental programming of chronic diseases more than bound fructose.

Effects of Cola-Flavored Beverages and Caffeine on Streptococcus mutans Biofilm Formation and Metabolic Activity.

OBJECTIVE: To examine the effects of cola-flavored beverages and caffeine on growth and metabolism of Streptococcus mutans biofilm. This study was designed to determine if carbonated beverages or caffeine can increase S. mutans growth and biofilm formation and metabolic activity in vitro, potentially leading to increased S. mutans-associated cariogenicity in children that consume them. STUDY DESIGN: Six different cola-flavored products, plus pure caffeine, and pure high fructose corn syrup (HFCS), at different concentrations similar to those in the beverages were tested. A 16-hour culture of S. mutans was treated with different dilutions in bacteriological media. To test for the effect on biofilm formation, the biofilm was stained with crystal violet. The absorbance was determined to evaluate biofilm growth. Biofilm metabolic activity was measured based on biofilm having the ability to reduce XTT to a water-soluble orange compound. RESULTS: The inclusion of HFCS in the beverages, as well as pure HFCS, significantly enhanced bacterial biofilm formation and metabolic activity. Pure caffeine and the presence of caffeine in beverages did not significantly increase biofilm formation, but pure caffeine significantly increased metabolism, and Diet Coke had significantly greater metabolic activity than Caffeine-Free Diet Coke. CONCLUSIONS: HFCS increases both the biofilm formation and metabolism of S. mutans, and caffeine in some cases increases metabolism of S. mutans.

Kefir peptides prevent high-fructose corn syrup-induced non-alcoholic fatty liver disease in a murine model by modulation of inflammation and the JAK2 signaling pathway.

OBJECTIVE: In recent years, people have changed their eating habits, and high-fructose-containing bubble tea has become very popular. High-fructose intake has been suggested to be a key factor that induces non-alcoholic fatty liver disease (NAFLD). Kefir, a fermented milk product composed of microbial symbionts, has demonstrated numerous biological activities, including antibacterial, antioxidant and immunostimulating effects. The present study aims to evaluate the effects of kefir peptides on high-fructose-induced hepatic steatosis and the possible molecular mechanism. RESULTS: An animal model of 30% high-fructose-induced NAFLD in C57BL/6J mice was established. The experiment is divided into the following six groups: (1) normal: H2O drinking water; (2) mock: H2O+30% fructose; (3) KL: low-dose kefir peptides (50 mg kg-1)+30% fructose; (4) KM: medium-dose kefir peptides (100 mg kg-1)+30% fructose; (5) KH: high-dose kefir peptides (150 mg kg-1)+30% fructose; and (6) CFM: commercial fermented milk (100 mg kg-1)+30% fructose. The results show that kefir peptides improve fatty liver syndrome by decreasing body weight, serum alanine aminotransferase, triglycerides, insulin and hepatic triglycerides, cholesterol, and free fatty acids as well as the inflammatory cytokines (TNF-α, IL-6 and IL-1ß) that had been elevated in fructose-induced NAFLD mice. In addition, kefir peptides markedly increased phosphorylation of AMPK to downregulate its targeted enzymes, ACC (acetyl-CoA carboxylase) and SREBP-1c (sterol regulatory element-binding protein 1), and inhibited de novo lipogenesis. Furthermore, kefir peptides activated JAK2 to stimulate STAT3 phosphorylation, which can translocate to the nucleus, and upregulated several genes, including the CPT1 (carnitine palmitoyltransferase-1) involved in fatty acid oxidation. CONCLUSION: Our data have demonstrated that kefir peptides can improve the symptoms of NAFLD, including body weight, energy intake, inflammatory reaction and the formation of fatty liver by activating JAK2 signal transduction through the JAK2/STAT3 and JAK2/AMPK pathways in the high-fructose-induced fatty liver animal model. Therefore, kefir peptides may have the potential for clinical application for the prevention or treatment of clinical metabolic syndrome.

No differential effect of beverages sweetened with fructose, high-fructose corn syrup, or glucose on systemic or adipose tissue inflammation in normal-weight to obese adults: a randomized controlled trial.

BACKGROUND: Sugar-sweetened beverage (SSB) consumption and low-grade chronic inflammation are both independently associated with type 2 diabetes and cardiovascular disease. Fructose, a major component of SSBs, may acutely trigger inflammation, which may be one link between SSB consumption and cardiometabolic disease. OBJECTIVE: We sought to determine whether beverages sweetened with fructose, high-fructose corn syrup (HFCS), and glucose differentially influence systemic inflammation [fasting plasma C-reactive protein and interleukin-6 (IL-6) as primary endpoints] acutely and before major changes in body weight. Secondary endpoints included adipose tissue inflammation, intestinal permeability, and plasma fetuin-A as potential mechanistic links between fructose intake and low-grade inflammation. DESIGN: We conducted a randomized, controlled, double-blind, crossover design dietary intervention (the Diet and Systemic Inflammation Study) in 24 normal-weight to obese adults without fructose malabsorption. Participants drank 4 servings/d of fructose-, glucose-, or HFCS-sweetened beverages accounting for 25% of estimated calorie requirements while consuming a standardized diet ad libitum for three 8-d periods. RESULTS: Subjects consumed 116% of their estimated calorie requirement while drinking the beverages with no difference in total energy intake or body weight between groups as reported previously. Fasting plasma concentrations of C-reactive protein and IL-6 did not differ significantly at the end of the 3 diet periods. We did not detect a consistent differential effect of the diets on measures of adipose tissue inflammation except for adiponectin gene expression in adipose tissue (P = 0.005), which was lowest after the glucose phase. We also did not detect consistent evidence of a differential impact of these sugars on measures of intestinal permeability (lactulose:mannitol test, plasma zonulin, and plasma lipopolysaccharide-binding protein). CONCLUSION: Excessive amounts of fructose, HFCS, and glucose from SSBs consumed over 8 d did not differentially affect low-grade chronic systemic inflammation in normal-weight to obese adults. This trial was registered at clinicaltrials.gov as NCT01424306.

Fructose Containing Sugars at Normal Levels of Consumption Do Not Effect Adversely Components of the Metabolic Syndrome and Risk Factors for Cardiovascular Disease.

The objective of the current study was to explore our hypothesis that average consumption of fructose and fructose containing sugars would not increase risk factors for cardiovascular disease (CVD) and the metabolic syndrome (MetS). A randomized, double blind, parallel group study was conducted where 267 individuals with BMI between 23 and 35 kg/m² consumed low fat sugar sweetened milk, daily for ten weeks as part of usual weight-maintenance diet. One group consumed 18% of calories from high fructose corn syrup (HFCS), another group consumed 18% of calories from sucrose, a third group consumed 9% of calories from fructose, and the fourth group consumed 9% of calories from glucose. There was a small change in waist circumference (80.9 ± 9.5 vs. 81.5 ± 9.5 cm) in the entire cohort, as well as in total cholesterol (4.6 ± 1.0 vs. 4.7 ± 1.0 mmol/L, p < 0.01), triglycerides (TGs) (11.5 ± 6.4 vs. 12.6 ± 8.9 mmol/L, p < 0.01), and systolic (109.2 ± 10.2 vs. 106.1 ± 10.4 mmHg, p < 0.01) and diastolic blood pressure (69.8 ± 8.7 vs. 68.1 ± 9.7 mmHg, p < 0.01). The effects of commonly consumed sugars on components of the MetS and CVD risk factors are minimal, mixed and not clinically significant.

Alterations of naltrexone-induced conditioned place avoidance by pre-exposure to high fructose corn syrup or heroin in Sprague-Dawley rats.

RATIONALE: It has been suggested that withdrawal from sugar produces a set of symptoms that resemble those observed following withdrawal from opiate drugs. OBJECTIVES: This study explored naltrexone-induced withdrawal in animals pre-exposed to acute, chronic, and intermittent high fructose corn syrup (HFCS) or acute and chronic heroin administration. METHODS: Experiment 1 examined conditioned place avoidance (CPA) induced by different doses of naltrexone (0.01-1 mg/kg) in naïve male Sprague-Dawley rats. In experiment 2, rats received continuous or intermittent home cage HFCS access (0 or 50 %) prior to conditioning with 1 mg/kg naltrexone. In experiment 3, HFCS ingestion was increased by food restriction and rats were conditioned with 3 mg/kg naltrexone. In experiment 4, the timing and quantity of HFCS ingestion (0, 0.5, 1, 2 g/kg) was controlled by intragastric administration, and rats were conditioned with 1 mg/kg naltrexone. In experiment 5, rats received acute (2 mg/kg) or chronic heroin (3.5 mg/kg/day) prior to conditioning with 1 mg/kg naltrexone. RESULTS: Administration of naltrexone produced moderate conditioned place avoidance in naïve rats. Importantly, acute, continuous, and intermittent HFCS pre-exposure did not significantly amplify this effect, but acute and chronic heroin pre-exposure did. CONCLUSIONS: As assessed by CPA, these results in rats fail to support the hypothesis that an opioid antagonist can precipitate similar affective withdrawal states following pre-exposure to sugars and opiates.

Metabolomic and Lipidomic Analysis of Serum Samples following Curcuma longa Extract Supplementation in High-Fructose and Saturated Fat Fed Rats.

We explored, using nuclear magnetic resonance (NMR) metabolomics and fatty acids profiling, the effects of a common nutritional complement, Curcuma longa, at a nutritionally relevant dose with human use, administered in conjunction with an unbalanced diet. Indeed, traditional food supplements have been long used to counter metabolic impairments induced by unbalanced diets. Here, rats were fed either a standard diet, a high level of fructose and saturated fatty acid (HFS) diet, a diet common to western countries and that certainly contributes to the epidemic of insulin resistance (IR) syndrome, or a HFS diet with a Curcuma longa extract (1% of curcuminoids in the extract) for ten weeks. Orthogonal projections to latent structures discriminant analysis (OPLS-DA) on the serum NMR profiles and fatty acid composition (determined by GC/MS) showed a clear discrimination between HFS groups and controls. This discrimination involved metabolites such as glucose, amino acids, pyruvate, creatine, phosphocholine/glycerophosphocholine, ketone bodies and glycoproteins as well as an increase of monounsaturated fatty acids (MUFAs) and a decrease of n-6 and n-3 polyunsaturated fatty acids (PUFAs). Although the administration of Curcuma longa did not prevent the observed increase of glucose, triglycerides, cholesterol and insulin levels, discriminating metabolites were observed between groups fed HFS alone or with addition of a Curcuma longa extract, namely some MUFA and n-3 PUFA, glycoproteins, glutamine, and methanol, suggesting that curcuminoids may act respectively on the fatty acid metabolism, the hexosamine biosynthesis pathway and alcohol oxidation. Curcuma longa extract supplementation appears to be beneficial in these metabolic pathways in rats. This metabolomic approach highlights important serum metabolites that could help in understanding further the metabolic mechanisms leading to IR.

Fructose:glucose ratios--a study of sugar self-administration and associated neural and physiological responses in the rat.

This study explored whether different ratios of fructose (F) and glucose (G) in sugar can engender significant differences in self-administration and associated neurobiological and physiological responses in male Sprague-Dawley rats. In Experiment 1, animals self-administered pellets containing 55% F + 45% G or 30% F + 70% G, and Fos immunoreactivity was assessed in hypothalamic regions regulating food intake and reward. In Experiment 2, rats self-administered solutions of 55% F + 42% G (high fructose corn syrup (HFCS)), 50% F + 50% G (sucrose) or saccharin, and mRNA of the dopamine 2 (D2R) and mu-opioid (MOR) receptor genes were assessed in striatal regions involved in addictive behaviors. Finally, in Experiment 3, rats self-administered HFCS and sucrose in their home cages, and hepatic fatty acids were quantified. It was found that higher fructose ratios engendered lower self-administration, lower Fos expression in the lateral hypothalamus/arcuate nucleus, reduced D2R and increased MOR mRNA in the dorsal striatum and nucleus accumbens core, respectively, as well as elevated omega-6 polyunsaturated fatty acids in the liver. These data indicate that a higher ratio of fructose may enhance the reinforcing effects of sugar and possibly lead to neurobiological and physiological alterations associated with addictive and metabolic disorders.

The mechanisms underlying fructose-induced hypertension: a review.

We are currently in the midst of an epidemic of metabolic disorders, which may, in part, be explained by excess fructose intake. This theory is supported by epidemiological observations as well as experimental studies in animals and humans. Rising consumption of fructose has been matched with growing rates of hypertension, leading to concern from public health experts. At this stage, the mechanisms underlying fructose-induced hypertension have not been fully characterized and the bulk of our knowledge is derived from animal models. Animal studies have shown that high-fructose diets up-regulate sodium and chloride transporters, resulting in a state of salt overload that increases blood pressure. Excess fructose has also been found to activate vasoconstrictors, inactivate vasodilators, and over-stimulate the sympathetic nervous system. Further work is required to determine the relevance of these findings to humans and to establish the level at which dietary fructose increases the risk of developing hypertension.

Fructose content and composition of commercial HFCS-sweetened carbonated beverages.

OBJECTIVE: The obesigenic and related health effects of caloric sweeteners are subjects of much current research. Consumers can properly adjust their diets to conform to nutritional recommendations only if the sugars composition of foods and beverages is accurately measured and reported, a matter of recent concern. We tested the hypothesis that high-fructose corn syrup (HFCS) used in commercial carbonated beverages conforms to commonly assumed fructose percentages and industry technical specifications, and fulfills beverage product label regulations and Food Chemicals Codex-stipulated standards. DESIGN: A high-pressure liquid chromatography method was developed and verified for analysis of sugars in carbonated beverages sweetened with HFCS-55. The method was used to measure percent fructose in three carbonated beverage categories. Method verification was demonstrated by acceptable linearity (R(2)>0.99), accuracy (94-104% recovery) and precision (RSD < 2%). RESULT: Fructose comprised 55.58% of total sugars (95% confidence interval 55.51-55.65%), based on 160 total measurements by 2 independent laboratories of 80 randomly selected carbonated beverages sweetened with HFCS-55. The difference in fructose measurements between laboratories was significant but small (0.1%), and lacked relevance. Differences in fructose by product category or by product age were not statistically significant. Total sugars content of carbonated beverages showed close agreement within product categories (95% confidence interval = 0.01-0.54%). CONCLUSIONS: Using verified analytical methodology for HFCS-sweetened carbonated beverages, this study confirmed the hypothesis that fructose as a percentage of total sugars is in close agreement with published specifications in industry technical data sheets, published literature values and governmental standards and requirements. Furthermore, total sugars content of commercial beverages is consistent with common industry practices for canned and bottled products and met the US Federal requirements for nutritional labeling and nutrient claims. Prior concerns about composition were likely owing to use of improper and unverified methodology.